Compositions and methods for molecular labeling

Information

  • Patent Grant
  • 11768198
  • Patent Number
    11,768,198
  • Date Filed
    Wednesday, February 19, 2020
    4 years ago
  • Date Issued
    Tuesday, September 26, 2023
    a year ago
Abstract
The invention provides barcode libraries and methods of making and using them including obtaining a plurality of nucleic acid constructs in which each construct comprises a unique N-mer and a functional N-mer and segregating the constructs into a fluid compartments such that each compartment contains one or more copies of a unique construct. The invention further provides methods for digital PCR and for use of barcode libraries in digital PCR.
Description
FIELD OF THE INVENTION

The present invention generally relates to methods and materials for building barcode libraries and labeling target materials, such as individual cells or molecules, with labels such as barcode-type and probe-type labels.


BACKGROUND OF THE INVENTION

The analysis of nucleic acids and proteins is an essential element of molecular biology. The ability to detect, discriminate, and utilize genetic and proteomic information allows sensitive and specific diagnostics, as well as the development of treatments. Most genetic and proteomic analysis requires labeling for detection of the analytes of interest. For example, in sequencing applications, nucleotides added to a template strand during sequencing-by-synthesis typically are labeled, or are intended to generate a label, upon incorporation into the growing strand. The presence of the label allows detection of the incorporated nucleotide. Effective labeling techniques are desirable in order to improve diagnostic and therapeutic results.


SUMMARY OF THE INVENTION

The present invention generally provides products and methods for labeling target material in a fluid compartment. In particular, the invention provides fluid compartmentss such as droplets for the sequestration, isolation, labeling, detection, identification, and analysis of target material. The invention further provides labels. Labels according to the invention include barcode-type labels and probe-type labels.


Principles of the invention can be applied to analyze all or a portion of an entire genome, transcriptome, or proteome. Techniques disclosed herein provide labeled materials isolated in fluid compartments for use with analytical techniques such as sequencing, haplotyping, and multiplex digital-PCR.


As disclosed herein, target material can be sequestered in a fluid compartment or partition such as a single droplet. Other reagents including labels (e.g., barcoded or optically-labeled N-mers) can be provided, optionally also sequestered in droplets. The other reagents can be introduced into the fluid partitions containing the target material, for example, by merging droplets, resulting in the labeling of the target molecules (e.g., by hybridization of N-mers to target nucleic acids). Target material can undergo optional processing such as selective enrichment, amplification, or capture on a substrate (e.g., beads). Where the labels are of the barcode type, the invention provides analytical methods including selective capture or enrichment, sequencing, haplotype phasing, genotyping, and improved sequence read assembly, as well as methods of producing barcode droplet libraries. Where the labels are of the probe-type, the invention provides novel digital PCR assays including multiplex assays.


Target material can be obtained from a sample, and can include nucleic acid, proteins, carbohydrates, or other materials. The sample may be a human tissue or body fluid. Exemplary body fluids include pus, sputum, semen, urine, blood, saliva, and cerebrospinal fluid.


In certain aspects, the invention provides fluidic compartments to contain all or a portion of a target material. In some embodiments, a compartment is droplet. While reference is made to “droplets” throughout the specification, that term is used interchangeably with fluid compartment and fluid partition unless otherwise indicated. A fluid compartment can be a slug, an area on an array surface, a globule, or a reaction chamber in a microfluidic device, such as for example, a microfluidic device fabricated using multilayer soft lithography (e.g., integrated fluidic circuits). Except where indicated otherwise, “droplet” is used for convenience and any fluid partition or compartment may be used.


A droplet according to the invention generally includes an amount of a first sample fluid in a second carrier fluid. Any technique known in the art for forming droplets may be used with methods of the invention. An exemplary method involves flowing a stream of the sample fluid containing the target material (e.g., nucleic acid template) such that it intersects two opposing streams of flowing carrier fluid. The carrier fluid is immiscible with the sample fluid. Intersection of the sample fluid with the two opposing streams of flowing carrier fluid results in partitioning of the sample fluid into individual sample droplets containing the target material.


The carrier fluid may be any fluid that is immiscible with the sample fluid. An exemplary carrier fluid is oil. In certain embodiments, the carrier fluid includes a surfactant, such as a fluorosurfactant.


The same method may be applied to create individual droplets that contain other reagents such as labels or reagents for an amplification reaction such as a polymerase chain reaction (PCR), or a non-PCR based amplification reaction such as multi-strand displacement amplification, or other methods known to one of ordinary skill in the art. Suitable reagents for conducting PCR-based amplification reactions are known to those of ordinary skill in the art and include, but are not limited to, DNA polymerases such as Taq polymerase, forward and reverse primers, deoxynucleotide triphosphates (dNTPs), and one or more buffers. Suitable reagents for conducing non-PCR amplification reactions include, for example, a high fidelity enzyme such as Φ29. Alternatively, a transposase can be used.


Either the droplets containing the first fluid, the droplets containing the second fluid, or both, may be formed and then stored in a library for later merging, aspects of certain implementations of which are described in U.S. Pub. 2010/0022414, hereby incorporated herein in its entirety for all purposes.


Once formed, droplets containing the target material can be merged with droplets containing other reagents. Merging can produce a set of droplets, each containing target and other reagents such as, in each droplet, a single nucleic acid template and heterogeneous mixture of primer pairs and probes. Merging can be accomplished, for example, in the presence of an electric field. Moreover, it is not required that both fluids be in the form of droplets when merging takes places. One exemplary method for merging of fluid portions with droplets is taught, for example, in U.S. Patent Application Nos. 61/441,985 and Ser. No. 13/371,222, the contents of each of which are incorporated by reference herein.


In certain embodiments, fluidic compartments are formed by providing one or more of a first fluid partition (e.g., a droplet) comprising a target material and a second fluid (e.g., as a fluid stream or within droplets) comprising a plurality of nucleic acid constructs, each containing a functional N-mer capable of hybridizing to a unique region of the target material, and a unique N-mer to label the target. The first and second fluids are merged to form a droplet. Merging can be accomplished by application of an electric field to the two fluids. In certain embodiments, the second fluid additionally contains reagents for conducting an amplification reaction, such as a polymerase chain reaction or a multiple displacement amplification reaction. Optionally, the genetic material can be fragmented or sheared using methods well known to those of skill in the art, for example, prior to sequestering into droplets or hybridizing to N-mers.


In certain aspects, the invention provides a method of making a barcode library including obtaining a plurality of nucleic acid constructs in which each construct includes a unique N-mer and a functional N-mer. The functional N-mer can be a random N-mer, a PCR primer, a universal primer, an antibody, a sticky end, or any other sequence. The method can include making M sets of a number N of fluid compartments each containing one or more copies of a unique construct. The method can create barcode libraries of higher complexity by adding an additional construct to each compartment in a set, and repeating that for each set to produce N×M compartments each containing a unique pair of constructs. The pairs can be hybridized or ligated to produce new constructs. In each construct in a barcode library, each unique N-mer can be adapted for identification by sequencing, probe hybridization, other methods, or a combination of methods.


In certain aspects, the invention provides a method for labeling target material comprising segregating each of a plurality of targets into a fluid compartment and providing one or more copies of a construct that is unique for each fluid compartment, in which each construct includes a unique N-mer and a functional N-mer. The method can include associating each target with a copies of a construct, for example, by hybridization. Optional steps of methods of the invention can include performing an amplification reaction to produce amplicons that each contain a copy of the construct; releasing the contents of fluid compartments into a bulk phase; performing a second amplification reaction on amplicons; sequencing products of the invention; and detecting products of the invention by digital PCR. Higher levels of complexity (e.g., for arbitrary high levels of multiplex parallel analysis) can obtained by introducing into each fluid partition one or more copies of an additional construct (for example, that are unique to a specific portion of a target) and linking each additional construct to a copy of the construct unique to each fluid partition. Target material can be unlabeled when segregated into the fluid compartments.


In certain aspects, the invention provides a compartment containing all or a portion of a target material, and a plurality of constructs including unique N-mers and functional N-mers (e.g., capable of hybridizing to a unique region of the target material). Examples of target material include but are not limited DNA, genomic DNA, chromosome(s), RNA, expressed RNA and/or protein molecules. In some embodiments, the target material includes a single cell segregated into a fluid compartment. The cell can be lysed within the compartment, and the lysate can be targeted for labeling. Lysate can include the genetic or proteomic material derived from the single cell (prokaryotic or eukaryotic) or a subset thereof (e.g., an entire genome, transcriptome, proteome, or a portion thereof). Droplets containing cells may be sorted according to a sorting operation prior to merging with the other reagents (e.g., as a second set of droplets). The other reagents may contain reagents or enzymes such as a detergent or a protease (e.g., a heat activatable protease) that facilitates the breaking open of the cell and release of the nucleic acids therein. Once the reagents are added to the droplets containing the cells (for example, through droplet merging) and the cells are lysed, primers can be hybridized to the target and then target (e.g., nucleic acid) can be amplified, for example, by PCR.


In certain embodiments, the invention provides a plurality of nucleic constructs including a functional N-mer that comprises a random sequence, for example, a 6-mer for use in a multiple displacement reaction (MDA). Alternatively, the N-mers can comprise a target specific sequence, such as a sequence specific for a gene, a gene mutation, a gene motif, a splice site, a regulatory region of a gene, or a single nucleotide polymorphism. In some embodiments, the N-mers can correspond to one or more consensus sequences, such as, for example, CPG motifs, or other sequence motifs that are related to known or suspected sequences indicative of splice sites, promoter regions, regulatory regions, or other functional genomic units, etc. The N-mers can each further comprise a common sequence, such as a universal primer sequence. In certain embodiments, the N-mers comprise oligo-dT labeled primers.


The invention generally provides methods and materials for labeling a target material (e.g., protein or nucleic acid). Labeling can involve barcode-type labeling using nucleic acid constructs or a probe-type label (e.g., for digital PCR). Nucleic acid constructs can involve informational (i.e, unique or of known sequence) or functional N-mers. In certain embodiments, one or more constructs contain different unique N-mers (i.e., unique labels). The label is preferably associated with a 5′ end of the N-mers. However, the label can be associated with a 3′ end of the N-mers.


The label associated with each of the N-mers can be a nucleic acid tag, or “barcode” sequence. Where a barcode is included, the N-mer generally hybridizes to the target material and is copied throughout subsequent steps such that the barcode is included in amplicons or sequence reads that may result. Where a probe-type label is included, the N-mer generally hybridizes to a specific material, for example, PCR product containing the target region, and can be detected in assays such as digital PCR. A probe-type label can include an optical label such as a fluorescent label. In some embodiments, an optical label is attached to an antibody specific for a target region of interest in a target material. Applications involving probe-type or barcode-type labels will be discussed in greater detail below.


Whatever construct is used, a target material can be labeled by merging droplets containing the target material with a fluid stream or droplet stream containing the desired construct or merging a fluid stream of the target material with the construct into droplets.


The methods of the invention can further include the step of amplifying or copying the target material so as to preserve, for each amplified product, an association between the amplified product and the label. In certain aspects of the invention, the amplified product is indicative of a haplotype. The nucleic acid template in each of the merged/formed droplets is amplified, e.g., by thermocycling the droplets under temperatures/conditions sufficient to conduct a PCR reaction. The resulting amplicons in the droplets can then be analyzed. For example, using probe-type labels, the presence or absence of the plurality of targets in the one or more droplets is detected optically, e.g., by the detectable label on the plurality of probes. Alternatively, amplicons can be sequenced and reads assembled based on the presence of barcode-type labels.


In some embodiments, capture sequences are introduced into droplets containing target material, for example, by merging the droplets with a second set of droplets containing the capture sequences. Capture sequences can include a barcode label and a portion that is capable of being captured on a solid surface (e.g., biotin/streptavidin on a surface; antibody/antigen; aptamers; anchored oligonucleotides; etc.). A droplet containing a nucleic acid can be merged with a second droplet containing the capture sequence, preferably with a tag (i.e., a barcode-type label). The capture sequence is allowed to hybridize to the target nucleic acid. The emulsion is then broken to release the hybridized capture sequence and target nucleic acid. The released nucleic acid is then captured on a solid support allowing the removal of elements such as cell debris, proteases and detergents that may inhibit subsequent steps. The tag is then incorporated by replication of the captured nucleic acid using the capture sequence with the tag as a primer. Replication can generate DNA from either DNA or RNA (cDNA synthesis). This material can either be processed directly or amplified further using methods known in the field such as PCR or multi-strand displacement amplification.


The capture sequences can be synthesized directly onto the beads or be attached by such means as biotinylated sequences and streptavidin beads. The use of streptavidin beads and biotinylated sequences has the advantage of allowing a generic bead to be used with new libraries of biotinylated capture sequences that can be assembled on demand. However, any method known in the art for attaching nucleic acid sequences to beads can be utilized.


In certain embodiments, droplets containing target material may be merged with droplets containing beads that are designed to capture the target. After capture, the emulsion (i.e., set of droplets) is broken and the beads are used to purify the target away from other components of the reaction that may inhibit subsequent steps such as cell debris, proteases and detergents. Target (e.g., nucleic acid) can be captured on beads by using random N-mers designed to capture all sequences. In some embodiments, N-mers that are designed to capture only portions of the target are attached to the beads. Where the N-mers include a barcode-type tag, the tag can be incorporated by replication of the captured nucleic acid using the capture sequence with the tag as a primer. The replication can generate DNA from DNA or RNA (cDNA synthesis). This material can either be processed directly or amplified further using methods known in the art such as PCR or multi-strand displacement amplification.


In certain embodiments, methods of the invention include enriching all or selected portions of a target material. N-mers can be provided that further contain a common nucleotide sequence, such as a universal PCR sequence. In an exemplary embodiment, the enrichment step is accomplished by incorporating an adapter onto the 5′ end of the amplified genetic material, such as a universal PCR primer sequence, and further amplifying the genetic material. Only those strands having a label will be amplified, thereby enriching for the labeled genetic material. Alternatively, enrichment of sequence specific labeled strands can be achieved through amplification using a primer specific for the universal priming sequence incorporated into the labeled strand, and a primer specific for a desired target sequence. An enrichment step can be specific for target regions of interest in the genetic material, such as consensus sequences like CPG motifs, or other sequence motifs that are related to known or suspected sequences indicative of splice sites, promoter regions, regulatory regions, poly-A tail etc. In some embodiments, a first portion of amplified product associated with the label is enriched relative to a second portion of amplified product not associated with the label (e.g., through the inclusion of universal priming sites with the label).


In certain embodiments, the invention provides long sequences from short-read sequencing technologies. A set of primers is used that is tiled across the sequence of interest. Target nucleic acid is isolated in fluid partitions (e.g., droplets). Optionally, a plurality of targets are isolated in droplets and analyzed in parallel. For each droplet, a set of primers is provided in which each primer includes a label sequence that is unique for the droplet. the target nucleic acid is amplified in each droplet, with the result that every amplicon strand includes the label sequence at each end. In some embodiments, the droplets are ruptured and the amplicons are sequenced in such a way that each sequence read contains the target label sequence. Since the primer pairs were tiled to cover a long sequence, the reads can be assembled into “long reads” covering the sequence. Because each read is associated with a unique starting molecule through the presence of the label sequence, each “long read” that is produced from short read assembly will correspond to a single molecule of template. Thus, the sequence reads can be mapped back to the targeted genome, transcriptome, proteome, or a portion thereof.


Suitable sequencing methods include, but are not limited to, sequencing by hybridization, sequencing by synthesis technology (e.g., HiSeq™ and Solexa™, Illumina), SMRT™ (Single Molecule Real Time) technology (Pacific Biosciences), true single molecule sequencing (e.g., HeliScope™, Helicos Biosciences), massively parallel next generation sequencing (e.g., SOLiD™ Applied Biosciences; Solexa and HiSeq™, Illumina), massively parallel semiconductor sequencing (e.g., Ion Torrent), and pyrosequencing technology (e.g., GS FLX and GS Junior Systems, Roche/454).


In certain aspects, the invention provides a barcode library, which can be, for example, a stable barcode library which can be stored (e.g., for a year or longer). A barcode library can comprise a plurality of fluid compartments, each containing one or more copies of a unique construct, in which each construct includes a unique N-mer and a functional N-mer. For a universal barcode library of general applicability, each functional N-mer may be a sticky end, capable of being associated with another sticky end. Other functional N-mers can include sequence-specific primers; random N-mers; antibodies; probe targets; and universal primer sites. The fluid compartments can be water-in-oil droplets. The unique N-mer offers a barcode of information and can generally be between about 2 and 21 nucleotides in length, and optional longer, e.g., up to 50, 100, or any length.


In certain aspects, the invention relates to methods for detecting or identifying one or a plurality of targets in a biological sample using digital PCR in fluid partitions. Methods of the invention include labeling target material with a probe-type label. A probe type label can include an optical label, and labeled target material can be identified or analyzed using digital PCR.


Target material can be labeled with any suitable probe-type label known in the art. Probes may generally include sequences designed to hybridize to a target of interest. Detection of hybridization can indicate that the target of interest is present. Hybridization can be detected, for example, by including a fluorescent label on a probe structured so that the label is quenched unless hybridized to the intended target of the probe. Quenched and unquenched probes can be detected optically.


One or a plurality of such probes can be provided in a fluid partition. Members of the plurality of probes can each include the same detectable label, or a different detectable label. The plurality of probes can include one or more groups of probes at varying concentrations. The one or more groups of probes can include the same detectable label which varies in intensity upon detection, due to the varying probe concentrations. The droplets of the invention can further contain one or more reagents for conducting a polymerase chain reaction (e.g., polymerase, dNTPs, primers, etc.), for example, to enable probes to hybridize to amplified product (i.e., amplicons).


In some embodiments, the invention provides microfluidic droplets for multiplex analysis. Each droplet can contain a plurality of probes that hybridize to amplicons produced in the droplets. Preferably, the droplet contains two or more probes, e.g., 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, 16, 18, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 60, 75, 80, 85, 90, 95, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 500, or more probes.


The ability to amplify and detect single nucleic acids in droplets enables digital PCR, detection, counting, and differentiation among nucleic acids, especially those present in heterogeneous samples. Thus, the invention applies to digital amplification techniques and, in specific embodiments enables multiplex PCR in droplets. For example, multiplexing primers in droplets enables the simultaneous increase in the number of PCR droplets while keeping the amount of input DNA the same or lower and generate the same or greater amplicon yield. This results in an overall increase in the amount of PCR positive droplets and amplicon yield without the consumption of more DNA. In some embodiments, even though the number of PCR primer pairs per droplet is greater than one, there is only one template molecule per droplet, and thus, in some implementations, there is only one primer pair per droplet that is being utilized at one time. As such, the advantages of droplet PCR for eliminating bias from either allele specific PCR or competition between different amplicons is maintained. However, as described below in relation to detection of haplotypes, other implementations advantageously allow detection of multiple loci on a single template using multiple primer pairs, preferably designed to minimize bias.


In certain aspects, the invention provides methods of forming fluid partitions including target and reagents for digital PCR in which the methods enable multiplex digital PCR at high “plexity” in fluid partitions. In some embodiments, one or more droplets are formed, each containing a single nucleic acid template and a heterogeneous mixture of primer pairs and probes, each specific for multiple target sites on the template. For example, a first fluid (either continuous, or discontinuous as in droplets) containing a single nucleic acid template (DNA or RNA) is merged with a second fluid (also either continuous, or discontinuous as in droplets) containing a plurality of primer pairs and a plurality of probes, each specific for multiple target sites on the nucleic acid template, to form a droplet containing the single nucleic acid template and a heterogeneous mixture of primer pairs and probes. The second fluid can also contain reagents for conducting a PCR reaction, such as a polymerase and dNTPs. The droplet contents can be amplified (e.g., by thermocycling). The probes are hybridized to the amplicons and hybridization is optically detected.





BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, like reference characters generally refer to the same or similar parts throughout the different views. Also, the drawings are not necessarily to scale, emphasis instead generally being placed upon illustrating the principles of the invention.



FIG. 1 is a flow chart of the depicting an example of a labeling method according to the invention.



FIG. 2A shows a method of merging droplets.



FIG. 2B is a block diagram of droplets for merging.



FIG. 2C shows a method of sequestering material in droplets



FIG. 2D shows products of a labeling step



FIG. 2E shows a 10-mer (SEQ ID NO: 1) and a schematic for a 6-mer.



FIG. 3A is a schematic depicting an example of barcode labeled strands in a droplet before sequencing (in droplet) and after sequencing (in bulk).



FIG. 3B is a schematic depicting an example of a labeled primer having a universal priming site before incorporation into/onto a target nucleic acid and after incorporation into a target nucleic acid.



FIG. 4A depicts a droplet formation device.



FIG. 4B depicts a portion of the droplet formation device of FIG. 4A.



FIGS. 5A-B show a method of making a universal barcode library.



FIGS. 6A-B show six types of barcodes with sticky end components.



FIGS. 7A-B show a universal barcode droplet library with targeting primers.



FIGS. 8A-B show a universal barcode droplet library.



FIGS. 9A-B show ligating sticky-ended universal barcodes to barcoded PCR primers.



FIGS. 10A-B show an overall workflow for single molecule barcoded haplotype phasing.



FIGS. 11A-C show is a schematic depicting the PCR details of the schematic depicted in FIGS. 35A-B.



FIGS. 12A-B show up front processing for amplification-based single molecule haplotyping with universal PCR barcodes.



FIGS. 13A-B show barcode addition for amplification-based single molecule haplotyping with universal PCR barcodes.



FIGS. 14A-B show labeling and release for amplification-based single molecule haplotyping with universal PCR barcodes.



FIGS. 15A-B show processing for amplification-free haplotyping.



FIGS. 16A-B show barcoding in amplification-free haplotyping.



FIGS. 17A-B show amplification free haplotyping.



FIGS. 18A-B show a general workflow for single cell genomics.



FIGS. 19A-B show single cell genomics using barcoded primers.



FIGS. 20A-B show single cell genomics using a universal barcode library.



FIG. 21 shows using a random hexamer library with phi29.



FIG. 22 shows a barcoded random hexamer library.



FIGS. 23A-B are a schematic depicting various exemplary barcode schemes for the generation of an barcoded mRNA primer droplet library.



FIGS. 24A-B show a sorted cell workflow for barcoding transcriptomes from single cells.



FIGS. 25A-B show a sorted cell workflow for barcoding transcriptomes from single cells using a barcode library in a detergent lysis buffer.



FIGS. 26A-B show a bead-in-droplet workflow for barcoding transcriptomes.



FIGS. 27A-C show barcoding biomarkers.



FIGS. 28A-C show barcoding biomarkers on a per-cell basis.



FIGS. 29A-B show a step for single cell digital biomarker counting.



FIGS. 30A-B show a step for single cell digital biomarker counting.



FIGS. 31A-D show a step for single cell digital biomarker counting.



FIGS. 32A-C show motifs for linking and releasing barcodes. FIGS. 32A-C also show SEQ IDs NO: 2-11.



FIGS. 33A-B show a workflow for digital droplet proteomics using barcoded antibodies.



FIGS. 34A-B show barcoding a binder.



FIGS. 35A-B are a schematic depicting an exemplary workflow of a sandwich assay.



FIGS. 36A-B show use of a universal barcode library in a single cell lysate sandwich assay.



FIGS. 37A-J show types of sandwich assays.



FIGS. 38A-B show use of universal barcodes in a binding partner identification assay.



FIGS. 39A-B show barcodes for high-plex bead-based barcode labeling.



FIGS. 40A-B depict a flowchart depicting the steps associated with isolation, encapsulation, molecular labeling, sorting and analysis of single cell genomes using fluidic droplets.



FIG. 41 depicts lysis/proteolysis of cells (before and after) inside fluidic droplets.



FIG. 42 are images depicting the merger of droplets containing lysed cells and droplets containing reagents for WGA, and subsequent whole genome amplification (WGA) in the merged fluidic droplets.



FIG. 43 shows high-accuracy next-generation sequencing (NGS).



FIG. 44 shows sequencing results.



FIG. 45 shows results from the 5× multiplexed droplet library FIG. 46 shows results from a multiplexed copy number analysis.



FIG. 47 shows a detection apparatus according to certain embodiments.



FIG. 48A shows a droplet generation chip.



FIG. 48B depicts the droplet spacing for readout.



FIG. 48C depicts a cartoon of droplet readout by fluorescence.



FIGS. 49A-49C depict the serial dilution of template DNA quantified by dPCR.



FIG. 50A is a schematic representation of a droplet having 5 sets of primers for PCR amplification of a template sequence and 5 probes, each labeled with a fluorescent dye, that binds specifically to the amplified sequences.



FIG. 50B is a time trace of fluorescence intensity detected from droplets.



FIG. 50C is a scatter plot showing clusters corresponding to amplified sequences.



FIG. 51 is a schematic representation of a droplet having 5 sets of primers.



FIG. 52A is a scatter plot showing clusters representing amplified sequences.



FIG. 52B is a table showing the copy number of specific sequences.



FIGS. 53A-E schematically depict one-color detection of a genetic sequence with a microfluidic device.



FIGS. 54A-D show detection of two genetic sequences with a microfluidic device.



FIGS. 55A-D show detection of three genetic sequences with a microfluidic device.



FIG. 56 shows dot plots depicting genetic sequences detected by fluorescence intensity.



FIG. 57A depicts a histogram of droplet peak fluorescence intensities.



FIG. 57B shows a comparison of gene copy numbers by monochromatic dPCR.



FIGS. 58A-C illustrate a schematic for tuning the intensity of a detectable label to a particular target with a microfluidic device.



FIG. 59 is a line graph depicting the linear dependence of droplet fluorescence intensity on probe concentration (Line, best linear fit (y=−0.092x+0.082, R2=0.995).



FIG. 60A is a 2D histogram of droplet fluorescence intensities.



FIG. 60B shows the results of the SMA pilot study.



FIG. 61 depicts a 9-plex dPCR assay for spinal muscular atrophy with only two fluorophores, showing the process of optimizing droplet intensities.



FIG. 62 depicts an optical schematic for combining optical labels with multiplexing.



FIG. 63 depicts a dPCR assay combining multiplexing with optical labels using co-flow microfluidics.



FIGS. 64A-C show single assay selections using optical labels.



FIGS. 65A-C show single assay selections using optical labels.



FIGS. 66 A-C show single assay selections using optical labels.



FIGS. 67A-J depict a dPCR assay combining multiplexing with optical labels.



FIG. 68 is a schematic showing haplotype detection in droplets.



FIGS. 69A-B show a workflow for restriction barcoding.



FIGS. 70A-B show a workflow for barcoding sandwich assays for dPCR readout.



FIGS. 71A-D show droplet generation, merging, and combining



FIGS. 72A-D show droplet library generation and use in binding assays.





DETAILED DESCRIPTION

The invention generally provides materials and methods for labeling target nucleic acid, protein, or other material using microfluidic droplet-based technology, and droplets produced using the same. The invention also provides the ability to associate sequencing reads with single cells in a heterogeneous mixture of cells. For example, one or more mutations are identified in subpopulations of cancer cells in a sample using the labeling methods of the invention. The ability to identify multiple mutations existing in one cell better informs research and physicians on the possibility of drug resistance or reoccurrence of disease, and also inform treatment. The invention further provides for the ability to identify metagenomic loss of identity in individual bacteria (e.g., bacteria having multiple mutations in the same organism versus multiple bacteria, each having different mutations, in the same population). In another aspect, the invention provides for the ability to pool multiple patient samples in a multiplex sequencing reaction and to accurately identify the source of the multiple samples after sequencing. Similarly, in proteomic assays (e.g., assays in which a labeled antibody or nucleic acid identifier (such as an aptamer) are used), methods of the invention provide accurate labeling and detection.


As discussed herein, the invention provides (I.) droplets for the analysis and labeling of target material. The invention further provides (II.) barcode-type labels and (III.) probe-type labels.


I. Droplets


The invention provides microfluidic devices and systems for the formation of droplets and their manipulation (e.g., merging, sorting, rupturing, storing) for the analysis (e.g., amplification, labeling, detecting) of a variety of target materials



FIG. 1 depicts a flow chart of the general methods of the invention. As shown in FIG. 1, the target material is encapsulated in a droplet, for example, using a microfluidic system. FIG. 2A-2C show droplet manipulation. FIG. 2D shows products of a labeling step. FIG. 2E shows a 10-mer and a schematic for a 6-mer. FIG. 2C shows one exemplary method of sequestering material in droplets. Preferably, the genetic material is diluted such that each droplet contains a single element (e.g., nucleic acid molecule, chromosome, genome, cell, protein, biological macromolecule, etc.). The elements can be from a single cell (prokaryotic or eukaryotic), or a portion or subset thereof (e.g., a single nucleic acid template). The droplets can optionally be sorted (e.g., to identify subspecies that will be subsequently labeled). Where the genetic material is a single cell, the cells are lysed to release the genetic element in the single cell. Lysis can be performed prior to encapsulation or after encapsulation (e.g., using proteases, alkaline reagents, and/or detergents). Labels (e.g., barcodes, fluorescent labels) can be introduced into the droplet and incorporated into or on the target. Optionally, an enrichment step can be performed to enrich for the labeled genetic element, or sequence specific enrichment.


Microfluidic Systems


Droplets can be generated using microfluidic systems or devices. As used herein, the “micro-” prefix (for example, as “microchannel” or “microfluidic”), generally refers to elements or articles having widths or diameters of less than about 1 mm, and less than about 100 microns (micrometers) in some cases. In some cases, the element or article includes a channel through which a fluid can flow. Additionally, “microfluidic”, as used herein, refers to a device, apparatus or system that includes at least one microscale channel.


Microfluidic systems and devices have been described in a variety of contexts, typically in the context of miniaturized laboratory (e.g., clinical) analysis. Other uses have been described as well. For example, International Patent Application Publication Nos. WO 01/89788; WO 2006/040551; WO 2006/040554; WO 2004/002627; WO 2008/063227; WO 2004/091763; WO 2005/021151; WO 2006/096571; WO 2007/089541; WO 2007/081385 and WO 2008/063227.


Specifically, the devices and methods described herein are based on the creation and manipulation of aqueous phase droplets (e.g., droplet libraries) surrounded by an immiscible carrier fluid. This combination enables precise droplet generation, highly efficient, electrically addressable droplet coalescence, and controllable, electrically addressable single droplet sorting.


Generally, microfluidic devices include one or more channels in one or more analysis units. An “analysis unit” is a microsubstrate, e.g., a microchip. The terms microsubstrate, substrate, microchip, and chip are used interchangeably herein. An analysis unit typically includes at least an inlet channel and a main channel. The analysis unit can further include coalescence, detection, or sorting modules. The sorting module can be in fluid communication with branch channels which are in fluid communication with one or more outlet modules (e.g., collection module or waste module). For sorting applications, at least one detection module cooperates with at least one sorting module to divert flow via a detector-originated signal. It shall be appreciated that the “modules” and “channels” are in fluid communication with each other and therefore may overlap; i.e., there may be no clear boundary where a module or channel begins or ends. A plurality of analysis units of the invention may be combined in one device. The dimensions of the substrate are those of typical microchips, ranging between about 0.5 cm to about 15 cm per side and about 1 micron to about 1 cm in thickness. The analysis unit and specific modules are described in further detail in WO 2006/040551; WO 2006/040554; WO 2004/002627; WO 2004/091763; WO 2005/021151; WO 2006/096571; WO 2007/089541; WO 2007/081385 and WO 2008/063227.


A variety of materials and methods can be used to form devices of the invention. For example, components can be formed from solid materials, in which the channels can be formed via molding, micromachining, film deposition processes such as spin coating and chemical vapor deposition, laser fabrication, photolithographic techniques, etching methods including wet chemical or plasma processes, and the like. See, for example, Angell, et al., Scientific American, 248:44-55, 1983. At least a portion of the fluidic system can be formed of silicone by molding a silicon chip. Devices of the invention can also be formed of a polymer, for example, an elastomeric polymer such as poly-dimethylsiloxane (PDMS), polytetrafluoroethylene (PTFE), Teflon®, or the like. PDMS polymers include those sold under the trademark Sylgard by Dow Chemical Co., Midland, Mich., and particularly Sylgard 182, Sylgard 184, and Sylgard 186. Silicone polymers such as PDMS are generally inexpensive, readily available, and can be solidified from a prepolymeric liquid via curing with heat. For example, PDMS is typically curable by exposure of the prepolymeric liquid to temperatures of about, for example, about 65° C. to about 75° C. for exposure times of, for example, about an hour. Also, silicone polymers can be elastomeric and thus may be useful for forming very small features with relatively high aspect ratios, necessary in certain embodiments of the invention.


Because PDMS can be oxidized, for example by exposure to an oxygen-containing plasma such as an air plasma, devices of the invention may contain, at their surface, chemical groups capable of cross-linking to other oxidized silicone polymer surfaces or to the oxidized surfaces of a variety of other polymeric and non-polymeric materials. Thus, components can be formed and then oxidized and essentially irreversibly sealed to other silicone polymer surfaces or to the surfaces without the need for separate adhesives or other sealing means. In most cases, sealing can be completed simply by contacting an oxidized silicone surface to another surface without the need to apply auxiliary pressure to form the seal. That is, the pre-oxidized silicone surface acts as a contact adhesive against suitable mating surfaces. Further, PDMS can also be sealed irreversibly to a range of oxidized materials other than itself including, for example, glass, silicon, silicon oxide, quartz, silicon nitride, polyethylene, polystyrene, glassy carbon, and epoxy polymers, which have been oxidized in a similar fashion to the PDMS surface (for example, via exposure to an oxygen-containing plasma). Molding, oxidation and sealing methods are described in the art, for example, in Duffy et al., “Rapid Prototyping of Microfluidic Systems and Polydimethylsiloxane,” Anal. Chem., 70:474-480, 1998.


Another advantage of oxidized silicone polymers is that these surfaces can be much more hydrophilic than the surfaces of typical elastomeric polymers (where a hydrophilic interior surface is desired).


Thus, a channel can have a hydrophilic surface, which can be more easily wetted compared to other surfaces, which makes the channel easier to fill with aqueous solutions Generally, “channel,” as used herein, means a feature on or in a substrate that at least partially directs the flow of a fluid. In some cases, the channel may be formed, at least in part, by a single component, e.g., an etched substrate or molded unit. The channel can have any cross-sectional shape, for example, circular, oval, triangular, irregular, square or rectangular (having any aspect ratio), or the like, and can be covered or uncovered (i.e., open to the external environment surrounding the channel). In embodiments where the channel is completely covered, at least one portion of the channel can have a cross-section that is completely enclosed, and/or the entire channel may be completely enclosed along its entire length with the exception of its inlet and outlet. A channel can be formed, for example by etching a silicon chip using conventional photolithography techniques, or using a micromachining technology called “soft lithography” as described by Whitesides and Xia, Angewandte Chemie International Edition 37, 550 (1998).


A fluid within a channel may partially or completely fill the channel. In some cases the fluid may be held or confined within the channel or a portion of the channel in some fashion, for example, using surface tension (e.g., such that the fluid is held within the channel within a meniscus, such as a concave or convex meniscus). In an article or substrate, some (or all) of the channels may be of a particular size or less, for example, having a largest dimension perpendicular to fluid flow of less than about 5 mm, less than about 2 mm, less than about 1 mm, less than about 500 microns, less than about 200 microns, less than about 100 microns, less than about 60 microns, less than about 50 microns, less than about 40 microns, less than about 30 microns, less than about 25 microns, less than about 10 microns, less than about 3 microns, less than about 1 micron, less than about 300 nm, less than about 100 nm, less than about 30 nm, or less than about 10 nm or less in some cases.


Channels can be configured to coalesce droplets or to flow material by a detection module or a sorting module. A main channel is typically in fluid communication with any coalescence, detection and/or sorting modules, as well as inlet, branch, or outlet channels and any collection or waste modules. These channels permit the flow of molecules, cells, small molecules or particles out of the main channel. An “inlet channel” permits the flow of molecules, cells, small molecules or particles into the main channel. One or more inlet channels communicate with one or more means for introducing a sample into the device of the present invention. A microfluidic device can also include fluid channels to inject or remove fluid in between droplets in a droplet stream for the purpose of changing the spacing between droplets.


A microfluidic substrate can also include a specific geometry designed to prevent the aggregation of material prior to encapsulation in droplets. The geometry of channel dimension can be changed to disturb the aggregates and break them apart by various methods, that can include, but is not limited to, geometric pinching (to force cells or particles through a narrow region, whose dimension is smaller or comparable to the dimension of a single cell) or a barricade (place a series of barricades on the way of the moving cells to disturb the movement and break up the aggregates of cells).


To prevent target material (e.g., cells, molecules, or other material as discussed below) from adhering to the sides of the channels, the channels (and coverslip, if used) may have a coating to minimize adhesion. The surface of the channels can be coated with any anti-wetting or blocking agent for the dispersed phase. The channel can be coated with any protein to prevent adhesion of the biological/chemical sample. Channels can be coated by any means known in the art. For example, the channels can be coated with Teflon®, BSA, PEG-silane and/or fluorosilane in an amount sufficient to prevent attachment and prevent clogging. In another example, the channels can be coated with a cyclized transparent optical polymer obtained by copolymerization of perfluoro (alkenyl vinyl ethers), such as the type sold by Asahi Glass Co. under the trademark Cytop. In such an example, the coating is applied from a 0.1-0.5 wt % solution of Cytop CTL-809M in CT-Solv 180. This solution can be injected into the channels of a microfluidic device via a plastic syringe. The device can then be heated to about 90° C. for 2 hours, followed by heating at 200° C. for an additional 2 hours. In another embodiment, the channels can be coated with a hydrophobic coating of perfluoro-alkylalkylsilane, described in U.S. Pat. No. 5,523,162. The surface of the channels in the microfluidic device can be also fluorinated by any means known in the art to prevent undesired wetting behaviors. For example, a microfluidic device can be placed in a polycarbonate dessicator with an open bottle of (tridecafluoro-1,1,2,2-tetrahydrooctyl)trichlorosilane. The dessicator is evacuated for 5 minutes, and then sealed for 20-40 minutes. The dessicator is then backfilled with air and removed. This approach uses a simple diffusion mechanism to enable facile infiltration of channels of the microfluidic device with the fluorosilane and can be readily scaled up for simultaneous device fluorination. By fluorinating the surfaces of the channels, the continuous phase preferentially wets the channels and allows for the stable generation and movement of droplets through the device. The low surface tension of the channel walls thereby minimizes the accumulation of channel clogging particulates, enhancing the processing of target material.


Target Material


Target materials for labeling, analysis, or detection according to the methods of the invention include, but are not limited to, cells, nucleic acids, proteins, multi-component complexes such as nucleic acid with associated proteins (e.g., histones), chromosomes, carbohydrates, or similar materials. Methods of the invention are applicable to whole cells or to portions of genetic or proteomic material obtained from cells. Target material generally includes anything that can be sequestered into a fluid partition (e.g., droplet) and labeled.


Nucleic acid molecules include deoxyribonucleic acid (DNA) and/or ribonucleic acid (RNA). Nucleic acid molecules can be synthetic or derived from naturally occurring sources. In one embodiment, nucleic acid molecules are isolated from a biological sample containing a variety of other components, such as proteins, lipids and non-template nucleic acids. Nucleic acid template molecules can be obtained from any cellular material, obtained from an animal, plant, bacterium, fungus, or any other cellular organism. In certain embodiments, the nucleic acid molecules are obtained from a single cell. Biological samples for use in the present invention include viral particles or preparations. Nucleic acid molecules can be obtained directly from an organism or from a biological sample obtained from an organism, e.g., from blood, urine, cerebrospinal fluid, seminal fluid, saliva, sputum, stool and tissue. Any tissue or body fluid specimen may be used as a source for nucleic acid for use in the invention. Nucleic acid molecules can also be isolated from cultured cells, such as a primary cell culture or a cell line. The cells or tissues from which template nucleic acids are obtained can be infected with a virus or other intracellular pathogen.


A sample can also be total RNA extracted from a biological specimen, a cDNA library, viral, or genomic DNA. In certain embodiments, the nucleic acid molecules are bound as to other target molecules such as proteins, enzymes, substrates, antibodies, binding agents, beads, small molecules, peptides, or any other molecule and serve as a surrogate for quantifying and/or detecting the target molecule. Generally, nucleic acid can be extracted from a biological sample by a variety of techniques such as those described by Sambrook and Russell, Molecular Cloning: A Laboratory Manual, Third Edition, Cold Spring Harbor, N.Y. (2001). Nucleic acid molecules may be single-stranded, double-stranded, or double-stranded with single-stranded regions (for example, stem- and loop-structures).


Proteins or portions of proteins (amino acid polymers) that can bind to high affinity binding moieties, such as antibodies or aptamers, are target molecules for oligonucleotide labeling, for example, in droplets, in some embodiments of this invention.


Droplet Formation


Methods of the invention involve forming droplets, which may contain no target material, target material from a single cell (e.g., a nucleic acid such as genomic DNA or expressed RNA), all or a portion of a target from a single cell, or all or a portion of target from multiple cells (corresponding to limiting or terminal dilution, respectively, as defined above).


In certain embodiments, the distribution of material within droplets obeys the Poisson distribution. However, methods for non-Poisson loading of droplets are known to those familiar with the art, and include but are not limited to active sorting of droplets, such as by laser-induced fluorescence, or by passive one-to-one loading.


The droplets are aqueous droplets that are surrounded by an immiscible carrier fluid. Methods of forming such droplets are discussed in U.S. Pub. 2008/0014589; U.S. Pub. 2008/0003142; U.S. Pub. 2010/0137163; U.S. Pat. No. 7,708,949; U.S. Pub. 2010/0172803; and U.S. Pat. No. 7,041,481, the content of each of which is incorporated by reference herein in its entirety.



FIG. 4A shows an exemplary embodiment of a device 100 for droplet formation. Device 100 includes an inlet channel 101, and outlet channel 102, and two carrier fluid channels 103 and 104. Channels 101, 102, 103, and 104 meet at a junction 105. Inlet channel 101 flows sample fluid to the junction 105. Carrier fluid channels 103 and 104 flow a carrier fluid that is immiscible with the sample fluid to the junction 105. Inlet channel 101 narrows at its distal portion wherein it connects to junction 105 (See FIG. 4B). Inlet channel 101 is oriented to be perpendicular to carrier fluid channels 103 and 104. Droplets are formed as sample fluid flows from inlet channel 101 to junction 105, where the sample fluid interacts with flowing carrier fluid provided to the junction 105 by carrier fluid channels 103 and 104. Outlet channel 102 receives the droplets of sample fluid surrounded by carrier fluid.


The sample fluid is typically an aqueous buffer solution, such as ultrapure water (e.g., 18 mega-ohm resistivity, obtained, for example by column chromatography), 10 mM Tris HCl and 1 mM EDTA (TE) buffer, phosphate buffer saline (PBS) or acetate buffer. Any liquid or buffer that is physiologically compatible with target material can be used. The carrier fluid is immiscible with the sample fluid. The carrier fluid can be a non-polar solvent, decane (e g., tetradecane or hexadecane), fluorocarbon oil, silicone oil or another oil (e.g., mineral oil).


In certain embodiments, the carrier fluid contains one or more additives, such as agents which increase, reduce, or otherwise create non-Newtonian surface tensions (surfactants) and/or stabilize droplets against spontaneous coalescence on contact. Surfactants can include Tween, Span, fluorosurfactants, and other agents that are soluble in oil relative to water. Suitable surfactants are known in the art. In some applications, performance is improved by adding a second surfactant, or other agent, such as a polymer or other additive, to the sample fluid. Surfactants can aid in controlling or optimizing droplet size, flow and uniformity, for example by reducing the shear force needed to extrude or inject droplets into an intersecting channel. This can affect droplet volume and periodicity, or the rate or frequency at which droplets break off into an intersecting channel. Furthermore, the surfactant can serve to stabilize aqueous emulsions in fluorinated oils from coalescing.


In certain embodiments, the droplets may be coated with a surfactant or a mixture of surfactants. In certain embodiments, the carrier fluid may be caused to flow through the outlet channel so that the surfactant in the carrier fluid coats the channel walls. In one embodiment, the fluorosurfactant can be prepared by reacting the perflourinated polyether DuPont Krytox 157 FSL, FSM, or FSH with ammonium hydroxide in a fluorinated solvent. The solvent, water, and ammonia can be removed with a rotary evaporator. The surfactant can then be dissolved (e.g., 2.5 wt %) in a fluorinated oil (e.g., Flourinert (3M)), which then serves as the carrier fluid.


Another approach to merging sample fluids involves forming a droplet, and contacting the droplet with a fluid stream, in which a portion of the fluid stream integrates with the droplet to form a mixed droplet.


A droplet is formed as described above. After formation of the sample droplet from the first sample fluid, the droplet is contacted with a flow of a second sample fluid stream. Contact between the droplet and the fluid stream results in a portion of the fluid stream integrating with the droplet to form a mixed droplet, which, as discussed below, form a basis for droplet libraries according to certain embodiments of the invention.


The monodisperse droplets of the first sample fluid flow through a first channel separated from each other by immiscible carrier fluid and suspended in the immiscible carrier fluid. The droplets are delivered to the merge area, i.e., junction of the first channel with the second channel, by a pressure-driven flow generated by a positive displacement pump. While droplet arrives at the merge area, a bolus of a second sample fluid is protruding from an opening of the second channel into the first channel. Preferably, the channels are oriented perpendicular to each other. However, any angle that results in an intersection of the channels may be used.


The bolus of the second sample fluid stream continues to increase in size due to pumping action of a positive displacement pump connected to channel, which outputs a steady stream of the second sample fluid into the merge area. The flowing droplet containing the first sample fluid eventually contacts the bolus of the second sample fluid that is protruding into the first channel. Contact between the two sample fluids results in a portion of the second sample fluid being segmented from the second sample fluid stream and joining with the first sample fluid droplet to form a mixed droplet. In certain embodiments, each incoming droplet of first sample fluid is merged with the same amount of second sample fluid.


In certain embodiments, an electric charge is applied to the first or second sample fluids. Applying electric charge is described in U.S. Pub. 2007/0003442, the content of which is incorporated by reference herein in its entirety. Electric charge may be created in a sample fluid within the carrier fluid using any suitable technique, for example, by placing the first and second sample fluids within an electric field (which may be AC, DC, etc.), and/or causing a reaction to occur that causes the first and second sample fluids to have an electric charge, for example, a chemical reaction, an ionic reaction, a photocatalyzed reaction, etc.


The electric field, in some embodiments, is generated from an electric field generator, i.e., a device or system able to create an electric field that can be applied to the fluid. The electric field generator may produce an AC field (i.e., one that varies periodically with respect to time, for example, sinusoidally, sawtooth, square, etc.), a DC field (i.e., one that is constant with respect to time), a pulsed field, etc. The electric field generator may be constructed and arranged to create an electric field within a fluid contained within a channel or a microfluidic channel. The electric field generator may be integral to or separate from the fluidic system containing the channel or microfluidic channel, according to some embodiments.


Techniques for producing a suitable electric field (which may be AC, DC, etc.) are known to those of ordinary skill in the art. For example, in one embodiment, an electric field is produced by applying voltage across a pair of electrodes, which may be positioned on or embedded within the fluidic system (for example, within a substrate defining the channel or microfluidic channel), and/or positioned proximate the fluid such that at least a portion of the electric field interacts with the fluid. The electrodes can be fashioned from any suitable electrode material or materials known to those of ordinary skill in the art, including, but not limited to, silver, gold, copper, carbon, platinum, copper, tungsten, tin, cadmium, nickel, indium tin oxide (“ITO”), etc., as well as combinations thereof. In some cases, transparent or substantially transparent electrodes can be used.


The electric field facilitates rupture of the interface separating the second sample fluid and the droplet. Rupturing the interface facilitates merging of a bolus of the second sample fluid and the first sample fluid droplet. The forming mixed droplet continues to increase in size until breaks free from the second sample fluid stream, for instance prior to the arrival of the next droplet containing the first sample fluid. The segmenting of the portion of the second sample fluid from the second sample fluid stream occurs as soon as the shear force exerted on the forming mixed droplet by the immiscible carrier fluid overcomes the surface tension whose action is to keep the segmenting portion of the second sample fluid connected with the second sample fluid stream. The now fully formed mixed droplet continues to flow through the first channel (e.g., for possible use in a droplet library).


Where material in droplets will be subject to PCR, those droplets can be merged with a second fluid containing reagents for a PCR reaction (e.g., Taq polymerase, dNTPs, magnesium chloride, and forward and reverse primers, all suspended within an aqueous buffer). The second fluid may also include detectably labeled probes and/or universal barcodes for detection of the amplified target material, the details of which are discussed below. A droplet containing the target or portion thereof is then caused to merge with the PCR reagents in the second fluid as described above, producing a droplet that includes target and PCR reagents as well as, optionally, detectably labeled probes.


Droplet Libraries


Droplet libraries are useful to perform large numbers of assays while consuming only limited amounts of reagents. A “droplet,” as used herein, is an isolated portion of a first fluid that is surrounded by a second fluid. In some cases, the droplets may be spherical or substantially spherical; however, in other cases, the droplets may be non-spherical, for example, the droplets may have the appearance of “blobs” or other irregular shapes, for instance, depending on the external environment. In some embodiments, a droplet is a first fluid completely surrounded by a second fluid. As used herein, a first entity is “surrounded” by a second entity if a closed loop can be drawn or idealized around the first entity through only the second entity (with the sometimes exception for portions of the first fluid that may be in contact with a wall or other boundary, where applicable).


In general, a droplet library is made up of a number of library elements that are pooled together in a single collection. Libraries may vary in complexity from a single library element to 1015 library elements or more. Each library element is one or more given components at a fixed concentration. The element may be, but is not limited to, cells, virus, bacteria, yeast, beads, amino acids, proteins, polypeptides, nucleic acids, polynucleotides or small molecule chemical compounds. The element may contain an identifier such as a label. The terms “droplet library” or “droplet libraries” are also referred to herein as an “emulsion library” or “emulsion libraries.” These terms are used interchangeably throughout the specification.


A cell library element can include, but is not limited to, hybridomas, B-cells, primary cells, cultured cell lines, cancer cells, stem cells, or any other cell type. Cellular library elements are prepared by encapsulating a number of cells from one to tens of thousands in individual droplets. The number of cells encapsulated is usually given by Poisson statistics from the number density of cells and volume of the droplet. However, in some cases the number deviates from Poisson statistics as described in Edd et al., “Controlled encapsulation of single-cells into monodisperse picolitre drops.” Lab Chip, 8(8):1262-1264, 2008. The discreet nature of cells allows for libraries to be prepared in mass with a plurality of cellular variants all present in a single starting media and then that media is broken up into individual droplet capsules that contain at most one cell. These individual droplets capsules are then combined or pooled to form a library consisting of unique library elements. Cell division subsequent to, or in some embodiments following, encapsulation produces a clonal library element.


A bead based library element contains one or more beads, and may also contain other reagents, such as antibodies, enzymes or other proteins. In the case where all library elements contain different types of beads, but the same surrounding media, the library elements can all be prepared from a single starting fluid or have a variety of starting fluids. In the case of cellular libraries prepared in mass from a collection of variants, the library elements will be prepared from a variety of starting fluids.


Often it is desirable to have exactly one cell per droplet with only a few droplets containing more than one cell when starting with a plurality of cells. In some cases, variations from Poisson statistics can be achieved to provide an enhanced loading of droplets such that there are more droplets with exactly one cell per droplet and few exceptions of empty droplets or droplets containing more than one cell.


Examples of droplet libraries are collections of droplets that have different contents, ranging from beads, cells, small molecules, DNA, primers, antibodies. The droplets range in size from roughly 0.5 micron to 500 micron in diameter, which corresponds to about 1 pico liter to 1 nano liter. However, droplets can be as small as 5 microns and as large as 500 microns. Preferably, the droplets are at less than 100 microns, about 1 micron to about 100 microns in diameter. The most preferred size is about 20 to 40 microns in diameter (10 to 100 picoliters). The preferred properties examined of droplet libraries include osmotic pressure balance, uniform size, and size ranges.


The droplets comprised within the droplet library provided by the instant invention are preferably uniform in size. That is, the diameter of any droplet within the library will vary less than 5%, 4%, 3%, 2%, 1% or 0.5% when compared to the diameter of other droplets within the same library. The uniform size of the droplets in the library is critical to maintain the stability and integrity of the droplets and is also essential for the subsequent use of the droplets within the library for the various biological and chemical assays described herein.


In certain embodiments, the droplet libraries are using an immiscible fluorocarbon oil. The oil can comprise at least one fluorosurfactant. In some embodiments, the fluorosurfactant comprised within immiscible fluorocarbon oil is a block copolymer consisting of one or more perfluorinated polyether (PFPE) blocks and one or more polyethylene glycol (PEG) blocks. In other embodiments, the fluorosurfactant is a triblock copolymer consisting of a PEG center block covalently bound to two PFPE blocks by amide linking groups. The presence of the fluorosurfactant (similar to uniform size of the droplets in the library) is critical to maintain the stability and integrity of the droplets and is also essential for the subsequent use of the droplets within the library for the various biological and chemical assays described herein. Fluids (e.g., aqueous fluids, immiscible oils, etc.) and other surfactants that can be utilized in the droplet libraries of the present invention are described in greater detail herein.


The droplet libraries of the present invention are very stable and are capable of long-term storage. The droplet libraries are determined to be stable if the droplets comprised within the libraries maintain their structural integrity, that is the droplets do not rupture and elements do not diffuse from the droplets. The droplets libraries are also determined to be stable if the droplets comprised within the libraries do not coalesce spontaneously (without additional energy input, such as electrical fields described in detail herein). Stability can be measured at any temperature. For example, the droplets are very stable and are capable of long-term storage at any temperature; for example, e.g., −70° C., 0° C., 4° C., 37° C., room temperature, 75° C. and 95° C. Specifically, the droplet libraries of the present invention are stable for at least 30 days. More preferably, the droplets are stable for at least 60 days. Most preferably, the droplets are stable for at least 90 days.


The invention provides a droplet library comprising a plurality of aqueous droplets within an immiscible fluid (optionally comprising a fluorosurfactant), wherein each droplet is preferably substantially uniform in size and comprises a different library element. The invention provides a method for forming the droplet library comprising providing a single aqueous fluid comprising different library elements, encapsulating each library element into an aqueous droplet within an immiscible fluid (optionally comprising a fluorosurfactant).


In certain embodiments, different types of elements (e.g., cells or beads), are pooled in a single source contained in the same medium. After the initial pooling, the elements are then encapsulated in droplets to generate a library of droplets wherein each droplet with a different type of bead or cell is a different library element. The dilution of the initial solution enables the encapsulation process. In some embodiments, the droplets formed will either contain a single element or will not contain anything, i.e., be empty. In other embodiments, the droplets formed will contain multiple copies of a library element. The elements being encapsulated are generally variants of a type. In one example, elements are cancer cells of a tissue biopsy, and each cell type is encapsulated to be screened for genomic data or against different drug therapies. Another example is that 1011 or 1015 different type of bacteria; each having a different plasmid spliced therein, are encapsulated. One example is a bacterial library where each library element grows into a clonal population that secretes a variant on an enzyme.


In certain embodiments, a droplet library comprises a plurality of aqueous droplets within an immiscible fluid, such that there is a single molecule contained within a droplet for every 20-60 droplets produced (e.g., 20, 25, 30, 35, 40, 45, 50, 55, 60 droplets, or any integer in between). Single molecules are encapsulated by diluting the solution containing the molecules to such a low concentration that the encapsulation of single molecules is enabled. In one specific example, a LacZ plasmid DNA was encapsulated at a concentration of 20 fM after two hours of incubation such that there was about one gene in 40 droplets, where 10 μm droplets were made at 10 kHz per second. Formation of these libraries relies on limiting dilutions.


The present invention also provides a droplet library comprising at least a first aqueous droplet and at least a second aqueous droplet within a fluorocarbon oil comprising at least one fluorosurfactant, wherein the at least first and the at least second droplets are uniform in size and comprise a different aqueous fluid and a different library element. The present invention also provides a method for forming the emulsion library comprising providing at least a first aqueous fluid comprising at least a first library of elements, providing at least a second aqueous fluid comprising at least a second library of elements, encapsulating each element of said at least first library into at least a first aqueous droplet within an immiscible fluorocarbon oil comprising at least one fluorosurfactant, encapsulating each element of said at least second library into at least a second aqueous droplet within an immiscible fluorocarbon oil comprising at least one fluorosurfactant, wherein the at least first and the at least second droplets are uniform in size and comprise a different aqueous fluid and a different library element, and pooling the at least first aqueous droplet and the at least second aqueous droplet within an immiscible fluorocarbon oil comprising at least one fluorosurfactant thereby forming an emulsion library.


For example, in one type of emulsion library, there are library elements that have different particles, i.e., cells or beads in a different medium and are encapsulated prior to pooling. In one example, a specified number of library elements, i.e., n number of different cells or beads, are contained within different mediums. Each of the library elements are separately emulsified and pooled, at which point each of the n number of pooled different library elements are combined and pooled into a single pool. The resultant pool contains a plurality of water-in-oil emulsion droplets each containing a different type of particle.


In some embodiments, the droplets formed will either contain a single library element or will not contain anything, i.e., be empty. In other embodiments, the droplets formed will contain multiple copies of a library element. The contents of the beads follow a Poisson distribution, where there is a discrete probability distribution that expresses the probability of a number of events occurring in a fixed period of time if these events occur with a known average rate and independently of the time since the last event. The oils and surfactants used to create the libraries prevent the exchange of the contents of the library between droplets.



FIG. 71A-D shows droplet generation, merging, and combining. As shown in panel A, monodisperse aqueous droplets are formed in a fluorocarbon oil using pressure-driven flow into a microfluidic nozzle. Panel B presents a schematic showing surfactant “wall” which provides stability for droplet manipulations. Panel C includes an image from a sequence enrichment application, combining DNA samples with PCR reagents (merging with Primer Droplet Library). The mixed droplets can be taken off-chip for PCR. In panel D, the top image shows ˜2×108 droplets before PCR, and bottom shows a microscope image of intact droplets after thermocycling.



FIG. 72A-D shows droplet library generation and use in binding assays (discussed in greater detail herein). As shown in Panel A, stable droplet library reagents can be formulated (5-member library shown) and aliquoted for later use. Panel B shows reinjection of a droplet library and re-spacing into single file droplets. Panel C presents two binding assays: microscope image on the top shows virus particles binding to embryonic fibroblasts; the image on the bottom shows individual beads binding to ELISA sandwich reagents in droplets.


Droplet Sorting


Methods of the invention may further include sorting the droplets based upon whether the droplets contain a homogeneous population of molecules or a heterogeneous population of molecules. A sorting module may be a junction of a channel where the flow of droplets can change direction to enter one or more other channels, e.g., a branch channel, depending on a signal received in connection with a droplet interrogation in the detection module. Typically, a sorting module is monitored and/or under the control of the detection module, and therefore a sorting module may correspond to the detection module. The sorting region is in communication with and is influenced by one or more sorting apparatuses.


A sorting apparatus includes techniques or control systems, e.g., dielectric, electric, electro-osmotic, (micro-) valve, etc. A control system can employ a variety of sorting techniques to change or direct the flow of molecules, cells, small molecules or particles into a predetermined branch channel. A branch channel is a channel that is in communication with a sorting region and a main channel. The main channel can communicate with two or more branch channels at the sorting module or branch point, forming, for example, a T-shape or a Y-shape. Other shapes and channel geometries may be used as desired. Typically, a branch channel receives droplets of interest as detected by the detection module and sorted at the sorting module. A branch channel can have an outlet module and/or terminate with a well or reservoir to allow collection or disposal (collection module or waste module, respectively) of the molecules, cells, small molecules or particles. Alternatively, a branch channel may be in communication with other channels to permit additional sorting.


A characteristic of a fluidic droplet may be sensed and/or determined in some fashion, for example, as described herein (e.g., fluorescence of the fluidic droplet may be determined), and, in response, an electric field may be applied or removed from the fluidic droplet to direct the fluidic droplet to a particular region (e.g. a channel). In certain embodiments, a fluidic droplet is sorted or steered by inducing a dipole in the uncharged fluidic droplet (which may be initially charged or uncharged), and sorting or steering the droplet using an applied electric field. The electric field may be an AC field, a DC field, etc. For example, a channel containing fluidic droplets and carrier fluid, divides into first and second channels at a branch point. Generally, the fluidic droplet is uncharged. After the branch point, a first electrode is positioned near the first channel, and a second electrode is positioned near the second channel. A third electrode is positioned near the branch point of the first and second channels. A dipole is then induced in the fluidic droplet using a combination of the electrodes. The combination of electrodes used determines which channel will receive the flowing droplet. Thus, by applying the proper electric field, the droplets can be directed to either the first or second channel as desired. Further description of droplet sorting is shown in U.S. Pub. 2008/0014589; U.S. Pub. 2008/0003142, and U.S. Pub. 2010/0137163.


Based upon the detected signal at the detection module, droplets containing a heterogeneous population of molecules are sorted away from droplets that contain a homogeneous population of molecules. Droplets may be further sorted to separate droplets that contain a homogeneous population of amplicons of the target from droplets that contain a homogeneous population of amplicons of the variant of the target.


Target Amplification


Methods of the invention may further involve amplifying the target genetic material in each droplet. Amplification refers to production of additional copies of a nucleic acid sequence and is generally carried out using polymerase chain reaction or other technologies well known in the art (e.g., Dieffenbach and Dveksler, PCR Primer, a Laboratory Manual, Cold Spring Harbor Press, Plainview, N.Y. [1995]). The amplification reaction may be any amplification reaction known in the art that amplifies nucleic acid molecules, such as polymerase chain reaction, nested polymerase chain reaction, ligase chain reaction (Barany F. (1991) PNAS 88:189-193; Barany F. (1991) PCR Methods and Applications 1:5-16), ligase detection reaction (Barany F. (1991) PNAS 88:189-193), strand displacement amplification, transcription based amplification system, nucleic acid sequence-based amplification, rolling circle amplification, and hyper-branched rolling circle amplification.


In certain embodiments, the amplification reaction is the polymerase chain reaction. Polymerase chain reaction (PCR) refers to methods by K. B. Mullis (U.S. Pat. Nos. 4,683,195 and 4,683,202, hereby incorporated by reference) for increasing concentration of a segment of a target sequence in a mixture of genomic DNA without cloning or purification. The process for amplifying the target sequence includes introducing an excess of oligonucleotide primers to a DNA mixture containing a desired target sequence, followed by a precise sequence of thermal cycling in the presence of a DNA polymerase. The primers are complementary to their respective strands of the double stranded target sequence.


To effect amplification, primers are annealed to their complementary sequence within the target molecule. Following annealing, the primers are extended with a polymerase so as to form a new pair of complementary strands. The steps of denaturation, primer annealing and polymerase extension can be repeated many times (i.e., denaturation, annealing and extension constitute one cycle; there can be numerous cycles) to obtain a high concentration of an amplified segment of a desired target sequence. The length of the amplified segment of the desired target sequence is determined by relative positions of the primers with respect to each other and by cycling parameters, and therefore, this length is a controllable parameter.


The sample droplet may be pre-mixed with a primer or primers, or the primer or primers may be added to the droplet. In some embodiments, droplets created by segmenting the starting sample are merged with a second set of droplets including one or more primers for the target nucleic acid in order to produce final droplets.


In embodiments involving merging of droplets, two droplet formation modules are used. In one embodiment, a first droplet formation module produces the sample droplets consistent with limiting or terminal dilution of target nucleic acid. A second droplet formation or reinjection module inserts droplets that contain reagents for a PCR reaction. Such droplets generally include the “PCR master mix” (known to those in the art as a mixture containing at least Taq polymerase, deoxynucleotides of type A, C, G and T, and magnesium chloride) and forward and reverse primers (known to those in the art collectively as “primers”), all suspended within an aqueous buffer. The second droplet also includes detectably labeled probes for detection of the amplified target nucleic acid, the details of which are discussed below. Different arrangements of reagents between the two droplet types is envisioned. For example, in another embodiment, the template droplets also contain the PCR master mix, but the primers and probes remain in the second droplets. Any arrangement of reagents and template DNA can be used according to the invention.


Primers can be prepared by a variety of methods including but not limited to cloning of appropriate sequences and direct chemical synthesis using methods well known in the art (Narang et al., Methods Enzymol., 68:90 (1979); Brown et al., Methods Enzymol., 68:109 (1979)). Primers can also be obtained from commercial sources such as Operon Technologies, Amersham Pharmacia Biotech, Sigma, and Life Technologies. The primers can have an identical melting temperature. The lengths of the primers can be extended or shortened at the 5′ end or the 3′ end to produce primers with desired melting temperatures. Also, the annealing position of each primer pair can be designed such that the sequence and, length of the primer pairs yield the desired melting temperature. The simplest equation for determining the melting temperature of primers smaller than 25 base pairs is the Wallace Rule (Td=2(A+T)+4(G+C)). Another method for determining the melting temperature of primers is the nearest neighbor method (SantaLucia, “A unified view of polymer, dumbbell, and oligonucleotide DNA nearest-neighbor thermodynamics”, 1998, P.N.A.S., 95 (4): 1460-5). Computer programs can also be used to design primers, including but not limited to Array Designer Software (Arrayit Inc.), Oligonucleotide Probe Sequence Design Software for Genetic Analysis (Olympus Optical Co.), NetPrimer, and DNAsis from Hitachi Software Engineering. The TM (melting or annealing temperature) of each primer is calculated using software programs such as Oligo Design, available from Invitrogen Corp.


In one embodiment, the droplet formation modules are arranged and controlled to produce an interdigitation of sample droplets and PCR reagent droplets flowing through a channel. Such an arrangement is described U.S. Pub. 2008/0014589; U.S. Pub. 2008/0003142, and U.S. Pub. 2010/0137163.


A sample droplet is then caused to merge with a PCR reagent droplet, producing a droplet that includes the PCR master mix, primers, detectably labeled probes, and the target nucleic acid. Droplets may be merged for example by: producing dielectrophoretic forces on the droplets using electric field gradients and then controlling the forces to cause the droplets to merge; producing droplets of different sizes that thus travel at different velocities, which causes the droplets to merge; and producing droplets having different viscosities that thus travel at different velocities, which causes the droplets to merge with each other. Further discussion can be found in U.S. Pub. 2007/0003442.


In another embodiment, called simple droplet generation, a single droplet formation module, or a plurality of droplet formation modules are arranged to produce droplets from a mixture already containing the template DNA, the PCR master mix, primers, and detectably labeled probes. In yet another embodiment, called co-flow, upstream from a single droplet formation module two channels intersect allowing two flow streams to converge. One flow stream contains one set of reagents and the template DNA, and the other contains the remaining reagents. In the preferred embodiment for co-flow, the template DNA and the PCR master mix are in one flow stream, and the primers and probes are in the other. On convergence of the flow streams in a fluidic intersection, the flow streams may or may not mix before the droplet generation nozzle. In either embodiment, some amount of fluid from the first stream, and some amount of fluid from the second stream are encapsulated within a single droplet. Following encapsulation, complete mixing occurs.


Once final droplets have been produced by any of the droplet forming embodiments above, or by any other embodiments, the droplets are thermal cycled, resulting in amplification of the target nucleic acid in each droplet. In certain embodiments, the droplets are collected off-chip as an emulsion in a PCR thermal cycling tube and then thermally cycled in a conventional thermal cycler. Temperature profiles for thermal cycling can be adjusted and optimized as with any conventional DNA amplification by PCR.


In certain embodiments, the droplets are flowed through a channel in a serpentine path between heating and cooling lines to amplify the nucleic acid in the droplet. The width and depth of the channel may be adjusted to set the residence time at each temperature, which can be controlled to anywhere between less than a second and minutes.


In certain embodiments, the three temperature zones are used for the amplification reaction. The three temperature zones are controlled to result in denaturation of double stranded nucleic acid (high temperature zone), annealing of primers (low temperature zones), and amplification of single stranded nucleic acid to produce double stranded nucleic acids (intermediate temperature zones). The temperatures within these zones fall within ranges well known in the art for conducting PCR reactions. See for example, Sambrook et al. (Molecular Cloning, A Laboratory Manual, 3rd edition, Cold Spring Harbor Laboratory Press, Cold Spring Harbor, New York, 2001).


In certain embodiments, the three temperature zones are controlled to have temperatures as follows: 95° C. (TH), 55° C. (TL), 72° C. (TM). The prepared sample droplets flow through the channel at a controlled rate. The sample droplets first pass the initial denaturation zone (TH) before thermal cycling. The initial preheat is an extended zone to ensure that nucleic acids within the sample droplet have denatured successfully before thermal cycling. The requirement for a preheat zone and the length of denaturation time required is dependent on the chemistry being used in the reaction. The samples pass into the high temperature zone, of approximately 95° C., where the sample is first separated into single stranded DNA in a process called denaturation. The sample then flows to the low temperature, of approximately 55° C., where the hybridization process takes place, during which the primers anneal to the complementary sequences of the sample. Finally, as the sample flows through the third medium temperature, of approximately 72° C., the polymerase process occurs when the primers are extended along the single strand of DNA with a thermostable enzyme. Methods for controlling the temperature in each zone may include but are not limited to electrical resistance, peltier junction, microwave radiation, and illumination with infrared radiation.


The nucleic acids undergo the same thermal cycling and chemical reaction as the droplets passes through each thermal cycle as they flow through the channel. The total number of cycles in the device is easily altered by an extension of thermal zones or by the creation of a continuous loop structure. The sample undergoes the same thermal cycling and chemical reaction as it passes through N amplification cycles of the complete thermal device.


In other embodiments, the temperature zones are controlled to achieve two individual temperature zones for a PCR reaction. In certain embodiments, the two temperature zones are controlled to have temperatures as follows: 95° C. (TH) and 60° C. (TL). The sample droplet optionally flows through an initial preheat zone before entering thermal cycling. The preheat zone may be important for some chemistry for activation and also to ensure that double stranded nucleic acid in the droplets are fully denatured before the thermal cycling reaction begins. In an exemplary embodiment, the preheat dwell length results in approximately 10 minutes preheat of the droplets at the higher temperature.


The sample droplet continues into the high temperature zone, of approximately 95° C., where the sample is first separated into single stranded DNA in a process called denaturation. The sample then flows through the device to the low temperature zone, of approximately 60° C., where the hybridization process takes place, during which the primers anneal to the complementary sequences of the sample. Finally the polymerase process occurs when the primers are extended along the single strand of DNA with a thermostable enzyme. The sample undergoes the same thermal cycling and chemical reaction as it passes through each thermal cycle of the complete device. The total number of cycles in the device is easily altered by an extension of block length and tubing.


In another embodiment the droplets are created and/or merged on chip followed by their storage either on the same chip or another chip or off chip in some type of storage vessel such as a PCR tube. The chip or storage vessel containing the droplets is then cycled in its entirety to achieve the desired PCR heating and cooling cycles.


In another embodiment the droplets are collected in a chamber where the density difference between the droplets and the surrounding oil allows for the oil to be rapidly exchanged without removing the droplets. The temperature of the droplets can then be rapidly changed by exchange of the oil in the vessel for oil of a different temperature. This technique is broadly useful with two and three step temperature cycling or any other sequence of temperatures.


Release from Droplet


Methods of the invention may further involve releasing amplified target molecules from the droplets for further analysis. Methods of releasing amplified target molecules from the droplets are shown in publications and patents referenced above.


In certain embodiments, sample droplets are allowed to cream to the top of the carrier fluid. By way of non-limiting example, the carrier fluid can include a perfluorocarbon oil that can have one or more stabilizing surfactants. The droplet rises to the top or separates from the carrier fluid by virtue of the density of the carrier fluid being greater than that of the aqueous phase that makes up the droplet. For example, the perfluorocarbon oil used in one embodiment of the methods of the invention is 1.8, compared to the density of the aqueous phase of the droplet, which is 1.0.


The creamed liquids are then placed onto a second carrier fluid which contains a de-stabilizing surfactant, such as a perfluorinated alcohol (e.g. 1H,1H,2H,2H-Perfluoro-1-octanol). The second carrier fluid can also be a perfluorocarbon oil. Upon mixing, the aqueous droplets begins to coalesce, and coalescence is completed by brief centrifugation at low speed (e.g., 1 minute at 2000 rpm in a microcentrifuge). The coalesced aqueous phase can now be removed and the further analyzed.


The released amplified material can also be subjected to further amplification by the use tailed primers and secondary PCR primers. In this embodiment the primers in the droplet contain an additional sequence or tail added onto the 5′ end of the sequence specific portion of the primer. The sequences for the tailed regions are the same for each primer pair and are incorporated onto the 5′ portion of the amplicons during PCR cycling. Once the amplicons are removed from the droplets, another set of PCR primers that can hybridize to the tail regions of the amplicons can be used to amplify the products through additional rounds of PCR. The secondary primers can exactly match the tailed region in length and sequence or can themselves contain additional sequence at the 5′ ends of the tail portion of the primer.


During the secondary PCR cycling these additional regions also become incorporated into the amplicons. These additional sequences can include, but are not limited to: adaptor regions utilized by sequencing platforms for library preparation; barcode sequences for the identification of samples multiplexed into the same reaction; molecules for the separation of amplicons from the rest of the reaction materials (e.g., biotin, digoxin, peptides, or antibodies); or molecules such as fluorescent markers that can be used to identify the fragments.


In certain embodiments, the amplified target molecules are sequenced. In a particular embodiment, the sequencing is single-molecule sequencing-by-synthesis. Single-molecule sequencing is shown in U.S. Pat. Nos. 7,169,560; 6,818,395; 7,282,337; U.S. Pub. 2002/0164629; and Braslaysky, et al., PNAS (USA), 100: 3960-3964 (2003), the contents of each of these references are incorporated by reference herein in its entirety.


Briefly, a single-stranded nucleic acid (e.g., DNA or cDNA) is hybridized to oligonucleotides attached to a surface of a flow cell. The single-stranded nucleic acids may be captured by methods known in the art, such as those shown in U.S. Pat. No. 7,666,593. The oligonucleotides may be covalently attached to the surface or various attachments other than covalent linking as known to those of ordinary skill in the art may be employed. Moreover, the attachment may be indirect, e.g., via the polymerases of the invention directly or indirectly attached to the surface. The surface may be planar or otherwise, and/or may be porous or non-porous, or any other type of surface known to those of ordinary skill to be suitable for attachment. The nucleic acid is then sequenced by imaging the polymerase-mediated addition of fluorescently-labeled nucleotides incorporated into the growing strand surface oligonucleotide, at single molecule resolution.


II. Barcode-Type Labels


Barcode Sequences


The invention provides labels for target materials comprising a detectable barcode-type label. A detectable barcode-type label can be any barcode-type label known in the art including, for example, radio-frequency tags, semiconductor chips, barcoded magnetic beads (e.g., from Applied Biocode, Inc., Santa Fe Springs, CA), and nucleic acid sequences. In certain embodiments, a barcode-type label is a nucleic acid construct such as a nucleic acid construct including a barcode-type sequence (e.g., a unique N-mer). A construct of the invention generally includes a functional portion. Thus, a barcode sequence generally refers to a nucleic acid construct that includes at least a unique N-mer portion and a functional N-mer portion. For example, the unique N-mer portion can be used to tag—by means of its unique sequence information—any target material labeled with that construct. The functional N-mer portion may be used to attach the construct to a target (e.g., cells, proteins, nucleic acids, other molecules, solid substrates, and other barcode constructs). Where, for example, the target material includes nucleic acid, the functional N-mer can include a complementary nucleic acid (primer, hexamer, randomer, universal primer, etc.) to hybridize to the target. In some embodiments, the unique N-mer (“barcode sequence”) is attached to the functional N-mer (e.g., “primer”) such that the barcode sequence is incorporated into a 5′ end of the primer. Alternatively, the barcode sequence may be incorporated into the 3′ end of the primer.


In some embodiments, more than one type of barcode-type label are included, for example, to be cross-combined. In one illustrative embodiment, nucleic acid constructs of the invention are combined (e.g., a set of constructs is cross combined one of each at a time with a set of other labels) with a labels of another type, such as magnetic barcoded beads from Applied BioCode.


The functional N-mer can operate as a primer sequence or sticky end to hybridize to nucleic acid. Functional N-mers can be designed to favor hybridization under certain conditions. For example, length or GC content can be varied to favor high-temperature (or stringent) conditions. Where a nucleic acid construct (barcode) will be made with sticky ends to append to other constructs, the melting temperature of the sticky ends can be tuned, for example, by tuning the length of those ends. No particular length is required in general, so any given length can be chosen based on intended melting temperature or other design considerations.


Attaching barcode sequences to nucleic acids is shown in U.S. Pub. 2008/0081330 and PCT/US09/64001, the content of each of which is incorporated by reference herein in its entirety. Methods for designing sets of barcode sequences and other methods for attaching barcode sequences are shown in U.S. Pat. Nos. 6,138,077; 6,352,828; 5,636,400; 6,172,214; 6,235,475; 7,393,665; 7,544,473; 5,846,719; 5,695,934; 5,604,097; 6,150,516; RE39,793; 7,537,897; 6,172,218; and 5,863,722, the content of each of which is incorporated by reference herein in its entirety.


Barcode sequences typically include a set of oligonucleotides ranging from about 4 to about 20 oligonucleotide bases (e.g., 8-10 oligonucleotide bases), which uniquely encode a discrete library member preferably without containing significant homology to any sequence in the targeted genome. The barcode sequence generally includes features useful in sequencing reactions. For example the barcode sequences are designed to have minimal or no homopolymer regions, i.e., 2 or more of the same base in a row such as AA or CCC, within the barcode sequence. The barcode sequences are also designed so that they are at least one edit distance away from the base addition order when performing base-by-base sequencing, ensuring that the first and last base do not match the expected bases of the sequence.


Synthesis of oligonucleotides for use as constructs (e.g., barcodes or functional portions) can be by any means known in the art. Oligonucleotides can be synthesized on arrays, or in bulk, for example.


In certain embodiments, the barcode sequences are designed to be correlated to a particular patient, allowing patient samples to be distinguished. The barcode sequences incorporated into a plurality of primers (and subsequently into DNA or RNA targets) within a single droplet may be the same, and vary from droplet to droplet. Alternatively, the barcode sequences incorporated into the plurality of primers (and subsequently into DNA or RNA target) within a single droplet may be different. Designing barcodes is shown U.S. Pat. No. 6,235,475, the contents of which are incorporated by reference herein in their entirety. In certain embodiments, the barcode sequences range from about 2 nucleotides to about 25 nucleotides, e.g., about 5 nucleotides to about 10 nucleotides. Since the barcode sequence is sequenced along with the template nucleic acid to which it is attached, the oligonucleotide length should be of minimal length so as to permit the longest read from the template nucleic acid attached. Generally, the barcode sequences are spaced from the template nucleic acid molecule by at least one base (minimizes homopolymeric combinations).


Methods of the invention include attaching the barcode sequences to a functional N-mer such as a primer, then incorporating the barcode into a target, or portion thereof using, for example, multiple displacement amplification. The labeled strands produced by MDA are able to be fragmented or sheared to desired length, e.g. generally from 100 to 500 bases or longer, using a variety of mechanical, chemical and/or enzymatic methods. DNA may be randomly sheared via sonication, e.g. Covaris method, brief exposure to a DNase, or using a mixture of one or more restriction enzymes, or a transposase or nicking enzyme. RNA may be fragmented by brief exposure to an RNase, heat plus magnesium, or by shearing. The RNA may be converted to cDNA before or after fragmentation.


Barcode Droplet Libraries


In certain embodiments, the invention provides libraries of barcodes in droplets, as well as methods of making and using them. Making a barcode library is shown in FIGS. 5A-FIG. 9B. A barcode droplet library generally is a set of droplets containing barcodes (e.g., unique N-mers) for incorporation into a target molecule. Barcodes can be provided in an oligonucleotide containing sequence to function as an amplification primer with the result that a nucleic acid subsequently introduced into the droplet will be amplified, and the copies that result will include the barcode of that droplet. However, barcodes can also be provided that are used to label proteins or other molecules of interest.


In various embodiments, there is a distinction between a droplet library that is used directly with samples (function N-mer is PCR primer, random hexamer, etc), and a library that can be used either for continued building of higher complexity composite barcodes, or directly with samples that have been prepared to contain appropriate sticky-ends (functional N-mer is a sticky end; the haplotyping with annealed samples is one example of this case).


Regardless of the library type, the functional N-mer can be chosen based on a type of target material. For example, for barcoding antibodies, one set of antibodies could all have a sticky-end that binds one class of barcodes, and another antibody set would have a different sticky end, for example, to bind a capture tag. In another example, a set of barcoded PCR primers could include one forward/reverse pair that could bind to one class of barcodes and a different ‘universal’ forward/reverse pair that binds to a different class of barcodes (with the compliment to the second for/rev pair).


Barcodes can be provided as oligonucleotides as discussed above. In certain embodiments, a barcode is provided as part of a tripartite construct (e.g., as shown in FIG. 7A-B) including a universal priming site, a barcode, and a sequence specific region. The sequence specific region can provide a PCR primer of known sequence, a random hexamer for MDA, or any other suitable nucleotide sequence that will bind to target. In other embodiments, the invention provides universal barcode libraries (e.g., droplets that each contain a plurality of universal primers or priming sites all having a single unique barcode, but without a sequence-specific region). A universal barcode generally includes a unique N-mer and a sticky end.


For creation of a library, a number of different barcodes will be obtained. For any given length, L, in nucleotides, the number N of unique barcodes that can be made using standard nucleotides (A, T, C, G) is given by N=4L. It can be seen by simple calculation, for example, that if barcodes are to be five nucleotides long, then 1,024 unique barcodes are possible. Six, seven, and eight nucleotides in a barcode allow for 4096, 16384, and 65536 unique barcodes, respectively. If each barcode includes 10 nucleotides, then more than one million unique libraries can be made. At 15 nucleotides, then N is greater than one billion. Combining such barcodes using sticky ends (shown in FIGS. 5A-B) gives N′=N×N. In creating a barcode droplet library, a number of droplets are formed, each preferably containing copies of a uniquely-barcoded construct.


For embodiments in which primer pairs are used, for example, where target nucleic acid is to be amplified using PCR, one step of creating a barcode droplet library involves creating a forward library. In a tripartite construct-based embodiment, each droplet in the forward library will contain a plurality of copies of uniquely-barcoded tripartite “forward” primers. That is, each tripartite construct in the forward library will comprise 5′-universal forward tail-barcode-forward primer-3′. While any number of droplets can be made in the forward library, in a preferred embodiment, the forward library contains sets that include a number of droplets equal to or less than the number of possible unique barcode given the number of nucleotides in each barcode. Thus, if a six nucleotide barcode is to be used, sets of approximately 4,000 droplets (or any arbitrarily-lower number) can be made.


A corresponding number of reverse tripartite constructs can be made (e.g., universal reverse tail-barcode-reverse primer). Then, microfluidic methods and devices as discussed herein can be used to add reverse constructs to each droplet containing forward constructs. Forward and reverse constructs can be put into droplets together in a variety of ways. For example, the forward and reverse constructs can be put into droplets a single well at a time. In some embodiments, flowing microfluidic systems are used. For example, a stream containing reverse constructs can be merged with a stream containing the forward droplets. As each droplet passes the merge point, the reverse construct is added.


Forward and reverse constructs can be put together randomly, or they can be put together in a serial fashion. In a serial approach, the first reverse construct can be added to all droplets (e.g., about 4,000) of a set of forward droplets by flowing those droplets through the merge point. Then, the second reverse construct can be used, and the steps repeated. A second complete set of forward droplets can be streamed into the second reverse construct, thereby creating 4,000 droplets, each of which contains a unique forward primer and the second reverse primer construct. After this process is repeated 4,000 times, 4,000×4,000 droplets will have been made, each containing uniquely-barcoded primer pairs (e.g., as tripartite constructs). Production of a large barcode library by these means need not include tripartite constructs and can use any constructs that include barcodes (e.g., primer pairs+barcodes; random hexamers+barcodes; universal primers+barcodes; etc.).


Where primer pairs are used, any number of primers or primer pairs can be used. Where a large number of cells will be assayed for information about a single locus of interest, a single PCR primer pair may be used in a large barcode droplet library. Where a barcode droplet library will be used to assay a number X of loci on a plurality of genomes, X primer pairs will be used. Where MDA will be used to amplify one or more target regions, a number of random hexamers will be used according to calculations discussed elsewhere.


In certain embodiments, only one type of construct is provided per droplet (i.e., forward only or reverse only, without a corresponding reverse). Thus, methods of the invention include preparation of barcode droplet libraries in which each droplet contains a single barcoded construct without a corresponding partner-pair barcode.


In certain embodiments, primers for an initial round of amplification are universal primers, for example, where the target to be amplified includes universal priming sites.


As discussed elsewhere herein, droplets of the invention are stable when stored. Thus a barcode droplet library can be prepared having any arbitrarily large size and stored to be later used in any of the suited assays described herein or known in the art.


In some embodiments, the invention provides methods involving a two-step “drop” PCR wherein multiple sets of primers are provided in a droplet. Either, both, or neither set of primers can include barcodes. Target material is added to the droplet. A first round of amplification is performed, and then a condition is changed, and amplification is performed again. For example, low-stringency conditions are created for the first amplification, through manipulation of temperature or chemical environment. Thus, even though other primers are present, an intended first set of primers outcompetes or predominates in amplification. By these means, target nucleic acid can be amplified and barcoded in multiple steps.


As discussed above, a barcode library generally includes constructs having a functional N-mer and a unique N-mer. In some embodiments, a functional N-mer is a sticky end.


The invention provides methods and materials to generate large, complex, or extensible barcode libraries, and applications for barcode libraries.


In order to facilitate generation of a sufficiently high number of barcoding oligonucleotide species for labeling a wide range of molecules, particles, or cells, one can generate a “Universal Barcoding Droplet Library” for combining with samples. This reagent can be used to barcode DNA, RNA, proteins, chemicals, beads or other species present in the sample if they contain complimentary binding moieties.


The concepts for generation and use of a droplet library for massively parallel molecular barcoding apply to all forms of binding agents that can have a readable identifying barcode appended. Expanded ‘plex’ for barcode identifiers is provided via the use of barcodes in droplets, such that one barcode can be linked to other barcodes via one or more library combinations, resulting in multiplicatively larger sets of unique barcodes.


In certain embodiments, antibodies or oligonucleotides are used as functional N-mers for binding to sample molecules with (optionally releasable) unique N-mers as barcodes. Both the types and numbers of each type of barcodes are determined by a digitally quantified readout, and thus correlated with the presence and concentration of various biomarker species in a sample.


Two basic types of universal barcoding droplet libraries are described as examples of the general concept for providing a means to append unique barcodes to target material for identification or quantification, but the concept is not limited to these examples and at least one example will be given where the two described library types are used together.


In the first set of examples, a universal binding barcode droplet library is described for use in a ‘bind and ligate’ approach (see FIG. 6). This library type consists of droplets containing oligonucleotide strands that encode barcodes and contain ligation competent ends, enabling the modular linking of barcodes by specific hybridization (also referred to as ‘annealing’ or ‘binding’) in droplets followed by ligation into a covalently bonded strand (or duplex) of bases. The Universal Binding Barcode Droplet Library can be used directly with samples that contain pre-bound barcoded binding moieties, as a ‘primary’ library that is combined with binding moieties targeting specific sample molecules, or can be used in the construction of ‘secondary’ or higher order binding barcode libraries through the successive combination of droplet libraries. The end use of such libraries can include assembly of the barcoded specific binding agents into a release-able and readable single molecule for use in digital quantification of bound targets for a variety of applications.


In the second set of examples, a universal priming barcode droplet library is described for use in a ‘bind and prime’ approach. FIGS. 7A-B show one example of a universal barcode droplet library with targeting primers (e.g., to “bind and prime”). This library type consists of droplets containing barcoded primers for PCR (or other polymerase) priming, such that after combination with a sample droplet containing at least one target sequence from the same single DNA or RNA molecule, or multiple molecules co-localized in a single droplet, a digitally readable oligonucleotide barcode is attached to the target molecule's sequence. Since all polymerase generated molecules in the same droplet will have the same barcode, the co-localization information is retained after release from the droplet, and any sequencer can be used to both determine the sequence and count the number of templates traceable to each original droplet.


Both library types enable molecular barcoding in droplets, providing a large excess of unique identifying barcodes compared to the number of sample droplets, or compared to the number of sample objects or molecules contained in the droplets, thus allowing digital quantification of many targets of interest on various reading platforms. Significantly, the two types are not exclusive of each other. For example, FIG. 9A-B shows ligating sticky-ended universal barcodes to barcoded PCR primers.


Sticky End Libraries



FIGS. 5A-B show the overall scheme for construction of a universal binding barcode droplet library. Pairs of overhanging complimentary oligonucleotide barcodes are chemically synthesized (using standard commercial manufacturing methods) such that the complementary barcoding sequences are flanked by ‘sticky-ends’ for subsequent annealing and ligation to the target species or other barcodes, or for polymerase or other enzymatic priming. The oligonucleotides may include 5-prime or 3-prime phosphorylation, or combinations of these or other modifications. Methods to make oligonucleotides resistant to nuclease activity may be used, including the use of 2′O-Methyl RNA bases and/or phosphorothioated bonds to form the entire backbone of the oligo or to cap the ends of the sequence. PNA, LNA, or other modified nucleotide structures can also be used. A sticky-end may be any length and sequence, with preferred embodiments containing base pairs including restriction endonuclease cleavage sites, or priming sites for sequencing or digital PCR, or array hybridization, and any number of sticky-ends with different sequences can be utilized. Sticky-end sequences may be used as barcode identifiers as part of composite barcodes.


Two example barcoded oligonucleotide pairs are shown in FIGS. 5A-B (1a and 2a, flanked by sticky-end Type1 and sticky-end Type2). To construct a droplet library each discrete complementary oligonucleotide pair can be placed together into a standard microtiter-plate well and formed into droplets, which can be subsequently mixed with other oligonucleotide pair-containing droplets to make a ‘primary barcode droplet library’. Forming droplets for a library is discussed in U.S. Pub. 2010/0022414. The number of pair types (N members) is not limited.


These storable stable droplets can either be used directly as an N-member barcoding library, or combined with another barcoding oligonucleotide set (M-members) to form a ‘tandem’ barcoded library with N×M=NM-plex. A 4000 N-member library combined with a 4000 M-member library will generate a 16 million-plex barcode library.


Combination of the N-member primary barcode library with the M secondary barcodes can be done in series (with each member of the M-barcode combined as an aqueous liquid one at a time with the N-member primary barcode library, using various methods including lambda or pico-injection modes and co-flow) or by combining the N-member and M-member library droplets in parallel (primary library combined with secondary library).


Heterogeneous mixtures of barcodes (e.g. barcodes synthesized using degenerate bases) can be converted into a unique set of droplet barcodes by addition of a unique sticky-end. Manipulation of droplets is described in U.S. Pat. No. 7,718,578 and U.S. Pub. 2011/0000560.


By combining complimentary sticky-ends from two barcode sets, the four oligonucleotide types present in the final combined droplet will specifically hybridize to create a sticky-ended tandem barcode (e.g., droplet 1 or 2 in FIG. 5A-B). This can then be ligated together. A similar specific hybridization will occur for additional numbers of barcodes containing complimentary sticky-ends. This is illustrated in FIG. 6A-B, with ‘single sticky-ended’barcoded oligonucleotide pairs shown on the left, where one end is capped such that there is no overhang, and ‘double sticky-ended’ barcode oligonucleotides shown in the middle panel (either different or similar sticky-ends can be used, with different ends precluding promiscuous concatamer formation). Additional modifications of the sticky-ends can also be included (e.g. biotin or desthiobiotin, shown on the bottom left of the figure).


After annealing the sticky ends together, adjacent strands can be ligated together.


The panel on the right of FIGS. 6A-B shows the initial binding barcode droplet library (only one droplet and one molecule of each type shown, with a barcode identifier 1a) on the top, a tandem barcoded droplet library formed by combination of a primary barcode and a secondary barcode in the middle (e.g. barcode identifier 1a:1b), and a triple barcoded library at the bottom (formed by combining a secondary barcoded library with a third barcode, resulting in barcode identifier 1a:1b:1c).


This modular construction is not limited to the combinations shown, with any composite sticky-ended barcode library able to be combined with additional barcodes in subsequent rounds of droplet combination. Even a low number of combinations can result in a very high level of barcode-plex.


For example, a 16 million-plex tandem barcode library (made from 4000 N×4000 M barcoded oligos) can be combined with another sticky-ended set of 4000 Z barcoded oligos to form a 64 billion-plex barcode library (16 million NM members×4000 Z-members=64 billion). As shown in FIGS. 6A-B, the oligonucleotides can be designed such that the resulting annealed oligo set can have a single or double sticky-ends (with different or similar ends).


A barcode library can also be made to include a sticky-end adapter specific for a sequencing platform. In certain embodiments, a construct is made that includes a sequencing platform N-mer and a sticky-end N-mer. A library of these constructs can be made. Separately, a universal barcode library as discussed above can be made. The, the universal barcode library can be combined with the sequencing platform adapter library by means of the sticky ends in view of a particular application. Thus products of any analysis discussed herein can be adapted to go directly into the workflow of any given sequencing platform (e.g. sticky-ended Illumina adaptors to anneal/ligate onto either the primer library or the output from a targeted sequencing run, so that it could be hybridized directly onto their flow cell. A different sticky-end adaptor set could be used for 454, etc.). This approach can minimize PCR bias.


A universal PCR primer barcode library can also be prepared with an unlimited amount of plex by creating sticky-ended forward and reverse primers that can be further combined with additional numbers of sticky-ended barcodes to generate combinatorial barcodes, as shown at the top of FIGS. 9A-B. The forward and reverse universal primers are constructed in an identical fashion as described above and in FIGS. 7A-B (primary barcoded primers) and then annealed to a sticky-ended barcode oligonucleotide pair (either single or double sticky-ended as shown in FIGS. 5A-B) and subsequently ligated, to make a contiguous forward (and/or reverse) primer annealed to the complimentary oligo that was used to anneal to the primary barcoded primer. The top right side of FIGS. 9A-B shows the ligated product after addition of both forward and reverse single sticky-ends to create a ‘secondary’ barcoded priming set. The bottom of FIGS. 9A-B shows a single droplet after combination of one prepared template-containing sample droplet with one universal PCR primer barcode library droplet. The annealed PCR primers can be amplified by using polymerase and dNTPs, and all of the amplicons from this droplet will be barcoded 1b:1a:1a:1b (with 1b:1a 5-prime to the target loci sequence, followed by 1a:1b, as read 5-prime to 3-prime).


Haplotype Phasing


The invention provides systems and methods for haplotype phasing and genotyping. A nucleic acid can be isolated from a sample and haplotyped through the examination of a number of loci. For example, the allelic form present for a number of suspect SNPs of interest can be determined along a single chromosome. By including barcodes in multiplexed tiled PCR reactions within droplets, this aspect of the invention enables ‘haplotype phase’ assignments to be made using existing sequencing platforms.


Several aspects of the invention are combined to enable assignment of sequencing information (e.g., a series of SNPs) to target DNA stretches. In certain embodiments, haplotype phasing involves preparing a barcode droplet library in which each droplet contains the set of primers to amplify the loci of interest. Preferably, each primer is part of a tripartite construct that also includes a universal priming site (for subsequent amplification, capture, or sequencing) and a barcode. In each droplet, every tripartite construct will preferably contain the same barcode. Multiplexed PCR primers that will not cross-hybridize with each other and which will uniquely amplify the target DNA locus can be used.


The overall workflow example is shown in FIG. 10A-B. Optionally, the target locus can be pre-amplified using a single pair of PCR primers that flanks the entire locus, before appropriate loading of the sample into droplets for amplification and barcoding (not depicted in the workflow in FIG. 10A-B).


Preferably, each tripartite construct includes a universal tail portion immediately 5′ to a barcode sequence followed by the sequence-specific targeting primer bases. A primer droplet library ‘member’ includes a droplet that contains all of the targeted primers sufficient for covering the target bases, each with the same barcode that will enable post-sequencing correlation to the target strand. The number of library members is determined by the ratio of barcode number to the number of target alleles to be analyzed. By way of example, without limitation, FIG. 10A-B shows 100 cells as input, with 4000 barcodes giving a 1/10 chance of duplicate barcodes for any allele. In this example, the DNA from 100 cells provides 400 target alleles, which are loaded (together with polymerase, buffer, and nucleotides) into one million droplets and combined with the barcoding primer library to generate a PCR-competent droplet emulsion. As an example for a 3 kb target region, 13 tiled primer pairs can be used to cover the target bases. Fewer primer pairs can be used if only subsets of the target bases are to be phased.


Droplets from the droplet library are merged with target nucleic acid. In the example pictured in FIG. 10A-B, genomic DNA has been sheared to a length of about 20 kilobases. Fragments of the target are introduced into droplets such that on average each droplet will generally contain no more than one molecule of target nucleic acid.


After this merging step, each droplet contains at least: a pair of tripartite constructs for each locus of interest; a single nucleic acid molecule; and PCR reagents (e.g., Taq, dNTPs). Each droplet is then thermocycled, producing numerous copies of each locus of interest in which each of those copies has a unique pair of barcodes at each end.


Droplet libraries are generally discussed herein as having pairs of barcodes and in some embodiments those barcodes may be necessarily the same or different, while in other embodiments, it may not matter whether the forward and reverse barcodes are the same or different. For example, if barcodes have six nucleotides, and millions of targets are to be analyzed, then using different forward and reverse barcodes will create ample unique barcode pairs. Here, an embodiment of haplotype phasing is presented in which the forward and reverse barcodes need not be the same. In some embodiments, those bar codes may be the same.


After thermocycling, the amplified products are released into a single bulk aqueous phase (e.g., using a droplet de-stabilizing reagent), and a subsequent amplification, sequencing, or capture is performed using the universal primer tail as well as any sequencing platform-specific adaptor (and additional barcodes) needed before sequencing. Examples of the PCR inputs and outputs are shown in FIG. 11A-C. Using a yield threshold of ˜150 sequencing reads as being more than sufficient for high confidence SNP calling, the total number of PCR cycles (droplet PCR plus bulk PCR) can be limited to 10 cycles (sufficient to generate 150 copies).


The amplified products are then sequenced according to any method known in the art including those discussed herein. Even though, in certain embodiments, the amplified products are provided for sequencing in a bulk aqueous phase, sequencing results can be haplotyped based on the presence of the barcode in the sequence reads. Particularly in embodiments in which the barcode is immediately 3′ to a sequencing primer binding site, every sequence read will have barcode information.


In certain embodiments, genetic material is haplotyped without amplification as shown in FIG. 15A-FIG. 17B. FIG. 8A-B shows the overall scheme for construction of a universal priming barcode droplet library for use in a ‘Bind and Primer Extend’ application (addition of sticky end component on right of FIG. 8A-B is optional). Primers as shown in FIG. 8A-B can be used as shown in FIGS. 15A-1B to provide haplotype information without amplification. In this example, a the initial ‘primary’ droplet library contains single universal priming barcodes for primer extension, constructed using similar methods as that described for construction of a universal binding barcode droplet library. Contiguous oligonucleotides are chemically synthesized with each of the sequence components including a universal forward tail (consisting of bases to be annealed to an analogous sticky-end), a sequence of bases used as a barcoding component, and a priming sequence that will anneal to the universal 5-prime end of the target sequence to be counted (the complimentary target is designated as ‘for’ in, for example, FIG. 15A-FIG. 17B).



FIG. 15A-B shows up-front processing for haplotyping a single molecule of DNA using a universal priming barcode library. A forward primer is used with a corresponding oligonucleotide (here labeled 3′ Tailed primer). Note that the corresponding 3′ oligonucleotide need not function as a primer. For convenience, they will be referred to as primers. To prepare for target molecule haplotyping, a set of specific targeting primers are prepared and annealed to the target DNA, with a 5′ oligonucleotide comprising oligonucleotides complimentary to the 5′ end of the target locus (3 loci are shown in FIG. 15A-B) and a universal ‘for’ sequence that will be used to anneal to the barcode library, and a 3-prime oligo comprising oligos complimentary to the 3-prime end of the target locus followed by a universal 3-tailed end. The target molecule to be haplotyped can be targeted by any number of primer pairs and targeted loci can be any distance from other loci (the shear length of the genome will limit the maximum distance that can be haplotyped).


Each of the uniquely barcoded primers can be reformatted from a well plate into a droplet format, either for direct use with samples or to be used in optional subsequent rounds of droplet combination to add complimentary sticky-ended barcoding sequences (right side of FIG. 8A-B, also shown in right side of FIG. 9A-B). Combination of the primary ‘forward barcode library’ with sticky-ended barcodes (either serial or library combination) provides another barcode encoding level. Alternatively, the primary droplet library can be generated from pairs of primers initially placed together in wells and reformatted into droplets, with a sticky-ended barcode oligo together with various forward barcoded primers. Additional rounds of droplet combination with either single or multiple sets of sticky-ended barcode members can be used to get to any required level of barcode-plex needed for the assay.


A universal priming barcode library having sufficient plex to uniquely barcode the sample targets is used by combination and annealing to target molecules that have been either prepared in bulk or in droplets (bulk prep is shown in FIG. 15A-B).


Hybridization of all of the targeting primer pairs with the target sample is followed by removal of unbound primers (e.g. purification by size or via use of biotinylated primers or targets), elongation of the forward hybridized primer for each locus using a polymerase (e.g. Klenow) that lacks exonuclease activity such that the elongation stops when the polymerase encounters the 3-prime primer, and subsequent ligation using ligase and ATP or photo-ligation or other ligation means. The resulting bulk sample preparation contains the target single stranded molecules with each targeted loci annealed to a contiguous oligonucleotide strand that contains the newly synthesized compliment to the target loci bracketed by the added primer pairs.


This output of the process shown in FIG. 15A-B is the target which the nucleic acid constructs (primers) shown in FIG. 16A-B bind to.


The bulk annealed sample prep is loaded into droplets, along with polymerase and dNTPs, such that a single contiguous molecule with its set of targets to be haplotyped is contained in a droplet. The Universal Barcode Library is combined with the prepared sample, either in a droplet to droplet combination mode, or in a droplet to aqueous stream combination mode (shown in FIG. 16A-B). FIG. 16A-B shows introducing primer pairs, each bearing a barcode.


As shown in FIG. 16A-B, a pair of primers for each locus of interest is incubated with a strand of target DNA and allowed to hybridize. Any unbound (un-hybridized) material is removed. The two forward ‘for’ primers can be elongated either inside droplets that include the polymerase and dNTPs, or following release of the primers annealed to the template (the workflow in FIG. 17A-B shows release before elongation outside of droplets). Polymerase synthesizes a complementary strand from the 5′ forward primer to the 3′ “reverse primer”. Ligase then ligates the complementary strand to the 3′ reverse primer. As a result, a complementary strand has been synthesized representing each locus of interest.


The droplets can be lysed (or “burst”, discussed elsewhere herein), and the contiguous strands (e.g., barcoded amplicons) released into bulk phase as shown in FIG. 17A-B.


The resulting contiguous strands containing barcodes are used for sequencing (or sequence determination using microarrays), and the sequences that contain identical barcodes have sequences that derive from the same sample strand (i.e. the same haplotype). This example shows a method for haplotype determination without any amplification (i.e. only elongation and ligation), and has the advantage of elimination of potential amplification bias. In addition, if a locus has copy number variation within the same sample target molecule, this can be seen as variation in the number of sequenced reads that have the same barcode and sequence.


In contrast to the “no-amplification” haplotype methods, the invention also provides methods for single-molecule haplotyping that include amplification. In certain embodiments, amplicons can provide target material according to a “bind and primer PCR” approach.



FIGS. 7A-B show the overall scheme for construction of a Universal Priming Barcode Droplet Library for use in a ‘PCR’ version of the haplotyping application, which provides haplotype information with amplification. In this example, the initial droplet library contains single ‘forward’ universal priming barcodes that will be subsequently paired with a ‘reverse’ barcoded primer to create a Universal PCR Primer Barcoded Droplet Library. Contiguous oligonucleotides are chemically synthesized with each of the sequence components including a universal forward tail (consisting of bases to be used as priming sites or for ligation to adaptors used for sequencing), a sequence of bases used as a barcoding component, and a forward priming sequence that will anneal to the universal 5-prime end of the target sequence to be counted (the complimentary target is designated as ‘for’ in FIG. 12A-FIG. 14B). Each of the uniquely barcoded primers is reformatted from a well plate into a droplet format. Combination of the forward primer barcoded droplet library with similarly constructed reverse primer barcodes (either serial or library combination, with the serial mode shown in FIG. 7A-B) generates the universal PCR primer barcoded droplet library. Alternatively, the a PCR primer droplet library can be generated from pairs of forward and reverse primers initially placed together in wells and reformatted into droplets, however this type of library will have the same number of unique forward/reverse barcode combinations as the number of paired primers wells.


A universal priming barcode library having sufficient plex to uniquely barcode the sample targets is used by combining with samples and annealing to complimentary target molecules present in the sample. An example sample preparation scheme is shown in FIG. 12A-B. To prepare for target molecule haplotyping, a set of specific targeting oligos are prepared and annealed in bulk phase to the target DNA, with a 5-prime oligonucleotide comprising oligonucleotides complimentary to the 5-prime end of the target locus (3 Loci present on the same contiguous target molecule are shown being targeted for haplotyping) and a universal ‘for’ sequence that will be used to anneal to the Universal Priming Barcode Library, and a 3-prime oligo comprising oligos complimentary to the 3-prime end of the target locus followed by a universal 3-tailed end. The target molecule to be haplotyped can be targeted by any number of primer pairs, and the targeted loci can be any distance from each other (the shear length of the genome will limit the maximum distance that can be haplotyped). Hybridization of all of the targeting primer pairs with the target sample is followed by removal of unbound primers (e.g. purification by size or via use of biotinylated primers or targets), elongation of the forward hybridized primer for each locus using a polymerase (e.g. Klenow) that lacks exonuclease activity such that the elongation stops when the polymerase encounters the 3-prime primer, and subsequent ligation using ligase and ATP or photo-ligation or other ligation means (bottom of FIG. 12A-B). The resulting bulk sample preparation contains the target single stranded molecules with each targeted loci annealed to a contiguous oligonucleotide strand that contains the newly synthesized compliment to the target loci bracketed by the added primer pairs.


Use of the universal PCR barcode primer library with prepared sample is shown in FIG. 13A-B. The bulk annealed sample prep is loaded into droplets, along with polymerase and dNTPs, such that a single contiguous molecule with its set of targets to be haplotyped is contained in a droplet. The universal barcode library is combined with the prepared sample, either using a droplet to droplet combination mode, or in a droplet to aqueous stream combination mode (shown in FIG. 13A-B).


The two forward ‘for’ complimentary base pairs are allowed to hybridize (two droplets from a combined library and sample are shown in FIG. 13A-B, and elongated either inside droplets that include polymerase and dNTPs, or following release of the primers annealed to the template (the workflow in FIG. 14A-B shows release before elongation outside of droplets), followed by ligation of the 3-prime primer to the elongated strand. The resulting contiguous strands shown on the right side of FIG. 14A-B containing barcodes are used for sequencing (or sequence determination using microarrays), and the sequences that contain identical barcodes have target loci sequences that derive from the same sample strand (i.e. the same haplotype phase).


Single Cell Genomics


Genotyping of single cells can be performed in a fashion similar to haplotyping discussed above. FIG. 18A-B depicts the steps associated with isolation, encapsulation, molecular labeling, sorting and analysis of single cell genomes using fluidic droplets (including optional upfront sorting, and cell lysis within droplets using a detergent and heat).


Preferably a first library of droplets is formed, each droplet containing genetic or proteomic material (e.g., from a single cell, or a portion thereof). In certain embodiments, single cell droplets are created and then the cells are lysed within the droplets.


The droplets can be merged with droplets from a barcode droplet library (e.g., containing nucleic acid constructs in which the functional N-mers are primer oligonucleotides to hybridize to the genome of the single cell). As a result, each droplet will contain at least: the entire genome from a single cell; nucleic acid constructs for hybridizing to the genome of interest with a barcode; and analysis reagents (e.g., polymerase and nucleotides).


A second library of droplets is formed, each containing a plurality of N-mers, each N-mer containing an associated label. In a preferred embodiment, each droplet in the second library of droplets contains the same label within the given droplet, and the labels preferably vary from droplet to droplet. Each droplet in the second library further contains reagents for the replication of the genetic material in the first droplet and subsequent incorporation of the tag. The replication can be DNA from DNA or DNA from RNA (cDNA). There can be a single replication of the genetic material, there can be a linear amplification of the genetic material or an exponential amplification of the genetic material such as PCR or multi-strand displacement amplification. The reagents for conducting the replication can include such things as polymerase, reverse transcriptase, nucleotides, buffers, etc.).


Alternatively, the second droplet could contain beads which are designed to capture the target nucleic acid. Capture sequences with a tag can be attached to bead and used to capture the genetic material from the first droplet introduced after merging with the second droplet. The capture sequence with the tag can be synthesized directly onto the beads or be attached by such means as biotinylated sequences and streptavidin beads. The use of streptavidin beads and biotinylated sequences has the advantage of allowing a generic bead to be used with new libraries of biotinylated capture sequences that can be assembled on demand. However, any method known in the art for attaching nucleic acid sequences to beads can be utilized.


Alternatively, the second droplet could contain capture sequences that have an attached molecule that is capable of being captured on a solid surface. Biotin would be such a molecule that could be captured by streptavidin attached to a solid surface. Other methods known in the art such as antibody/antigen or aptamers could also be utilized.


The target regions of the genome can be amplified according to the workflow shown in FIG. 18A-B. Amplification of the target region of the genome can be accomplished by any method known in the art. For example, amplification and barcoding can involve barcoded primers, as shown in FIG. 19A-B. FIG. 20A-B shows single cell genomics using primers for a first round of amplification followed by subsequent merging with a universal barcode library. Primers as shown in FIG. 19A-B or in FIG. 20A-B generally can amplify target material by a PCR reaction.


The new library of droplets then undergoes amplification (see “1st Round PCR” in FIG. 19A-B) to incorporate the labels into the genetic target (i.e., DNA or RNA).


Target material can also be amplified using multiple displacement amplification (MDA) or any other method known in the art. In certain embodiments (e.g., certain MDA embodiments), a random hexamer (or similar oligo) is used in conjunction with a barcode. For example, FIG. 21 shows generating a barcoded random hexamer library and using the random hexamer library with phi29. FIG. 22 shows a barcode/primer library used with transposase.


In the description that follows, amplification is described in terms of the use of MDA for incorporating the labeled primers into or onto the target material, but it is understood that this choice of description is not limiting for the invention, and that similar methods (e.g., using a transposase) are compatible with all other methods of the reaction. Where the target is genomic DNA, the label can be incorporated into the DNA using, for example, multiple displacement amplification with random hexamer primers having a label incorporated at the 5′end.


Multiple displacement amplification (MDA) is a non-PCR based DNA amplification technique. This method can rapidly amplify minute amount of DNA samples to reasonable quantity for genomic analysis. The reaction starts by annealing random hexamer primers to the template and DNA synthesis is carried out by high fidelity enzyme, preferentially Φ29 at a constant temperature. Compared with the conventional PCR amplification techniques, MDA generates larger sized products with lower error frequency. MDA reaction starts with the annealing of random hexamer primers to the DNA template and then continues with the chain elongation Φ29. Increasing number of primer annealing events happens along the amplification reaction. The amplification reaction initiates when multiple primer hexamers anneal to the template. When DNA synthesis proceeds to the next starting site, the polymerase displaces the newly produced DNA strand and continues its strand elongation. The strand displacement generates newly synthesized single stranded DNA template for more primers to anneal. Further primer annealing and strand displacement on the newly synthesized template results in a hyper-branched DNA network. The sequence debranching during amplification results in high yield of the products. To separate the DNA branching network, S1 nucleases is used to cleave the fragments at displacement sites. The nicks on the resulting DNA fragments are repaired by DNA polymerase I. The generated DNA fragments can be directly used for analysis or be ligated to generate genomic libraries for further sequencing analysis. Using MDA, the DNA would simultaneously be amplified and have a barcode incorporated into the sequence.


Alternatively, if the second droplet contains beads to which are attached tagged sequences designed to capture the genetic material, the merged droplets are incubated in a manner that releases the genetic material from a cell if present and allows the hybridization of the genetic material to the capture sequences attached to the bead. Reagents such as proteases, alkaline reagents, detergents or other methods known in the art can be used to release the genetic material from the cells if present. After capture the emulsion is broken and the beads used to purify the genetic material away from other components of the reaction that may inhibit subsequent steps such as cell debris, proteases and detergents. The beads would capture the genetic material using attached sequences that were random N-mers of length N designed to capture all sequences or variations of N-mers designed to capture only portions of the genetic material present. The tag is then incorporated by replication of the captured nucleic acid using the capture sequence with the tag as a primer. The replication can either generate DNA from a DNA strand or DNA from an RNA strand (cDNA synthesis). This material can either be processed directly or amplified further using methods known in the art such as PCR or multi-strand displacement amplification.


The capture sequences can be synthesized directly onto the beads or be attached by such means as utilizing biotinylated sequences and streptavidin beads. The use of streptavidin beads and biotinylated sequences has the advantage of allowing a generic bead to be used with new libraries of biotinylated capture sequences that can be assembled on demand. However, any method known in the art for attaching nucleic acid sequences to beads can be utilized.


Alternatively, if the second droplet contains capture sequences with the tag and an attached binding molecule the merged droplets are incubated in a manner that releases the genetic material from a cell if present and allows the hybridization of the genetic material to the capture sequences with the binding molecule. Reagents such as proteases, alkaline reagents, detergents or other methods known in the art can be used to release the genetic material from the cells if present. The emulsion is then broken to release the hybridized capture sequence and genetic material. The released genetic material hybridized to the capture sequence is then captured on a solid support allowing the removal of elements such as cell debris, proteases and detergents that may inhibit subsequent steps. The tag is then incorporated by replication of the captured nucleic acid using the capture sequence with the tag as a primer. The replication can generate DNA from a DNA strand or DNA from an RNA strand (cDNA synthesis). This material can either be processed directly or amplified further using methods known in the art such as PCR or multi-strand displacement amplification.


Where the target is RNA, the label can be incorporated in the RNA using MDA with random hexamers having barcodes attached at the 5′ ends. Alternatively, poly dT primers having barcodes attached at the 5′ ends can be used. A promoter region, such as T7 or SP6 RNA polymerase promoter could also be incorporated at the same time, which could be used to amplify the RNA and incorporate a barcode.


After the target is labeled, the amplified genetic material can be analyzed. For example, the amplified material can be released from encapsulation (e.g., “Release from Droplet” in FIG. 19A-B) or from the bead or solid support and prepared for direct sequencing using, for example, sequencing library preparation protocols well known to those skilled in the art. For example, the amplified genetic material can be sheared/fragmented using methods well known to those of ordinary skill in the art, and adaptors can be ligated onto the ends of the fragments to be utilized, for example in direct sequencing, or in an enrichment process.


While the entire encapsulated target can be tiled with a labeled primer using the methods described herein, it should be noted that a majority of the fragments input into the sequencing reaction may not contain a label due to the shearing/fragmentation preparation step required for short read sequencing technology. In other words, each of the MDA amplified labeled strands are sheared/fragmented such that one or more fragments from the same labeled strand become disassociated from the label incorporated into that strand (see FIG. 3A). This issue can be resolved in a number of ways. For example, once encapsulated the target can be fragmented prior to the amplification step to incorporate the labels, thus ensuring that each fragment is labeled when it is input into the sequencing reaction. Alternatively, the MDA amplified labeled strands can be enriched in a subsequent PCR reaction prior to sequencing.


In an exemplary embodiment, enrichment of the labeled strands can be accomplished by incorporating a universal sequence into a 5′ end of each of the plurality of labeled primers such that each of the primers has a sequence as follows: 3′-(N-mer)-label-(universal priming sequence)-5′ (see FIG. 3B). Once the labels are incorporated into the encapsulated genetic material (using, e.g., multiple displacement amplification, as described above), the amplified material can be released from encapsulation using one or more methods described in further detail below. A universal primer can then be ligated onto the 3′ ends of the amplified mix and input into a standard PCR reaction (FIG. 3B). Only those strands having the incorporated label with the universal PCR sequence will be amplified, and thereby enriched.


Alternatively, sequence-specific enrichment can be achieved using a similar method to enrich for fragments that have barcodes and for targeted regions of interest. For example, a plurality of labeled primers each having a universal PCR sequence incorporated into a 5′ end (i.e., 3′-(N-mer)-label-(universal PCR sequence)-5′) is introduced into a droplet containing the target. The labels are incorporated into the encapsulated genetic material using, e.g., amplification. The droplet containing the amplified mixture is then re-merged with another droplet containing a universal primer and a primer specific for a targeted sequence of interest, as well as reagents sufficient for conducting a PCR reaction. This merged droplet is then exposed to conditions sufficient for conducting a PCR reaction, and only those fragments having barcodes and the targeted regions of interest will be amplified.


The labels incorporated within each droplet enables a plurality of sequences from multiple different genomes to be simultaneously amplified, pooled for sequencing, then mapped back to their original genome/transcriptome. Like paired read/paired end sequencing, the methods of the invention provide a researcher/clinician/physician with the ability to link two strands that are physically separated within a single genome/transcriptome to the same genome/transcriptome by tiling the same label along an entire genome/transcriptome. The skilled artisan will readily recognize that reads from high repeat regions and/or regions of high homology can be easily mapped, haplotype information can be obtained, and rearragements or deletions can be identified using the methods described herein. Additionally, mutations in subpopulations of cells in a sample, and metagenomic loss of identity can be traced using the methods of the invention.


Barcoding Transcriptomes


The invention provides methods for analyzing transcriptomes that include labeling transcriptomes with nucleic acid constructs comprising unique N-mers and functional N-mers. FIG. 23A-B is a schematic depicting various exemplary barcode schemes for the generation of a barcoded mRNA primer droplet library. As shown in FIG. 23A-B, a construct can include a biotinylated universal primer, a barcode, and a poly-T region. These constructs can be used to generate mRNA barcoding primer droplet libraries wherein each droplet contains one or more copies of a unique construct. As shown in FIG. 23A-B, a variety of primer types can be used to copy mRNA. Primer type variations include poly-T oligonucleotides, sequence specific primers, and random hexamers.



FIG. 23A-B shows a flow chart for barcoding mRNA. The mRNA is hybridized to a barcoded primer, released from fluid compartments, purified on streptavidin beads, and copied with reverse transcriptase. The resulting cDNA can be analyzed by sequencing.



FIG. 24 is a flowchart depicting the steps associated with isolation, encapsulation, molecular labeling, sorting and analysis of single cell transcriptomes using fluidic droplets (including optional upfront sorting, and cell lysis within droplets using a temperature-inducible protease). As shown in FIG. 24, a sorting mechanism can be used to sort the mRNA-containing droplets.



FIG. 25A-B shows a sorted cell workflow for barcoding transcriptomes from single cells using a barcode library in a detergent lysis buffer. FIG. 25A-B shows a workflow for barcoding transcriptomes from single cells. FIG. 26A-B is an alternative flowchart depicting the steps associated with isolation, encapsulation, molecular labeling, sorting and analysis of single cell transcriptomes using fluidic droplets (capture beads are included in the droplet library).


With these described modifications for target material being mRNA, the above described approaches to haplotyping and genotyping can be applied to transcriptomes.


Biomarker Counting


In certain embodiments, a universal barcode droplet library (e.g., of a bind-and-ligate type) is used to count biomarkers associated with a single cell.


A barcode library can be used in combination with binding molecules that are also barcoded to provide target identification, linking information about the type and number of target molecules present in a sample with their co-incident presence in the same droplet. FIG. 27A-C first illustrates the construction of sticky-ended barcoded binders, and then shows how they can be used for generating cell population averages of the identified biomarkers, before FIGS. 28-31 illustrates how the same sticky-ended barcoded binder constructions work using dropletized versions of both the samples and the barcoded reagents.


The barcoded binding reagents are constructed by linking in a reversible manner a sticky-end oligonucleotide onto the binding reagent (e.g. antibody binding reagents are shown in FIGS. 27A-31D). Two examples of linking motifs tying the barcode to the binder are shown in FIG. 32A-C, one using a photo-activatable linking base 5-prime to a photo-cleavable base and the other using a restriction enzyme cleavage site 5-prime to the barcode that identifies the binding species. By linking an oligonucleotide that contains a cleavable linker, an optional adaptor sequence (to enable interfacing with the downstream sequencing method), a barcode identifying the binding species, and a sticky-end for combining with the complimentary sticky-ended barcode library to a particular binding species, a ‘sticky-ended barcoded binder’ is created (e.g. barcoded binder #1 in FIG. 27A-C). A variety of commercial kits and reagents are available for linking the oligonucleotide to the binder (e.g. chemical cross-linking agents for linking to a protein binder, hybridization and ligation or synthesis of the entire sequence for linking with an oligonucleotide binder). A second similar set of motifs linking a second binding species to a second identifying barcode with the same universal sticky-end is constructed as ‘barcoded binder #2’. Additional barcoded binders are constructed such that a set of n barcoded binders is available for use either to determine bulk average quantification of biomarkers (FIG. 27A-C), or for droplet-based quantification of single species (e.g. single cells, single capture reagents, etc.).



FIG. 27A-C shows the workflow for determination of biomarker averages for a cell population. The set of barcoded binders is incubated with the cell population, resulting in localization of the barcoded binders on the cell biomarkers (e.g. biomarker #1 on the cell surface is bound by antibody #1, which has a linked oligonucleotide sequence that encodes the identity of antibody #1). After washing unbound binders, the linkage to the binder is cleaved (e.g. with a restriction enzyme), and the released barcode is quantified (e.g. by sequencing). The total number of cells used divided by the total number of antibody #1 barcodes will give the average number of biomarker #1 molecules on a cell in the population. The total number of cells used divided by the total number of antibody #2 barcodes will give the average number of biomarker #2 molecules on a cell in the population, and so on. As there is no limit to the number of different types of barcoded binders that can be used to bind to the cell population (other than the number of separate constructions needed of barcoded binders), this method has unlimited multiplexing capability.


Compared to FIG. 27A-C, which shows steps for average (i.e., “bulk”) biomarker analysis, FIGS. 28-31 show a scheme for single-cell biomarker counting. Single-cell biomarker counting can include the same barcode binder construction, binding, and washing steps as shown in FIG. 27A-C. For single-cell biomarker counting, however, the labeled cells are individually loaded into droplets, and each droplet is combined with a droplet from a universal barcode droplet library (FIG. 28A-C and FIG. 29A-B show cell marker barcodes and universal barcodes of a sticky-end type, but any suitable type can be used). The cells can be loaded at a dilution such that most droplets are empty and the cell-containing droplets have a single cell. Each droplet that contains a single cell combines with a droplet that contains a unique barcode, such that all of the biomarkers on one cell will have an identical droplet-identifying barcode appended, thus enabling later determination of the set of biomarkers that were present on the same single cell.


Use of a sticky-ended barcoding droplet library in combination with sample droplets enables collections of individual cells to have their biomarkers digitally counted, with different target components in a droplet being labeled with a unique, droplet-identifying barcode, allowing identification and digital quantification of targets present in the same droplet shown in FIG. 28A-C. The same unlimited multiplexing level for cell biomarker analysis is provided for individual cells as with the bulk averaged cell experiment, and the universal barcoding library can be scaled to have enough binding barcodes to uniquely label a very large number of single cells for digital biomarker analysis. Ligation of the target-identifying and droplet-identifying barcodes into a composite barcode, as shown in FIG. 29A-B, is followed by processing to read both sequence identity and counts of each composite barcode type (e.g. by sequencing, digital PCR, or microarray detection).


The individual steps for this workflow are shown in FIGS. 28A-31D. FIG. 28, panel A shows the preparation of sticky-ended barcoded binders. Panel B shows binding barcoded binders to cell population. Cells can be washed to remove unbound barcoded binders (Panel C) and then loaded into a microfluidic device to generate single cell droplets (Panel D) (e.g., loaded at such a dilution that cell-containing droplets primarily contain single cells according to Poisson statistics). In FIG. 29, Panel E shows sample droplets being combined with the universal barcoding droplet library (combination is achieved by droplet interdigitation followed by dielectrophoretic pair-wise coalescence). Panel F in FIG. 30 releasing the barcoded cells into a single aqueous phase (e.g., lysis by a chemical droplet destabilizer). Cells are washed to remove unbound material (Panel G). Ligase and ATP are added to ligate the annealed composite barcodes (alternatively, the ligase and ATP can be included in the droplet for in-droplet ligation), as shown in Panel H. In FIG. 31, Panel I shows releasing the barcodes by cleavage (e.g. restriction enzyme). According to Panel J, information from the ligated composite barcode can be read (e.g. NextGen sequencer). Note that the barcode members shown in Figure J can be optionally ligated back together into constructs of any length before sequencing according to any known method. Sequencing reveals the type and number of each barcode present. The type and number of each barcode corresponds to the type and number of biomarkers present on each individual cell. Cell #1-associated biomarkers are identified by the 5-prime binder barcode (e.g. biomarker #1 is bound by binder #1 that contains barcode #1 ligated to cell identifier barcode #1a: 1b) and the number of each type of biomarker on that cell matches the number of barcodes with all three sequences (i.e. 1:1a:1b). In this example, Cell #1 has 1 molecule of biomarker #1, 3 molecules of biomarker #2, and 1 molecule of biomarker #n; Cell #2 has 2 molecules of biomarker #1, 2 molecules of biomarker #2, and 1 molecule of biomarker # n.


Note that in the foregoing, a cleavable linker is included in barcoded binders (Panel A in FIG. 27A-C); barcode products are ligated together (Panel H, FIG. 30); and the cleavable linkers are subsequently released (Panel I, FIG. 31). The invention provides methods for linking and releasing oligos. Methods of cleaving and releasing are not limited to the examples shown in FIGS. 27-30, and may be used generally in methods of the invention.



FIG. 32A-C illustrates methods for linking and for releasing barcodes. FIG. 32, panel A, shows coupling barcodes by photoligation and releasing barcodes by photocleavage. FIG. 32, panel B, illustrates including restriction sites or binder-specific loops for cleavage enzymes for subsequent cleavage of barcodes (or for blocking of enzymes).


Barcodes with dPCR


The invention generally provides methods for labeling target material including providing copies of a construct that includes a unique N-mer and a functional N-mer. In some embodiments, constructs of the invention are further analyzed in combination with digital PCR.


For example, sticky-ended Barcodes containing dPCR optimized counter sequences can be provided for use in counting barcoded digital sandwich assays. The optimized multiplexing dPCR set can be used in conjunction with dELISA panels of any “plexity” including, for example, moderate-plex (e.g. 15-100 plex for just FAM/VIC probes) or higher-plex for any dELISA panel known in the art (e.g. cytokine panel; viral antigen panel; bacterial antigen panel).


In some embodiments, barcodes can be used with digital PCR for a copy-number variant (CNV) analysis. Methods include generating a sticky-ended barcode set that will hybridize to a set of targets that have disease-associated copy number variation. Using the non-amplified version of the priming universal barcode library on purified DNA will result in digitally countable (e.g. by optimized multiplex dPCR) CNV analysis. If a diverse collection of these sticky-ended barcoded priming probe pairs are provided in a droplet (i.e. each library droplet has the same barcode, but a mixture of targeting probes) this collection can be combined with genetic material (e.g., a genome, transcriptome, a chromosome, a target nucleic acid). The constructs are allowed to hybridize to the target, and then detected or counted according to the methods described herein. From these results, variations in copy number can be ascertained.


Barcoded Binders



FIG. 33A-B depicts barcoding binders generally (e.g., for digital proteomics). Binders are shown in a form generally representing an antibody for purposes of illustration, but methods of barcoding binders are not labeled to antibodies and include any known binder. As shown in Panel A, a barcode is attached to a binder, optionally via a cleavable linker and adaptor end. The barcoded binder can be further functionalized by including an optional universal barcode library binding end. The binder shown in a droplet on the right side of Panel A can also be provided with a binder that is capture-tagged (for example, with biotin) for subsequent selective capture of target material.


Panel B illustrates an optional additional step for adding additional barcode information to the barcoded binder. A sticky-end barcode is merged into the droplet with ligase, the sticky ends hybridize, and the construct is ligated together. This produces a binder linked to a barcode including barcode information from two supplied barcodes.


As shown in Panel C, this step can optionally be repeated—any number of times—to produce barcodes of increasing complexity, or greater numbers of unique barcodes.


While additional barcodes are shown here being added with ligase, this is optional. Barcodes can be hybridized on without ligation. Additional barcodes can optionally be added with strand-displacement polymerase or transposase. Suitable binders include, without limit, antibodies, aptamers, nucleic acids, proteins, cofactors, and other binding molecules discussed elsewhere herein.



FIG. 34A-B shows an approach to high-plex barcoding of binders. Steps shown in FIG. 34A-B are generally followed, although multiple binders are provided. In a first step (e.g., Panel A of FIG. 34A-B), different binders are first individually barcoded. The second barcoding step (e.g., Panel B) then adds a droplet-specific barcode to the multiple binders.


Barcode Sandwich Assays


In certain embodiments, an ELISA sandwich can be formed, for example, by combining a serum droplet with a droplet containing ELISA reagents (e.g., with one antibody immobilized on a bead and the other in solution). FIG. 35A-B shows a general schematic for a sandwich assay using barcoded binders.


This aspect of the invention involves several components, such as creating tagged binding reagent droplet libraries consisting of individual members targeting single protein markers, with expandability to high levels of multiplexing (e.g. 1000 member library targets 1000 proteins/motifs); binding samples to the tagged detecting molecules in picoliter volume droplets in a highly parallel “single-plex” manner, performing pair-wise combination of droplet reagent libraries and sample droplets; digital counting of productive binding events after washing and release of a readable DNA sequence tag.


Although the instant invention can utilize any species suitable for binding to a protein or protein fragment (e.g. aptamers, affibodies), in one example provided herein, the binding species include antibody reagents. The sandwich principle will be identical (described for antibodies), using appropriate concentrations of two antibodies binding to different epitopes of the same target antigen for co-encapsulation in the reagent droplet. One of the antibodies can be biotinylated (available from many commercial sources, or can be made using a number of kits) and the other can be covalently tagged with a synthetic oligonucleotide. The oligonucleotide tags will be synthesized as amine-linked oligos by a commercial manufacturer (e.g. Sigma Genosys, IDT) and can include restriction enzyme motifs if desired. Well established methods for performing the oligo-tagging of antibodies are used.


Sandwich antibody pairs for many biologically and therapeutically relevant (e.g., cancer) targets are readily available. In one example, well characterized pairs are selected that bind proteins and protein motifs that are important in common cancer signaling pathways (using cell lysate samples), or which have been identified as relevant clinical biomarkers (using serum samples). Initial candidates for target proteins in cell lysate analysis include: Akt and phosphorylated AKT, EGFR and phosphorylated EGFR, Src and phosphorylated Src and TNFRI/II. Initial targets in serum include, but are not limited to: PSA, soluble TNFRI/II, soluble RANKL, CEA, AFP, CA125, beta2 microglobin.


Automated equipment for generation of primer droplet libraries is described above. This equipment can be used to generate a number of types of droplet libraries, including viral particles, antibodies, and beads. For the binding reagent library, a standard microtiter plate is prepared containing each mixed pair of sandwich reagents at the appropriate concentration as input to the library generation process.


Library reagent droplets of two types are prepared, with or without a streptavidin (SA) capture bead. The binding reagent droplet library is mixed and aliquoted for use in assay development. In preferred embodiments, a droplet library is stable and can be stored for longer than a year (e.g., 4° C.).


After pair-wise combination of the sample droplets and the tagged-antibody library droplets, and incubation (e.g., FIG. 37A), productive sandwiches containing all target molecules (and uncomplexed biotinylated antibody) bound to an immobilized streptavidin-containing surface (either SA beads co-encapsulated with the library reagents, or post release from the droplets). Washing the binding surface removes unbound material, including all background from non-targeted proteins. Finally, the remaining tags can be released by any means known in the art (e.g., by denaturation or restriction enzyme digestion) for digital quantification.


Any known method known in the art may be utilized to read the tags. Some examples include, quantitative PCR with standard equipment, digital PCR techniques or a tag readout scheme based on NextGen sequencing, including the use of barcoding strategies, and microarrays



FIG. 35A-B shows the use of sticky-end barcodes with sticky-end barcoded binders for labeling a sample in a sandwich assay. To couple sample barcode information to a barcode sandwich assay as shown in FIG. 35A-B, a sticky-ended barcode is added to bulk Sample A, then made into droplets (Step A). In step B, sample droplets are combined with binders having sticky-ended barcodes and incubated to form a sandwich centered around an analyte. The binder barcode then anneals to the sample barcode. Ligation can be performed before or after release of sandwich from droplet. The droplet contents are released and the full sandwich on the capture surface is washed. The combined barcode is released (e.g. restriction digest) as shown in panel D. Then, reads for each barcode are counted (e.g. using sequencing).



FIG. 36A-B shows the use of a universal barcode droplet library in a single-cell lysate sandwich assays. In the embodiment shown in FIG. 36A-B, a bind-and-ligate version of a library is generally illustrated. As shown in FIG. 36A-B, the universal barcoding droplet library can be combined with barcoded binders that are used in droplet-based sandwich assays, enabling very high-plex digital sandwich assays, including single cell lysate sandwich assays.


Cleavable sticky-ended barcoded binders are constructed (e.g., see FIG. 34A-B) and combined with matching binders that contain a ‘capture-tag’ (see FIG. 34A-B, right hand side) for use as paired binding and capture agents. Each binding pair targets one biomarker or complex, with each binder directed to a different epitope of the same biomarker or complex component. The Universal Barcode Droplet Library can be used to generate a very high number of uniquely barcoded binders, by successive addition of sticky-ended barcodes to the previously barcoded binders (two rounds of additional sticky-ended barcode addition are shown in FIG. 34A-B). By leaving a sticky-end available with the last barcode addition before use with a sample, a sticky-ended barcode that is provided along with the sample to be targeted by the binding pair can be annealed to the barcoded binder and subsequently ligated (see FIG. 36A-B). Association of the sample identifier with the barcoded binder pair identifier results in a combined barcode, that if captured and read, will identify both the binding agent pair and the sample source for the specific analyte targeted by the binding pair. As an example, in the case where the sample droplet contains a lysed single cell, the combination of the sample identifier and the unique binding pair barcode will allow determination of co-localization of the target molecules coming from the same cell lysate after the droplet contents are released, captured on a solid support and washed, and released and read (see FIG. 36A-B).



FIG. 36A-B shows an example workflow for quantifying analytes in a sample using barcoded binders in a sandwich assay. As shown in Panel A, two binding reagents types are constructed: barcoded binders and capture-tag binders. If the barcoded binder has a sticky-end, successive combination with a universal barcode droplet library enables building very high levels of barcode complexity, such that the number of barcodes exceeds the number of analytes or analyte droplets. Pairs of target-specific binders are made into a droplet library (Panel B), with each set of target binders in separate droplets. As shown in Panel C, a sticky-ended sample barcode identifier is added to the sample and sample droplets are generated, and (Panel D) combined with the library droplets to initiate highly parallel ‘single-plex’ binding reactions. After binding is complete, productive sandwiches are captured via the capture-tag (streptavidin (SA) biotin (B) interaction shown in Panel F), and washed to remove unbound material. The captured barcodes are released, recovered, and processed for reading as shown in Panel G. Reads for each barcode are counted (e.g. using sequencing).



FIG. 37A-J shows a number of examples of single or multiple target barcode sandwich assays. Panel A shows a binder pair targeting two different regions of the same analyte enable counting single target analytes. As shown in Panels B and C, binder pairs targeting different analytes in a complex enable identification and digital quantification of analyte complexes. Panel D shows a binder pair targeting two different regions of the same analyte, with one target being a specific modification (e.g. protein post-translational). Panel E shows cross-linked or stable complexes that can be analyzed (e.g. protein-nucleic acid). Panels F-J show the identification and counting of various nucleic acid molecules and motifs. Note that the binder barcode information includes details on which binders are in the library droplet (e.g. “3:1:2” in example C means Binder3 in the same droplet as Binder1 and Capture-Tag Binder2).


Sequencing Barcodes


Having labeled the DNA, RNA, or protein of cell-free material, a collection of cells, single cell, or portion thereof, using the methods described herein, the labeled (and possibly amplified) sample may be sequenced. Sequencing can be carried out using any suitable sequencing technique. A particularly useful method for nucleic acid sequencing is one wherein nucleotides are added successively to a free 3′ hydroxyl group, resulting in synthesis of a polynucleotide chain in the 5′ to 3′ direction. The nature of the nucleotide added may be determined after each nucleotide addition or at the end of the sequencing process. Sequencing techniques using sequencing by ligation, wherein not every contiguous base is sequenced, and techniques such as massively parallel signature sequencing (MPSS) where bases are removed from, rather than added to the strands on the surface are also within the scope of the invention.


The invention also encompasses methods of sequencing amplified nucleic acids generated by solid-phase amplification. Thus, the invention provides a method of nucleic acid sequencing comprising amplifying a pool of nucleic acid templates using solid-phase amplification and carrying out a nucleic acid sequencing reaction to determine the sequence of the whole or a part of at least one amplified nucleic acid strand produced in the solid-phase amplification reaction. The initiation point for the sequencing reaction may be provided by annealing of a sequencing primer to a product of a solid-phase amplification reaction. In this connection, one or both of the adaptors added during formation of the template library may include a nucleotide sequence which permits annealing of a sequencing primer to amplified products derived by whole genome or solid-phase amplification of the template library.


The products of solid-phase amplification reactions wherein both forward and reverse amplification primers are covalently immobilized on the solid surface are so-called bridged structures formed by annealing of pairs of immobilized polynucleotide strands and immobilized complementary strands, both strands being attached to the solid support at the 5′ end. Arrays comprised of such bridged structures provide inefficient templates for typical nucleic acid sequencing techniques, since hybridization of a conventional sequencing primer to one of the immobilized strands is not favored compared to annealing of this strand to its immobilized complementary strand under standard conditions for hybridization.


In order to provide more suitable templates for nucleic acid sequencing, it may be advantageous to remove or displace substantially all or at least a portion of one of the immobilized strands in the bridged structure in order to generate a template which is at least partially single-stranded. The portion of the template which is single-stranded will thus be available for hybridization to a sequencing primer. The process of removing all or a portion of one immobilized strand in a ‘bridged’ double-stranded nucleic acid structure may be referred to herein as linearization, and is described in further detail in U.S. Pub. 2009/0118128, the contents of which are incorporated herein by reference in their entirety.


Bridged template structures may be linearized by cleavage of one or both strands with a restriction endonuclease or by cleavage of one strand with a nicking endonuclease. Other methods of cleavage can be used as an alternative to restriction enzymes or nicking enzymes, including inter alia chemical cleavage (e.g. cleavage of a diol linkage with periodate), cleavage of abasic sites by cleavage with endonuclease (for example ‘USER’, as supplied by NEB, part number M5505S), or by exposure to heat or alkali, cleavage of ribonucleotides incorporated into amplification products otherwise comprised of deoxyribonucleotides, photochemical cleavage or cleavage of a peptide linker.


Following the cleavage step, regardless of the method used for cleavage, the product of the cleavage reaction may be subjected to denaturing conditions in order to remove the portion(s) of the cleaved strand(s) that are not attached to the solid support. Suitable denaturing conditions, for example sodium hydroxide solution, formamide solution or heat, will be apparent to the skilled reader with reference to standard molecular biology protocols (Sambrook et al., supra; Ausubel et al. supra). Denaturation results in the production of a sequencing template which is partially or substantially single-stranded. A sequencing reaction may then be initiated by hybridization of a sequencing primer to the single-stranded portion of the template.


Thus, the invention encompasses methods wherein the nucleic acid sequencing reaction comprises hybridizing a sequencing primer to a single-stranded region of a linearized amplification product, sequentially incorporating one or more nucleotides into a polynucleotide strand complementary to the region of amplified template strand to be sequenced, identifying the base present in one or more of the incorporated nucleotide(s) and thereby determining the sequence of a region of the template strand.


One sequencing method which can be used in accordance with the invention relies on the use of modified nucleotides having removable 3′ blocks, for example as described in WO04018497, US 2007/0166705A1 and U.S. Pat. No. 7,057,026, the contents of which are incorporated herein by reference in their entirety. Once the modified nucleotide has been incorporated into the growing polynucleotide chain complementary to the region of the template being sequenced there is no free 3′-OH group available to direct further sequence extension and therefore the polymerase can not add further nucleotides. Once the nature of the base incorporated into the growing chain has been determined, the 3′ block may be removed to allow addition of the next successive nucleotide. By ordering the products derived using these modified nucleotides, it is possible to deduce the DNA sequence of the DNA template. Such reactions can be done in a single experiment if each of the modified nucleotides has a different label attached thereto, known to correspond to the particular base, to facilitate discrimination between the bases added during each incorporation step. Alternatively, a separate reaction may be carried out containing each of the modified nucleotides separately.


The modified nucleotides may be labeled (e.g., fluorescent label) for detection. Each nucleotide type may thus carry a different fluorescent label, for example, as described in U.S. Pub. 2010/0009353, the contents of which are incorporated herein by reference in their entirety. The detectable label need not, however, be a fluorescent label. Any label can be used which allows the detection of an incorporated nucleotide.


One method for detecting fluorescently labeled nucleotides comprises using laser light of a wavelength specific for the labeled nucleotides, or the use of other suitable sources of illumination. The fluorescence from the label on the nucleotide may be detected by a CCD camera or other suitable detection means. Suitable instrumentation for recording images of clustered arrays is described in WO07123744 and U.S. Pub. 2010/0111768, the contents of which are incorporated herein by reference in their entirety.


In all cases, regardless of the incorporation of molecular barcodes or the location of the barcodes in the event that they are incorporated, sequencing adaptors can be attached to the nucleic acid product in a bi-directional way such that in the same sequencing run there will be sequencing reads from both the 5′ and 3′ end of the target sequence. In some cases it is advantage to use the location of the barcode on the 5′ or 3′ end of the target sequence to indicate the direction of the read. It is well known to one skilled in the art how to attach the sequencing adaptors using techniques such as PCR or ligation.


The invention is not intended to be limited to use of the sequencing method outlined above, as essentially any sequencing methodology which relies on successive incorporation of nucleotides into a polynucleotide chain can be used. Suitable alternative techniques include, for example, the genome sequencers from Roche/454 Life Sciences (Margulies et al. (2005) Nature, 437:376-380; U.S. Pat. Nos. 6,274,320; 6,258,568; 6,210,891), the SOLiD system from Life Technologies Applied Biosystems (Grand Island, NY), the HELISCOPE system from Helicos Biosciences (Cambridge, MA) (see, e.g., U.S. Pub. 2007/0070349), and the Ion sequencers from Life Technologies Ion Torrent, Ion Torrent Systems, Inc. (Guilford, CT).


High Accuracy NGS


Methods of the invention can be used for highly accurate nucleic acid sequencing, particularly by enabling the discrimination between true SNPs and sequencing errors. This is particularly valuable where an allele frequency may be much lower than 50% (e.g., 1%, 0.01%, etc.), for example, when testing for loss of heterzygosity in a tumor. The presence of low percentage mutants in cancer samples due to the heterogeneity of the tumor or the presence of normal cells can result in a mutant allele frequencies below 5%. Other applications such as the detection of cell free circulating tumor DNA from blood and the detection of minimal residual disease (MRD) in cancer are other applications requiring the correct identification of low percentage alleles in a mixture of other alleles. Detection of mutations in bacteria or virus that are at a low percentage, but which convey resistance to drug therapies, can alter treatment regiments if the potential for resistance is known ahead of time.


For the applications mentioned above as well as others, there is a need to accurately detect base changes at frequencies 5% or lower. However, this level can be below what is expected for the error rate encountered throughout the entire sequencing process. A method is provided that can distinguish between true base changes from those that were introduced through error. Methods of the invention include labeling each target molecule going into the process with a unique barcode that ends up in the sequencing read. This allows each sequencing read to be traced back to the original molecule in the sample. This enables the ability to distinguish between base errors and true base changes.


In one illustrative example shown in FIG. 43, a sample has two fragments for the same target region of interest (Target Fragment A and Target Fragment B). In this target region there are two bases of interest (X and Y). The base at site X is the same in both fragments (C:G). The base at site Y is different, an A:T in Fragment A and a G:C in Fragment B. The first step is to label each fragment with a unique barcode. Fragment A is labeled with barcode 1 (BC1) and Fragment B is labeled with barcode 2 (BC2). In addition in this example sequence corresponding to PCR primers is also added to the fragment so that each of the fragments can be amplified by PCR (PCR F, PCR R). After barcode labeling, each of the fragments go through one cycle of PCR. Fragment B is replicated correctly, however, there is base change introduced into Fragment A at site X changing the C to a T in one of the strands (drawn-in oval in FIG. 43). The sample is subjected to another round of PCR generating four PCR products for each fragment. If this sample was sent out for sequencing at this point in which both the barcode and the target sequence were read and associated, BC1 in the results would reveal a sequencing error. This is shown in FIG. 44.


The barcoding allows a user to determine whether a detected base change is real or an artifact of some kind. In this case sequencing without a barcode would identify the base change at site X of a C to a T to be a true change present at 12.5% (1 out of 8 reads with a T). However, examining the associated barcode would identify that the there are two different bases (C and T) associated with the same barcode. This could only happen if the change happened after barcoding and thus is an artifact of the process. However, the base change at site Y is a true change because all the bases at site Y are the same for each barcode (BC1 all A, BC2 all G). The attachment of a barcode to DNA or RNA prior to processing allows a user to distinguish a real base change from a sequencing artifact even down to very low percentages.


Padlock Probe Library


In certain embodiments, the invention provides a gap-filling padlock probe library. A padlock barcode library can have sticky-ends, for example, to combine with universal barcode library building block.


Padlock probes can be hybridized to target (in either a sequence-specific manner, or with universal or random sequences), and polymerase plus ligase can be used to fill in the gap between probe ends. This can produce a circular DNA template including a (optionally barcoded) copy of a target template for downstream processing.


Restriction Barcoding


In certain embodiments, the invention includes restriction barcoding. FIG. 69A-B shows a workflow for restriction barcoding. Cells or nucleic acid are sequestered in droplets. If cells, these can be lysed. Any restriction enzyme or combination of restriction enzymes can be introduced into the cells.


Any nucleic acid can be provided (e.g., a barcode construct of the invention) having a restriction site. Nucleic acids can be provided sticky-ended, or can be exposed to restriction enzymes to expose sticky ends. Barcode sticky ends can be hybridized to target sticky ends, and optionally ligated.


In some embodiments, a barcode in provided with a restriction site or associated sticky end, and a capture tag or moiety such as a bead. After target is connected to the barcode via the sticky end, functional steps can exploit the bead or capture moiety (e.g., to isolate target). Then in subsequent downstream processing, for example, target can be released by subsequent restriction digestion.


Sticky-Ended Motif-Probes


In certain embodiments, the invention provides (amplified and non-amplified versions of) probes having sticky ends of a certain motif. General or specific motifs can be used and include transcription factor binding sites, TATA-box, telomeric sequences, known promoters, or any other known motif.


For example, a probe having a TATA-box can be provided (e.g. as a singlet, without a corresponding “downstream/3′” partner, or as part of a pair. A plurality of such probes can be hybridized to a target sample, and polymerase can synthesize a copy of the target from the probe-binding positions (e.g., the probe can provide a 3′ free hydroxyl group to seed polymerization). This can proceed by primer extension (e.g., synthesizing a single copy of each target area) or via an amplification reaction.


In certain embodiments, a barcoded sticky-ended motif probe is bound to telomeres, and the count is correlated to telomere length.


III. Probe-Type Labels


In addition to barcode-based methods discussed above, labeled target material can be analyzed using digital PCR methods or by counting of fluorescent probe labels. Digital PCR is discussed below. Methods further include incorporating labels having a fluorescent or other colorimetric probe using the methods described herein. In some embodiments, labels are incorporated and amplified material is released from encapsulation and can be input into a digital PCR reaction to simultaneously screen for multiple genotypes and/or mutations for a plurality of target genes in the sample.


Ideally, the sensitivity of digital PCR is limited only by the number of independent amplifications that can be analyzed, which has motivated the development of several ultra-high throughput miniaturized methods allowing millions of single molecule PCR reactions to be performed in parallel (discussed in detail elsewhere). In a preferred embodiment of the invention, digital PCR is performed in aqueous droplets separated by oil using a microfluidics system. In another preferred embodiment, the oil is a fluorinated oil such as the Fluorinert oils (3M). In a still more preferred embodiment the fluorinated oil contains a surfactant, such as PFPE-PEG-PFPE triblock copolymer, to stabilize the droplets against coalescence during the amplification step or at any point where they contact each other. Microfluidic approaches allow the rapid generation of large numbers (e.g. 106 or greater) of very uniformly sized droplets that function as picoliter volume reaction vessels (see reviews of droplet-based microfluidics). But as will be described, the invention is not limited to dPCR performed in water-in-oil emulsions, but rather is general to all methods of reaction compartmentalization for dPCR. In the description that follows, the invention is described in terms of the use of droplets for compartmentalization, but it is understood that this choice of description is not limiting for the invention, and that all of the methods of the invention are compatible with all other methods of reaction compartmentalization for dPCR. In yet another embodiment, the labeled, amplified genetic mixture is analyzed using an array (e.g., microarray) readout.


Methods of the invention involve novel strategies for performing multiple different amplification reactions on the same sample simultaneously to quantify the abundance of multiple different DNA targets, commonly known to those familiar with the art as “multiplexing”. Methods of the invention for multiplexing dPCR assays promise greater plexity—the number of simultaneous reactions—than possible with existing qPCR or dPCR techniques. It is based on the singular nature of amplifications at terminal or limiting dilution that arises because most often only a single target allele is ever present in any one droplet even when multiple primers/probes targeting different alleles are present. This alleviates the complications that otherwise plague simultaneous competing reactions, such as varying arrival time into the exponential stage and unintended interactions between primers.


In one aspect, the invention provides materials and methods for improving amplicon yield while maintaining the quality of droplet-based digital PCR. More specifically, the invention provides droplets containing a single nucleic acid template and multiplexed PCR primers and methods for detecting a plurality of targets in a biological sample by forming such droplets and amplifying the nucleic acid templates using droplet-based digital PCR.


Reactions within microfluidic droplets yield very uniform fluorescence intensity at the end point, and ultimately the intensity depends on the efficiency of probe hydrolysis. Thus, in another aspect of the methods of the invention, different reactions with different efficiencies can be discriminated on the basis of end point fluorescence intensity alone even if they have the same color. Furthermore, in another method of the invention, the efficiencies can be tuned simply by adjusting the probe concentration, resulting in an easy-to-use and general purpose method for multiplexing. In one demonstration of the invention, a 5-plex TaqMan® dPCR assay worked “right out of the box”, in contrast to lengthy optimizations that typify qPCR multiplexing to this degree. In another aspect of the invention, adding multiple colors increases the number of possible reactions geometrically, rather than linearly as with qPCR, because individual reactions can be labeled with multiple fluorophores. As an example, two fluorophores (VIC and FAM) were used to distinguish five different reactions in one implementation of the invention.


Detection


In certain embodiments, after amplification, droplets are flowed to a detection module for detection of amplification products. For embodiments in which the droplets are thermally cycled off-chip, the droplets require re-injection into either a second fluidic circuit for read-out—that may or may not reside on the same chip as the fluidic circuit or circuits for droplet generation—or in certain embodiments the droplets may be re-injected for read-out back into the original fluidic circuit used for droplet generation. The droplets may be individually analyzed and detected using any methods known in the art, such as detecting the presence or amount of a reporter.


An apparatus can include optical or electrical detectors or combinations thereof. Examples of suitable detection apparatuses include optical waveguides, microscopes, diodes, light stimulating devices, (e.g., lasers), photo multiplier tubes, and processors (e.g., computers and software), and combinations thereof, which cooperate to detect a signal representative of a characteristic, marker, or reporter, and to determine and direct the measurement or the sorting action at a sorting module. FIG. 47 shows a detection apparatus according to certain embodiments. Detecting labeled material in droplets is discussed in U.S. Pub. 2008/0014589; U.S. Pub. 2008/0003142, and U.S. Pub. 2010/0137163.


In certain aspects, the droplets of the invention contain a plurality of detectable probes that hybridize to amplicons produced in the droplets. Members of the plurality of probes can each include the same detectable label, or a different detectable label. The plurality of probes can also include one or more groups of probes at varying concentration. The groups of probes at varying concentrations can include the same detectable label which vary in intensity, due to varying probe concentrations.


In a separate embodiment the detection can occur by the scanning of droplets confined to a monolayer in a storage device that is transparent to the wavelengths or method or detection. Droplets stored in this fashion can be scanned either by the movement of the storage device by the scanner or the movement of the scanner over the storage device.


The invention is not limited to the TaqMan assay, as described above, but rather the invention encompasses the use of all fluorogenic DNA hybridization probes, such as molecular beacons, Solaris probes, scorpion probes, and any other probes that function by sequence specific recognition of target DNA by hybridization and result in increased fluorescence on amplification of the target sequence.


Optical Labels


In particular embodiments, the labels incorporated into the DNA or RNA of a single cell, or portion thereof, are optically labeled probes, such as fluorescently labeled probes that are attached to a primer (or N-mer) that hybridizes to a unique region of the target. Examples of fluorescent labels include, but are not limited to, Atto dyes, 4-acetamido-4′-isothiocyanatostilbene-2,2′disulfonic acid; acridine and derivatives: acridine, acridine isothiocyanate; 5-(2′-aminoethyl)aminonaphthalene-1-sulfonic acid (EDANS); 4-amino-N-[3-vinylsulfonyl)phenyl]naphthalimide-3,5 disulfonate; N-(4-anilino-1-naphthyl)maleimide; anthranilamide; BODIPY; Brilliant Yellow; coumarin and derivatives; coumarin, 7-amino-4-methylcoumarin (AMC, Coumarin 120), 7-amino-4-trifluoromethylcouluarin (Coumaran 151); cyanine dyes; cyanosine; 4′,6-diaminidino-2-phenylindole (DAPI); 5′5″-dibromopyrogallol-sulfonaphthalein (Bromopyrogallol Red); 7-diethylamino-3-(4′-isothiocyanatophenyl)-4-methylcoumarin; diethylenetriamine pentaacetate; 4,4′-diisothiocyanatodihydro-stilbene-2,2′-disulfonic acid; 4,4′-diisothiocyanatostilbene-2,2′-disulfonic acid; 5-[dimethylamino]naphthalene-1-sulfonyl chloride (DNS, dansylchloride); 4-dimethylaminophenylazophenyl-4′-isothiocyanate (DABITC); eosin and derivatives; eosin, eosin isothiocyanate, erythrosin and derivatives; erythrosin B, erythrosin, isothiocyanate; ethidium; fluorescein and derivatives; 5-carboxyfluorescein (FAM), 5-(4,6-dichlorotriazin-2-yl)aminofluorescein (DTAF), 2′,7′-dimethoxy-4′5′-dichloro-6-carboxyfluorescein, fluorescein, fluorescein isothiocyanate, QFITC, (XRITC); fluorescamine; IR144; IR1446; Malachite Green isothiocyanate; 4-methylumbelliferoneortho cresolphthalein; nitrotyrosine; pararosaniline; Phenol Red; B-phycoerythrin; o-phthaldialdehyde; pyrene and derivatives: pyrene, pyrene butyrate, succinimidyl 1-pyrene; butyrate quantum dots; Reactive Red 4 (Cibacron™ Brilliant Red 3B-A) rhodamine and derivatives: 6-carboxy-X-rhodamine (ROX), 6-carboxyrhodamine (R6G), lissamine rhodamine B sulfonyl chloride rhodamine (Rhod), rhodamine B, rhodamine 123, rhodamine X isothiocyanate, sulforhodamine B, sulforhodamine 101, sulfonyl chloride derivative of sulforhodamine 101 (Texas Red); N,N,N′,N′tetramethyl-6-carboxyrhodamine (TAMRA); tetramethyl rhodamine; tetramethyl rhodamine isothiocyanate (TRITC); riboflavin; rosolic acid; terbium chelate derivatives; Cy3; Cy5; Cy5.5; Cy7; IRD 700; IRD 800; La Jolta Blue; phthalo cyanine; and naphthalo cyanine. Preferred fluorescent labels are FAM and VIC™ (from Applied Biosystems). Labels other than fluorescent labels are contemplated by the invention, including other optically-detectable labels.


In a particular embodiment, the optical label can be conjugated to an antibody, an siRNA, an aptamer, or a ribozyme specific for target gene or region of interest on the target.


Labels can be used for identification of the library elements of the various types of droplet libraries. Libraries can be labeled for unique identification of each library element by any means known in the art. The label can be an optical label, an enzymatic label or a radioactive label. The label can be any detectable label, e.g., a protein, a DNA tag, a dye, a quantum dot or a radio frequency identification tag, or combinations thereof. Preferably the label is an optical label.


The label can be detected by any means known in the art. Preferably, the label is detected by fluorescence polarization, fluorescence intensity, fluorescence lifetime, fluorescence energy transfer, pH, ionic content, temperature or combinations thereof. Various labels and means for detection are described in greater detail herein.


Specifically, after a label is added to each of the various library elements, the elements are then encapsulated and each of the droplets contains a unique label so that the library elements may be identified. In one example, by using various combinations of labels and detection methods, it is possible to use two different colors with different intensities or to use a single color at a different intensity and different florescence anisotropy.


Quality Control


Optical labels are also utilized in quality control in order to ensure that the droplet libraries are well controlled, and that equal number of each library elements are contained within uniform volumes in each droplet library. After 120 minutes of mixing, using 8-labels in a 96-member library, the average number of droplets is 13,883 for each of the library elements.


In some quality control examples, 384-member libraries were prepared with eight optical labels; typically 5 to 20 micro-liters of each library element are emulsified into approximately 10 picoliter volume droplets so there are about 1 million droplets of each library element and 384 million droplets in the library.


The eight optical labels are a dye at concentrations that increase by a factor of c (where c ranges from about 1.2 to 1.4) from one optical label to the next so that the nth optical label has (c)(n−1) the dye concentration of the lowest concentration. Optical labels are used with concentrations between 10 nM and 1 uM. Typically, the range of optical label concentrations for one series of labels is 1 order of magnitude (e.g., 10 nM to 100 nM with a multiplier of 1.43 for each increasing label concentration). A larger range of droplet label concentrations can also be used. Further, multiplexed two-color labels can be used as well.


Plates are prepared with 384 separate library elements in separate wells of the 384-well plates; 8 of which have optical labels. The library elements are made into droplets, collected in a vial, (also known as a creaming tower) and mixed for several hours. The mixer works by flipping the vial over about once every 30 seconds and then allowing the droplets to rise. Multiple plates can be emulsified and pooled or collected sequentially into the same vial.


A small fraction of the droplets are taken out of the vial to verify 1) that the droplets are present in the correct predetermined ratio and 2) that the droplets are of uniform size. Typically, 1,000 to 10,000 droplets of each library element (0.384 to 3.84 million QC-droplets) are removed from the vial through a PEEK line in the center opening in the vial cap by positive displacement with a drive oil infused through the side opening in vial cap. The PEEK line takes the droplets into a port on a microfluidic chip at a rate of several thousand droplets/second; for 10 picoliter droplets at a rate of 3000 droplets/s corresponds to a typical infusion rate of roughly 110 micro-liters/hr. Once on chip the droplets are spaced out by adding oil before they are imaged and pass one droplet at a time through a laser excitation spot. Maximum fluorescence intensity data from individual droplets is collected for all of the QC-droplets and histograms are built to show the number of droplets within a given fluorescence intensity range. As expected, if eight of the library elements have optical labels, then there are eight peaks in the histograms. The increasing concentration factor c=1.38 results in uniformly separated peaks across one decade when plotted on a log scale. The relative number of droplets in each peak is used as a quality metric to validate that the libraries were prepared with the expected relative representation. In this example, the percent variation is determined to be only 2.7% demonstrating that all library elements have uniform representation.


Image analysis can be utilized to determine and monitor osmotic pressure within the droplets. Osmotic pressure (e.g., two member library prepared with a small difference in buffer concentration) can effect droplets. Specifically, droplets with a lower salt concentration shrink over time and droplets with higher salt concentration grow over time, until uniform salt concentrations are achieved.


Image analysis can also be utilized for quality control of the library reformatting process. After the various library elements are generated, pooled and mixed, optical labels can be used to verify uniform representation of all library elements. Additionally, image analysis is used to verify uniform volume for all droplets.


Further, image analysis can be used for shelf life testing by quantifying the materials performance. Droplets are stored in vials under a variety of conditions to test droplets stability against droplet-droplet coalescence events. Conditions tested include temperature, vibration, presence of air in vials, surfactant type, and surfactant concentration. A Quality Score of percent coalescence is calculated by image analysis. Shelf-life for the droplet libraries of the present invention exceed 90 days.


Droplet Digital PCR


In certain aspects, the invention provides methods and systems for droplet digital PCR including high plexity multiplexing.


An exemplary microfluidic system for droplet generation and readout is depicted in FIG. 48. The microfluidic system for droplet generation and readout. As shown in FIG. 48a (droplet generation chip), a continuous aqueous phase containing the PCR master mix, primers, and probes, and template DNA is flowed into the fluidic intersection from the left, and the carrier oil enters from the top and bottom. An emerging bolus of aqueous liquid is imaged inside the intersection just prior to snapping off into a discrete 4 pL droplet as the fluidic strain began to exceed the surface tension of the aqueous liquid. The steady train of droplets leaving the intersection toward the right is collected off chip as a stable emulsion for thermal cycling. FIG. 48b depicts the droplet spacing for readout. Flows are arranged as in FIG. 48a, except instead of a continuous phase, the emulsion from (a) is injected from the left into the intersection after thermal cycling. The oil drains from the emulsion during off-chip handling, hence the emulsion appears tightly packed in the image before the intersection. The oil introduced in the intersection separates the droplets and the fluorescence of each droplet is measured at the location marked by the arrow. FIG. 48c depicts a cartoon of droplet readout by fluorescence. The relatively infrequent PCR(+) droplets (light gray) flow along with the majority of PCR(−) droplets (dark gray) toward the detector. The droplets are interrogated sequentially by laser induced fluorescence while passing through the detection region.


In a serial dilution the average number of target DNA molecules per droplet—called the “occupancy” from this point forward—decreases in direct proportion to the DNA concentration. The occupancy is calculated from Poisson statistics using the following equation well known to those experienced in the art:











occupancy

=

ln


(


P
+
N

N

)



,




(
1
)







where P and N are the numbers of PCR(+) and PCR(−) droplets respectively.


Digital PCR performance in the emulsion format is validated by measuring a serial dilution of a reference gene, branched chain keto acid dehydrogenase E1 (BCKDHA). Mixtures of the PCR master mix, 1× primers and probe for BCKDHA, and varying concentrations of a mixture of human genomic DNA (1:1 NA14091 and NA13705) are compartmentalized into over one million 5.3 pL droplets in a water-in-fluorinated oil emulsion using the droplet generation microfluidic chip. The emulsion is thermally cycled off-chip and afterwards the fluorescence of each droplet is analyzed by fluorescence in the readout chip (see FIG. 48).


Droplets are analyzed by fluorescence while flowing through the readout chip to count the numbers of PCR(+) and PCR(−) droplets (see FIG. 48c). As each droplet passes the detection zone (marked with an arrow in FIG. 48b), a burst of fluorescence is observed. To account for small run-to-run differences in the fluorescence intensity that can occur due to different chip positioning, etc., each set of data is scaled such that the average fluorescence intensity of the empty droplets is 0.1 V.



FIG. 49a shows droplet fluorescence during readout for the most concentrated sample. Each discrete burst of fluorescence corresponds to an individual droplet. Two different groups of droplets are evident: PCR(+) droplets peaking at ˜0.8 V and PCR(−) droplets at ˜0.1 V; FIG. 49b shows a histogram of the peak fluorescence intensities of droplets from the complete data trace in 6a. PCR(+) and PCR(−) droplets appear as two very distinct populations centered at 0.78 and 0.10 V, respectively; FIG. 49c shows the serial dilution of template DNA. Open circles: measured occupancies; solid line: the best fit to Eqn 2 (A=0.15, f=4.8, R2−0.9999).



FIG. 49a shows a very short duration of a typical trace of fluorescence bursts from individual droplets for the sample with the highest DNA concentration in the series. PCR(+) and PCR(−) droplets are easily discriminated by fluorescence intensity. The two large bursts of fluorescence peaking at ˜0.8 V arose from the PCR(+) droplets, whereas the smaller bursts due to incomplete fluorescence quenching in the PCR(−) droplets peaked at ˜0.1 V. A histogram of peak intensities from the complete data set reveals two clear populations centered at 0.10 and 0.78 V (FIG. 49b), demonstrating that the trend evident in the short trace in FIG. 49a is stable over much longer periods of time. Integration over the two populations in FIG. 49b yields a total of 197,507 PCR(+) and 1,240,126 PCR(−) droplets. Hence the occupancy is 0.15 for this sample by Eqn. 1, corresponding to the expected occupancy of 0.18 based on the measured DNA concentration of 110 ng/μL. The occupancy is measured for each sample in the serial dilution and fit to the dilution equation:












occupancy



(
n
)


=

A

f
n



,




(
2
)







where n is the number of dilutions, A is the occupancy at the starting concentration (n=0), and f is the dilution factor. The linear fit is in excellent agreement with the data, with an R2 value of 0.9999 and the fitted dilution factor of 4.8 in close agreement with the expected value of 5.0.


Multiplexing Primers in Digital PCR


Droplet-based digital PCR technology uses a single primer pair per droplet. This library droplet is merged with a template droplet which contains all the PCR reagents including genomic DNA except for the primers. After merging of the template and the primer library droplets the new droplet now contains all the reagents necessary to perform PCR. The droplet is then thermocycled to produce amplicons. In one embodiment, the template DNA is diluted in the template mix such that on average there is less than one haploid genome per droplet. Droplet-based digital PCR is described in U.S. Pat. No. 7,041,481; U.S. Pub. 2008/0014589; U.S. Pub. 2008/0003142; and U.S. Pub. 2010/0137163, the contents of each of which are incorporated by reference herein in their entireties.


Having only one haploid genome (i.e., one allele) per droplet gives droplet PCR advantages over standard singleplex or multiplex PCR in tubes or microwells. For example, in traditional PCR, both alleles are present in the reaction mix so if there is a difference in the PCR efficiency between alleles, the allele with the highest efficiency will be over represented. Additionally, there can be variances in the sequence to which the PCR primers hybridize, despite careful primer design. A variance in the primer hybridization sequence can cause that primer to have a lower efficiency for hybridization for the allele that has the variance compared to the allele that has the wild type sequence. This can also cause one allele to be amplified preferentially over the other allele if both alleles are present in the same reaction mix.


These issues are avoided in droplet-based PCR because there is only one template molecule per droplet, and thus one allele per droplet. Thus, even if primer variance exists that reduces the PCR efficiency for one allele, there is no competition between alleles because the alleles are separated and thus uniformly amplified.


Because droplet-based digital PCR utilizes only one template molecule per droplet, even if there are multiple PCR primer pairs present in the droplet, only one primer pair will be active. Since only one amplicon is being generated per droplet, there is no competition between amplicons, resulting in uniform amplicon yield between different amplicons.


A certain amount of DNA is required to generate either a specific quantity of DNA and/or a specific number of PCR positive droplets to achieve sufficient sequencing coverage per base. Because only a percentage of the droplets are PCR positive, approximately 1 in 3 in the standard procedure, it takes more DNA to achieve the equivalent PCR yield per template DNA molecule. The number of PCR positive droplets and thus the amplicon yield can be increased by adding more genomic DNA. For instance, increasing the amount of genomic DNA twofold while maintaining the number of droplets constant will double the amplicon yield. However there is a limit to the amount of genomic DNA that can be added before there is a significant chance of having both alleles for a gene in the same droplet, thereby eliminating the advantage of droplet PCR for overcoming allele specific PCR and resulting in allelic dropout.


One way to allow the input of more genomic DNA is by generating more droplets to keep the haploid molecules per droplet ratio constant. For instance doubling the amount of DNA and doubling the amount of droplets increases the amplicon yield by 2× while maintaining the same haploid genome per droplet ratio. However, while doubling the number of droplets isn't problematic, increasing the amount of DNA can be challenging to users that have a limited amount of DNA.


The multiplexing of PCR primers in droplets enables the simultaneous increase in the number of PCR droplets while keeping the amount of input DNA the same or lower to generate an equal or greater amplicon yield. This results in an overall increase in the amount of PCR positive droplets and amplicon yield without the consumption of more DNA.


By way of example, if there is an average of 1 haploid genome per every 4 droplets or ¼ of the haploid genome per droplet and one PCR primer pair per droplet, the chances of the correct template being present for the PCR primer in the droplet is 1 out of 4. However, if there are 2 PCR primer pairs per droplet, then there is double the chance that there will be the correct template present in the droplet. This results in 1 out of 2 droplets being PCR positive which doubles the amplicon yield without doubling the input DNA. If the number of droplets containing the 2× multiplexed primers is doubled and the DNA kept constant, then the number of PCR positive droplets drops back to 1 in 4, but the total number of PCR droplets remains the same because the number of droplets have been doubled. If the multiplexing level in each droplet is increased to 4× and the input DNA is the same, the chance of the correct template molecule being present in each droplet doubles. This results in the number of PCR positive droplets being increased to 1 in 2 which doubles the amount of amplicon yield without increasing the amount of input DNA. Thus, by increasing the multiplexing of PCR primers in each droplet and by increasing the number of droplets overall, the amplicon yield can be increased by 4-fold without increasing the amount of input DNA.


Alternatively, if the amplicon yield is already sufficient, by increasing the multiplexing level for the PCR primers in each droplet, the amount of input genomic DNA can be dropped without sacrificing amplicon yield. For example if the multiplexing level of the PCR primers goes from 1× to 2×, the amount of input genomic DNA can be decreased by 2× while still maintaining the same overall amplicon yield.


Even though the number of PCR primer pairs per droplet is greater than one, there is still only one template molecule per droplet and thus there is only one primer pair per droplet that is being utilized at one time. This means that the advantages of droplet PCR for eliminating bias from either allele specific PCR or competition between different amplicons is maintained.


An example demonstration of droplet-based amplification and detection of multiple target sequences in a single droplet is shown in FIG. 50. Multiple copies of 5 sets of primers (primers for TERT, RNaseP, E1a, SMN1 and SMN2) were encapsulated in a single droplet at various concentrations along with the template DNA and the PCR master mix.



FIG. 50A is a schematic representation of a droplet having 5 sets of primers for PCR amplification of a template sequence and 5 probes, each labeled with a fluorescent dye, that binds specifically to the amplified sequences; FIG. 50B is a time trace of fluorescence intensity detected from droplets after PCR amplification; FIG. 50C is a scatter plot showing clusters representing droplets that contain specific amplified sequences (TERT, RNaseP, E1a, SMN1 and SMN2).


Probes that specifically bind to TERT, RNaseP, E1a, SMN1 or SMN2 were also encapsulated in the droplets containing the primers. Probes for TERT, RNaseP and E1a were labeled with the VIC dye and probes for SMN1 and SMN2 were labeled with the FAM dye. The sequences for TERT RNaseP, E1a, SMN1 and SMN2 were amplified by PCR. The PCR was conducted with a standard thermal cycling setting. For example:

    • 95° C. for 10 min
    • 31 cycles
      • 92° C. for 15 s
      • 60° C. for 60 s


At the end of the PCR, the fluorescence emission from each droplet was determined and plotted on a scattered plot based on its wavelength and intensity. Six clusters, each representing droplets having the corresponding fluorescence wavelength and intensity were shown. The TERT, RNaseP and E1a clusters showed the fluorescence of the VIC dye at three distinct intensities and SMN1 and SMN1 clusters showed the fluorescence of the FAM dye at two distinct intensities (FIG. 50C). The number of droplets, each having sequences selected from TERT, RNaseP, E1a, SMN1 and SMN2, can be determined from the scattered plot.



FIG. 51 and FIG. 52 show another demonstration of droplet-based amplification and detection of multiple target sequences in a single droplet. Here, five sets of primers (for TERT, RNaseP, E1a, 815A and 815G) were encapsulated in a single droplet at various concentrations along with the template DNA, the PCR master mix, and the probes. The five different probes TERT, RNaseP, E1a, 815A and 815G were also encapsulated in the droplets containing the primers. Probes for TERT and 815A were labeled with the VIC dye and probes for 815G were labeled with the FAM dye. For each of RNaseP and E1a, two probes, one labeled with the VIC dye and the other labeled with the FAM dye, were encapsulated.


The primer-plus-probe droplets were fused with template droplets. PCR reactions were conducted with the fused droplets to amplify the sequences for TERT, RNaseP, E1a, 815A and 815G. The PCR was conducted with a standard thermal cycling setting.


At the end of the PCR, the fluorescence emission from each fused droplet was determined and plotted on a scattered plot based on its wavelength and intensity. FIG. 52 shows six clusters, each representing droplets having the corresponding fluorescence wavelength and intensity. The TERT and 815A clusters showed the fluorescence of the VIC dye at two distinct intensities; the 815G clusters showed the fluorescence of the FAM dye; and the RNaseP and E1a clusters showed the fluorescence of both the FAM and the VIC dye at distinct intensities (FIG. 52). The number of droplets, each having one or more sequences selected from TERT, RNaseP, E1a, 815A and 815G, can be determined from the scattered plot. The copy number of RNaseP, E1a, 815A and 815G in the template were determined by the ratio between the number of droplets having the RNaseP, E1a, 815A and/or 815G sequences and the number of droplets having the TERT sequence (FIGS. 51-52). FIG. 52B is a table showing the copy number of specific sequences shown in FIG. 49B.


In yet another exemplary demonstration of multiplexed primer pairs in a droplet-based digital PCR reaction, two droplet libraries were generated: droplet library A was generated where each droplet contained only one primer pair; and droplet library B was generated where the primer pairs were multiplexed at 5× level in each droplet. HapMap sample NA18858 was processed in duplicate with droplet libraries A or B using standard procedures. Two μg sample DNA was used for droplet library A and one μg sample DNA was used for the 5× multiplex droplet library B. After PCR amplification, both droplet libraries were broken and purified over a Qiagen MinElute column and then run on an Agilent Bioanalyzer. Samples were sequenced by Illumina on the Illumina GAII with 50 nucleotide reads and the sequencing results were analyzed using the standard sequencing metrics. The results from the 5× multiplexed droplet library B were compared to the singleplex droplet library A as shown in FIG. 45.


The results obtained from the 5× multiplexed droplet library B were equivalent or better than what was obtained from droplet library A. The multiplexing of primers delivers the same sequencing results for base coverage, specificity and uniformity that the singleplexing does with the added advantage of reduced input DNA as shown in FIG. 45.


In FIG. 45, the following entries appear:


Total reads: total number of sequencing read found within the provided sample data.


Mapped reads (%): percentage of total reads that mapped to the human genome.


Specificity: percentage of mapped reads that include the target. The target includes all amplicon sequences with primer sequences excluded.


Mean base coverage: average base coverage within the target. The target includes all amplicon sequences with primer sequences excluded.


C1: % of target that has at least 1× base coverage. Note: non-unique sequencing reads are mapped randomly.


C20: % of target that has at least 20× base coverage.


C100: % of target that has at least 100× base coverage.


Base coverage (0.2× of mean): % of target that has at least 20% of mean base coverage.


Monochromatic Copy Number Assay


Traditional digital PCR methods involve the use of a single labeled probe specific for an individual target. FIG. 53A-E is a schematic depicting one-color detection of a target sequence using droplet-based digital PCR. As shown in Panel A of FIG. 53A-E, a template DNA is amplified with a forward primer (F1) and a reverse primer (R1). Probe (P1) labeled with a fluorophore of color 1 binds to the target genetic sequence (target 1). Droplets are made of diluted solution of template DNA under conditions of limiting or terminal dilution. Droplets containing the target sequence emit fluorescence and are detected by laser (Panels B and C). The number of microcapsules either containing or not containing the target sequence is shown in a histogram (D) and quantified (E).



FIG. 54A-D is a schematic depicting two-color detection of two genetic sequences with a microfluidic device. As shown in Panel A of FIG. 54A-D, a template DNA is amplified with two sets of primers: forward primer (F1) and a reverse primer (R1), and forward primer (F2) and a reverse primer (R2). Probe (P1) labeled with a fluorophore of color 1 binds to the target 1 and probe (P2) labeled with a fluorophore of color 2 binds to the target 2 (Panels B and C). Droplets are made of diluted solution of template DNA under conditions of limiting or terminal dilution. Droplets containing the target sequence 1 or 2 emit fluorescence of color 1 or 2 respectively and are optically detected by laser (Panels B and C). The number of microcapsules containing target 1 or 2 is shown by histogram in Panel D.


Methods of the invention involve performing accurate quantitation of multiple different DNA targets by dPCR using probes with the same fluorophore. FIG. 55A-D is a schematic depicting two-color detection of three genetic sequences with a microfluidic device. As shown in Panel A of FIG. 55A-D, a template DNA is amplified with three sets of primers: forward primers (F1, F2 and F3) and reverse primers (R1, R2 and R3). Probes (P1, P2 and P3) are labeled with fluorophores (color 1, color 2 and color 1) and bind to the target genetic sequences (target 1, target 2 and target 3) (Panels B and C). Droplets are made of diluted solution of template DNA under conditions of limiting or terminal dilution. Droplets containing target sequence 1 or 3 emit fluorescence of color 1 at two different intensities; and droplets containing target sequence 2 emit fluorescence of color 2. The number of droplets containing target 1, 2 or 3 is shown by histogram in Panel D.


Recent results from the droplet digital PCR (dPCR) shows that multiple independent PCR reactions can be run and separately quantified using the same fluorophore. Specifically, an SMN2 assay yields an unexpected population of droplets with slightly elevated signal in the FAM detection channel.


The results are depicted in FIG. 56, which shows two dot plots depicting clusters of genetic sequences detected through fluorescence intensity. The left panel is a dot plot showing four clusters, where SMN1 blocker was present, each corresponding to droplet containing: top left—reference sequence (SMARCC1); bottom left—no sequence; bottom middle—SMN1; and bottom right—SMN2. Right panel is a dot plot showing four clusters. No block for SMN1 sequence was present. Top left: droplets containing the reference sequence (SMARCC1); bottom left: droplets not containing any sequence; bottom middle: droplets containing sequence for SMN1; and bottom right: droplets containing sequence for SMN2. The shift of the bottom middle cluster in right panel as compared to left panel confirms that fluorescence intensity provides a very sensitive measurement for the presence of a sequence.


Without intending to be bound by any theory, the simplest explanation is that the cluster arises from weak association of the SMN2 probe to the SMN1 gene despite the presence of a blocker to that gene (a non-fluorescent complementary probe to the SMN1 gene).


One confirmation of SMN1 as the source of the unexpected cluster was an observed dependence of the intensity of this feature on the presence of the SMN1 blocker. A shift toward higher FAM fluorescent intensities was observed in the absence of the blocker (FIG. 56). In another definitive confirmation the ratio of the SMN1 (putative) population size to the reference size of 0.96 in perfect agreement with expectation (two copies of each) (S_131 sample). Another sample, S_122, with the same number of SMN1 copies yielded a ratio of 0.88 in one run and 0.93 in another, also consistent with the proposed explanation of the unexpected cluster.


Without intending to be bound by any theory, these observations indicate that SMN2 probe binding to SMN1 DNA yields an elevated fluorescent signal. A simple kinetic model explaining this phenomenon assumes that the hybridization of the SMN2 probe to the SMN1 DNA achieves equilibrium at a faster rate than the polymerase fills in the complementary strand. The amount of probe fluorophore that is released in each thermal cycle is therefore proportional to (or even equal to) the number of bound probes. Thus the lower the binding affinity the fewer the number of probe fluorophores that are released. Due to SMN1 sequence mismatch(es) with the SMN2 probe, the affinity of the probe is certainly expected to be lower to SMN1 than SMN2. This model also explains the signal dependence on the sMN1 blocker: the blocker competitively inhibits the SMN2 probe hydrolysis by the polymerase exonuclease activity.


It may also be, however, that the probe hybridization does not reach equilibrium before exonuclease activity. In this case, the association rates would play a more dominant role. Similar logic applies. The binding rate to the matching site is likely to be faster than to the mismatch site, and the blocker would act to decelerate probe binding to the mismatch site. The binding of SMN2 probe to SMN1 DNA might be detectable by conventional bulk qPCR, especially in absence of SMN2, but highly quantitative results like those shown here are very unlikely. Definitely, there is no report of qPCR or any other technique quantifying two different DNA sequence motifs with the same color fluorophore. Sequestration of the individual reactions by single molecule amplification within droplets eliminates any confusion regarding mixed contributions to the signal.


The advantage of quantifying DNA with multiple probes of the same color fluorophore goes beyond two highly homologous sequences, as shown here. Rather, any plurality of sequences of any degree of similarity or dissimilarity can be quantified so long as the different probes have significantly different binding occupancies to their respective DNA binding sites.


Another advantage of dPCR for multiplexed reactions is that the different reactions do not compete with each other for reagents as they would in qPCR. However, the possibility for unintended cross-reactivity remains. A multiplexed assay can require a more dilute sample. For instance, at 10% occupancy a duplex reaction would have double occupancy 1% of the time. Hence 1 in 10 PCR+ droplets would be doubles, resulting in a final intensity at least as high and possibly higher than the brighter of the two probes. For a simple duplex system the contribution from each probe could be recovered. In this example the total number of PCR+ droplets for probe 1 would be (Probe 1)+(Probe1+Probe2).


Higher degrees of multiplexing would require greater dilution. For example, for a 4-plex at 1% occupancy the probability of one probe overlapping any of the other 3 is ˜3%, and that error may be too high for some applications. The need for large dilutions strongly favors the large number of dPCR reactions.


In another example of the invention, a single fluorophore (FAM) was used in a gene copy number assay for both the reference and the target DNA. A model system was used with varying concentrations of plasmid DNA to represent a change in the target gene copy number, relative to a reference gene, equivalent to 0-16 copies of the target gene per cell. BCKDHA and SMN2 plasmid DNA served as the reference and target with 1× and 0.5×primers and probes respectively. With a starting ratio of 8:1 SMN2 to BCKDHA, the sample was diluted serially by 2× into a solution of BCKDHA at the same concentration to vary just the amount of SMN2. The resultant samples were emulsified, thermally cycled, and over 105 droplets were analyzed for each sample as described in the previous section. The process was repeated in triplicate.


Methods of the invention also include analytical techniques for identification of fluorescence signatures unique to each probe. FIGS. 57a-57b depict histograms of a duplex gene copy number assay using only one type of fluorophore by digital PCR.


In this example of the invention, histograms of the droplet fluorescence intensities are shown in FIG. 57a for three different template DNA samples: a no template control (dotted line), BCKDHA only (solid line), and 1:1 BCKDHA to SMN2 (dashed line). For clarity, the histograms are shown both overlapped to highlight the similarity for certain peaks, and offset from each other to reveal all of the features. In the case of 1:1 BCKDHA to SMN2, three populations were readily apparent: a dominant feature appeared at 0.08 V, and two smaller peaks were evident at 0.27 and 0.71 V. The dominant feature at 0.08 V was assigned to PCR(−) droplets since both small peaks disappeared, but the large one remained, in the no template control. The peak at 0.71 V was assigned to BCKDHA since it was the sole feature arising with the addition of just BCKDHA, and the peak at 0.27 V appeared on subsequent addition of SMN2, completing the assignments. A very small peak appeared at ˜0.9 V, not visible on the scale of FIG. 57a, that corresponded to droplets occupied by both genes. As another method of the invention, once the different peaks are identified, droplets within each peak were counted corresponding to each possible state (PCR(+) for either BCKDHA or SMN2, or both, or PCR(−)), and the gene copy number was then determined from the ratio of occupancies. Gene copy numbers for each sample in the serial dilution are plotted in FIG. 57b against expected values (observed ratios of SMN2 to BCKDHA to expected ratios of SMN2 to BSKDHA), with an excellent linear fit (y=1.01x) across the full range (R2=0.9997, slope=1.01), demonstrating accurate and precise measurement of the equivalent of 0 to 16 copies of SMN2 per cell.


It is possible to determine if a heterogeneous sample contained components with different copy level numbers. If the copy number variants to be assayed were spaced close enough along the chromosome, the DNA from a sample could be fragmented and encapsulated in droplets at a level of one haploid genomic equivalent or less per droplet. The droplet would also contain a TaqMan assay specific for the copy number variant. The intensity of the signal in each droplet would depend on the number of copy number variants are present for the sample. Counting of the number of droplets of different intensities would indicate things like how many cells in a particular sample had what level of copy number variants.


Splice Variants


In certain embodiments, target material includes alternatively spliced transcripts, and the invention provides labels for detecting or counting the splice variant. TaqMan assays can be designed that are specific for each of the exons in an RNA transcript. After the RNA is turned into cDNA it can be encapsulated into a droplet at 1 copy or less per droplet. The droplet would also contain the multiplexed TaqMan assay for each of the exons. Each of the TaqMan assays would contain a different probe but all the probes would have the same fluorescent dye attached. The droplets would be thermocycled to generate signal for each of the TaqMan assays. If there are multiple splice variants in the sample they each will contain a different number of exons depending on the splicing events. The fluorescent intensity of each droplet would be different depending on the number of exons present. By counting the number of droplets with different intensities it would be possible to identify the presence and abundance of different splice variants in a sample.


Tuning Probe Intensity


Identifying probes by fluorescence intensity often requires adjusting the brightness of the probes, particularly for higher-plex assays with dense probe patterns. In the previous section the probes for the gene copy number assay yielded very well resolved peaks (FIG. 57a). Clearly room exists to accommodate one or multiple extra probes in the copy number assay within the resolution of the measurement, but a method for adjusting the fluorescence intensity of the new probes is required to avoid interference with the existing assay. One method of the invention involves varying the probe and primer concentrations together as a very simple technique to optimize relative intensities in higher-plex reactions.



FIG. 58A-C is a schematic for tuning the intensity of a detectable label to a particular target with a microfluidic device. As shown in Panel A of FIG. 58A-C, a template DNA is amplified with two sets of primers: forward primers (F1 and F2) and reverse primers (R1 and R2). Probes (P1 and P2) are labeled with fluorophore of color 1 and bind to target 1 and target 2 respectively. Fluorescence from target 2 is lower in intensity than that from target 1 due to single base mismatch between P2 and target 2. As shown in Panel B, template DNA is amplified with two sets of primers: forward primers (F1 and F2) and reverse primers (R1 and R2) (Panel B). Fluorescence from target 2 is lower in intensity than that from target 1 due to the presence of a competing probe 2 that is not labeled with the fluorophore. As shown in Panel C, template DNA is amplified with two sets of primers: forward primers (F1 and F2) and reverse primers (R1 and R2). Probes (P1 and P2) are labeled with fluorophore of color 1 and bind to target 1 and target 2 respectively. Fluorescence from target 2 is lower in intensity than that from target 1 due to the presence of a competing probe 2 that is labeled with a different fluorophore.



FIG. 59 shows probe fluorescence intensities throughout a serial dilution of the probes and primers for a different reference gene, ribonuclease P (RNaseP), against a constant amount of genomic DNA from the Coriell cell line NA3814 at an occupancy of 0.02 target DNA molecules per droplet. The probe fluorescent intensities varied in direct proportion to probe concentration over a narrow concentration range spanning ˜0.15 to 0.4 μM (R2=0.995)—roughly centered about the typical probe concentration of 0.2 μM—after compensation for dilution errors and other run-to-run differences such as optical realignments using the intensity of the PCR(−) droplets as a reference. In summary, probe intensities can be varied by dilution over a small but adequate range for the purpose of tuning multiplexed assays without affecting the amplification itself.


Although the example above for adjusting probe fluorescence intensities involves varying probe and primer concentrations together by the same factor, the invention is not limited to this method alone for varying probe intensity. Other methods include varying just the probe concentration; varying just the primer concentrations; varying just the forward primer concentration; varying just the reverse primer concentration; varying the probe, forward, and reverse primers concentrations in any way; varying the thermal cycling program; varying the PCR master mix; incorporating into the assay some fraction of probes that lack fluorophores; or incorporating into the assay any hybridization-based competitive inhibitors to probe binding, such as blocking oligomer nucleotides, peptide nucleic acids, and locked nucleic acids. The invention incorporates such methods by themselves or in any combination.


Higher-Plex Reactions


One method of the invention involves performing higher-plex assays with a single probe color (e.g., fluorophore). As described above, probe fluorescent intensities can be adjusted by a variety of means such that each intensity level uniquely identifies a DNA target. For example, targets T1, T2, T3, and T4 might be uniquely identified by intensity levels I1, I2, I3, and I4. Not intending to be bound by theory, the maximum number of intensity levels possible for unique identification of targets is related to the resolution of the different intensity levels—that is the spread of intensities for each particular probe compared to the separation between the average intensities of the probes—and it is also related to the intensity of the empty droplets that tends to grow with increasing numbers of probes. The number of intensity levels can be 0, 1, 2, 3, 4, 10, 20, 50, or any number (e.g., up to 100, or higher). In the examples show below, as many as three intensity levels are demonstrated.


Another method of the invention involves performing higher-plex assays using multiple different probe colors (i.e. fluorophores). As above for the monochromatic multiplexing assay, for each color probe, multiple targets can be identified based on intensity. Additionally, multiple colors that are spectrally separable can be used simultaneously. For example, a single droplet might contain four different probes for measuring four different targets. Two probes might be of color A with different intensities (say, A1 and A2), and the other two probes of color B with different intensities (say B1 and B2). The corresponding targets are T1, T2, T3, and T4 for A1, A2, B1, and B2 respectively. If a droplet shows an increase in fluoresce in color A, the droplet therefore contained either targets T1 or T2. Then, based on the fluorescence intensity of color A, the target could be identified as T1 or the target could be identified as T2. If, however, a droplet shows an increase in fluorescence in color B, the droplet therefore contained either targets T3 or T4. Then, based on the fluorescence intensity of color B, the target could be identified as T3 or the target could be identified as T4. Not intending to be bound by theory, the maximum number of different colors possible is limited by spectral overlap between fluorescence emission of the different fluorophores. The maximum number of colors can be 1, or 2, or 3, or 4, or up to 10, or up to 20. The maximum number of colors can be higher than 20. In the demonstrations that follow, the largest number of colors is two.


Another method of the invention involves performing higher-plex assays using multiple different probe colors (i.e. fluorophores), however unlike the strategy above where each target is identified by single type of probe with a unique color and intensity, instead in this method a single target may be identified by multiple probes that constitute a unique signature of both colors and intensities. For example, a single droplet might contain four different probes for measuring three different targets (say, T1, T2, and T3). Two probes might be of color A (say, A1, and A2), and two probes might be of color B (say, B1 and B2). T1 is measured by probe A1, T2 is measured by probe B1, but T3 is measured by both probes A2 and B2. Thus, when a droplet contains T1 only increased fluorescence appears in color A. When a droplet contains T2 only increased fluorescence appears in color B. However when a droplet contains T3, increased fluorescence appears in both colors A and B.


Generally, without wishing to be constrained by theory, the above three methods for higher-plex dPCR are simplest to implement under conditions of terminal dilution, that is when the probability of multiple different target molecules co-occupying the same droplet is very low compared to the probability of any single target occupying a droplet. With multiple occupancy arises the complexity of simultaneous assays competing within the same reaction droplet, and also complexity of assigning the resulting fluorescence intensity that involves a combination of fluorescence from two different reaction products that may or may not be equal to the sum of the two fluorescence intensities of the individual reaction products. However, methods of the invention can accommodate these complications arising from multiple occupancy.


Methods of the invention for higher-plex reactions also include methods for primer and probe pairing. In the simplest case targets are unlikely to reside on the same DNA fragments, such as when targets are from different cells; or when targets are from different chromosomes within a single cell type; or when targets are distant from each other within a single chromosome such that they become physically separated during DNA fragmentation; or when targets are very close to each other within a chromosome, but nevertheless become separated by targeted cleavage of the DNA, such as by restriction enzyme digestion; or for any other reason. In such cases each probe can be paired with a single set of primers (forward and reverse). However, in other cases the target regions might frequently reside on the same DNA fragments, for example when targets reside within the same codon, or for any other reason. In such cases, a single set of primers might serve for multiple probes (for an example, see Pekin et al.).


Higher multiplex reactions can be performed to distinguish the haplotypes of two SNPs. For example, assume that at position one there can be genotypes A or A′ and at position two there can be genotypes of B or B′. In a diploid genome four unique haplotypes are possible (A,B; A,B′; A′,B; and A′,B′). If for example A′ and B′ represent drug resistant mutations for infection, it is often the case that A′B and AB′ are less severe and treated differently than A′B′ which represents a significant drug resistance that must be treated with extreme care. Digital PCR with intensity discrimination is ideally suited for identifying low prevalence of A′B′ in a background of mixtures of the other three haplotypes. Haplotyping information is also important for construction of haplotypes (e.g., human leukocyte antigen (HLA) haplotypes). One way that the present example can be constructed is by assay design such that color one is used for A and is of high or low intensity indicative of allele A or A′ respectively and color two is used for B and is of high or low intensity respectively indicative of B or B′. Populations of [color1,color2] corresponding to [Low, Low] would be a measure of an allele of AB and [high, low] allele A′B and an allele of [A′B′] will be readily distinguishable as [high, high] even in a background that is predominately a mixture of A′B and AB′. See FIG. 68. In some cases it will be advantageous to start by encapsulating into the droplets long single molecules of nucleic acid that contain both A and B SNP location and in other cases it will be desirable to start by encapsulating single cells, bacteria or other organism within the droplets prior to releasing the nucleic acid from the organism. In still other embodiments the multiplex intensity detection of multiple simultaneous targets can be used as surrogate markers for multiple types of binding interactions or labeling of target materials. This technique is also not limited to single molecule detection and can be used for haplotype detection in single cells (e.g., bacteria, somatic cells, etc.). In single cell analysis, a sorting step may be applied prior to haplotyping.


5-Plex SMA Assay


The invention in general provides multiplex assays for genetic markers. Here is discussed a 5-plex assay for spinal muscular atrophy (SMA). The invention includes other “plex” levels and other genetic markers. SMA was selected for one example due to both its important clinical significance as well as its complicated genetics. It is the second-most prevalent fatal neurodegenerative disease and affects ˜1 in 10,000 live births. SMA is most often caused by homozygous absence of exon 7 within the survival of motor neuron 1 gene (SMN1, reviewed by Wirth et al.), however the severity of the condition is modulated by the number of gene copies of SMN2 with prognosis ranging from lethal to asymptomatic over 1-5 copy numbers (reviewed by Elsheikh et al.). Hence accurate quantitation of SMN2 copy number is important for clinical prognosis and genetic counseling. Aside from large deletions of SMN1, a number of single point mutations or short deletions/duplications within the same gene also account for ˜4% of cases of SMA. In a significant step toward a comprehensive SMA assay, the multiplexed dPCR assay demonstrated here contains both copy number assays (for SMN1 & 2) and an assay for one of the prevalent SNPs (c.815A>G).


One embodiment of the invention is a multi-plex assay for diagnostics. Here, a 5-plex assay quantifies common genetic variants impacting SMA including two copy number assays for the SMN1 and SMN2 genes with BCKDHA as a reference, and a SNP assay for the c.815A>G mutation. Two differently colored fluorophores, FAM and VIC, were used to uniquely identify each of the assays. The probes for SMN1 and SMN2 contained only FAM, and for c.815A only VIC. However, mixtures of VIC and FAM-labeled probes were used for BCKDHA and c.815G. The use of VIC and FAM fluorophores in this example does not limit the invention, rather the 5-plex assay can be used with any suitable hybridization-based probe chemistries. For validating the assay, a model chromosome was synthesized containing a single target region for each of the different primer/probe pairs. EcoRV restriction sites flanked each target, allowing separation of the fragments.


As another method of the invention, histogram-based data presentation and analysis is incorporated into the invention for identifying and characterizing statistically similar populations of droplets that arise from one probe signature (color and intensity), and for discriminating one population of droplets from the others. FIG. 60a shows a 2-dimensional histogram of droplet fluorescence intensities as a contoured heat map, with hotter colors representing higher occurrences. Standard techniques were used to compensate for spectral overlap of the FAM and VIC signals. Samples were run at 0.006 occupancy per target. Six populations were clearly evident, five for the assay and one for PCR(−) droplets. As one method of the invention, the populations were assigned by selective exclusion of assay components. For example, excluding the SMN2 primers and probe eliminated the population at the bottom right in the histogram, but otherwise the distribution remained unchanged.



FIG. 60a is a 2-D histogram of droplet fluorescence intensities, shown as a heat map, for the 5-plex assay against the synthetic model chromosome for validation. The six well resolved droplet populations corresponded to the five individual assays plus the empty droplets; FIG. 60b shows the results of the SMA pilot study.


Assignments are labeled in FIG. 60a. As we have found to be generally true for this method of multiplexing, the assay worked immediately with well resolved or at least distinguishable populations for each target. As another method of the invention, the relative positions of the different populations in the histogram were then adjusted into a regularly spaced rectangular array by tuning the probe concentration as described in the previous section. Usually no more than two iterations are required for optimization.


In another method of the invention, the different populations were sufficiently well resolved to allow droplets within each population to be counted by integration across rectangular boundaries. The boundaries were positioned at mid-sections between neighboring peaks. The methods of the invention are not constrained to rectangular boundaries, or to specific boundary locations between peaks. Rather, any closed or unclosed boundary condition can suffice. Boundary conditions do not need to be “binary” either, in the sense that weighted integrations can also be performed across the boundaries to arrive at droplet counts. The peak position of each cluster varied by no more than 2% from run to run after normalization to the intensity of the empty droplets to account for variations in detection efficiency (data not shown). Hence, once identified, the same boundaries for integration could be reused between samples. The methods of the invention are not limited to fixed boundary positions. Dynamic population identification and boundary selection in between samples or studies is anticipated. Twenty different patient samples from the Coriell cell repositories were analyzed with this assay: 4 afflicted with SMA, 1 SMA carrier, and 15 negative controls. Assay results are shown in FIG. 60b. Gene copy number was calculated as before, as the ratio of occupancies derived from the number of target droplets vs. reference droplets. Like the copy number measurement in FIG. 57, each assay yielded ratios very close to the expected integer values, but when all of the patient data was plotted as actual ratio vs. expected integer ratio a small systematic deviation from the ideal slope of 1 was observed. Measured slopes were 0.92, 0.92, and 0.99 for SMN1, SMN2, and c.815A respectively. For clarity, the data in FIG. 60b was scaled to the ideal slope of 1.


The measured genotypes of the different patients were consistent with their disease conditions (unafflicted, carrier, or afflicted). The patients afflicted with SMA each had zero copies of SMN1 (numbers SMA 1-4 in FIG. 60b), the carrier had just one copy, and the negative controls all had two or three copies (numbers 1-15). Three unrelated individuals (numbers 6, 8, and 9) had three copies of SMN1, occurring at a rate of 20% which is similar to a previous report for healthy individuals. Variability in SMN1 copy number is not surprising since it lies within an unstable region of chromosome 5q13. A larger variety of SMN2 copy numbers was observed. One to two copies were most common in the control group, although one individual had zero copies, a distribution consistent with expectations for normal individuals. The SMA carrier and afflicted patients had elevated copy numbers of SMN2 on average: 5 for the carrier, two afflicted with 3 copies, and the others with 2 copies. The afflicted patients were all diagnosed as SMA Type I, the most severe form, based on clinical observations according to the Coriell repository. The strong genotype/phenotype correlation between SMN2 copy number and disease severity suggests that the two individuals with three copies of SMN2 might have an improved Type II prognosis, especially for the patient SMA 1 who had survived to three years at the time of sampling, much beyond the typical maximum life expectancy for SMA Type I of 2 years. However there remains reluctance to predict disease outcome based on SMN2 copies alone since other less well characterized or unknown modifying genes may impact prognosis and because not all SMN2 copies may be complete genes. Furthermore some Type I patients have begun surviving longer in newer clinical settings. Hence, with little clinical information regarding the patients available to us, we can conclude that our SMN2 assay results were consistent with broad expectations for disease severity.


The SNP assay revealed that all patients carried the normal c.815A genotype and no instances of c.815G were observed. The mutation is relatively rare and hence was not expected to appear in a small patient panel. Of interest, however, was the presence of an apparent extra gene fragment in two unrelated individuals that was uncovered with the SNP assay. The c.815A>G assay does not discriminate between SMN1 and SMN2 due to their high sequence similarity, and hence the total copies of c.815A and G should equal the sum of the copies of SMN1 and SMN2. This was true for all patients except for healthy patients number 1 and 2, both of whom had one extra copy of c.815A. c.815 lies on exon 6, and the SNP that discriminates between the SMN1 and SMN2 genes lies on exon 7, hence the extra genes may be fragments of SMN1 lacking exon 7. This seems reasonable because the deletion of exon 7 is the common mutation causing 95% of cases of SMA (reviewed by Wirth et al.) and it is carried by 1/40 to 1/60 adults. Thus these patients might have been typical carriers of SMA but for the acquisition of at least one compensating healthy copy of SMN1 on the same chromosome.


9-Plex SMA Assay


A 9-plex assay for certain SMA related targets was also demonstrated with just two colors (probes containing FAM and VIC fluorophores). Aside from the optimized primer and probe concentrations, assay conditions and experimental procedures were identical to the 5-plex assay above. FIG. 61a shows the various droplet populations in 2-D histograms before optimization of probe concentrations. The identity of the different targets is shown on the figure itself. As one method of the invention, the identification of the different populations was made as before, by selective exclusion and/or addition of one or more assays. Most of the populations were already well resolved, with the exception of the probe for the c.815A genotype that was in close proximity with the cluster corresponding to empty droplets. After three iterations of optimization of probe concentrations, all of the target populations were well resolved from each other, and well resolved from the empty droplets (FIG. 61b). Three methods of the invention were highlighted in this demonstration: (1) nine DNA targets were uniquely identified in a two-dimensional histogram, far beyond the capabilities of conventional qPCR; (2) target DNA molecules were distinguished on the basis of some combination of both color and intensity arising from one or multiple probes against the same target; and (3) the relative positions of the target molecules within the histogram were adjusted by varying the probe concentrations to optimize the pattern of colors and intensities for increased resolution amongst the various droplet populations.


As one method of the invention, different droplet populations were identified by selective addition or exclusion of assays in the examples above. However the invention is not limited to this method alone. Rather, any method for population assignments known to those in the art are considered. Methods of the invention include any method that can cause an identifiable displacement, appearance, or disappearance of one or more populations within the histograms including changing the probe and primer concentrations together, either by the same factor or by different factors; changing the probe concentration alone; changing the primer concentrations alone; changing the thermal cycling conditions; and changing the master mix composition. Another method of the invention takes advantage of prior knowledge of the position of an assay within a histogram to assist assignment.


Multiplexing Capacity


The level of multiplexing demonstrated in the preceding SMA example was 9×, significantly exceeding the maximum practicable number with qPCR. Without wishing to be constrained by theory, the two main limitations are the resolution between assays and the increasing fluorescence intensity of empty droplets with higher loading of probes. A method of the invention involves optimizing the pattern of colors and intensities of the different probes for maximum multiplexing while still achieving adequate specificity for each individual reaction. Although rectangular arrays of droplet populations were demonstrated for the 5- and 9-plex reactions, another desirable pattern is the tight-packed hexagonal array. However the invention is not constrained to any particular array strategy.


Adding extra colors would increase the capability even further, however with some diminishing returns because the fluorescence of the empty droplets would continue to rise. The capacity could be yet further increased with better probes yielding larger differential signals, such as hybrid 5′-nuclease/molecular beacon probes that reduce background by contact quenching yet exhibit the bright signals typical of free unquenched fluorophores. With such improvements multiplexing capacity exceeding 50× can be envisioned.


Multiplexing with Optical Labeling


Using droplet-based microfluidics, multiple targets can also be measured simultaneously by a different method. According to the alternative method, primers and probes can be loaded individually into droplets along with an optical label to uniquely identify the assay. Typically the optical label is a fluorophore, or a combination of different fluorophores, that are spectrally distinct from the probe fluorophore. Various different types of droplets, each containing different assays that are uniquely identified by different optical labels, can be mixed into a “library” of droplets. Then, according to methods of the invention above, library droplets are merged one-to-one with droplets containing template DNA. After thermal cycling, some droplets that contain template DNA will exhibit brighter fluorescence at the emission wavelengths of the probes. The specific target DNA molecules giving rise to these PCR(+) signals are subsequently identified by the optical probes. In one study, the six common mutations in KRAS codon 12 were screened in parallel in a single experiment by one-to-one fusion of droplets containing genomic DNA with any one of seven different types of droplets (a seven-member library), each containing a TaqMan® probe specific for a different KRAS mutation, or wild-type KRAS, and an optical code.


In one method of the invention, optical labeling can be combined with the various methods for multiplexing dPCR already incorporated into this invention. For example, a single optical label might code for the entire 5-plex SMA assay, above, instead of just a single assay as in the KRAS example above. In this manner, other optical labels might code for different screening assays for newborn infants. According to other methods of the invention, above, a single DNA sample from an infant could then be analyzed with all of the assays simultaneously by merging droplets containing the DNA one-to-one with library droplets containing the optically encoded assays.


As an example of combining multiplexing with optical labels, a so called 3×3×3 combination multiplex reaction with optical labeling was demonstrated (3×3 optical labeling with two fluorophores, each encoding a triplex assay, for a total of 27-plex). Two fluorophores were employed for optical labeling, Alexa633 and CF680 (excited by a 640 nm laser), with three intensity levels each producing nine total optical labels. As before with the 5- and 9-plex assays for SMA, TaqMan assays were used with FAM and VIC fluorophores (excited by a 488 nm laser). The fluorescence from the FAM and VIC fluorophores were recorded simultaneously with the fluorescence from the optical labels, requiring modifications to the optical layout of the instrumentation described for the SMA assay (the optical schematic for two-laser excitation and 4-color detection is shown in entirety in FIG. 62). Also, co-flow microfluidics were used in this example (the use of co-flow based microfluidics for this application is one of the methods of the invention described above). In this case, the template DNA was introduced into the chip in one flow, and the PCR master mix, the primers and probes for one triplex assay, and the unique composition of fluorophores for the optical label were introduced into the chip in another flow simultaneously. The two flow streams converged in a fluidic intersection upstream from the droplet forming module, and thus each droplet formed contained the contents of both flow streams. Methods to implement co-flow microfluidics are well known to those in the art. The droplets were collected, and then the procedure was repeated with the next triplex assay and optical label. The procedure was repeated a total of nine times, once for each pair of assays and optical labels. All of the droplets were collected into a single PCR tube and thermally cycled off chip. The mixture of thermally cycled droplets was reinjected into the same read-out chip as used for the SMA assay, above, and the fluorescence intensities of the assays from all four fluorophores was recorded.



FIG. 63 shows the cumulative results from all droplets in the 3×3×3 assay using co-flow microfluidics. The figure shows two 2-D histograms of droplet fluorescence intensities, the histogram on the left from all of the optical labels, and the histogram on the right from the assays. The contributions from all droplets are shown, that is, from three different triplex assays. (Both panels) 2-D histograms shown as heat maps with hotter colors representing higher droplet counts. (Left panel) histogram of optical labels, i.e. fluorescence intensities of droplets measured at wavelengths for the two fluorophores comprising the optical labels. (Right panel) assay histogram, i.e. fluorescence intensities of droplets measured at wavelengths suitable for FAM detection (x-axis), and VIC detection (y-axis). Both histograms were compensated for spectral overlap by standard techniques.


Standard methods were used to compensate for spectral overlap. The histograms if FIG. 63 are shown as a heat maps, with hotter colors designating larger numbers of droplets. Nine different clusters of droplets were clearly evident in the histogram of the optical labels, corresponding to each of the nine different optical labels: there is a small group of four clusters at the bottom left corner of the histogram, corresponding to optical labels with the lowest fluorescent intensities; and there are five clusters appearing as linear streaks at the higher intensities. The droplet clusters were less distinct in the histogram, but this was as expected because the droplets shown contained all of the triplex assays. The individual assays became clearly distinct once a single type of assay was selected by using the optical labels, as follows.


Methods of the invention involve selecting individual populations of droplets all containing the same optical labels, or groups of optical labels. In some methods of the invention, boundaries of fluorescence intensity were used to specify populations. In the example shown here, a rectangular boundary was used specifying the minimum and maximum fluorescence intensities for each fluorophore. However the methods of the invention are not restricted to rectangular boundaries. Any boundary, closed or unclosed, can be employed. Furthermore, according to methods of the invention, selections of droplet populations can be made by any method, and is not restricted to threshold-based methods such as boundary selection.



FIG. 64A shows the droplet fluorescence intensities for the assay (right histogram) when only one optical label was selected (left histogram). Selections were taken from all of the droplets from FIG. 64A-C. Each of the three different selections in panels A-C were for optical labels encoding the same assay (TERT, SMN1, and SMN2). Histograms are as described in FIG. 63. (Left histograms, optical labels) Superimposed lines demark the bounding box for selecting a single optical label. (Right histograms, assay) Only droplets containing the selected optical label are displayed.


The lines overlaid on the histogram of the optical labels identify the rectangular boundary used to select just the optical label with the lowest fluorescence for both fluorophores. Both histograms showed only the droplets that were selected. After selection, four distinct clusters of droplets appeared in the assay histogram, three for the different assays (in this case, assays for SMN1, SMN2, and TERT, where TERT is another common reference gene) and one for the empty droplets. The copy numbers for SMN1 and SMN2 were measured by the same methods of the invention as described above for the 5-plex SMA assay, with values of 1.8 and 0.94 close to the expected values of 2 and 1, respectively. The same assay was encoded with two other optical labels, and their selections are shown in FIGS. 20B and C. Similar results were achieved, with an overall measurement of 1.9±0.1 and 0.9±0.1 copies of SMN1 and SMN2 respectively, showing the measurement to be accurate within experimental uncertainty.



FIGS. 65A, B, and C show optical label selections for a different assay (TERT, c.5C in the SMN1 gene, and BCKDHA (labeled E1a in the figure)). Selections were taken from all of the droplets from FIG. 19. Each of the three different selections in panels A-C were for optical labels encoding the same assay (TERT, c.5C from SMN1, and BCKDHA). Histograms are as described in FIG. 63. (Left histograms, optical labels) Superimposed lines demark the bounding box for selecting a single optical label. (Right histograms, assay) Only droplets containing the selected optical label are displayed.


In each case shown in FIG. 65A-C four distinct clusters also appeared, and accurate measurements of gene copy number were made for c.5C and BCKDHA, referenced to TERT, of 2.9±0.1 and 2.0±0.2 compared to 3 and 2, respectively.



FIGS. 66, B, and C show optical label selections for a third assay (TERT, c.88G in the SMN1 gene, and RNaseP, where RNaseP is a common reference gene). Selections were taken from all of the droplets from FIG. 63. Each of the three different selections in panels A-C were for optical labels encoding the same assay (TERT, c.88G from SMN1, and BCKDHA). Histograms are as described in FIG. 63. (Left histograms, optical labels) Superimposed lines demark the bounding box for selecting a single optical label. (Right histograms, assay) Only droplets containing the selected optical label are displayed. Accurate gene copy numbers of 2.1±0.1 were measured for both c.88G and RNaseP, referenced to TERT, compared to the expected value of 2.


In summary, the demonstration here shows use of nine different optical labels to enable independent measurement of three triplex assays in a single experiment. Although some of the optical labels encoded for redundant assays in this example (there were only three different assays despite having nine optical labels), the invention is not constrained to any particular formatting of assays and optical labels. Embodiments of the invention include formats where all of the assays are the same across all of the optical labels; where none of the assays are the same across all of the optical labels; where some of the assays are the same across all of the optical labels; where some of the assays have greater plexity than others across all of the optical labels; where all of the assays have the same plexity across all of the optical labels; and any other arrangements of assays across all of the optical labels are considered.


Although two different fluorophores were used to create the optical labels in this example, the invention is not constrained to any particular number of fluorophores comprising the optical labels. Embodiments of the invention include optical labels comprised of 1 fluorophore, or 2 fluorophores, or 3 fluorophores, or 4 fluorophores, or up to 10 fluorophores, or up to 20 fluorophores. Optical labels can also comprise more than 20 fluorophores. Although solely triplex assays were used in the example demonstration here, the invention is not constrained to use of triplex assays with optical labels. Embodiments of the invention include plexities of the following amounts when used with optical labels: single plex, duplex, triplex, 4-plex, up to 10-plex, up to 20-plex, up to 50-plex, and up to 100-plex. Embodiments of the invention also include plexities exceeding 100 when used with optical labels.


Another method of the invention involves the use of droplet merging, instead of co-flow, for combining multiplexing with optical labels. A demonstration using droplet merging was performed with the same 3×3×3 assay as in the preceding example with co-flow. The assays (probes and primers) combined with their unique optical labels were first encapsulated into droplets along with the PCR master mix. Subsequently, according to methods of the invention described above, a library containing a mixture of droplets from all nine optically labeled assays was merged one-to-one with droplets containing template DNA from the same patient as in the preceding example. As another method of the invention, the droplet merge was performed using a lambda-injector style merge module, as described in U.S. Provisional Application, Ser. No. 61/441,985, incorporated by reference herein. Aside from the differences between co-flow and merge, the assays and experimental procedures were identical to those above for the co-flow experiment. FIG. 67A-J shows 2-D histograms of droplet fluorescence intensity for the optical labels and the assays that are similar to those in FIGS. 63-66. FIG. 67A-J depicts a dPCR assay combining multiplexing with optical labels using droplet merging. As in the case for co-flow, upon selection of droplets containing individual optical labels, the expected distinct clusters of droplets corresponding to each assay were clearly evident. Furthermore for each assay the measured gene copy number matched or very nearly matched the expected values within experimental uncertainty (See FIG. 46).


Although methods of the invention include using either microfluidics with co-flow or droplet merging, the invention is not limited in this regard. Any fluidic method capable of generating optically labeled droplets that also contain fluorogenic DNA hybridization probes are considered. For example, other embodiments well known in the art are mixing optical labels and assays in the macrofluidic environment before injection into a droplet generating chip; and mixing optical labels and assays thoroughly upstream from the droplet forming module in dedicated mixing modules, such as with a serpentine mixer.


Data Analysis


One method of the invention involves histogram-based data presentation and analysis for identifying and characterizing populations of statistically similar droplets that arise from unique probe signatures (color and intensity), and for discriminating one population of droplets from the others. Another method of the invention involves histogram-based data presentation and analysis for identifying and selecting populations of droplets based on unique signatures from optical labels. Examples of one and two-dimensional histograms have been provided for these methods, but the invention is not limited in this regard. As described above, it is anticipated that greater numbers of colors will be used for both multiplexing and for optical labels. Hence, embodiments of the invention include histograms of dimensionality greater than two, such as 3, or 4, or up to 10, or up to 20. Histograms of dimensionality greater than 20 are also incorporated into the invention.


Another method of the invention involves the selection of droplets within histograms, either for counting, or for assay selection as in the use of optical labels, or for any other purpose. Methods of the invention include selections by boundaries, either closed or unclosed, of any possible shape and dimension. Methods of the invention also include selections of droplets that exhibit fluorescence from single types of fluorophores, or from multiple types of fluorophores, such as arising from multiple probes against a common DNA target.


EXAMPLES

The following examples, including the experiments conducted and results achieved are provided for illustrative purposes only and are not to be construed as limiting upon the present invention.


Example 1: Oligonucleotide Labeling of Single Cell Genomes

Barcoding of single cell genomes is performed following encapsulation, cell lysis, and temperature-sensitive proteolysis of single cells in droplets (see FIG. 40A-B for overall workflow). Single cell droplets are generated using a limited dilution regime loading of a dispersed cell suspension into a microfluidic droplet generation device (as previously described). Additional droplet manipulations can also be performed (e.g. droplet sorting) in advance of the step where the droplets are combined with the labeling droplet library. After combining the single genome-containing droplets with barcoded droplet libraries, and either multiple displacement amplification (MDA) enzymes for whole genome amplification (WGA) (e.g. using the enzyme phi29 (see FIG. 21)), transposase enzymes (see FIG. 22)), or other amplification enzymes and reagents, each cell's genome becomes labeled with a barcode that will identify the amplified genomic loci as coming from a unique genome during subsequent sequencing and analysis. In the example scheme shown in FIG. 21 for MDA WGA, the ‘tailed barcoded primer’ labeling reagent is tri-partite, with a universal tail portion (e.g., oligonucleotide sequences for use in sequencing library construction) immediately 5′ to a barcode sequence, followed by one of a set of random hexamer bases that enable priming from multiple places in the genome. In the example scheme for using a transposase (FIG. 22), the ‘tailed barcoded primer’ labeling reagent is bi-partite, with a universal tail portion immediately 5′ to a barcode sequence. The labeling enzyme and any required buffer or co-reaction component can either be included in the primer droplet library or added subsequently via droplet fusion methods. Data regarding the cell lysis and temperature-responsive proteolysis steps are shown in FIG. 41. Data regarding whole genome amplification using phi29 in droplets is shown in FIG. 42.


Example 2: Oligonucleotide Labeling of Single Chromosomes

Barcoding of single chromosomes can be performed following encapsulation of individual chromosomes in droplets (see FIG. 43 for overall workflow). First cells are treated (e.g. nocadazole) to cause metaphase arrest (synchronizing the cell cycle and condensing the chromosomes) and the cell membranes are lysed (e.g. osmotic pressure) to release the condensed chromosomes. Limited proteolysis separates the chromosome pairs into individual chromatids. Single-chromosome droplets are generated using a limited dilution regime loading of a dispersed chromatid suspension into a microfluidic droplet generation device (previously described). Additional droplet manipulations can also be performed (e.g. droplet sorting, additional proteolysis using a thermo-responsive protease) in advance of the step where the droplets are combined with the labeling droplet library. After combining the single chromosome-containing droplets with barcoded droplet libraries, and either MDA enzymes for WGA (e.g. phi29) (see FIG. 21) or transposase enzymes (see FIG. 22), each chromosome becomes labeled with a barcode that will identify the amplified genomic locus as coming from a unique chromosome during subsequent sequencing and post-process analysis.


Example 3: Oligonucleotide Labeling of Single Cell RNAs

Barcoding of single cell RNAs can be performed following encapsulation and lysis of single cells in droplets (see FIG. 23A-B for overall workflow). Single cell droplets are first generated using limited dilution regime loading of a dispersed cell suspension into a microfluidic droplet generation device (previously described). Additional droplet manipulations can also be performed (e.g. droplet sorting) in advance of the step where the droplets are combined with the labeling droplet library. One can choose to label and recover several types of RNA collections: polyA-tailed mRNA (using poly dT affinity reagents), sequence-selected subsets of RNA species using sequence-specific primers, or other subsets (e.g. using random hexamer primers). The example scheme described here (and shown in FIG. 23A-FIG. 26B) is for recovering and labeling the entire polyA+ mRNA compliment of a cell, i.e. the transcriptome. For this example (FIG. 23A-B), the ‘biotinylated tailed barcoded primer’ labeling reagent is tri-partite, with a biotinylated universal tail portion (including a 5′ biotinylated oligonucleotide sequence that will be used for both capture onto streptavidin beads and for use in subsequent amplification) immediately 5′ to a barcode sequence, followed by a string of T's (poly dT) ending in an ‘anchoring’ sequence (NV; with V degenerate for the 3 bases other than T, and N degenerate for all bases). Example workflows are shown in FIG. 23A-B (Flow Chart), FIG. 24 (including optional upfront sorting, and cell lysis within droplets using a temperature-inducible protease), FIG. 40A-B (including optional upfront sorting, and cell lysis within droplets using a detergent and heat), and FIG. 26A-B (capture beads are included in the droplet library). Following combination of the lysed cell droplet with the barcoded mRNA capture primer library, the droplets are incubated for a time sufficient for binding the mRNA to the primer library, and the resulting hybrids are subsequently released from the droplet emulsion by addition of a droplet destabilizing reagent. The aqueous phase containing the mRNA hybridized to the biotinylated capture primers is incubated with immobilized streptavidin (or a workflow is used that includes capture beads in the primer droplet library, see FIG. 40A-B), and the bound complexes are washed in preparation for reverse transcription using the universal tail primer. The resulting material from these procedures is barcoded first strand cDNA, with all of the mRNA from each individual cell encoded with the same barcode. Standard steps for processing cDNA for sequencing are performed, and sequencing of this collection will provide a digital count of each captured mRNA assigned to a barcode that is unique for each cell. The above process can be conducted on selected RNAs from the transcriptome using the procedure outline above or using sequence-specific capture primers.


Example 4: Oligonucleotide Labeling of Single DNA Molecules

Haplotype-like information about variation in DNA sequence along a contiguous stretch of DNA is challenging to acquire using current sample prep and sequencing technologies. In particular, there is a need for determining ‘haplotype phasing’ of long stretches of genomic sequence data derived from ‘short read’ sequencing platforms. Individual single nucleotide polymorphism (SNP) and collections of SNPs can be determined, but the assignment of a series of SNPs to either of the 2 alleles present in a diploid genome cannot be performed beyond the ‘read-length’ of the sequencing platform (unless individual chromosomes are isolated for sequencing). By including barcodes in multiplexed tiled PCR reactions within droplets, this aspect of the invention enables ‘haplotype phase’ assignments to be made using current short-read sequencing platforms, and allows this haplotype information to be correlated with patient's disease propensity, and ultimately to be used as a genomic biomarker for disease propensity and therapeutic treatment.


As an example, the Illumina sequencing platform generates sequence data with a read length of 125 bp per amplicon. If paired-end reads are used, one can potentially generate high quality reads 125 bp from both ends of a 250 bp amplicon. As each 250 bp amplicon is generated from a single molecule of target DNA, any number of SNPs identified along this amplicon are unambiguously ‘in phase’ with each other, allowing a ‘haplotype’ to be defined for this 250 bp region. However, it is not currently possible to get phased haplotype information across a longer target DNA stretch using ‘tiled’ amplicons, as sequence from adjacent 250 bp amplicons could come from either allele in the sample, and one would need to know that the tiled amplicons were all generated from the same DNA template strand.


Several aspects of the invention are combined to enable assignment of a series of SNPs to target DNA stretches longer than the read-length of the sequencing platform, such as a PCR primer library that contains primers with a large number of barcodes, multiplexed PCR primers that will not cross-hybridize with each other and which will uniquely amplify the target DNA locus, and droplet based amplification. The overall workflow example is shown in FIG. 35A-B. Optionally, the target locus can be pre-amplified using a single pair of PCR primers that flanks the entire locus, before appropriate loading of the sample into droplets for amplification and barcoding (not depicted in the workflow in FIG. 35A-B).


In an exemplary embodiment, the ‘tailed barcoded primer’ labeling reagent is tri-partite, with a universal tail portion (for use in subsequent amplification) immediately 5′ to a barcode sequence followed by the sequence-specific targeting primer bases. A primer droplet library ‘member’ includes a droplet that contains all of the targeted primers sufficient for covering the target bases, each with the same barcode that will enable post-sequencing correlation to the target strand. The number of library members is determined by the ratio of barcode number to the number of target alleles to be analyzed. By way of example, without limitation, FIG. 35A-B shows 100 cells as input, with 4000 barcodes giving a 1/10 chance of duplicate barcodes for any allele. In this example, the DNA from 100 cells provides 400 target alleles, which is loaded (together with polymerase, buffer, and nucleotides) into one million droplets and combined with the barcoding primer library to generate a PCR-competent droplet emulsion. As an example for a 3 kb target region, 13 tiled primer pairs can be used to cover all of the target bases. Fewer primer pairs can be used if only subsets of the target bases need to be phased. After thermocycling, the amplified products are released into a single bulk aqueous phase (e.g., using a droplet de-stabilizing reagent), and a subsequent PCR reaction is performed using the universal primer tail and any sequencing platform-specific adaptor (and additional barcodes) needed before sequencing. Examples of the PCR inputs and outputs are shown in FIG. 11A-C. Using a yield threshold of ˜150 sequencing reads as being more than sufficient for high confidence SNP calling, the total number of PCR cycles (droplet PCR plus bulk PCR) can be limited to 10 cycles (sufficient to generate 150 copies).


Example 5: Oligonucleotide Labeling of Digital Sandwich Assays with dPCR Readout

Barcoding of digital sandwich assays is performed using barcoded binders and capture tagged-binders (e.g. antibody ELISA pair) constructed in a similar manner as shown in FIG. 33A-B or FIG. 37A-J, constituting a sandwich assay barcoded binder library. The overall workflow for the droplet barcoded sandwich assay is shown in FIG. 70A-B: A) Two binding reagents types are constructed: Barcoded Binders and Capture-Tag Binders; B) Pairs of target-specific binders are made into a droplet library, with each set of target binders in separate droplets; C) The sample is made into sample droplets, and D) combined with the library droplets to initiate highly parallel ‘single-plex’ binding reactions. After binding is complete, productive sandwiches are E) captured via the capture-tag (e.g. streptavidin (SA) biotin (B) interaction shown), and washed to remove unbound material; F) The captured barcodes are released, recovered, and processed for reading; G) Reads for each barcode are counted.


In this example the barcodes added to the barcoded binders are constituted such that they are targets for dPCR analysis, with optimized barcode sequences that enable optically resolved multiplex dPCR analysis. For example, if an optimized set of 15 barcode targets is constructed for identification of 15 different target proteins, then counting the number of each barcode type using the optimized dPCR readout will enable a 15-plex sandwich assay (e.g. 15 different cytokines can be quantified from a blood sample after combination with the Sandwich Assay Barcoded Binder Library and readout using a 16-plex optimized dPCR scheme with 4 concentrations of FAM and 4 concentrations of VIC TaqMan probes).


In addition, the dPCR optimized barcodes can be sticky-ended, enabling additional barcoding information to be added (e.g. a sticky-ended barcode present in the sample droplet can be ligated to the barcoded binder, such that the final released barcode has an additional motif that can include a fluorescent moiety that is optically resolved from FAM and VIC, enabling higher-plex analysis).


EQUIVALENTS

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The foregoing embodiments are therefore to be considered in all respects illustrative rather than limiting on the invention described herein.


INCORPORATION BY REFERENCE

References and citations to other documents, such as patents, patent applications, patent publications, journals, books, papers, web contents, have been made throughout this disclosure. All such documents are hereby incorporated herein by reference in their entirety for all purposes.

Claims
  • 1. A method for protein detection, the method comprising: introducing a protein-specific binding reagent linked to an oligonucleotide barcode to a sample comprising a population of cells;encapsulating the cells in sample droplets such that each sample droplet comprises a single cell and said protein-specific binding reagent by merging droplets containing said cells and said protein-specific binding reagents; anddetermining the presence of proteins of said cells that are bound to said protein-specific binding reagents.
  • 2. The method of claim 1, further comprising the step of lysing said cells.
  • 3. The method of claim 1, wherein said protein-specific binding reagent is selected from an antibody, an aptamer, a nucleic acid-labeled protein.
  • 4. The method of claim 1, wherein the protein-specific binding reagents are coupled to beads.
  • 5. The method of claim 1, wherein the protein-specific binding reagents are cleavable from the proteins to which they bind.
  • 6. The method of claim 1, wherein the proteins are cell-surface proteins.
  • 7. The method of claim 1, wherein the encapsulating step comprises loading the cells into a microfluidic chip.
  • 8. The method of claim 1, wherein the protein-specific binding reagents further comprise a universal binding site.
  • 9. The method of claim 1, further comprising quantifying the proteins.
  • 10. The method of claim 1, wherein the oligonucleotide barcodes linked to the protein-specific binding reagents have ligation-competent ends and the method includes ligating copies of droplet-identifying barcodes to the oligonucleotide barcodes linked to said protein-specific binding reagents.
  • 11. The method of claim 2, wherein lysing occurs within said droplets.
REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. Nonprovisional application Ser. No. 16/400,858, filed May 1, 2019, which is a continuation is a continuation of U.S. Nonprovisional application Ser. No. 14/995,744, filed Jan. 14, 2016, which is a continuation of U.S. Nonprovisional application Ser. No. 14/874,553, filed Oct. 5, 2015, which is a continuation of U.S. Nonprovisional application Ser. No. 13/398,677, filed Feb. 16, 2012, which claims the benefit of U.S. Provisional Application Ser. No. 61/444,612, filed Feb. 18, 2011, and U.S. Provisional Application Ser. No. 61/476,714, filed Apr. 18, 2011. The above-referenced applications are incorporated by reference herein in their entireties.

US Referenced Citations (1191)
Number Name Date Kind
2097692 Fiegel Nov 1937 A
2164172 Dalton Jun 1939 A
2636855 Schwartz Apr 1953 A
2656508 Coulter Oct 1953 A
2692800 Nichols et al. Oct 1954 A
2797149 Skeggs Jun 1957 A
2879141 Skeggs Mar 1959 A
2971700 Peeps Feb 1961 A
3479141 Smythe et al. Nov 1969 A
3608821 Simm et al. Sep 1971 A
3621059 Bartlett Nov 1971 A
3658430 Rashkin et al. Apr 1972 A
3698635 Sickles Oct 1972 A
3784471 Kaiser Jan 1974 A
3816331 Brown, Jr. et al. Jun 1974 A
3828085 Price et al. Aug 1974 A
3930061 Scharfenberger Dec 1975 A
3960187 Stock et al. Jun 1976 A
3980541 Aine Sep 1976 A
3982541 L'Esperance, Jr. Sep 1976 A
4014469 Sato Mar 1977 A
4022575 Hansen et al. May 1977 A
4034966 Suh et al. Jul 1977 A
4059552 Zweigle et al. Nov 1977 A
4091042 Alexanderson et al. May 1978 A
4117550 Folland et al. Sep 1978 A
4130394 Negersmith Dec 1978 A
4210809 Pelavin Jul 1980 A
4253846 Smythe et al. Mar 1981 A
4266721 Sickles May 1981 A
4279345 Allred Jul 1981 A
4297345 Howarth Oct 1981 A
4315754 Ruzicka et al. Feb 1982 A
4378957 Malkin et al. Apr 1983 A
4383767 Jido May 1983 A
4439980 Biblarz et al. Apr 1984 A
4508265 Jido Apr 1985 A
4533634 Maldonado et al. Aug 1985 A
4566908 Nakatani et al. Jan 1986 A
4585209 Aine et al. Apr 1986 A
4618476 Columbus Oct 1986 A
4675285 Clark et al. Jun 1987 A
4676274 Brown Jun 1987 A
4683195 Mullis et al. Jul 1987 A
4683202 Mullis Jul 1987 A
4739044 Stabinsky Apr 1988 A
4757141 Fung et al. Jul 1988 A
4767515 Scott et al. Aug 1988 A
4767929 Valentine Aug 1988 A
4779805 Jackson et al. Oct 1988 A
4795330 Noakes et al. Jan 1989 A
4801086 Noakes Jan 1989 A
4801529 Perlman Jan 1989 A
4829996 Noakes et al. May 1989 A
4853336 Saros et al. Aug 1989 A
4856363 LaRocca et al. Aug 1989 A
4859363 Davis et al. Aug 1989 A
4865444 Green et al. Sep 1989 A
4883750 Whiteley et al. Nov 1989 A
4908112 Pace Mar 1990 A
4931225 Cheng Jun 1990 A
4941959 Scott Jul 1990 A
4962885 Coffee Oct 1990 A
4963498 Hillman et al. Oct 1990 A
4981580 Auer Jan 1991 A
4996004 Bucheler et al. Feb 1991 A
5055390 Weaver et al. Oct 1991 A
5091652 Mathies et al. Feb 1992 A
5096615 Prescott et al. Mar 1992 A
5104813 Besemer et al. Apr 1992 A
5122360 Harris et al. Jun 1992 A
5149625 Church et al. Sep 1992 A
5180662 Sitkovsky Jan 1993 A
5185099 Delpuech et al. Feb 1993 A
5188290 Gebauer et al. Feb 1993 A
5188291 Cross Feb 1993 A
5192659 Simons Mar 1993 A
5204112 Hope et al. Apr 1993 A
5207973 Harris et al. May 1993 A
5241159 Chatteriee et al. Aug 1993 A
5260466 McGibbon Nov 1993 A
5262027 Scott Nov 1993 A
5270163 Gold et al. Dec 1993 A
5296375 Kricka et al. Mar 1994 A
5304487 Wilding et al. Apr 1994 A
5310653 Hanausek-Walaszek et al. May 1994 A
5313009 Guenkel et al. May 1994 A
5333675 Mullis et al. Aug 1994 A
5344489 Matijevic et al. Sep 1994 A
5344594 Sheridon Sep 1994 A
5354670 Nickoloff et al. Oct 1994 A
5376252 Ekstrom et al. Dec 1994 A
5378957 Kelly Jan 1995 A
5397605 Barbieri et al. Mar 1995 A
5399461 Van et al. Mar 1995 A
5399491 Kacian et al. Mar 1995 A
5403617 Haaland Apr 1995 A
5413924 Kosak et al. May 1995 A
5417235 Wise et al. May 1995 A
5427946 Kricka et al. Jun 1995 A
5445934 Fodor et al. Aug 1995 A
5452878 Gravesen et al. Sep 1995 A
5452955 Lundstrom Sep 1995 A
5454472 Benecke et al. Oct 1995 A
5460945 Springer et al. Oct 1995 A
5468613 Erlich et al. Nov 1995 A
5475096 Gold et al. Dec 1995 A
5475610 Atwood et al. Dec 1995 A
5480614 Kamahori Jan 1996 A
5486335 Wilding et al. Jan 1996 A
5498392 Wilding et al. Mar 1996 A
5498523 Tabor et al. Mar 1996 A
5500415 Dollat et al. Mar 1996 A
5503851 Mank et al. Apr 1996 A
5512131 Kumar et al. Apr 1996 A
5516635 Ekins et al. May 1996 A
5518709 Sutton et al. May 1996 A
5523162 Franz et al. Jun 1996 A
5587128 Wilding et al. Dec 1996 A
5589136 Northrup et al. Dec 1996 A
5602756 Atwood et al. Feb 1997 A
5604097 Brenner Feb 1997 A
5610016 Sato et al. Mar 1997 A
5612188 Shuler et al. Mar 1997 A
5616478 Chetverin et al. Apr 1997 A
5617997 Kobayashi et al. Apr 1997 A
5635358 Wilding et al. Jun 1997 A
5636400 Young Jun 1997 A
5641658 Adams et al. Jun 1997 A
5643729 Taniguchi et al. Jul 1997 A
5655517 Coffee Aug 1997 A
5656155 Norcross et al. Aug 1997 A
5656493 Mullis et al. Aug 1997 A
5661222 Hare Aug 1997 A
5662874 David Sep 1997 A
5670325 Lapidus et al. Sep 1997 A
5681600 Antinone et al. Oct 1997 A
5695934 Brenner Dec 1997 A
5726026 Wilding et al. Mar 1998 A
5726404 Brody Mar 1998 A
5733526 Trevino et al. Mar 1998 A
5739036 Parris Apr 1998 A
5744366 Kricka et al. Apr 1998 A
5750988 Apffel et al. May 1998 A
5762775 DePaoli Jun 1998 A
5779868 Parce et al. Jul 1998 A
5783431 Peterson et al. Jul 1998 A
5789206 Tavtigian et al. Aug 1998 A
5813988 Alfano et al. Sep 1998 A
5830633 Matsumoto Nov 1998 A
5830663 Embleton et al. Nov 1998 A
5840506 Giordano Nov 1998 A
5846719 Brenner et al. Dec 1998 A
5849491 Radomski et al. Dec 1998 A
5851769 Gray et al. Dec 1998 A
5858187 Ramsey et al. Jan 1999 A
5858655 Arnold Jan 1999 A
5858670 Lam et al. Jan 1999 A
5863722 Brenner Jan 1999 A
5868322 Loucks Feb 1999 A
5872010 Karger et al. Feb 1999 A
5876771 Sizer et al. Mar 1999 A
5880071 Parce et al. Mar 1999 A
5882680 Suzuki et al. Mar 1999 A
5882856 Shuber Mar 1999 A
5884846 Tan Mar 1999 A
5887755 Hood, III Mar 1999 A
5888746 Tabiti et al. Mar 1999 A
5888778 Shuber Mar 1999 A
5904933 Riess et al. May 1999 A
5921678 Desai et al. Jul 1999 A
5927852 Serafin Jul 1999 A
5928870 Lapidus et al. Jul 1999 A
5932100 Yager et al. Aug 1999 A
5935331 Naka et al. Aug 1999 A
5942056 Singh Aug 1999 A
5942443 Parce et al. Aug 1999 A
5958203 Parce et al. Sep 1999 A
5972187 Parce et al. Oct 1999 A
5980936 Krafft et al. Nov 1999 A
5989815 Skolnick et al. Nov 1999 A
5989892 Nishimaki et al. Nov 1999 A
5995341 Tanaka et al. Nov 1999 A
5997636 Gamarnik et al. Dec 1999 A
6008003 Haak-Frendscho et al. Dec 1999 A
6023540 Walt et al. Feb 2000 A
6028066 Unger Feb 2000 A
6042709 Parce et al. Mar 2000 A
6045755 Lebl et al. Apr 2000 A
6046056 Parce et al. Apr 2000 A
6048551 Hilfinger et al. Apr 2000 A
6048690 Heller et al. Apr 2000 A
6068199 Coffee May 2000 A
6074879 Zelmanovic et al. Jun 2000 A
6080295 Parce et al. Jun 2000 A
6081612 Gutkowicz-Krusin et al. Jun 2000 A
6086740 Kennedy Jul 2000 A
6096495 Kasai et al. Aug 2000 A
6103537 Ullman et al. Aug 2000 A
6105571 Coffee Aug 2000 A
6105877 Coffee Aug 2000 A
6107059 Hart Aug 2000 A
6116516 Ganan-Calvo Sep 2000 A
6118849 Tanimori et al. Sep 2000 A
6119953 Ganan-Calvo et al. Sep 2000 A
6120666 Jacobson et al. Sep 2000 A
6124388 Takai et al. Sep 2000 A
6124439 Friedman et al. Sep 2000 A
6130052 Van Baren et al. Oct 2000 A
6130098 Handique et al. Oct 2000 A
6137214 Raina Oct 2000 A
6138077 Brenner Oct 2000 A
6139303 Reed et al. Oct 2000 A
6140053 Koster Oct 2000 A
6143496 Brown et al. Nov 2000 A
6146828 Lapidus et al. Nov 2000 A
6149789 Benecke et al. Nov 2000 A
6150180 Parce et al. Nov 2000 A
6150516 Brenner et al. Nov 2000 A
6155710 Nakajima et al. Dec 2000 A
6162421 Ordino et al. Dec 2000 A
6165778 Kedar Dec 2000 A
6171796 An et al. Jan 2001 B1
6171850 Nagle et al. Jan 2001 B1
6172214 Brenner Jan 2001 B1
6172218 Brenner Jan 2001 B1
6174160 Ee et al. Jan 2001 B1
6174469 Ganan-Calvo Jan 2001 B1
6177479 Nakajima Jan 2001 B1
6180372 Franzen Jan 2001 B1
6184012 Neri et al. Feb 2001 B1
6187214 Ganan-Calvo Feb 2001 B1
6189803 Ganan-Calvo Feb 2001 B1
6196525 Ganan-Calvo Mar 2001 B1
6197335 Sherman Mar 2001 B1
6197835 Ganan-Calvo Mar 2001 B1
6203993 Shuber et al. Mar 2001 B1
6207372 Shuber Mar 2001 B1
6207397 Ynch et al. Mar 2001 B1
6208749 Gutkowicz-Krusin et al. Mar 2001 B1
6210396 MacDonald et al. Apr 2001 B1
6210891 Nyren et al. Apr 2001 B1
6210896 Chan Apr 2001 B1
6214558 Shuber et al. Apr 2001 B1
6221654 Quake et al. Apr 2001 B1
6227466 Hartman et al. May 2001 B1
6234402 Ganan-Calvo May 2001 B1
6235383 Hong et al. May 2001 B1
6235475 Brenner et al. May 2001 B1
6241159 Ganan-Calvo et al. Jun 2001 B1
6243373 Turock Jun 2001 B1
6248378 Ganan-Calvo Jun 2001 B1
6251661 Urabe et al. Jun 2001 B1
6252129 Coffee Jun 2001 B1
6258568 Nyren Jul 2001 B1
6258858 Nakajima et al. Jul 2001 B1
6261661 Ohno et al. Jul 2001 B1
6261797 Sorge et al. Jul 2001 B1
6263222 Diab et al. Jul 2001 B1
6266459 Walt et al. Jul 2001 B1
6267353 Friedline et al. Jul 2001 B1
6267858 Parce et al. Jul 2001 B1
6268152 Fodor et al. Jul 2001 B1
6268165 O'Brien Jul 2001 B1
6268222 Chandler et al. Jul 2001 B1
6274320 Rothberg et al. Aug 2001 B1
6274337 Parce et al. Aug 2001 B1
6280948 Guilfoyle et al. Aug 2001 B1
6292756 Lievois et al. Sep 2001 B1
6294344 O'Brien Sep 2001 B1
6296020 McNeely et al. Oct 2001 B1
6296673 Santarsiero et al. Oct 2001 B1
6299145 Ganan-Calvo Oct 2001 B1
6301055 Egrand et al. Oct 2001 B1
6306659 Parce et al. Oct 2001 B1
6307957 Gutkowicz-Krusin et al. Oct 2001 B1
6309842 Dower et al. Oct 2001 B1
6310354 Hanninen et al. Oct 2001 B1
6310653 Malcolm, Jr. et al. Oct 2001 B1
6316208 Roberts et al. Nov 2001 B1
6316213 O'Brien Nov 2001 B1
6318640 Coffee Nov 2001 B1
6324417 Cotton Nov 2001 B1
6326145 Whitcombe et al. Dec 2001 B1
6336463 Ohta Jan 2002 B1
6344325 Quake et al. Feb 2002 B1
6352828 Brenner Mar 2002 B1
6355193 Stott Mar 2002 B1
6355198 Kim et al. Mar 2002 B1
6357670 Ganan-Calvo Mar 2002 B2
6386463 Ganan-Calvo May 2002 B1
6391559 Brown et al. May 2002 B1
6394429 Ganan-Calvo May 2002 B2
6399339 Wolberg et al. Jun 2002 B1
6399389 Parce et al. Jun 2002 B1
6403373 Scanlan et al. Jun 2002 B1
6405936 Ganan-Calvo Jun 2002 B1
6408878 Unger et al. Jun 2002 B2
6409832 Weigl et al. Jun 2002 B2
6428053 Tai et al. Aug 2002 B1
6429025 Parce et al. Aug 2002 B1
6429148 Chu et al. Aug 2002 B1
6432143 Kubiak et al. Aug 2002 B2
6432148 Ganan-Calvo Aug 2002 B1
6432630 Blankenstein Aug 2002 B1
6439103 Miller Aug 2002 B1
6440706 Vogelstein et al. Aug 2002 B1
6440760 Cho et al. Aug 2002 B1
6450139 Watanabe Sep 2002 B1
6450189 Ganan-Calvo Sep 2002 B1
6454193 Busick et al. Sep 2002 B1
6464336 Sharma Oct 2002 B1
6464886 Ganan-Calvo Oct 2002 B2
6469094 Keoshkerian et al. Oct 2002 B1
6475441 Parce et al. Nov 2002 B1
6481648 Zimmermann Nov 2002 B1
6489103 Griffiths et al. Dec 2002 B1
6503933 Moloney et al. Jan 2003 B1
6506609 Wada et al. Jan 2003 B1
6508988 Van Dam et al. Jan 2003 B1
6511803 Church et al. Jan 2003 B1
6520425 Reneker Feb 2003 B1
6524456 Ramsey et al. Feb 2003 B1
6530944 West et al. Mar 2003 B2
6540395 Muhlbauer et al. Apr 2003 B2
6540895 Spence et al. Apr 2003 B1
6551836 Chow et al. Apr 2003 B1
6553944 Allen et al. Apr 2003 B1
6553960 Yoshikawa et al. Apr 2003 B1
6554202 Ganan-Calvo Apr 2003 B2
6557334 Jager May 2003 B2
6557834 Ganan-Calvo May 2003 B2
6558944 Parce et al. May 2003 B1
6558960 Parce et al. May 2003 B1
6560030 Legrand et al. May 2003 B2
6565010 Anderson et al. May 2003 B2
6569631 Pantoliano et al. May 2003 B1
6576420 Carson et al. Jun 2003 B1
6591852 McNeely et al. Jul 2003 B1
6592321 Bonker et al. Jul 2003 B2
6592821 Wada et al. Jul 2003 B1
6601613 McNeely et al. Aug 2003 B2
6608726 Legrand et al. Aug 2003 B2
6610499 Fulwyler et al. Aug 2003 B1
6614598 Quake et al. Sep 2003 B1
6627603 Bibette et al. Sep 2003 B1
6630006 Santarsiero et al. Oct 2003 B2
6630353 Parce et al. Oct 2003 B1
6632619 Harrison et al. Oct 2003 B1
6637463 Lei et al. Oct 2003 B1
6638749 Beckman et al. Oct 2003 B1
6645432 Anderson et al. Nov 2003 B1
6646253 Rohwer et al. Nov 2003 B1
6653626 Fischer et al. Nov 2003 B2
6656267 Newman Dec 2003 B2
6659370 Inoue Dec 2003 B1
6660252 Matathia et al. Dec 2003 B2
6670142 Lau et al. Dec 2003 B2
6679441 Borra et al. Jan 2004 B1
6680178 Harris et al. Jan 2004 B2
6682890 Mack et al. Jan 2004 B2
6717136 Andersson et al. Apr 2004 B2
6729561 Hirae et al. May 2004 B2
6738502 Coleman et al. May 2004 B1
6739036 Koike et al. May 2004 B2
6744046 Valaskovic et al. Jun 2004 B2
6752922 Huang et al. Jun 2004 B2
6753147 Vogelstein et al. Jun 2004 B2
6766817 da Silva Jul 2004 B2
6767194 Jeon et al. Jul 2004 B2
6767704 Waldman et al. Jul 2004 B2
6790328 Jacobson et al. Sep 2004 B2
6793753 Unger et al. Sep 2004 B2
6797056 David Sep 2004 B2
6800849 Staats Oct 2004 B2
6806058 Jesperson et al. Oct 2004 B2
6808382 Anfranchi Oct 2004 B2
6808882 Griffiths et al. Oct 2004 B2
6814980 Levy et al. Nov 2004 B2
6818395 Quake et al. Nov 2004 B1
6832787 Renzi Dec 2004 B1
6833242 Quake et al. Dec 2004 B2
6841350 Ogden et al. Jan 2005 B2
6844377 Auweter et al. Jan 2005 B1
6872250 David et al. Mar 2005 B2
6890487 Sklar et al. May 2005 B1
6897018 Yuan et al. May 2005 B1
6905844 Kim Jun 2005 B2
6918404 Dias da Silva Jul 2005 B2
6926313 Renzi Aug 2005 B1
6935768 Lowe et al. Aug 2005 B2
6936417 Orntoft Aug 2005 B2
6942978 O'Brien Sep 2005 B1
6949342 Golub et al. Sep 2005 B2
6960437 Enzelberger et al. Nov 2005 B2
6964847 Englert Nov 2005 B1
6974667 Horne et al. Dec 2005 B2
6998232 Feinstein et al. Feb 2006 B1
7022472 Robbins et al. Apr 2006 B2
7041481 Anderson et al. May 2006 B2
7049072 Seshi May 2006 B2
7056674 Baker et al. Jun 2006 B2
7057026 Barnes et al. Jun 2006 B2
7066586 da Silva Jun 2006 B2
7068874 Wang et al. Jun 2006 B2
7078180 Genetta Jul 2006 B2
7081192 Wang et al. Jul 2006 B1
7081340 Baker et al. Jul 2006 B2
7090983 Muramatsu et al. Aug 2006 B1
7115230 Sundararajan Oct 2006 B2
7118910 Unger et al. Oct 2006 B2
7129091 Ismagilov et al. Oct 2006 B2
7138233 Griffiths et al. Nov 2006 B2
7153700 Pardee et al. Dec 2006 B1
7156917 Moriyama et al. Jan 2007 B2
7163801 Reed Jan 2007 B2
7169560 Lapidus et al. Jan 2007 B2
7171311 Dai et al. Jan 2007 B2
7198899 Schleyer et al. Apr 2007 B2
7204431 Li et al. Apr 2007 B2
7229760 Zohlnhofer et al. Jun 2007 B2
7229770 Price et al. Jun 2007 B1
7252943 Griffiths et al. Aug 2007 B2
7267938 Anderson et al. Sep 2007 B2
7268167 Higuchi et al. Sep 2007 B2
7282337 Harris Oct 2007 B1
7291462 O'Brien et al. Nov 2007 B2
7294503 Quake et al. Nov 2007 B2
7300765 Patel Nov 2007 B2
7308364 Shaughnessy et al. Dec 2007 B2
7314721 Gure et al. Jan 2008 B2
7316906 Chiorazzi et al. Jan 2008 B2
7323305 Leamon et al. Jan 2008 B2
7323309 Mirkin et al. Jan 2008 B2
7326529 Ali et al. Feb 2008 B2
7332280 Levy et al. Feb 2008 B2
7332590 Nacht et al. Feb 2008 B2
7341211 Ganan Calvo et al. Mar 2008 B2
7348142 Wang Mar 2008 B2
7358231 McCaffey et al. Apr 2008 B1
7361474 Siegler Apr 2008 B2
7364862 Ali et al. Apr 2008 B2
7368255 Bae et al. May 2008 B2
7378233 Sidransky et al. May 2008 B2
7378280 Quake et al. May 2008 B2
7390463 He et al. Jun 2008 B2
7393634 Ahuja et al. Jul 2008 B1
7393665 Brenner Jul 2008 B2
7405002 Ying et al. Jul 2008 B2
7416851 Davi et al. Aug 2008 B2
7429467 Holliger et al. Sep 2008 B2
7432064 Salceda et al. Oct 2008 B2
7442507 Polsky et al. Oct 2008 B2
7449303 Coignet Nov 2008 B2
7468271 Golovchenko et al. Dec 2008 B2
7473530 Huttemann Jan 2009 B2
7473531 Domon et al. Jan 2009 B1
7476506 Schleyer et al. Jan 2009 B2
7479370 Coignet Jan 2009 B2
7479371 Ando et al. Jan 2009 B2
7479376 Waldman et al. Jan 2009 B2
7482129 Soyupak et al. Jan 2009 B2
7501244 Reinhard et al. Mar 2009 B2
7504214 Erlander et al. Mar 2009 B2
7507532 Chang et al. Mar 2009 B2
7507541 Raitano et al. Mar 2009 B2
7510707 Platica et al. Mar 2009 B2
7510842 Podust et al. Mar 2009 B2
7514209 Dai et al. Apr 2009 B2
7514210 Holliger et al. Apr 2009 B2
7524633 Sidransky Apr 2009 B2
7527933 Sahin et al. May 2009 B2
7537897 Brenner et al. May 2009 B2
7541383 Fu et al. Jun 2009 B2
7544473 Brenner Jun 2009 B2
7556776 Fraden et al. Jul 2009 B2
7582446 Griffiths et al. Sep 2009 B2
7595195 Lee et al. Sep 2009 B2
7604938 Takahashi et al. Oct 2009 B2
7622076 Davies et al. Nov 2009 B2
7622081 Chou et al. Nov 2009 B2
7632562 Nair et al. Dec 2009 B2
7635562 Harris et al. Dec 2009 B2
7638276 Griffiths et al. Dec 2009 B2
7655435 Holliger et al. Feb 2010 B2
7655470 Ismagilov et al. Feb 2010 B2
7666593 Lapidus Feb 2010 B2
7691576 Holliger et al. Apr 2010 B2
7698287 Becker et al. Apr 2010 B2
7708949 Stone et al. May 2010 B2
7718578 Griffiths et al. May 2010 B2
7736890 Sia et al. Jun 2010 B2
7741130 Lee, Jr. et al. Jun 2010 B2
RE41780 Anderson et al. Sep 2010 E
7814175 Chang et al. Oct 2010 B1
7824889 Vogelstein et al. Nov 2010 B2
7888017 Quake et al. Feb 2011 B2
7897044 Hoyos et al. Mar 2011 B2
7897341 Griffiths et al. Mar 2011 B2
7901939 Ismagliov et al. Mar 2011 B2
7915015 Vogelstein et al. Mar 2011 B2
7968287 Griffiths et al. Jun 2011 B2
7990525 Kanda Aug 2011 B2
8012382 Kim et al. Sep 2011 B2
8067159 Brown et al. Nov 2011 B2
8153402 Holliger et al. Apr 2012 B2
8252539 Quake et al. Aug 2012 B2
8257925 Brown et al. Sep 2012 B2
8278071 Brown et al. Oct 2012 B2
8278711 Rao et al. Oct 2012 B2
8318434 Cuppens Nov 2012 B2
8337778 Stone et al. Dec 2012 B2
8367326 Griffiths et al. Feb 2013 B2
8383061 Prakash et al. Feb 2013 B2
8436993 Kaduchak et al. May 2013 B2
8462269 Cheng et al. Jun 2013 B2
8528589 Miller et al. Sep 2013 B2
8535889 Larson et al. Sep 2013 B2
8592221 Fraden et al. Nov 2013 B2
8673595 Nakamura et al. Mar 2014 B2
8715934 Diehl et al. May 2014 B2
8765485 Link et al. Jul 2014 B2
8772046 Fraden et al. Jul 2014 B2
8841071 Ink Sep 2014 B2
8857462 Miller et al. Oct 2014 B2
8871444 Griffiths et al. Oct 2014 B2
9012390 Holtze et al. Apr 2015 B2
9029083 Griffiths et al. May 2015 B2
9029085 Agresti et al. May 2015 B2
9038919 Link et al. May 2015 B2
9074242 Larson et al. Jul 2015 B2
9080056 Glennon et al. Jul 2015 B2
9127310 Larson et al. Sep 2015 B2
9150852 Samuels et al. Oct 2015 B2
9176031 Watson Nov 2015 B2
9186643 Griffiths et al. Nov 2015 B2
9194772 Lee et al. Nov 2015 B2
9228229 Olson et al. Jan 2016 B2
9266104 Link Feb 2016 B2
9273308 Link et al. Mar 2016 B2
9273349 Nguyen et al. Mar 2016 B2
9322511 Davies et al. Apr 2016 B2
9328344 Ink et al. May 2016 B2
9341594 Miller et al. May 2016 B2
9364803 Yurkovetsky et al. Jun 2016 B2
9366632 Link et al. Jun 2016 B2
9399797 Hutchison et al. Jul 2016 B2
9410151 Link et al. Aug 2016 B2
9441266 Larson et al. Sep 2016 B2
9448172 Griffiths et al. Sep 2016 B2
9494520 Link Nov 2016 B2
9498761 Holtze et al. Nov 2016 B2
9528106 Griffiths et al. Dec 2016 B2
9534216 Link et al. Jan 2017 B2
9556470 Link et al. Jan 2017 B2
9562837 Link Feb 2017 B2
9562897 Samuels et al. Feb 2017 B2
9733168 Miller et al. Aug 2017 B2
9745617 Arson et al. Aug 2017 B2
9752141 Link et al. Sep 2017 B2
9816121 Agresti et al. Nov 2017 B2
9839890 Griffiths et al. Dec 2017 B2
9840734 Samuels Dec 2017 B2
9857202 Seki Jan 2018 B2
9857303 Griffiths et al. Jan 2018 B2
9896722 Link Feb 2018 B2
9919277 Griffiths et al. Mar 2018 B2
9925501 Griffiths et al. Mar 2018 B2
9925504 Griffiths et al. Mar 2018 B2
9944977 Link et al. Apr 2018 B2
9981230 Link et al. May 2018 B2
10011865 Link Jul 2018 B2
10041113 Lee et al. Aug 2018 B2
10052605 Griffiths et al. Aug 2018 B2
10139411 Link et al. Nov 2018 B2
10144950 Nolan Dec 2018 B2
10151698 Griffiths et al. Dec 2018 B2
10155207 Yurkovetsky et al. Dec 2018 B2
10351905 Link et al. Jul 2019 B2
10357772 Fraden et al. Jul 2019 B2
10428369 Miller et al. Oct 2019 B2
10450604 Wiyatno et al. Oct 2019 B2
10520500 El Harrak et al. Dec 2019 B2
10526605 Liu et al. Jan 2020 B2
10527529 Miller et al. Jan 2020 B2
10533998 Link et al. Jan 2020 B2
10551382 Link et al. Feb 2020 B2
10584332 Samuels et al. Mar 2020 B2
10596541 Weitz et al. Mar 2020 B2
10612081 Hutchison et al. Apr 2020 B2
10625220 Link et al. Apr 2020 B2
10626442 Nolan Apr 2020 B2
10626451 Davies et al. Apr 2020 B2
10633652 Link et al. Apr 2020 B2
10639597 Link et al. May 2020 B2
10639598 Griffiths et al. May 2020 B2
10647981 Luckey May 2020 B1
10675626 Fraden et al. Jun 2020 B2
10676786 Davies et al. Jun 2020 B2
10724082 Samuels Jul 2020 B2
10730051 Davies et al. Aug 2020 B2
10761090 Samuels et al. Sep 2020 B2
10808279 Link et al. Oct 2020 B2
10837883 Kleinschmidt et al. Nov 2020 B2
10927407 Link Feb 2021 B2
10960397 Fraden et al. Mar 2021 B2
11077415 Yurkovetsky et al. Aug 2021 B2
11168353 Samuels et al. Nov 2021 B2
11174509 Link et al. Nov 2021 B2
20010010338 Ganan-Calvo Aug 2001 A1
20010020011 Mathiowitz et al. Sep 2001 A1
20010023078 Bawendi et al. Sep 2001 A1
20010024790 Kambara et al. Sep 2001 A1
20010029983 Unger et al. Oct 2001 A1
20010032053 Hielscher et al. Oct 2001 A1
20010034025 Modlin et al. Oct 2001 A1
20010034031 Short et al. Oct 2001 A1
20010041343 Pankowsky Nov 2001 A1
20010041344 Sepetov et al. Nov 2001 A1
20010041357 Fouillet et al. Nov 2001 A1
20010042793 Ganan-Calvo Nov 2001 A1
20010048900 Bardell et al. Dec 2001 A1
20010050881 Depaoli et al. Dec 2001 A1
20020004532 Matathia et al. Jan 2002 A1
20020005354 Spence et al. Jan 2002 A1
20020008028 Jacobson et al. Jan 2002 A1
20020012971 Mehta Jan 2002 A1
20020015997 Lafferty Feb 2002 A1
20020022038 Biatry et al. Feb 2002 A1
20020022261 Anderson et al. Feb 2002 A1
20020033422 Ganan-Calvo Mar 2002 A1
20020034737 Drmanac Mar 2002 A1
20020036018 McNeely et al. Mar 2002 A1
20020036139 Becker et al. Mar 2002 A1
20020041378 Peltie et al. Apr 2002 A1
20020058332 Quake et al. May 2002 A1
20020065609 Ashby May 2002 A1
20020067800 Newman et al. Jun 2002 A1
20020084417 Khalil et al. Jul 2002 A1
20020085961 Morin et al. Jul 2002 A1
20020090720 Mutz et al. Jul 2002 A1
20020106667 Yamamoto et al. Aug 2002 A1
20020119455 Chan Aug 2002 A1
20020119459 Griffiths Aug 2002 A1
20020127591 Wada et al. Sep 2002 A1
20020142344 Akeson et al. Oct 2002 A1
20020143437 Handique et al. Oct 2002 A1
20020155080 Glenn et al. Oct 2002 A1
20020158027 Moon et al. Oct 2002 A1
20020164271 Ho Nov 2002 A1
20020164629 Quake et al. Nov 2002 A1
20020166582 O'Connor et al. Nov 2002 A1
20020179849 Maher et al. Dec 2002 A1
20030008308 Enzelberger et al. Jan 2003 A1
20030012586 Iwata et al. Jan 2003 A1
20030015425 Bohm et al. Jan 2003 A1
20030017305 Roitman et al. Jan 2003 A1
20030017579 Corn et al. Jan 2003 A1
20030038865 Inamura Feb 2003 A1
20030039169 Ehrfeld et al. Feb 2003 A1
20030040620 Angmore et al. Feb 2003 A1
20030059764 Ravkin et al. Mar 2003 A1
20030061687 Hansen et al. Apr 2003 A1
20030064414 Benecky et al. Apr 2003 A1
20030082795 Shuler et al. May 2003 A1
20030083276 Li et al. May 2003 A1
20030104372 Ahmadian et al. Jun 2003 A1
20030108900 Oliphant et al. Jun 2003 A1
20030124586 Griffiths et al. Jul 2003 A1
20030143599 Makarov et al. Jul 2003 A1
20030144260 Gilon Jul 2003 A1
20030148273 Dong et al. Aug 2003 A1
20030148335 Shen et al. Aug 2003 A1
20030148544 Nie et al. Aug 2003 A1
20030180748 Braun et al. Sep 2003 A1
20030181574 Adam et al. Sep 2003 A1
20030183525 Elrod et al. Oct 2003 A1
20030207295 Gunderson et al. Nov 2003 A1
20030219754 Oleksy et al. Nov 2003 A1
20030224509 Moon et al. Dec 2003 A1
20030229376 Sandhu Dec 2003 A1
20030230486 Chien et al. Dec 2003 A1
20030232356 Dooley et al. Dec 2003 A1
20040005582 Shipwash Jan 2004 A1
20040005594 Holliger et al. Jan 2004 A1
20040018525 Wirtz et al. Jan 2004 A1
20040027915 Lowe et al. Feb 2004 A1
20040030255 Alfano et al. Feb 2004 A1
20040031688 Shenderov Feb 2004 A1
20040037739 McNeely et al. Feb 2004 A1
20040037813 Simpson et al. Feb 2004 A1
20040041093 Schultz et al. Mar 2004 A1
20040050946 Wang et al. Mar 2004 A1
20040053247 Cordon-Cardo et al. Mar 2004 A1
20040057906 Hsu et al. Mar 2004 A1
20040058450 Pamula et al. Mar 2004 A1
20040068019 Higuchi et al. Apr 2004 A1
20040071781 Chattopadhyay et al. Apr 2004 A1
20040079881 Fischer et al. Apr 2004 A1
20040086892 Crothers et al. May 2004 A1
20040091923 Reyes et al. May 2004 A1
20040092824 Stamnes et al. May 2004 A1
20040096515 Bausch et al. May 2004 A1
20040101822 Wiesner et al. May 2004 A1
20040134854 Tiguchi et al. Jul 2004 A1
20040136497 Meldrum et al. Jul 2004 A1
20040142329 Erikson et al. Jul 2004 A1
20040146866 Fu Jul 2004 A1
20040146921 Veleigh et al. Jul 2004 A1
20040159633 Whitesides et al. Aug 2004 A1
20040180346 Anderson et al. Sep 2004 A1
20040181131 Maynard et al. Sep 2004 A1
20040181343 Wigstrom et al. Sep 2004 A1
20040182712 Basol Sep 2004 A1
20040185484 Costa et al. Sep 2004 A1
20040188254 Spaid Sep 2004 A1
20040209299 Pinter et al. Oct 2004 A1
20040224325 Knapp et al. Nov 2004 A1
20040224419 Zheng et al. Nov 2004 A1
20040229349 Daridon Nov 2004 A1
20040241693 Ricoul et al. Dec 2004 A1
20040253731 Holliger et al. Dec 2004 A1
20040258203 Yamano et al. Dec 2004 A1
20040259083 Oshima Dec 2004 A1
20050000970 Kimbara et al. Jan 2005 A1
20050003380 Cohen et al. Jan 2005 A1
20050008592 Gardel et al. Jan 2005 A1
20050019776 Callow et al. Jan 2005 A1
20050022764 Kawai et al. Feb 2005 A1
20050032238 Karp et al. Feb 2005 A1
20050032240 Lee et al. Feb 2005 A1
20050037392 Griffiths et al. Feb 2005 A1
20050037397 Mirkin et al. Feb 2005 A1
20050042639 Knapp et al. Feb 2005 A1
20050042648 Griffiths et al. Feb 2005 A1
20050048467 Sastry et al. Mar 2005 A1
20050064460 Holliger et al. Mar 2005 A1
20050069920 Griffiths et al. Mar 2005 A1
20050079501 Koike et al. Apr 2005 A1
20050079510 Berka et al. Apr 2005 A1
20050084923 Mueller et al. Apr 2005 A1
20050087122 Ismagliov et al. Apr 2005 A1
20050095611 Chan et al. May 2005 A1
20050100895 Waldman et al. May 2005 A1
20050103690 Kawano et al. May 2005 A1
20050123937 Thorp et al. Jun 2005 A1
20050129582 Breidford et al. Jun 2005 A1
20050130173 Eamon et al. Jun 2005 A1
20050152908 Liew et al. Jul 2005 A1
20050161669 Jovanovich et al. Jul 2005 A1
20050164239 Griffiths et al. Jul 2005 A1
20050169797 Oshima Aug 2005 A1
20050170373 Monforte Aug 2005 A1
20050170431 Ibrahim et al. Aug 2005 A1
20050172476 Stone et al. Aug 2005 A1
20050183995 Deshpande et al. Aug 2005 A1
20050202429 Trau et al. Sep 2005 A1
20050202489 Cho et al. Sep 2005 A1
20050207940 Butler et al. Sep 2005 A1
20050208495 Joseph et al. Sep 2005 A1
20050208529 Winther et al. Sep 2005 A1
20050214173 Acer et al. Sep 2005 A1
20050221339 Griffiths et al. Oct 2005 A1
20050221341 Shimkets et al. Oct 2005 A1
20050226742 Unger et al. Oct 2005 A1
20050227264 Nobile et al. Oct 2005 A1
20050248066 Esteban Nov 2005 A1
20050251049 Cane et al. Nov 2005 A1
20050260566 Fischer et al. Nov 2005 A1
20050272159 Ismagilov et al. Dec 2005 A1
20050287572 Mathies et al. Dec 2005 A1
20060003347 Griffiths et al. Jan 2006 A1
20060003429 Frost et al. Jan 2006 A1
20060003439 Ismagilov et al. Jan 2006 A1
20060008824 Ronaghi et al. Jan 2006 A1
20060035386 Hattori et al. Feb 2006 A1
20060036348 Handique et al. Feb 2006 A1
20060040197 Kabai Feb 2006 A1
20060040297 Eamon et al. Feb 2006 A1
20060046257 Pollock et al. Mar 2006 A1
20060051329 Lee et al. Mar 2006 A1
20060068398 McMillan Mar 2006 A1
20060078475 Tai et al. Apr 2006 A1
20060078888 Griffiths et al. Apr 2006 A1
20060078893 Griffiths et al. Apr 2006 A1
20060094119 Ismagilov et al. May 2006 A1
20060096923 Wagler et al. May 2006 A1
20060100788 Carrino et al. May 2006 A1
20060105170 Dobson et al. May 2006 A1
20060108012 Barrow et al. May 2006 A1
20060110759 Paris et al. May 2006 A1
20060115821 Einstein et al. Jun 2006 A1
20060147909 Rarbach et al. Jul 2006 A1
20060153924 Griffiths et al. Jul 2006 A1
20060154298 Griffiths et al. Jul 2006 A1
20060160762 Zetter et al. Jul 2006 A1
20060163385 Link et al. Jul 2006 A1
20060169800 Rosell et al. Aug 2006 A1
20060177832 Brenner Aug 2006 A1
20060195269 Yeatman et al. Aug 2006 A1
20060223127 Yip et al. Oct 2006 A1
20060234254 An et al. Oct 2006 A1
20060234259 Rubin et al. Oct 2006 A1
20060234264 Hardenbol Oct 2006 A1
20060245971 Burns et al. Nov 2006 A1
20060246431 Balachandran Nov 2006 A1
20060247532 Ramanujam et al. Nov 2006 A1
20060252057 Raponi et al. Nov 2006 A1
20060257893 Takahashi et al. Nov 2006 A1
20060258841 Michl et al. Nov 2006 A1
20060263888 Fritz et al. Nov 2006 A1
20060269558 Murphy et al. Nov 2006 A1
20060269934 Woudenberg et al. Nov 2006 A1
20060269971 Diamandis Nov 2006 A1
20060281089 Gibson et al. Dec 2006 A1
20060281098 Miao et al. Dec 2006 A1
20060286570 Rowlen et al. Dec 2006 A1
20070003442 Link et al. Jan 2007 A1
20070009914 Wallace et al. Jan 2007 A1
20070009954 Wang et al. Jan 2007 A1
20070016078 Hoyt et al. Jan 2007 A1
20070020617 Trnovsky et al. Jan 2007 A1
20070026439 Faulstich et al. Feb 2007 A1
20070031829 Yasuno et al. Feb 2007 A1
20070039866 Schroeder et al. Feb 2007 A1
20070042400 Choi et al. Feb 2007 A1
20070042419 Barany et al. Feb 2007 A1
20070045117 Pamula et al. Mar 2007 A1
20070048744 Apidus Mar 2007 A1
20070053896 Ahmed et al. Mar 2007 A1
20070054119 Garstecki et al. Mar 2007 A1
20070056853 Aizenberg et al. Mar 2007 A1
20070065823 Dressman et al. Mar 2007 A1
20070077572 Tawfik et al. Apr 2007 A1
20070077579 Griffiths et al. Apr 2007 A1
20070092914 Griffiths et al. Apr 2007 A1
20070111303 Inoue et al. May 2007 A1
20070120899 Ohnishi et al. May 2007 A1
20070123430 Pasquier et al. May 2007 A1
20070141593 Lee et al. Jun 2007 A1
20070142720 Ridder et al. Jun 2007 A1
20070154889 Wang Jul 2007 A1
20070156037 Pilon et al. Jul 2007 A1
20070166705 Milton et al. Jul 2007 A1
20070172873 Brenner et al. Jul 2007 A1
20070184439 Guilford et al. Aug 2007 A1
20070184489 Griffiths et al. Aug 2007 A1
20070195127 Ahn et al. Aug 2007 A1
20070202525 Quake et al. Aug 2007 A1
20070213410 Hastwell et al. Sep 2007 A1
20070241068 Pamula et al. Oct 2007 A1
20070242105 Srinivasan et al. Oct 2007 A1
20070243634 Pamula et al. Oct 2007 A1
20070259351 Chinitz et al. Nov 2007 A1
20070259368 An et al. Nov 2007 A1
20070259374 Griffiths et al. Nov 2007 A1
20070269804 Liew et al. Nov 2007 A1
20070275415 Srinivasan et al. Nov 2007 A1
20070292869 Becker et al. Dec 2007 A1
20080003142 Link et al. Jan 2008 A1
20080003571 McKeman et al. Jan 2008 A1
20080004436 Tawfik et al. Jan 2008 A1
20080009005 Kruk Jan 2008 A1
20080014589 Link et al. Jan 2008 A1
20080014590 Dahary et al. Jan 2008 A1
20080020940 Stedronsky et al. Jan 2008 A1
20080021330 Hwang et al. Jan 2008 A1
20080023330 Viovy et al. Jan 2008 A1
20080032413 Kim et al. Feb 2008 A1
20080038754 Farias-Eisner et al. Feb 2008 A1
20080044828 Kwok Feb 2008 A1
20080050378 Nakamura et al. Feb 2008 A1
20080050723 Belacel et al. Feb 2008 A1
20080053205 Pollack et al. Mar 2008 A1
20080057514 Goldenring Mar 2008 A1
20080058432 Wang et al. Mar 2008 A1
20080063227 Rohrseitz Mar 2008 A1
20080064047 Zetter et al. Mar 2008 A1
20080081330 Kahvejian Apr 2008 A1
20080081333 Mori et al. Apr 2008 A1
20080092973 Lai Apr 2008 A1
20080113340 Schlegel May 2008 A1
20080118462 Alani et al. May 2008 A1
20080124726 Monforte May 2008 A1
20080138806 Chow et al. Jun 2008 A1
20080166772 Hollinger et al. Jul 2008 A1
20080166793 Beer et al. Jul 2008 A1
20080171078 Gray Jul 2008 A1
20080176211 Spence et al. Jul 2008 A1
20080176236 Tsao et al. Jul 2008 A1
20080181850 Thaxton et al. Jul 2008 A1
20080206756 Lee et al. Aug 2008 A1
20080213377 Bhatia et al. Sep 2008 A1
20080216563 Reed et al. Sep 2008 A1
20080220986 Gormley et al. Sep 2008 A1
20080222741 Chinnaiyan Sep 2008 A1
20080234138 Shaughnessy et al. Sep 2008 A1
20080234139 Shaughnessy et al. Sep 2008 A1
20080241830 Vogelstein et al. Oct 2008 A1
20080261295 Butler et al. Oct 2008 A1
20080268473 Moses et al. Oct 2008 A1
20080269157 Srivastava et al. Oct 2008 A1
20080274513 Shenderov et al. Nov 2008 A1
20080274908 Chang Nov 2008 A1
20080280285 Chen et al. Nov 2008 A1
20080280302 Kebebew Nov 2008 A1
20080286199 Livingston et al. Nov 2008 A1
20080286801 Arjol et al. Nov 2008 A1
20080286811 Moses et al. Nov 2008 A1
20080293578 Shaugnessy et al. Nov 2008 A1
20080299565 Schneider et al. Dec 2008 A1
20080305482 Brentano et al. Dec 2008 A1
20080311570 Lai Dec 2008 A1
20080311604 Elting et al. Dec 2008 A1
20090004687 Mansfield et al. Jan 2009 A1
20090005254 Griffiths et al. Jan 2009 A1
20090009855 Nakatsuka et al. Jan 2009 A1
20090012187 Chu et al. Jan 2009 A1
20090017463 Bhowmick Jan 2009 A1
20090021728 Heinz et al. Jan 2009 A1
20090023137 Van Der Zee et al. Jan 2009 A1
20090026082 Rothberg et al. Jan 2009 A1
20090029372 Wewer Jan 2009 A1
20090035770 Mathies et al. Feb 2009 A1
20090042737 Katz et al. Feb 2009 A1
20090053700 Griffiths et al. Feb 2009 A1
20090053732 Vermesh et al. Feb 2009 A1
20090060797 Mathies et al. Mar 2009 A1
20090062144 Guo Mar 2009 A1
20090068170 Weitz et al. Mar 2009 A1
20090069194 Ramakrishnan Mar 2009 A1
20090075265 Budiman et al. Mar 2009 A1
20090075307 Fischer et al. Mar 2009 A1
20090075311 Karl Mar 2009 A1
20090081237 D'Andrea et al. Mar 2009 A1
20090081685 Beyer et al. Mar 2009 A1
20090087849 Malinowski et al. Apr 2009 A1
20090092973 Erlander et al. Apr 2009 A1
20090098542 Budiman et al. Apr 2009 A1
20090098543 Budiman et al. Apr 2009 A1
20090098555 Roth et al. Apr 2009 A1
20090105959 Braverman et al. Apr 2009 A1
20090118128 Liu et al. May 2009 A1
20090118158 Quay May 2009 A1
20090124569 Bergan et al. May 2009 A1
20090124789 Yoshida et al. May 2009 A1
20090127454 Ritchie et al. May 2009 A1
20090127589 Rothberg et al. May 2009 A1
20090131353 Insel et al. May 2009 A1
20090131543 Weitz et al. May 2009 A1
20090134027 Jary May 2009 A1
20090134331 Miyamae et al. May 2009 A1
20090169482 Zheng et al. Jul 2009 A1
20090191565 Lapidus et al. Jul 2009 A1
20090197248 Griffiths et al. Aug 2009 A1
20090197772 Griffiths et al. Aug 2009 A1
20090215633 Van Eijk et al. Aug 2009 A1
20090226971 Beer et al. Sep 2009 A1
20090226972 Beer et al. Sep 2009 A1
20090233802 Bignell et al. Sep 2009 A1
20090246788 Albert et al. Oct 2009 A1
20090317798 Heid et al. Dec 2009 A1
20090325217 Uscher Dec 2009 A1
20090325236 Griffiths et al. Dec 2009 A1
20100003687 Simen et al. Jan 2010 A1
20100009353 Barnes et al. Jan 2010 A1
20100015617 Toyama Jan 2010 A1
20100021984 Edd et al. Jan 2010 A1
20100022414 Link et al. Jan 2010 A1
20100035252 Rothberg et al. Feb 2010 A1
20100041046 Chiu et al. Feb 2010 A1
20100055677 Colston, Jr. et al. Mar 2010 A1
20100055708 Maus et al. Mar 2010 A1
20100058908 O'Banion et al. Mar 2010 A1
20100075436 Urdea et al. Mar 2010 A1
20100086914 Bentley et al. Apr 2010 A1
20100092973 Davies et al. Apr 2010 A1
20100093107 Clarizia Apr 2010 A1
20100105112 Holtze et al. Apr 2010 A1
20100111768 Banerjee et al. May 2010 A1
20100120098 Grunenwald et al. May 2010 A1
20100124759 Wang et al. May 2010 A1
20100129896 Knapp et al. May 2010 A1
20100130369 Shenderov et al. May 2010 A1
20100136544 Agresti et al. Jun 2010 A1
20100137143 Rothberg et al. Jun 2010 A1
20100137163 Link et al. Jun 2010 A1
20100159592 Dolliger et al. Jun 2010 A1
20100172803 Stone et al. Jul 2010 A1
20100173293 Woudenberg et al. Jul 2010 A1
20100173394 Colston, Jr. et al. Jul 2010 A1
20100183504 Chen Jul 2010 A1
20100184069 Fernando et al. Jul 2010 A1
20100188073 Rothberg et al. Jul 2010 A1
20100197507 Rothberg et al. Aug 2010 A1
20100210479 Griffiths et al. Aug 2010 A1
20100213628 Bausch et al. Aug 2010 A1
20100216128 Davies et al. Aug 2010 A1
20100233026 Ismagliov et al. Sep 2010 A1
20100233083 Dias et al. Sep 2010 A1
20100240101 Lieberman et al. Sep 2010 A1
20100248237 Froehlich et al. Sep 2010 A1
20100252118 Fraden et al. Oct 2010 A1
20100273173 Hirai et al. Oct 2010 A1
20100282617 Rothberg et al. Nov 2010 A1
20100285975 Mathies et al. Nov 2010 A1
20100300559 Schultz et al. Dec 2010 A1
20100300895 Nobile et al. Dec 2010 A1
20100301398 Rothberg et al. Dec 2010 A1
20100304378 Griffiths et al. Dec 2010 A1
20100304982 Hinz et al. Dec 2010 A1
20110000560 Miller et al. Jan 2011 A1
20110009294 Jones et al. Jan 2011 A1
20110024455 Bethuy et al. Feb 2011 A1
20110033854 Drmanac et al. Feb 2011 A1
20110045462 Fu et al. Feb 2011 A1
20110053151 Hansen et al. Mar 2011 A1
20110053798 Hindson et al. Mar 2011 A1
20110059435 Vogelstein et al. Mar 2011 A1
20110059556 Strey et al. Mar 2011 A1
20110104725 Pamula et al. May 2011 A1
20110104816 Pollack et al. May 2011 A1
20110111981 Love et al. May 2011 A1
20110142734 Ismagliov et al. Jun 2011 A1
20110151444 Albers et al. Jun 2011 A1
20110159499 Hindson et al. Jun 2011 A1
20110174622 Ismagilov et al. Jul 2011 A1
20110176966 Ismagilov et al. Jul 2011 A1
20110177494 Smagilov et al. Jul 2011 A1
20110177586 Smagilov et al. Jul 2011 A1
20110177609 Smagilov et al. Jul 2011 A1
20110188717 Baudry et al. Aug 2011 A1
20110190146 Boehm et al. Aug 2011 A1
20110218123 Weitz et al. Sep 2011 A1
20110223314 Zhang et al. Sep 2011 A1
20110244455 Larson et al. Oct 2011 A1
20110250597 Larson et al. Oct 2011 A1
20110257031 Bodeau et al. Oct 2011 A1
20110267457 Weitz et al. Nov 2011 A1
20110274706 Nelson et al. Nov 2011 A1
20110275063 Weitz et al. Nov 2011 A1
20110311978 Makarewicz, Jr. et al. Dec 2011 A1
20120010085 Rava et al. Jan 2012 A1
20120010098 Griffiths et al. Jan 2012 A1
20120010107 Griffiths et al. Jan 2012 A1
20120014977 Furihata et al. Jan 2012 A1
20120015382 Weitz et al. Jan 2012 A1
20120015822 Weitz et al. Jan 2012 A1
20120021919 Scholl et al. Jan 2012 A1
20120021930 Schoen et al. Jan 2012 A1
20120058908 Li Mar 2012 A1
20120088691 Chen et al. Apr 2012 A1
20120122714 Samuels et al. May 2012 A1
20120132288 Weitz et al. May 2012 A1
20120164652 Clemens et al. Jun 2012 A1
20120165219 Van Der Zaag et al. Jun 2012 A1
20120167142 Hey Jun 2012 A1
20120171667 Shoemaker et al. Jul 2012 A1
20120190032 Ness et al. Jul 2012 A1
20120208241 Link Aug 2012 A1
20120208705 Steemers et al. Aug 2012 A1
20120219947 Yurkovetsky et al. Aug 2012 A1
20120220494 Samuels et al. Aug 2012 A1
20120231972 Golyshin et al. Sep 2012 A1
20120244043 Leblanc et al. Sep 2012 A1
20120252012 Armougom et al. Oct 2012 A1
20120253689 Rogan Oct 2012 A1
20120258516 Schultz et al. Oct 2012 A1
20120264646 Link et al. Oct 2012 A1
20120288857 Livak Nov 2012 A1
20120302448 Hutchison et al. Nov 2012 A1
20120309002 Link Dec 2012 A1
20120322058 Regan et al. Dec 2012 A1
20130064776 El Harrak et al. Mar 2013 A1
20130090248 Link et al. Apr 2013 A1
20130099018 Miller et al. Apr 2013 A1
20130109575 Kleinschmidt et al. May 2013 A1
20130109577 Korlach et al. May 2013 A1
20130123339 Heyes et al. May 2013 A1
20130143745 Christen et al. Jun 2013 A1
20130157870 Pushkarev et al. Jun 2013 A1
20130157872 Griffiths et al. Jun 2013 A1
20130178368 Griffiths et al. Jul 2013 A1
20130178378 Hatch et al. Jul 2013 A1
20130183659 Link et al. Jul 2013 A1
20130196324 Larson et al. Aug 2013 A1
20130203606 Pollack et al. Aug 2013 A1
20130210638 Olson et al. Aug 2013 A1
20130210639 Link et al. Aug 2013 A1
20130210659 Watson et al. Aug 2013 A1
20130217071 Montesclaros et al. Aug 2013 A1
20130217583 Link et al. Aug 2013 A1
20130217601 Griffiths et al. Aug 2013 A1
20130224751 Olson et al. Aug 2013 A1
20130225418 Watson Aug 2013 A1
20130225623 Buxbaum et al. Aug 2013 A1
20130244906 Collins Sep 2013 A1
20130260447 Link Oct 2013 A1
20130274117 Church et al. Oct 2013 A1
20130288254 Pollack et al. Oct 2013 A1
20130295567 Link et al. Nov 2013 A1
20130295568 Link Nov 2013 A1
20130296535 Church et al. Nov 2013 A1
20140045712 Link et al. Feb 2014 A1
20140057799 Johnson et al. Feb 2014 A1
20140065631 Froehlich et al. Mar 2014 A1
20140076430 Miller et al. Mar 2014 A1
20140099637 Nolan et al. Apr 2014 A1
20140113300 Samuels Apr 2014 A1
20140154695 Miller et al. Jun 2014 A1
20140155274 Xie et al. Jun 2014 A1
20140235452 Rothberg et al. Aug 2014 A1
20140256568 Link Sep 2014 A1
20140256585 McCoy Sep 2014 A1
20140256595 Link et al. Sep 2014 A1
20140274786 McCoy et al. Sep 2014 A1
20140295421 Link et al. Oct 2014 A1
20140323317 Link et al. Oct 2014 A1
20140329239 Arson et al. Nov 2014 A1
20150018236 Green et al. Jan 2015 A1
20150027892 Miller et al. Jan 2015 A1
20150038356 Karlin-Neumann et al. Feb 2015 A1
20150099266 Samuels et al. Apr 2015 A1
20150126400 Watson et al. May 2015 A1
20150167066 Link et al. Jun 2015 A1
20150184256 Samuels et al. Jul 2015 A1
20150197790 Tzonev Jul 2015 A1
20150217246 Holtze et al. Aug 2015 A1
20150247191 Zhang et al. Sep 2015 A1
20150258520 Griffiths et al. Sep 2015 A1
20150298091 Weitz et al. Oct 2015 A1
20150336072 Weitz et al. Nov 2015 A1
20160060621 Agresti et al. Mar 2016 A1
20160200847 Chiari Jul 2016 A1
20160201125 Samuels et al. Jul 2016 A1
20160209303 Miller et al. Jul 2016 A1
20160222433 Arson et al. Aug 2016 A1
20160281140 Miller et al. Sep 2016 A1
20160289670 Samuels et al. Oct 2016 A1
20160304954 Lin et al. Oct 2016 A1
20160346748 Yurkovetsky et al. Dec 2016 A1
20170002400 Hutchison et al. Jan 2017 A1
20170028365 Link et al. Feb 2017 A1
20170067047 Link et al. Mar 2017 A1
20170131279 Link et al. May 2017 A1
20170176429 Samuels et al. Jun 2017 A1
20170183722 Link Jun 2017 A1
20170304785 Link et al. Oct 2017 A1
20170336306 Miller et al. Nov 2017 A1
20180057863 Larson et al. Mar 2018 A1
20180057868 Walder et al. Mar 2018 A1
20180080020 Link et al. Mar 2018 A1
20180100185 Samuels Apr 2018 A1
20180135117 Link May 2018 A1
20180178174 Link et al. Jun 2018 A1
20180223348 Link et al. Aug 2018 A1
20180272294 Griffiths et al. Sep 2018 A1
20180272295 Link et al. Sep 2018 A1
20180272296 Link et al. Sep 2018 A1
20180272299 Griffiths et al. Sep 2018 A1
20180280897 Link et al. Oct 2018 A1
20180304222 Weitz et al. Oct 2018 A1
20180305747 Link Oct 2018 A1
20180353913 Link et al. Dec 2018 A1
20180355350 Link et al. Dec 2018 A1
20180361346 Griffiths et al. Dec 2018 A1
20180363050 Hutchison et al. Dec 2018 A1
20190024261 Griffiths et al. Jan 2019 A1
20190094226 Link et al. Mar 2019 A1
20190107489 Griffiths et al. Apr 2019 A1
20190134581 Yurkovetsky et al. May 2019 A1
20190255530 Fraden et al. Aug 2019 A1
20190316119 Samuels et al. Oct 2019 A1
20190330683 Link et al. Oct 2019 A1
20200002748 Miller et al. Jan 2020 A1
20200217843 El Harrak et al. Jul 2020 A1
20200225129 Miller et al. Jul 2020 A1
20200225232 Link et al. Jul 2020 A1
20200249230 Link et al. Aug 2020 A1
20200254400 Griffiths et al. Aug 2020 A1
20200270600 Samuels et al. Aug 2020 A1
20200318157 Hutchison et al. Oct 2020 A1
20200360876 Link et al. Nov 2020 A1
20200399635 Samuels et al. Dec 2020 A1
20210002703 Link et al. Jan 2021 A1
20210041432 Samuels et al. Feb 2021 A1
20210088424 Kleinschmidt et al. Mar 2021 A1
20210088519 Link et al. Mar 2021 A1
20210230681 Patterson et al. Jul 2021 A1
20210262020 Link Aug 2021 A1
20220064711 Samuels et al. Mar 2022 A1
Foreign Referenced Citations (344)
Number Date Country
140025 Jul 1996 AT
140880 Aug 1996 AT
155711 Aug 1997 AT
167816 Jul 1998 AT
4032078 Apr 1980 AU
6415380 May 1981 AU
1045983 Jun 1984 AU
2177292 Jan 1993 AU
4222393 Nov 1993 AU
4222593 Nov 1993 AU
4222693 Nov 1993 AU
4222793 Nov 1993 AU
4223593 Nov 1993 AU
677197 Apr 1997 AU
677781 May 1997 AU
680195 Jul 1997 AU
2935197 Jan 1998 AU
3499097 Jan 1998 AU
3501297 Jan 1998 AU
1276099 Jun 1999 AU
4955799 Dec 1999 AU
3961100 Oct 2000 AU
4910300 Nov 2000 AU
747464 May 2002 AU
768399 Dec 2003 AU
2004225691 Jun 2010 AU
2010224352 Oct 2010 AU
8200642 Dec 1982 BR
9710052 Jan 2000 BR
1093344 Jan 1981 CA
2258481 Jan 1998 CA
2520548 Oct 2004 CA
563087 Jun 1975 CH
563807 Jul 1975 CH
101910415 Dec 2010 CN
104812915 Jul 2015 CN
2100685 Jul 1972 DE
3042915 Sep 1981 DE
43 08 839 Apr 1997 DE
69126763 Feb 1998 DE
199 61 257 Jul 2001 DE
100 15 109 Oct 2001 DE
100 41 823 Mar 2002 DE
10322893 Dec 2004 DE
0047130 Feb 1985 EP
0402995 Dec 1990 EP
0249007 Mar 1991 EP
0418635 Mar 1991 EP
0476178 Mar 1992 EP
0476178 Mar 1993 EP
0546174 Jun 1993 EP
0618001 Oct 1994 EP
620432 Oct 1994 EP
0637996 Feb 1995 EP
0637997 Feb 1995 EP
0718038 Jun 1996 EP
0540281 Jul 1996 EP
0528580 Dec 1996 EP
0486351 Jul 1997 EP
0895120 Feb 1999 EP
1362634 Nov 2003 EP
1447127 Aug 2004 EP
1462517 Sep 2004 EP
0782399.2 May 2006 EP
1741482 Jan 2007 EP
2017910 Jan 2009 EP
2127736 Dec 2009 EP
2212437 Aug 2010 EP
2047910 Jan 2012 EP
13165665.4 Nov 2013 EP
13165667.0 Nov 2013 EP
2363205 Jun 2014 EP
2534267 Apr 2018 EP
2 095 413 Feb 1997 ES
2 404 834 Apr 1979 FR
2 451 579 Oct 1980 FR
2 469 714 May 1981 FR
2 470 385 May 1981 FR
2 650 657 Feb 1991 FR
2 669 028 May 1992 FR
2 703 263 Oct 1994 FR
1148543 Apr 1969 GB
1 446 998 Aug 1976 GB
2 005 224 Apr 1979 GB
2 047 880 Dec 1980 GB
2 062 225 May 1981 GB
2 064 114 Jun 1981 GB
2097692 Nov 1982 GB
2 210 532 Jun 1989 GB
922432 Feb 1993 IE
S5372016 Jun 1978 JP
S5455495 May 1979 JP
55125472 Sep 1980 JP
S5636053 Apr 1981 JP
56-124052 Sep 1981 JP
59-49832 Mar 1984 JP
59-102163 Jun 1984 JP
H0665609 Mar 1994 JP
6-265447 Sep 1994 JP
7-489 Jan 1995 JP
8-153669 Jun 1996 JP
10-217477 Aug 1998 JP
3-232525 Oct 1998 JP
2000-271475 Oct 2000 JP
2001-517353 Oct 2001 JP
2001-1301154 Oct 2001 JP
2002-085961 Mar 2002 JP
2003-501257 Jan 2003 JP
2003-502656 Jan 2003 JP
2003-149136 May 2003 JP
2003-222633 Aug 2003 JP
2005-037346 Feb 2005 JP
2005-192944 Jul 2005 JP
2007-190364 Aug 2007 JP
2009-0536313 Oct 2009 JP
2009-265751 Nov 2009 JP
2010-198393 Sep 2010 JP
2012-204765 Oct 2012 JP
2013-143959 Jul 2013 JP
2016063824 Apr 2016 JP
0164332 Sep 2001 NO
2006040554 Apr 2006 NO
264353 May 1996 NZ
8402000 May 1984 WO
9015807 Dec 1990 WO
9105058 Apr 1991 WO
9107772 May 1991 WO
9116966 Nov 1991 WO
9203734 Mar 1992 WO
9221746 Dec 1992 WO
9303151 Feb 1993 WO
9308278 Apr 1993 WO
9322053 Nov 1993 WO
9322054 Nov 1993 WO
9322055 Nov 1993 WO
9322058 Nov 1993 WO
9322421 Nov 1993 WO
9416332 Jul 1994 WO
9423738 Oct 1994 WO
9424314 Oct 1994 WO
9426766 Nov 1994 WO
9800705 Jan 1995 WO
9511922 May 1995 WO
9519922 Jul 1995 WO
9524929 Sep 1995 WO
9533447 Dec 1995 WO
9634112 Oct 1996 WO
9638730 Dec 1996 WO
9640057 Dec 1996 WO
9640062 Dec 1996 WO
9640723 Dec 1996 WO
9700125 Jan 1997 WO
9700442 Jan 1997 WO
9704297 Feb 1997 WO
9704748 Feb 1997 WO
9723140 Jul 1997 WO
9728556 Aug 1997 WO
9738318 Oct 1997 WO
9739814 Oct 1997 WO
9740141 Oct 1997 WO
9745644 Dec 1997 WO
9747763 Dec 1997 WO
9747763 Dec 1997 WO
9800231 Jan 1998 WO
9802237 Jan 1998 WO
9810267 Mar 1998 WO
9813502 Apr 1998 WO
9822625 May 1998 WO
9823733 Jun 1998 WO
9831700 Jul 1998 WO
9833001 Jul 1998 WO
9834120 Aug 1998 WO
9837186 Aug 1998 WO
9841869 Sep 1998 WO
9852691 Nov 1998 WO
9858085 Dec 1998 WO
9902671 Jan 1999 WO
9922858 May 1999 WO
9928020 Jun 1999 WO
9928507 Jun 1999 WO
9931019 Jun 1999 WO
9942539 Aug 1999 WO
9954730 Oct 1999 WO
9961888 Dec 1999 WO
0004139 Jan 2000 WO
0047322 Feb 2000 WO
0052455 Feb 2000 WO
0037924 Jun 2000 WO
0040712 Jun 2000 WO
0054735 Sep 2000 WO
0061275 Oct 2000 WO
0070080 Nov 2000 WO
0076673 Dec 2000 WO
00078455 Dec 2000 WO
0112327 Feb 2001 WO
0114589 Mar 2001 WO
0118244 Mar 2001 WO
0164332 Sep 2001 WO
0168257 Sep 2001 WO
0169289 Sep 2001 WO
0172431 Oct 2001 WO
0180283 Oct 2001 WO
01089787 Nov 2001 WO
0189788 Nov 2001 WO
0194635 Dec 2001 WO
0216017 Feb 2002 WO
0218949 Mar 2002 WO
0222869 Mar 2002 WO
0223163 Mar 2002 WO
0223163 Mar 2002 WO
0227660 Apr 2002 WO
0231203 Apr 2002 WO
2002036815 May 2002 WO
0247665 Aug 2002 WO
02060275 Aug 2002 WO
02060591 Aug 2002 WO
02066992 Aug 2002 WO
02068104 Sep 2002 WO
02078845 Oct 2002 WO
02103011 Dec 2002 WO
02103363 Dec 2002 WO
03011443 Feb 2003 WO
03026798 Apr 2003 WO
03037302 May 2003 WO
03044187 May 2003 WO
03078659 Sep 2003 WO
2003003015 Oct 2003 WO
03099843 Dec 2003 WO
2004002627 Jan 2004 WO
2004018497 Mar 2004 WO
2004024917 Mar 2004 WO
2004026453 Apr 2004 WO
2004037374 May 2004 WO
2004038363 May 2004 WO
04071638 Aug 2004 WO
2004069849 Aug 2004 WO
2004069849 Aug 2004 WO
2004074504 Sep 2004 WO
2004083443 Sep 2004 WO
2004087308 Oct 2004 WO
2004088314 Oct 2004 WO
2004091763 Oct 2004 WO
2004102204 Nov 2004 WO
2004103565 Dec 2004 WO
2005000970 Jan 2005 WO
2005002730 Jan 2005 WO
2005002730 Jan 2005 WO
2005003375 Jan 2005 WO
200511867 Feb 2005 WO
05021151 Mar 2005 WO
2005021151 Mar 2005 WO
2005023427 Mar 2005 WO
2005028674 Mar 2005 WO
2005041884 May 2005 WO
05049787 Jun 2005 WO
2005103106 Nov 2005 WO
2005118138 Dec 2005 WO
2005118867 Dec 2005 WO
2006002641 Jan 2006 WO
2006009657 Jan 2006 WO
2006027757 Mar 2006 WO
2006027757 Mar 2006 WO
2006038035 Apr 2006 WO
2006038035 Apr 2006 WO
2006040551 Apr 2006 WO
2006040554 Apr 2006 WO
2006042303 Apr 2006 WO
2006076810 Jul 2006 WO
2006078841 Jul 2006 WO
2006096571 Sep 2006 WO
2006101851 Sep 2006 WO
2007012638 Feb 2007 WO
2007021343 Feb 2007 WO
2007030501 Mar 2007 WO
2007026884 Mar 2007 WO
2007081385 Jul 2007 WO
2007081387 Jul 2007 WO
2007089541 Aug 2007 WO
2007114794 Oct 2007 WO
2007114794 Oct 2007 WO
2007123744 Nov 2007 WO
2007123744 Nov 2007 WO
2007133710 Nov 2007 WO
2007138178 Dec 2007 WO
2007140015 Dec 2007 WO
2008021123 Feb 2008 WO
2008052138 May 2008 WO
2008063227 May 2008 WO
2008097559 Aug 2008 WO
2008115626 Sep 2008 WO
2008121342 Oct 2008 WO
2008130623 Oct 2008 WO
2007092473 Nov 2008 WO
2008134153 Nov 2008 WO
2009013492 Jan 2009 WO
2009015296 Jan 2009 WO
2009029229 Mar 2009 WO
2009037266 Mar 2009 WO
2009049889 Apr 2009 WO
2009059430 May 2009 WO
2009085929 Jul 2009 WO
2009094623 Jul 2009 WO
2009117485 Sep 2009 WO
2009137415 Nov 2009 WO
2009137415 Nov 2009 WO
2009137606 Nov 2009 WO
2010009365 Jan 2010 WO
2010009365 Jan 2010 WO
2010056728 May 2010 WO
2010056728 May 2010 WO
2010040006 Aug 2010 WO
2010115154 Oct 2010 WO
2010115154 Oct 2010 WO
2010127550 Nov 2010 WO
WO-2010127550 Nov 2010 WO
2010151776 Dec 2010 WO
2010151776 Dec 2010 WO
2011042564 Apr 2011 WO
2011079176 Jun 2011 WO
2011100604 Aug 2011 WO
2012022976 Feb 2012 WO
2012036679 Mar 2012 WO
2012045012 Apr 2012 WO
2012047297 Apr 2012 WO
2012048341 Apr 2012 WO
2012083225 Jun 2012 WO
2012103339 Aug 2012 WO
2012106385 Aug 2012 WO
2012142213 Oct 2012 WO
2012167142 Dec 2012 WO
201314356 Jan 2013 WO
2013120089 Aug 2013 WO
2013165748 Nov 2013 WO
2014026031 Feb 2014 WO
2014065756 May 2014 WO
2014165559 Oct 2014 WO
2014194131 Dec 2014 WO
2014204939 Dec 2014 WO
2015013681 Jan 2015 WO
2015164212 Oct 2015 WO
2015200541 Dec 2015 WO
2015200893 Dec 2015 WO
2017100350 Jun 2017 WO
2017117358 Jul 2017 WO
Non-Patent Literature Citations (1446)
Entry
Flanagan et al. Fab Antibody Fragments: Some Applications in Clinical Toxicology. Drug Safety 27(14):1115-1133. (Year: 2004).
Chiu, 2008, Noninvasive prenatal diagnosis of chromosomal aneuploidy by massively paralel genomic seuqencing of DNA in maternal plasma, PNAS 105(51):20458-20463.
Eijk-Van Os, 2011, Multiplex ligation-dependent probe amplification (MLPA(R)) for the detection of copy number variation in genomic sequences, Meth Mol Biol 688:97-126.
Gruner, 2015, Stabilisers for water-in-fluorinated-oil dispersions, Curr Op Coll Int Sci 20:183-191.
Guo, 2010, Simultaneous detection of trisomies 13, 18, and 21 with multiplex ligation dependent probe amplification-based real-time PCR, Clin Chem 56(9):1451-1459.
Shendure, 2008, Next-generation DNA sequencing, Nature Biotechnology, 26(10):1135-1145.
Abate, 2011, Synthesis of monidisperse microparticles from non-Newtonian polymer solutions with microfluidic devices, Adv Mat 23(15):1757-1760.
Adang, 2001, The contribution of combinatorial chemistry to lead generation: an interim analysis, Curr Med Chem 8:985-998.
Affholter 1999, Engineering a Revolution, Chemistry in Britain 48-51.
Agrawal, 1990, Site-specific functionalization of oligodeoxynucleotides for non-radioactive labelling, Tetrahedron Let 31:1543-1546.
Aharoni, 2005, High-Throughput screens and selections of enzyme-encoding genes, Curr Opin Chem Biol, 9(2):210-6.
Ahn, 2006, Dielectrophoretic manipulation of drops for high-speed microluidic sorting devices, Applied Phys Lett 38:024104.
Akasheh, 2004, Development of piezoelectric micromachined ultrasonic transducers, Sensors and Actuators A Physical, 111:275-287.
Allen, 2000, High throughput fluorescence polarization: a homogeneous alternative to radioligand binding for cell surface receptors J Biomol Screen. 5(2):63-69.
Ammar, 2003, UV/Vis absorption and fluorescence spectroscopic study of novel symmetrical biscoumarin dyes, Dyes and Pigments 57:259-265.
Amstutz, 2001, In vitro display technologies: novel developments and applications. Curr Opin Biotech 12:400-405.
Anarbaev, 1998, Klenow fragment and DNA polymerase alpha-primase fromserva calf thymus in water-in-oil microemulsions, Biochim Biophy Acta 1384:315-324.
Anderson, 1983, Preparation of a cell-free protein-synthesizing system from wheat germ, Methods Enz 101:635-644.
Anderson, 1993, Restriction endonucleases and modification methylases, Curr Op Struct Biol 3:24-30.
Ando, 1999, PLGA microspheres containing plasmid DNA: preservation of supercoiled DNA via cryopreparation and carbohydrate stabilization, J Pharm Sci 88(1):126-130.
Angell, 1983, Silicon micromechanical devices, Scientific Am 248:44-55.
Anhuf, 2003, Determination of SMN1 and SMN2 copy number using TaqMan technology, Hum Mutat 22(1):74-78.
Anna, 2003, Formation of dispersions using flow focusing in microchannels, Appl Phys Lett82(3):364-366.
Armstrong, 1996, Multiple-Component condensation strategies for combinatorial library synthesis, Acc Chem Res 29 (3):123-131.
Ashkin, 1987, Optical trapping and manipulation of single cells using infrared laser beams, Nature 330:769-771.
Ashkin, 1987, Optical trapping and manipulation of viruses and bacteria, Science 235(4795):1517-20.
Auroux, 2002, Micro Total Analysis Systems 2: Analytical standard operations and applications, Anal Chem 74 (12):2637-2652.
Baccarani, 1977, Escherichia coli dihydrofolate reductase: isolation and characterization of two isozymes, Biochemistry 16(16):3566-72.
Bagwe, 2001, Improved drug delivery using microemulsions: rationale, recent progress, and new horizons, Crit Rev Ther Drug Carr Sys 18(1):77-140.
Baker, 2010, Clever PCR: more genotyping, smaller vols. Nat Meth 7:351-356.
Ballantyne, 1973, Selective area metallization by electron-beam controlled direct metallic deposition, J Vac Sci Tech 10:1094.
Barany, 1991, Genetic disease detection and DNA amplification using cloned thermostable ligase, PNAS 88(1):189-93.
Barany, 1991, The ligase chain reaction in a PCR World, PCR Meth App 1(1):5-16.
Baret, 2009, Fluorescence-activated droplet sorting (FADS): efficient microfluidic cell sorting based on enzymatic activity, Lab Chip 9:1850-1858.
Baret, 2009, Kinetic aspects of emulsion stabilization by surfactants: a microfluidic analysis, Langmuir 25:6088-6093.
Baroud, 2004, Multiphase flows in microfluidics, Physique 5:547-555.
Bauer, 1999, Advances in cell separation: recent developments in counterflow centrifugal elutriation and continuous flow cell separation, J Chromot 722:55-69.
Beebe, 2000, Functional hydrogel structures for autonomous flow control inside microfluidic channels, Nature 404:588-590.
Beer, 2007, On-chip, real-time, single-copy polymerase chain reaction in picoliter droplets, Anal Chem 79 (22):8471-8475.
Beer, 2008, On-chip single-copy real-time reverse transcription PCR in isolated picoliter droplets, Anal Chem 80 (6):1854-1858.
Bein, 1999, Efficient assays for combinatorial methods for the eiscovery of catalysts, Agnew Chem Int Ed 38:3:323-26.
Benichou, 2002, Double emulsions stabilized by new molecular recognition hybrids of natural polymers, Polym Adv Tech 13:1019-1031.
Benner, 1994, Expanding the genetic lexicon, Trends Biotech 12:158-63.
Benning, 2000, The binding of substrate analogs to phosphotriesterase. J Biol Chem 275:30556-30560.
Berman, 1987, An agarose gel electrophoresis assay for the detection of DNA-binding activities in yeast cell extracts, Meth Enz 155:528-37.
Bernath, 2004, In Vitro Compartmentalization by double emulsions: sorting and gene enrichment by FACS Anal Biochem 325:151-157.
Bernath, 2005, Directed evolution of protein inhibitors of DNA-nucleases by in vitro compartmentalization (IVC) and nano-droplet delivery, J Mol Biol 345(5):1015-26.
Betlach, 1976, A restriction endonuclease analysis of the bacterial plasmid controlling the EcoRI restriction and modification of DNA, Fed Proc 35:2037-2043.
Bibette, 1999, Emulsions: basic principles, Rep Prog Phys 62:969-1033.
Bico, 2002, Rise of liquids and bubbles in angular capillary tubes, J Colloid & Interface Sc 247:162-166.
Bico, 2002, Self-Propelling Slugs, J Fluid Mech 467:101-127.
Binder, 2009, Mismatch and G-stack modulated probe signals on SNP microarrays, PLOS One, 4(11):e7862.
Binladen, 2007, The use of coded PCR primers enables high-throughput sequencing of multiple homolog amplification products by 454 parallel sequencing, PLOSOne 2(2):e197.
Blanchet, 1993, Laser Ablation and the Production of Polymer Films, Science, 262(5134):719-721.
Boder, 1997, Yeast surface display for screening combinatorial polypeptide libraries, Nat Biotech 15(6):553-7.
Bosque, 2009, Induction of HIV-1 latency and reactivation in primary memory CD4+ T cells, Blood, 113(1):58-65.
Gold et al., Diversity of Oligonucleotide Functions Annu Rev Biochem, 64: 763-97 (1995).
Goodall, J. L. et al., Operation of Mixed-Culture Immobilized Cell Reactors for the Metabolism of Meta- and Para-Nitrobenzoate by Comamonas Sp. JS46 and Comamonas Sp. JS47, Biotechnology and Bioengineering, 59 (1):21-27 (1998).
Gordon and Balasubramanian, Solid phase synthesis—designer linkers for combinatorial chemistry: a review, J. Chem. Technol. Biotechnol., 74(9):835-851 (1999).
Grasland-Mongrain et al., Droplet coalescence in microfluidic devices, 30 pages (Jul. 2003) From internet: http://www.eleves.ens.fr/home/grasland/rapports/stage4.pdf.
Green, R. and Szostak, J.W., Selection of a Ribozyme That Functions as a Superior Template in a Self Copying Reaction, Science, 258: 1910-5 (1992).
Gregoriadis, G., Enzyme entrapment in liposomes, Methods Enzymol 44:218-227 (1976).
Griffiths et al., Directed evolution of an extremely fast phosphotriesterase by in vitro compartmentalization, EMBO J, 22:24-35 (2003).
Griffiths et al., Isolation of high affinity human antibodies directly from large synthetic repertoires, Embo J 13 (14):3245-60 (1994).
Griffiths et al., Man-made enzymes-from design to in vitro compartmentalisation, Curr Opin Biotechnol 11:338-353 (2000).
Griffiths, A., and Tawfik, D., Miniaturising the laboratory in emulsion droplets, Trend Biotech 24(9):395-402 (2006).
Griffiths, A.D. et al., Strategies for selection of antibodies by phage display, Curr Opin Biotechnol, 9:102-8 (1998).
Grothues et al. (1993) Nucl. Acids Res vol. 21 No 5 pp. 1321-1 322.
Guatelli, J.C. et al., Isothermal, in vitro amplification of nucleic acids by a multienzyme reaction modeled after retroviral replication, PNAS, 87(5):1874-8 (1990).
Guixe et al., Ligand-Induced Conformational Transitions in Escherichia coli Phosphofructokinase 2: Evidence for an Allosteric Site for MgATP2n, Biochem., 37: 13269-12375 (1998).
Gupta, K.C., et al., A general method for the synthesis of 3′-sulfhydryl and phosphate group containing oligonucleotides, Nucl Acids Res 19 (11): 3019-3026 (1991).
Haber et al., Activity and spectroscopic properties of bovine liver catalase in sodium bis(2-ethylhexyl) sulfosuccinate/sooctane reverse micelles, Eur J Biochem 217(2): 567-73 (1993).
Tabig and Jakoby, Assays for differentiation of glutathione S-transferases, Methods in Enzymology, 77: 398-405 (1981).
Hadd et al., Microchip Device for Performing Enzyme Assays, Anal. Chem 69(17): 3407-3412 (1997).
Haddad et al., A methodology for solving physiologically based pharmacokinetic models without the use of simulation software, Toxicol Lett. 85(2): 113-26 (1996).
Hagar and Spitzer, The effect of endotoxemia on concanavalin A induced alterations in cytoplasmic free calcium in rat spleen cells as determined with Fluo-3, Cell Calcium 13:123-130 (1992).
Hai et al., Investigation on the release of fluorescent markers from the w/o/w emulsions by fluorescence-activated cell sorter, J Control Release, 96(3): 393-402 (2004).
Haies et al., Morphometric study of rat lung cells. I. Numerical and dimensional characteristics of parenchymal cell population, Am. Rev. Respir. Dis. 123:533-54 (1981).
Hall, Experimental evolution of Ebg enzyme provides clues about the evolution of catalysis and to evolutionary potential, FEMS Microbiol Lett, 174(1):1-8 (1999).
Hall, The EBG system of E. coli: origin and evolution of a novel beta-galactosidase for the metabolism of lactose, Genetica 118(2-3):143-56 (2003).
Hamady et al. Error-correcting barcoded primers for pyrosequencing hundreds of samples in multiplex. Nature Nethods vol. 5, No. 3, p. 235-237. (2008).
Han et al., Quantum-dot-tagged Microbeads for Multiplexed Optical Coding of Biomolecules, Nat Biotech 19(7): 631-635 (2001).
Handen, J.S., High-throughput screening- challenges for the future, Drug Discov World, 47-50 (2002).
Tandique, K. et al., On-Chip Thermopneumatic Pressure for Discrete Drop Pumping, Analytical Chemistry, 73:1831-1838 (2001).
Hanes et al., Degradation of porous poly(anhydide-co-imide) microspheres and implication for controlled macromolecule delivery, Biomaterials, 19(1-3): 163-172(1998).
Hanes et al., In vitro selection and evolution of functional proteins by using ribosome display, PNAS 94:4937-42 (1997).
Hansen et al., A robust and scalable microfluidic metering method that allows protein crystal growth by free interface diffusion, PNAS 99(26):16531-16536 (2002).
Harada et al., Monoclonal antibody G6K12 specific for membrane-associated differentiation marker of human stratified squamous epithelia and squamous cell carcinoma, J. Oral Pathol. Med 22(4):145-152 (1993).
Harder, K.W. et al., Characterization and kinetic analysis of the intracellular domain of human protein tyrosine phosphatase beta (HPTP beta) using synthetic phosphopeptides, Biochem J 298 (Pt 2): 395-401 (1994).
Harries et al., A Numerical Model for Segmented Flow in a Microreactor, Int J of Heat and Mass Transfer, 46:3313-3322 (2006).
Harris et al., Single-molecule DNA sequencing of a viral genome, Science 320(5872):106-109 (2008).
Harrison et al., Micromachining a miniaturized capillary electrophoresis-based chemical analysis system on a chip, Science 261(5123):895-897 (1993).
Tasina et al., Plasminogen activator inhibitor-2: a molecular biomarker for head and neck cancer progression, Cancer Research 63:555-559 (2003).
Hayward et al., Dewetting Instability during the Formation of Polymersomes from BloceCopolymer-Stabilized Double Emulsions, Langmuir, 22(10): 4457-4461 (2006).
He et al., Selective encapsulation of single cells and subcellular organelles into picoliter- and femtoliter-volume droplets, Anal Chem 77(6):1539-1544 (2005).
Heim et al., Engineering Green Fluorescent Protein for Improved Brightness, Longer Wavelengths and Fluorescence Response Energy Transfer, Carr. Biol, 6(2): 178-182 (1996).
Hellman et al., Differential tissue-specific protein markers of vaginal carcinoma, Br J Cancer, 100(8): 1303-131 (2009).
Hergenrother et al., Small-Molecule Microarrays: Covalent Attachment and Screening of Alcohol-Containing Small Molecules on Glass Slides, J. Am. Chem. Soc, 122: 7849-7850 (2000).
Herzer (DNA Purification, in Molecular Biology Problem Solver: A Laboratory Guide, Edited by Alan S. Gerstein, Ch. 1, 2001).
Hildebrand et al., Liquid-Liquid Solubility of Perfluoromethylcyclohexane with Benzene, Carbon Tetrachloride, Chlorobenzene, Chloroform and Toluene, J. Am. Chem. Soc, 71: 22-25 (1949).
Hjelmfelt et al., Pattern-Recognition in Coupled Chemical Kinetic Systems, Science, 260(5106):335-337 (1993).
Ho, S.N. et al., Site-directed mutageneiss by overlap extension using the polymerase chain reaction, Gene, 77(1):51-9 (1989).
Hoang, Physiologically based pharmacokinetic models: mathematical fundamentals and simulation implementations, Toxicol Lett 79(1-3):99-106 (1995).
Hochuli et al., New metal chelate adsorbent selective for proteins and peptides containing neighbouring histidine residues, J Chromatogr 411: 177-84 (1987).
Montigiani, 1996, Alanine substitutions in calmodulin-binding peptides result in unexpected affinity enhancement, J Mol Biol, 258:6-13.
Moore, 1995, Exploration by lamp light, Nature, 374:766-7.
Morrison, 1984, Chimeric human antibody molecules: mouse antigen-binding domains with human constant region domains, PNAS 81:6851-6855.
Moudrianakis, 1965, Base sequence determination in nucelic acids with the electron microscope 3. Chemistry and microscopy of guanine-labeled DNA, PNAS 53:564-71.
Mueth, 1996, Origin of stratification in creaming emulsions, Physical Review Letters 77(3):578-581.
Mulbry, 1989, Parathion hydrolase specified by the Flavobacterium opd gene: relationshio between the gene and protein. J Bacteriol, 171: 6740-6746.
Mulder, 1993, Characterization of two human monoclonal antibodies reactive with HLA-B12 and HLA-B60, respectively, raised by in vitro secondary immunization of peripheral blood lymphocytes, Hum. Immunol 36(3):186-192.
Munson, 1980, Ligand: a versatile computerized approach for characterization of ligand-binding systems, Analytical Biochemistry, 107:220-239.
Nakano, 1994, High speed polymerase chain reaction in constant flow, Biosci Biotech and Biochem, 58:349-52.
Nakano, 2003, Single-molecule PCR using water-in-oil emulsion, J Biotech, 102:117-124.
Nakano, 2005, Single-molecule reverse transcription polymerase chain reaction using water-in-oil emulsion, J Biosci Bioeng 99:293-295.
Nametkin, 1992, Cell-free translation in reversed micelles, FEB Letters, 309(3):330-32.
Narang, 1979, Improved phosphotriester method for the synthesis of gene fragments, Methods Enzymol, 68:90-98.
Neiman, 2011, Decoding a substantial set of samples in parallel by massive sequencing, Plos ONE 6(3):1-7.
Nelson, 1989, Bifunctional oligonucleotide probes synthesized using a novel CPG support are able to detect single base pair mutations, Nucl Acids Res 17(18): 7187-7194.
Nemoto, 1997, In vitro virus: bonding of mRNA bearing puromycin at the 3 terminal end to the C-terminal end of its encoded protein on the ribosome in vitro, Federation of European Biochemical Societies, 414:405-8.
Ness, 2000, Molecular Breeding: the natural approach to protein design. Adv Protein Chem, 55: 261-292.
Ng, 2003, Protein crystallization by capillary counter-diffusion for applied crystallographic structure determination, J. Struct. Biol, 142:218-231.
Ng, 2006, Factors affecting flow karyotype resolution, Cytometry, Part A 69A: 1028-1036.
Nguyen, 2006, Optical detection for droplet size control in microfluidic droplet-based analysis systems, Sensors and Actuators B 117(2):431-436.
Nihant, 1994, Polylactide Microparticles Prepared by Double Emulsion/Evaporation Technique. I. Effect of Primary Emulsion Stability, Pharmaceutical Research, 11(10):1479-1484.
Nisisako, 2002, Droplet formation in a microchannel network, Lab Chip 2:24-26.
Nisisako, 2002, Formation of droplets using branch channels in a microfluidic circuit, Proceedings of the SICE Annual Conference. International Session Papers 1262-1264.
Nisisako, 2005, Controlled formulation of monodisperse double emulsions in a multiple-phase microluidic system, Sot Matter, 1:23-27.
Nisisako, 2008, Microstructured Devices for Preparing Controlled Multiple Emulsions. Chem. Eng. Technol 31 (8):1091-1098.
Nof, 2002, Drug-releasing scaffolds fabricated from drug-loaded microspheres, J. Biomed Mater Res 59:349-356.
Norman, 1980, Flow Cytometry, Med. Phys., 7(6):609-615.
Nygren, 1982, Conjugation of horseradish peroxidase to Fab fragments with different homobifunctional and heterobifunctional cross-linking reagents. A comparative study, J. Histochem. and Cytochem. 30:407-412.
Oberholzer, 1995, Enzymatic RNA replication in self-reproducing vesicles: an approach to a minimal cell, Biochem Biophys Res Commun 207(1):250-7.
Oberholzer, 1995, Polymerase chain reaction in liposomes, Chem. Biol. 2(10):677-82.
Obukowicz, 1988, Secretion and export of IGF-1 in Escerichia coli strain JM101, Mol Gen Genet, 215:19-25.
Ogura, 1955, Catalase activity at high concentrations of hydrogen peroxide, Archs Biochem Biophys, 57: 288-300.
Oh, 2002, Distribution of Macropores in Silica Particles Prepared by Using Multiple Emulsions, Journal of Colloid and Interface Science, 254(1): 79-86.
Oh, 2005, World-to-chip microfluidic interface with built-in valves for multichamber chip-based PCR assays, Lab Chip, 6, 845-850.
Okuno, 2003, Recent Advances in Optical Switches Using Silica-based PLC Technology, NTT Technical Review 1 (7):20-30.
Okushima, 2004, Controlled production of monodisperse double emulsions by two -step droplet breakup in microfluidic devices, Langmuir 20(23): 9905-8.
Olsen, 2000, Function-based isolation of novel enzymes from a large library, Nat Bioteoltnol 13(10):1071-4.
Omburo, 1992, Characterization of the zinc binding site of bacterial phosphotriesterase, J of Biological Chem, 267:13278-83.
Oroskar, 1996, Detection of immobilized amplicons by ELISA-like techniques, Clin. Chem. 42:1547-1555.
Ostermeier, 1999, A combinatorial approach to hybrid enzymes independent of DNA homology, Nat Biotechnol, 17 (12):1205-9.
Ott, 1967, Biological and medical research annual report, Los Alamos Scientific Laboratory, 14 pages.
Ouelette, 2003, A new wave of microfluidic devices, Indust Physicist pp. 14-17.
Pabit, 2002, Laminar-Flow Fluid Mixer for Fast Fluorescence Kinetics Studies, Biophys J 83:2872-2878.
Paddison, 2002, Stable suppression of gene expression by RNAi in mammalian cells, PNAS 99(3):1443-1448.
Pain, 1981, Preparation of protein A-peroxidase mono conjugate using a heterobifunctional reagent, and its use in enzyme immunoassays, J Immunol Methods, 40:219-30.
Pannacci, 2008, Equilibrium and Nonequilibrium States in Microluidic Double Emulsions Physical Review Leters, 101 (16):164502.
Park, 2001, Model of Formation of Monodispersed Colloids, J. Phys. Chem. B 105:11630-11635.
Park, 2003, Cylindrical compact thermal-cycling device for continuous-flow polymeras chain reaction, Anal Chem, ACS, 75:6029-33.
Parker, 2000, Development of high throughput screening assays using fluorescence polarization: nuclear receptor-ligand-binding and kinase/phosphatase assays, J Biomol Screen, 5(2): 77-88.
Pasternak, 2013, Cell-associated HIV RNA: a dynmic biomarker of viral persistence, Retrovirology 10:41.
Soumillion, 2001, Novel concepts for the selection of catalytic activity. Curr Op Biotech 12:387-394.
Spiro, 2000, A bead-based method for multiplexed identification and quantitation of DNA sequences using flow cytometry, Appl Env Micro 66:4258-4265.
Sproat, 1987, The synthesis of protected 5′-mercapto-2',5′-dideoxyribonucleoside-3′-0-phosphorainidites, uses of 5′- mercapto-oligodeoxyribonucleotides, Nucleic Acids Res 15:4837-4848.
Squires, 2005, Microfluidics: fluid physics at the nanoliter scale, Rev Mod Phys 77:977-1026.
Stauber, 1993, Rapid generation of monoclonal antibody-secreting hybridomas against African horse sickness virus by in vitro immunization and the fusion/cloning technique, J Immunol Meth 161(2):157-168.
Stemmer, 1994, DNA shuffling by random fragmentation and reassembly: in vitro recombination for molecular evolution. PNAS 91(22):10747-51.
Stemmer, 1994, Rapid evolution of a protein in vitro by DNA shuffling, Nature 370(6488):389-91.
Stober, 1998, Controlled growth of monodisperse silica spheres in the micron size range, J Colloid Interface Sci 26 (1):62-69.
Stofko, 1992, A single step purification for recombinant proteins, Febs Lett 302:274-278.
Stone, 2004, Engineering flows in small devices: microfluidics toward a lab-on-a-chip, Ann Rev Fluid Mech 36:381-441.
Strizhkov, 2000, PCR amplification on a microarray of gel-immobilized oligonucleotides: Detection of bacterial toxin- and drug- resistant genes and their mutations, BioTechniques 29(4):844-857.
Strommenger, 2003, Multiplex PCR assay for simultaneous detection of nine clinicly relevant antibiotic resistance genes in S aureus, J Clin Microb 41(9):4089-4094.
Stroock, 2002, Chaotic mixer for microchannels, Science 295(5555):647-651.
Studer, 1997, Fluorous synthesis: a fluorous-phase strategy for improving separation efficiency in organic synthesis, Science 275:823-826.
Sugiura, 2001, Interfacial tension driven monodispersed droplet formation from mtcrofabricated channel array, angmuir 17:5562-5566.
Sugiura, 2002, Effect of channel structure on microchannel emuisification, Langmuir 18:5708-5712.
Sundberg, 1995, Spatially-addressable immobilisation of macromolecules on solid supports, J Am Chem Soc 117:12050-12057.
Sung, 2005, Chip-based microfluidic devices coupled with electrospray ionization-mass spectrometry, Electrophoresis 26:1783-1791.
Sutcliffe, 1986, Dynamics of UV laser ablation of organic polymer surfaces, J Appl Phys 60(9):3315-3322.
Suzuki, 1996, Random mutagenesis of thermus aquaticus DNA polmerase I: concordance of immutable sites in vivo with the crystal structure, PNAS 93:96701-9675.
Syed, 2009, Next-generation sequencing library preparation: simultaneous fragmentation and tagging using in vitro transposition, Nat Meth 6:1-2.
Takayama, 1999, Patterning cells and their environmnets using multiple laminar fluid flows in cappillary networks, PNAS 96:5545-5548.
Takeuchi, 2005, An axisymmetric flow-focusing microfluidic device, Adv Mater 17(8):1067-1072.
Taly, 2007, Droplets as microreactors for high-throughput biology, Chembiochem 8(3):263-272.
Tan, 2003, Controlled fission of droplet emulsions in bifurcating microfluidic channels, 12th Int Conf SSAM 28-31.
Tan, 2003, Microfluidic liposome generation from monodisperse droplet emulsion, Summer Bioeng Conf, Florida, 2 pages.
Tan, 2003, Monodisperse droplet emulsions in co-flow microfluidic channels, Micro TAS, 2 pages.
Tan, 2004, Design of microluidic channel geometries for the control of droplet volume chemical concentration, and sorting, Lab Chip 4(4):292-298.
Tang, 2009, A multi-color fast-switching microfluidic droplet dye laser, Lab Chip 9:2767-2771.
Taniguchi, 2002, Chemical reactions in microdroplets by electrostatic manipulation of droplets in liquid media, Lab Chip 2:19-23.
Tawfik, 1998, Man-made cell-like compartments for molecular evolution, Nat Biotech 7(16):652-56.
Taylor, 1934, The formation of emulsions in definable field of flow, Proc R Soc London A 146(858):501-523.
Taylor, 1991, Characterization of chemisorbed monolayers by surface potential measurments, J Phys D Appl Phys 24:1443.
Tencza, 2000, Development of a fluorescence polarization-based diagnostic assay for equine infectious anemia virus, Clin Microbiol 38(5):1854-185.
Terray, 2002, Fabrication of linear colloidal structures for microfluidic applications, Applied Phys Lett 81(9):1555-1557.
Terray, 2002, Microfluidic control using colloidal devices, Science 296(5574):1841-1844.
Tewhey, 2009, Microdroplet based PCR environment for large scale targeted sequence, Nat Biotech 27(11):1025-1031.
Theberge, 2010, Microdroplets in microfluidics: an evolving platform for discoveries in chemistry and biology, Angew Chem Int Ed 49(34):5846-5868.
Thompson, 1983, Introduction to Lithography, ACS Symp Ser 219:1-13.
Thorsen, 2001, Dynamic pattern formation in a vesicle-generating microfluidic device, Phys Rev Lett 86(18):4163-4166.
Thorsen, 2002, Microfluidic large-scale integration, Science 298:580-584.
Thorsen, 2003, Microfluidic technologies for highthroughput screening applications, California Institute of Technology.
Tice, 2003, Formation of droplets and mixing in multiphase microfluidics at low values of the reynolds and the capillary Nos. Langmuir 19:9127-9133.
Tice, 2004, Effects of viscosity on droplet formation and mixing in microfluidic channels, Analytica Chimica Acta 507:73-77.
Titomanlio, 1990, Capillary experiments of flow induced crystallization of HDPE, AIChe J 36(1):13-18.
Tleugabulova, 2004, Evaluating formation and growth mechanisms of silica particles using fluorescence anisotropy decay analysis, Langmuir 20(14):5924-5932.
Tokatlidis, 1995, Nascent chains: folding and chaperone intraction during elongation on ribosomes, Philos Trans R Soc Lond B Biol Sci, 348:89-95.
Tokeshi, 2002, Continuous-flow chemical processing on a microchip by combining microunit operations and a multiphase flow network, Anal Chem 74(7):1565-1571.
Tokumitsu, 1999, Preparation of gadopentetic acid-loaded chitosan microparticles for gadolinium neutron-capture therapy of cancer by a novel emulsion-droplet coalescence technique, Chem Pharm Bull 47(6):838-842.
Tonelli et al., 2002, Perfluoropolyether functional oligomers: unusual reactivity in organic chemistry, Journal of fluorine Chemistry, 118; 107-121.
Abstract of Sanchez et al., Breakup of Charged Capillary Jets, Bulletin of the American Physical Society Division of Fluid Dynamics 41:1768-1768 (1996).
Adang, A.E. et al., The contribution of combinatorial chemistry to lead generation: an interim analysis, Curr Med Chem 8: 985-998 (2001).
Advisory Action for U.S. Appl. No. 11/360,845, dated Jun. 14, 2010.
Advisory Action for U.S. Appl. No. 11/698,298 dated May 20, 2011.
Affholter et al., Engineering a Revolution, Chemistry in Britain, Apr. 1999, p. 48.
Aharoni et al., High-Throughput screens and selections of enzyme-encoding genes, Curr Opin Chem Biol, 9(2):210-6 (2005).
Ahn et al., Dielectrophoretic manipulation of drops for high-speed microluidic sorting devices, Applied Phys Lett 88, 024104 (2006).
Allen et al., High throughput fluorescence polarization: a homogeneous alternative to radioligand binding for cell surface receptors J Biomol Screen. 5(2):63-9 (2000).
Altman et al., Solid-state laser using a rhodamine-doped silica gel compound, IEEE Photonics technology letters 3(3):189-190 (1991).
Amstutz, P. et al., In vitro display technologies: novel developments and applications. Curr Opin Biotechnol, 12, 400-405 (2001).
Anarbaev et al., Klenow fragment and DNA polymerase alpha-primase fromserva calf thymus in water-in-oil microemulsions, Biochim Biophy Acta 1384:315-324 (1998).
Anderson et al., Preparation of a cell-free protein-synthesizing system from wheat germ, Methods Enzymol 101:635-44 (1983).
Anderson, Restriction endonucleases and modification methylases, Curr. Op. Struct. Biol., 3:24-30 (1993).
Ando et al., PLGA microspheres containing plasmid DNA: preservation of supercoiled DNA via cryopreparation and carbohydrate stabilization, J Pharm Sci, 88(1):126-130 (1999).
Angell et al., Silicon micromechanical devices, Scientific American 248:44-55 (1983).
Anhuf et al., Determination of SMN1 and SMN2 copy No. using TaqMan technology, Hum Mutat 22(1):74-78 (2003).
Anna et al., Formation of dispersions using flow focusing in microchannels, Applied Physics Letters,82(3): 364-366 (2003).
Arkin, M.R. et al., Probing the importance of second sphere residues in an esterolytic antibody by phage display, J Mol Biol 284(4):1083-94 (1998).
Armstrong et al., Multiple-Component Condensation Strategies for Combinatorial Library Synthesis, Acc. Chem. Res. 29(3):123-131 (1996).
Ashkin and Dziedzic, Optical trapping and manipulation of viruses and bacteria, Science 235(4795):1517-20 (1987).
Ashkin et al., Optical trapping and manipulation of single cells using infrared laser beams, Nature 330:769-771 (1987).
Atwell, S. & Wells, J.A., Selection for Improved Subtiligases by Phage Display, PNAS 96: 9497-9502(1999).
Auroux, Pierre-Alain et al., Micro Total Analysis Systems. 2. Analytical Standard Operations and Applications, Analytical Chemistry, vol. 74, No. 12, 2002, pp. 2637-2652.
Baccarani et al., Escherichia coli dihydrofolate reductase: isolation and characterization of two isozymes, Biochemistry 16(16):3566-72 (1977).
Baez et al., Glutathione transferases catalyse the detoxication of oxidized metabolites (o-quinones) of catecholamines and may serve as an antioxidant system preventing degenerative cellular processes, Biochem. J 324:25-28 (1997).
Baker, M., Clever PCR: more genotyping, smaller volumes Nature Methods 7:351-356 (2010).
Ball and Schwartz, CMATRIX: software for physiologically based pharmacokinetic modeling using a symbolic matrix representation system, Comput Biol Med 24(4):269-76 (1994).
Ballantyne and Nixon, Selective Area Metallization by Electron-Beam Controlled Direct Metallic Deposition, J. Vac. Sci. Technol. 10:1094 (1973).
Barany F., The ligase chain reaction in a PCR World, PCR Methods and Applications 1(1):5-16 (1991).
Barany, F. Genetic disease detection and DNA amplification using cloned thermostable ligase, PNAS 88(1): 189-93 (1991).
Baret et al., Fluorescence-activated droplet sorting (FADS): efficient microfluidic cell sorting based on enzymatic activity, Lab on a Chip 9:1850-1858 (2009).
Baret et al., Kinetic aspects of emulsion stabilization by surfactants: a microfluidic analysis, Langmuir 25:6088-6093 (2009).
Bass et al., Hormone Phage: An Enrichment Method for Variant Proteins With Altered Binding Properties, Proteins 8:309-314(1990).
Bauer, J., Advances in cell separation: recent developments in counterflow centrifugal elutriation and continuous flow cell separation, J Chromotography, 722:55-69 (1999).
Beebe et al., Functional hydrogel structures for autonomous flow control inside microfluidic channels, Nature 404:588-590 (2000).
Beer et al., On-Chip, Real-Time, Single-Copy Polymerase Chain Reaction in Picoliter Droplets, Anal. Chem., 79:847-8475 (2007).
Bein, Thomas, Efficient Assays for Combinatorial methods for the Discovery of Catalysts, Agnew. Chem. Int. Ed. 38:3, 323-26 (1999).
Benichou et al., Double Emulsions Stabilized by New Molecular Recognition Hybrids of Natural Polymers, Polym. Adv. Tehcnol 13:1019-1031 (2002).
Benner, S.A., Expanding the genetic lexicon: incorporating non-standard amino acids into proteins by ribosome-based synthesis, Trends Biotechnol 12:158-63 (1994).
Benning, M.M. et al., The binding of substrate analogs to phosphotriesterase. J Biol Chem, 275:30556-30560 (2000).
Berman et al., An agarose gel electrophoresis assay for the detection of DNA-binding activities in yeast cell extracts, Methods Enzymol 155:528-37 (1987).
Bernath et al., In Vitro Compartmentalization by Double Emulsions: Sorting and Gene Enrichment by Fluorescence Activated Cell Sorting, Anal. Biochem 325:151-157 (2004).
Bernath et al., Directed evolution of protein inhibitors of DNA-nucleases by in vitro compartmentalization (IVC) and nano-droplet delivery, J. Mol. Biol 345(5):1015-26 (2005).
Betlach, L. et al., A restriction endonuclease analysis of the bacterial plasmid controlling the EcoRI restriction and modification of DNA. Federation Proceedings, 35:2037-2043 (1976).
Bibette et al., Emulsions: basic principles, Rep. Prog. Phys. 62:969-1033 (1999).
Bico, Jose et al., Rise of Liquids and Bubbles in Angular Capillary Tubes, Journal of Colloid and Interface Science, 247:162-166 (2002).
Bico, Jose et al., Self-Propelling Slugs, J. Fluid Mech., 467:101-127 (2002).
Binladen et al., 2007, The use of coded PCR primers enables high-throughput sequencing of multiple homolog amplification products by 454 parallel sequencing, Plos ONE.
Blattner and Dahlberg, RNA synthesis startpoints in bacteriophage lambda: are the promoter and operator transcribed, Nature New Biol 237(77):227-32 (1972).
Kumaresan, 2008, High-throughput single copy DNA amplification and cell analysis in engineered nanoliter droplets, Anal Chem, 80:3522-3529.
Lage, 2003, Whole genome analysis of genetic alterations in small DNA samples using hyperbranched strand displacement amplification and array-CGH, Genome Res 13:294-307.
Laird, 2013, Rapid Quantification of the Latent Reservoir for HIV-1 Using a Viral Outgrowth Assay, Plos Pathogens 9(5):e1003398.
Lamprecht, 2004, pH-sensitive microsphere delivery increases oral bioavailability of calcitonin, J Control Rei 98(1):1-9.
Lancet, 1993, Probability model for molecular recognition in biological receptor repertoirs, PNAS 90(8):3715-9.
Landergren, 1988, A ligase mediated gene detection technique, Science 241(4869):1077-80.
Lasheras, 1998, Breakup and atomization of a round water jet by a high speed annular air jet, J Fluid Mech 357:351-379.
Laufer, 1996, Introduction to Optics and Lasers in Engineering, Cambridge University Press, Cambridge UK:156-162.
Leamon, 2003, A massively parallel pictoterplate based platform for discrete picoliter-scale PCR, Electrophoresis 24:3769-3777.
Leary, 2000, Application of advanced cytometric and molecular technologies to minimal residual disease monitoring, Proc SPIE 3913:36-44.
Lee, 2000, Circulating flows inside a drop under time-periodic non-uniform electric fields, Phys Fuilds 12(8):1899-1910.
Lee, 2001, Preparation of silica particles encapsulating retinol using O/W/O multiple emulsions, J Coll Interface Sci 240(1):83-89.
Lee, 2002, Effective formation of silicone-in-fluorocarbon-in-water double emulsions, J Disp Sci Tech 23(4):491-497.
Lee, 2002, Investigating the target recognition of DNA cytosine-5 methyltransferase Hhal by library selection using in vitro compartmentalisation (IVC), Nucleic Acids Res 30:4937-4944.
Lee, 2004, Special issue on biomedical applications for MEMS and microfluidics, Proc IEEE 92(1):3-5.
Lemof, 2003, An AC magnetohydrodynamic microfluidic switch for Micro Total Analysis Systems, Biomed Microdev 5(I):55-60.
Leng 2009, Microfluidic crystalizaiton,Lab Chip 9:24-23.
Leng, 2010, Agarose droplet microfluidics for highly parallel and efficient single molecule emulsion PCR, Lab Chip 10:2841-2843.
Lesley, 1991, Use of in vitro protein synthesis from PCR-generated templates to study interaction of E coli transcription factors with core RNA polymerase, J Biol Chem 266(4):2632-8.
Lesley, 1995, Preparation and use of E. coli S-30 extracts, Methods Mol Biol 37:265-78.
Leung, 1989, A method for random mutagenesis of a defined DNA segment using a modified polymerase chain reaction, Technique 1:11-15.
Li, 1995, Single-step procedure for labeling DNA strand breaks with fllourescein—or BODIPY—conjugated deoxynucleotides. Cytometry 20:172-180.
Li, 1997, Transport, manipulation, and reaction of biological cells on-chip using electrokinetic effects, Anal Chem 69(8):1564-1568.
Li, 2005, Multiplexed detection of pathogen DNA with DNA-based fluorescence nanobarcodes, Nat Biotech 23(7):885-889.
Li, 2006, Nanoliter microfluidic hybrid method for simultaneous screening and optimization validated with crystallization of membrane proteins, PNAS 103:19243-19248.
Li, 2018, Microfluidic fabrication of microparticles for biomedical applications, Chem Soc Rev 47(15):5646-5683.
Liao, 1986, Isolation of a thermostable enzyme variant by cloning and selection in a thermophile, PNAS 83:576-80.
Lim, 1980, Microencapsulated islets as bioartificial endocrine pancreas, Science 210(4472):908-10.
Lin, 2007, Self-assembled combinatorial encoding nanoarrays for multiplexed biosensing, Nano Lett 7(2):507-512.
Link, 2004, Geometrically mediated breakup of drops in microfluidic devices, Phys Rev Lettv92(5):054503-1-4.
Link, 2006, Electric control droplets in microfluidic devices, Angew Chem Int Ed 45:2556-2560.
Lipinski, 2001, Experimental and computational approaches to estimate solubility and permeability in drug discovery, , Adv Drug Deliv Rev 46:3-26.
Lipkin, 1988, Biomarkers of increased susceptibility to gastreointestinal cancer: new application to studies of cancer prevention in human subjects, Cancer Res 48:235-245.
Liu, 2000, Passive mixing in a three-dimensional serpentine microchannel, J MEMS 9(2):190-197.
Liu, 2002, Fabrication and characterization of hydrogel-based microvalves, Mecoelectromech. Syst.11:45-53.
Lizardi, 1998, Mutation detection and single-molecule counting using isothermal rolling-circle amplification. Nat Genet 19(3):225-32.
Lo, 2007, Digital PCR for the molecular detection of fetal chromosomal aneuploidy, PNAS 104(32):13116-13121.
Loakes, 1994, 5-Nitroindole as a universal base analogue, Nucleic Acids Res 22:4039-4043.
Loakes, 1997, Stability and structure of DNA oligonucleotides containing non-specific base analogues, J Mol Biol 270:426-435.
Lodish, 2000, Structure of Nucleic Acids, Section 4.1 , Molecular Cell Biology, 4th edition, New York, 1-3.
Loeker, 2003, FTIR analysis of water in supercritical carbon dioxide microemulsions using monofunctional perfluoropolyether surfanctants, Colloids and Surfaces A: Phys Eng Asp 214:143-150.
Loo, 2004, Nanoshell Enabled Photonics-Based Imaging and Therapy of Cancer, Technology in Cancer Research & Treatment 3(1):33-40.
Lopez-Herrera, 1995, The electrospraying of viscous and non-viscous semi-insulating liquids: scaling laws, Bull Am Phys Soc 40 (12):2041.
Lopez-Herrera, 1999, One-dimensional simulation of the breakup of capillary jets of conducting liquids application to EHD spraying, Aerosol Set 30(7):895-912.
Lopez-Herrera, 2003, Coaxial jets generated from electrified Taylor cones, Aerosol Sci 34:535-552.
Lorenceau, 2005, Generation of polymerosomes from double-emulsions, Langmuir 21(20):9183-9186.
Lorenz, 1991, Isolation and expression of a cDNA encoding Renilla reniformis luciferase, PNAS 88(10):4438-42.
Loscertales, 2002, Micro/nano encapsulation via electrified coaxial liquid jets, Science 295(5560):1695-1698.
Lowe, 2002, Perfluorochemical respiratory gas carriers: benefits to cell culture systems, J Fluorine Chem 118:19-26.
Lu, 2007, Robust fluorescein-doped silica nanoparticles via dense-liquid treatment, Colloids and Surfaces A Phys Eng Asp 303(3):207-210.
Hermankova, 2003, Analysis of human immunodeficiency virus type 1 gene expression in lately infected reseting CD4 T lymphocytes in vivo, J Virology 77(13):7383-7392.
Herzer, 2001, DNA Purification, in Molecular Biology Problem Solver: A Laboratory Guide, Edited by Alan S. Gerstein, Ch.1.
Heyries, 2011, Megapixel digital PCR, Nat. Methods 8, 649-651.
Hildebrand, 1949, Liquid-Liquid Solubility of Perfluoromethylcyclohexane with Benzene, Carbon Tetrachloride, Chlorobenzene, Chloroform and Toluene, J. Am. Chem. Soc, 71: 22-25.
Hindson, 2011, High-Throughput Droplet Digital PCR System for Absolute Quantitation of DNA Copy Number, Anal. Chem., 83, 8604-8610.
Hjelmfelt, 1993, Pattern-Recognition in Coupled Chemical Kinetic Systems, Science, 260(5106):335-337.
Ho, 1989, Site-directed mutageneiss by overlap extension using the polymerase chain reaction, Gene, 77(1):51-9.
Hochuli, 1987, New metal chelate adsorbent selective for proteins and peptides containing neighbouring histidine residues, J Chromatogr 411: 177-84.
Holmes, 1995, Reagents for Combinatorial Organic Synthesis: Development of a New O-Nitrobenzyl Photolabile Linder for Solid Phase Synthesis, J. OrgChem., 60: 2318-2319.
Holtze, 2008, Biocompatible surfactants for water-in-fluorocarbon emulsions, Lab Chip, 8, 1632-1639.
Hong, 1999, Stereochemical constraints on the substiate specificity of phosphodiesterase, Biochemistry, 38:1159-1165.
Hoogenboom, 1997, Designing and optimizing library selection strategies for generating high-affinity antibodies, Trends Biotechnol, 15:62-70.
Hopfinger, 1996, Explosive Breakup of a Liquid Jet by a Swirling Coaxial Jet, Physics of Fluids 8(7):1696-1700.
Hopman, 1998, Rapid synthesis of biotin-, digoxigenin-, trinitrophenyl-, and fluorochrome-labeled tyramides and their application for In situ hybridization using CARD amplification, J of Histochem and Cytochem, 46(6):771-77.
Horton, 1989, Engineering hybrid genes without the use of restriction enzymes: gene splicing by overlap extension, Gene 77(1):61-8 (.
Hosokawa, 1999, Handling of Picoliter Liquid Samples in a Poly(dimethylsiloxane)-Based Microfluidic Device, Analytical Chemistry, 71(20):4781-4785.
Hsieh, 2009, Rapid label-free DNA analysis in picoliter microfluidic droplets using FRET probes, Microfluidics and nanofluidics 6(3):391-401.
Hsu, 1999, et al., Comparison of process parameters for microencapsulation of plasmid DNA in poly(D, L-lactic-co-glycolic acid microspheres, J Drug Target, 7:313-23.
Hua, 2010, Multiplexed Real-Time Polymerase Chain Reaction on a Digital Microfluidic Platform, Analytical Chemistry 82(6):2310-2316.
Huang, 1991, Kinetic assay of fluorescein mono-beta-D-galactosidase hydrolysis by beta-galactosidase: a front-face measurement for strongly absorbing fluorogenic substrates, Biochemistry, 30:8530-4.
Huang, 1992, A sensitive competitive ELISA for 2,4-dinitrophenol using 3,6-fluorescein diphosphate as a fluorogenic substrate, J Immunol Meth, 149:261.
Huang, 2004, Continuous particle separation through deterministic lateral displacement, Science 304(5673):987-990.
Huang, 2007, Identification of 8 foodborne pathogens by multicolor combinational probe coding technology in a single real-time PCR, Clin Chem., 53(10):1741-8.
Hubert, 2003, Data Concordance from a Comparison between Filter Binding and Fluorescence Polarization Assay Formats for Identification of RUOCK-II Inhibitors, J biomol Screen 8(4):399-409.
Huebner, 2007, Quantitative detection of protein expression in single cells using droplet microfluidics, Chem Com 12:1218-1220.
Hug, 2003, Measurement of the number of molecules of a single mRNA species in a complex mRNA preparation. J Theor Biol.; 221(4):615-24.
Hung, 2004, Controlled Droplet Fusion in Microfluidic Devices, MicroTAS, Sep. 26-30, 2004, Malmo, Sweden.
Hung, 2004, Optimization of Droplet Generation by controlling PDMS Surface Hydrophobicity, 2004 ASME International Mechanical Engineering Congress and RD&D Expo, Nov. 13-19, Anaheim, CA, 47-48.
Hutchison, 2005, Cell-free cloning using Phi29 polymerase, PNAS 102(48):17332-17336.
Ibrahim, 2003, High-speed cell sorting: fundamentals and recent advances, Curr Opin Biotchnol, 14(1):5-12.
Ikeda, 2000, Bioactivation of tegafur to 5-fluorouracil is catalyzed by cytochrome P-450 2A6 in human liver microsomes in vitro, Clin Cancer Res 6(11):4409-4415.
Illumina, 2010, Genomic Sequencing, data Sheet, 6 pages.
Inai, 1993, Immunohistochemical detection of an enamel protein-related epitope in rat bone at an early stage of osteogenesis. Histochemistry 99(5):335-362.
Invitrogen, 2008, Specification sheet for Dynabeads® Oligo (dT)25, http://www.invitrogen.com, 2 pages.
Ismagilov, 2003, Integrated Microfluidic SYstems, Angew. Chem. Int. Ed., 42:4130-4132.
Jakobovits, 1993, Analysis of homozygous mutant chimeric mice:deletion of the immunoglobulin heavy-chain joining region blocks B-cell development and antibody production, PNAS USA 90:2551-255.
Jakobovits, 1993, Germ-line transmission and expression of a human-derived yeast artificial chromosome, Nature 362:255-258.
Janda, 1997, Chemical selection for catalysis in combinatorial antibody libraries, Science, 275:945-948.
Jang, 2003, Controllable delivery of non-viral DNA from porous scaffold, J Controlled Release 86(1):157-168.
Jarvie, 2007, Amplicon Sequencing, Roche Dx Application Note No. 5 (16 pages).
Jermutus, 1998, et al., Recent advances in producing and selecting functional proteins by using cell-free translation, Curr Opin Biotechnol 9(5): 534-48.
Jo, 2003, Encapsulation of Bovine Serum Albumin in Temperature-Programmed Shell-in-Shell Structures, Macromol. Rapid Comm 24:957-962.
Joerger, 1995, Analyte detection with DNA-labeled antibodies and polymerase chain reaction, Clin. Chem. 41(9):1371-7.
Johannsson, 1988, Amplification by Second Enzymes, In ELISA and Other Solid Phase Immunoassays, Kemeny et al. (ed.), Chapter 4, pp. 85-106 John Wiley.
Johannsson, 1991, Heterogeneous Enzyme Immunoassays, In Principles and Practice of Immunoassay, pp. 295-325 Stockton Press.
Johnson, 1993, Human antibody engineering: Current Opinion in Structural Biology, 3:564-571.
Johnson, 2002, Protein tyrosine phosphatase 1B inhibitors for diabetes, Nature Review Drug Discovery 1, 696-709.
Jones, 1986, Replacing the complementarity-determining regions in a human antibody with those from a mouse, Nature, 321:522-525.
Jones, 1997, Quenched BODIPY dye-labeled casein substrates for the assay of protease activity by direct fluorescence measurement, Anal Biochem, 251:144-152.
Jones, 1999, Glowing jellyfish, luminescence and a molecule called coelenterazine, Trends Biotechnol. 17(12):477-81.
Bougueleret, 1984, Characterization of the gene coding for the EcoRV restriction and modification system of E coli, Nucleic Acids Res 12(8):3659-76.
Branebjerg, 1996, Fast mixing by lamination, MEMS Proc 9th Ann 9:441-446.
Braslavsky, 2003, Sequence information can be obtained from single DNA molecules, PNAS 100(7):3960-3964.
Breslauer, 2006, Microfluidics based systems biology, Mol Bio Syst 2:97-112.
Bringer, 2004, Microfluidic systems for chemical kinetics that rely on chaotic mixing in droplets, Phil Trans A Math Phys Eng Sci 362:1-18.
Brown, 1979, Chemical synthesis and cloning of a tyrosine tRNA gene, Methods Enzymol 68:109-151.
Bru, 1991, Product inhibition of alpha-chymotrypsin in reverse micelles. Eur J Biochem 199(1):95-103.
Bru, 1993, Catalytic activity of elastase in reverse micelles, Biochem Mol Bio Int, 31(4):685-92.
Brummelkamp, 2002, A system for stable expression of short interfering RNAs in mammalian cells, Science 296(5567):550-3.
Buican, 1987, Automated single-cell manipulation and sorting by light trapping, Appl Optics 26(24):5311-5316.
Burbaum, 1998, Miniaturization technologies in HTS, Drug Disc Today 3:313-322.
Burns, 1996, Microfabricated structures for integrated DNA analysis, PNAS 93:5556-5561.
Burns, 1998, An Integrated Nanoliter DNA Analysis Device, Science, 282:484-487.
Burns, 2002, The intensification of rapid reactions in multiphase systems using slug flow in capillaries, Lab on a Chip 1:10-15.
Byrnes, 1982, Sensitive fluorogenic substrates for the detection of trypsin-like proteases and pancreatic elastase, Anal Biochem 126:447.
Cahill, 1991, Polymerase chain reaction and Q beta replicase amplification, Clin Chem 37(9):1482-5.
Caldwell, 1991, Limits of diffusion in the hydrolysis of substrates by the phosphodiesterase from Pseudomonas diminuta, Biochem 30:7438-7444.
Calvert, 2001, Inkjet printing for materials and devices, Chem Mater 13:3299-3305.
Caruccio, 2009, Nextura technology for NGS DNA library preparation: simulaneous fragmentation and tagging by in vitro transposition, Epibio Newsletter.
Caruthers, 1985, Gene synthesis machines: DNA chemistry and its uses, Science 230:281-285.
Cavalli, 2010, Nanosponge formulations as oxygen delivery systems, Int J Pharmaceutics 402:254-257.
Chakrabarti, 1994, Production of RNA by a polymerase protein encapsulated within phospholipid vesicles, J Mol Evol 39(6):555-9.
Chamberlain, 1973, Characterization of T7-specific ribonucleic acid polymerase. 1. General properties of the enzymatic reaction and the template specificity of the enzyme, J Biol Chem 248:2235-44.
Chan, 2003, Size-Controlled Growth of CdSe Nanocrystals in Microfluidic Reactors, Nano Lett 3(2):199-201.
Chan, 2008, New trends in immunoassays, Adv Biochem Engin/Biotech 109:123-154.
Chang, 1987, Recycling of NAD(P) by multienzyme systems immobilized by microencapsulation in artifical cells, Methods Enzymol, 136(67):67-82.
Chang, 2008, Controlled double emulsification utilizing 3D PDMS microchannels, Journal of Micromechanics and Microengineering 18:1-8.
Chao, 2004, Control of Concentalion and Volume Gradients in Microfluidic Droplet Arrays for Protein Crystallization Screening, 26th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, San Francisco, California Sep. 1-5.
Chao, 2004, Droplet Arrays in Microfluidic Channels for Combinatorial Screening Assays, Hilton Head: A Solid State Sensor, Actuator and Microsystems Workshop, Hilton Head Island, South Carolina, Jun. 6-10.
Chapman, 1994, In vitro selection of catalytic RNAs, Curr. op. Struct. Biol., 4:618-22.
Chayen, 1999, Crystallization with oils: a new dimension in macromolecular crystal growth Journal of Crystal Growth,196:434-441.
Chen, 2001, Capturing a Photoexcited Molecular Structure Through Time-Domain X-ray Absorption Fine Structure, Science 292(5515):262-264.
Chen, 2003, Microfluidic Switch for Embryo and Cell Sorting The 12th International Conference on Solid State Sensors, Actuators, and Microsystems, Boston, MA, Transducers, 1: 659-662.
Chen-Goodspeed, 2001, Enhancement, relaxation, and reversal of the stereoselectivity for phosphotriesterase by rational evolution of active site residues, Biochemistry, 40: 1332-1339.
Chen-Goodspeed, 2001, Structural Determinants of the substrate and stereochemical specificity of phosphotriesterase, Biochemistry, 40(5):1325-31.
Cheng, 2003, Electro flow focusing inmicrofluidic devices, Microfluidics Poster, presented at DBAS, Frontiers in Nanoscience, 1 page.
Cheng, 2006, Nanotechnologies for biomolecular detection and medical diagnostics, Current Opinion in Chemical Biology, 10:11-19.
Chetverin, 1995, Replicable RNA vectors: prospects for cell-free gene amplification, expression, and cloning, Prog Nucleic Acid Res Mol Biol, 51:225-70.
Chiang, 1993, Expression and purification of general transcription factors by FLAG epitope-tagging and peptide elution, Pept Res, 6:62-64.
Chiba, 1997, Controlled protein delivery from biodegradable tyrosino-containing poly(anhydride-co-imide) microspheres. Biomaterials, 18(13):893-901.
Chiou, 2001, A closed-cycle capillary polymerase chain reaction machine, Analytical Chemistry, American Chamical Society, 73:2018-21.
Chiu, 1999, Chemical transformations in individual ultrasmall biomimetic containers, Science, 283:1892-1895.
Chou, 1998, A microfabricated device for sizing and sorting DNA molecules 96:11-13.
Clackson, 1994, In vitro selection from protein and peptide libraries, Trends Biotechnol, 12:173-84.
Clausell-Tormos, 2008, Droplet-based microfluidic platforms for the encapsulation and screening of Mammalian cells and multicellular organisms, Chem Biol 15(5):427-437.
Cohen, 1991, Controlled delivery systems for proteins based on poly(lactic/glycolic acid) microspheres, Pharm Res, 8(6):713-720.
Collins, 2003, Optimization of Shear Driven Droplet Generation in a Microluidic Device, ASME International Mechanical Engineering Congress and R&D Expo, Washington, 4 pages.
Collins, 2004, Microfluidic flow transducer based on the measurements of electrical admittance, Lab on a Chip, 4:7-10.
Compton, 1991, Nucleic acid sequence-based amplification, Nature, 350(6313):91-2.
Cook, 2007, Use and misuse of receiver operating characteristic curve in risk prediction, Circulation 115(7):928-35.
Mastrobattista et al., High-throughput screening of enzyme libraries: in vitro evolution of a beta-galactosidase by fluorescence-activated sorting of double emulsions, Chem. Biol. 12(12): 1291-1300 (2005).
Masui et al., Probing of DNA-Binding Sites of Escherichia coli RecA Protein Utilizing 1-anilinonaphthalene-8-Sulfonic Acid, Biochem 37(35):12133-12143 (1998).
Matayoshi E.D. et al., Novel fluorogenic substrates for assaying retroviral proteases by resonance energy transfer, Science 247:954 (1990).
Mattheakis et al., An in vitro polysome display system for identifying ligands from very large peptide libraries, PNAS 91:9022-6 (1994).
Mayr, L.M., and Fuerst, The Future of High-Throughput Screening, JBiomol Screen 13:443-448 (2008).
Mazutis et al., Droplet-Based Microfluidic Systems for High-Throughput Single DNA Molecule Isothermal Amplification and Analysis, Anal Chem 81(12):4813-4821 (2009).
Mazutis et al., Multi-step microfluidic droplet processing: kinetic analysis of an in vitro translated enzyme, Lab Chip 9:2902-2908 (2009).
McCafferty et al., Phage antibodies: filamentous phage displaying antibody variable domains, Nature, 348: 552-4 (1990).
McDonald and Whitesides, Poly(dimethylsiloxane) as a material for fabricating microfluidic devices, Account Chem. Res. 35:491-499 (2002).
McDonald et al., Fabrication of microfluidic systems in poly(dimethylsiloxane), Electrophoresis 21(1):27-40 (2000).
Melton et al., Efficient in vitro synthesis of biologically active RNA and RNA hybridization probes from plasmids containing a bacteriophage SP6 promoter, Nucl. Acids Res. 12(18):7035-7056 (1994).
Mendel, D. et al., Site-Directed Mutagenesis with an Expanded Genetic Code, Annu Rev Biophys Biomol Struct, 24:435-62 (1995).
Menger and Yamada, Enzyme catalysis in water pools, J. Am. Chem. Soc., 101:6731-4 (1979).
Metzker, M. L., 2010, “Sequencing Technologies—the next generation,” Nature Reviews, vol. 11, pp. 31-46.
Meylan and Howard, Atom/fragment contribution method for estimating octanol-water partition coefficients, J Pharm Sci. 84(1):83-92 (1995).
Miele et al., Autocatalytic replication of a recombinant RNA, J Mol Biol, 171:281-95 (1983).
Minshuil, J. and Stemmer, W.P., Protein evolution by molecular breeding, Curr Opin Chem Biol 3(3): 284-90 (1999).
Miroux and Walker, Over-production of proteins in Escherichia coli: mutant hosts that allow synthesis of some membrane proteins and globular proteins at high levels, J of Mol Biol 260(3):289-98 (1996).
Miyawaki et at., Fluorescent Indicators for Ca2+ Based on Green Fluorescent Proteins and Calmodulin, Nature, 388: 882-887 (1997).
Mize et al., Dual-enzyme cascade -- an amplified method for the detection of alkaline phosphatase, Anal Biochem 179 (2): 229-35 (1989).
Mock et al., A fluorometric assay for the biotin-avidin interaction based on displacement of the fluorescent probe 2-anilinonaphthalene-6-sulfonic acid, Anal Biochem, 151:178-81 (1985).
Moldavan, A., Photo-electric technique for the counting of microscopical cells, Science 80:188-189 (1934).
Montigiani, S. et al., Alanine substitutions in calmodulin-binding peptides result in unexpected affinity enhancement, J Mol Biol, 258:6-13 (1996).
Moore, M.J., Exploration by lamp light, Nature, 374:766-7 (1995).
Moudrianakis and Beer, Base sequence determination in nucelic acids with the electron microscope 3. Chemistry and microscopy of guanine-labeled DNA, PNAS 53:564-71 (1965).
Mueth et al., Origin of stratification in creaming emulsions, Physical Review Letters 77(3):578-581 (1996).
Mulbry, W.W. et al., Parathion hydrolase specified by the Flavobacterium opd gene: relationshio between the gene and protein. J Bacteriol, 171: 6740-6746 (1989).
Mulder et al., Characterization of two human monoclonal antibodies reactive with HLA-B12 and HLA-B60, respectively, raised by in vitro secondary immunization of peripheral blood lymphocytes, Hum. Immunol 36(3):186-192 (1993).
Nakano et al., High speed polymerase chain reaction in constant flow, Biosci Biotech and Biochem, 58:349-52 (1994).
Nakano et al., Single-molecule PCR using water-in-oil emulsion, J Biotech, 102:117-24 (2003).
Nakano et al., Single-molecule reverse transcription polymerase chain reaction using water-in-oil emulsion, J Biosci Bioeng 99:293-295 (2005).
Nametkin, S.N. et al., Cell-free translation in reversed micelles, FEB Letters, 309(3):330-32 (1992).
Narang et al., Improved phosphotriester method for the synthesis of gene fragments, Methods Enzymol, 68:90-98 (1979).
Neiman et al., 2011, “Decoding a substantial set of samples in parallel by massive sequencing.”, Plos ONE 6(3):1-7.
Nelson, P. S., et al., Bifunctional oligonucleotide probes synthesized using a novel CPG support are able to detect single base pair mutations, Nucl Acids Res 17(18): 7187-7194 (1989).
Nemoto et al., In vitro virus: bonding of mRNA bearing puromycin at the 3 terminal end to the C-terminal end of its encoded protein on the ribosome in vitro, Federation of European Biochemical Societies, 414:405-8 (1997).
Ness, J.E. et al., Molecular Breeding: the natural approach to protein design. Adv Protein Chem, 55: 261-292 (2000).
Ng et al., Protein crystallization by capillary counter-diffusion for applied crystallographic structure determination, J. Struct. Biol, 142:218-231(2003).
Ng, B.L. et al., Factors affecting flow karyotype resolution, Cytometry, Part A 69A: 1028-1036 (2006).
Nguyen et al., Optical detection for droplet size control in microfluidic droplet-based analysis systems, Sensors and Actuators B 117(2):431-436 (2006).
Nihant et al., Polylactide Microparticles Prepared by Double Emulsion/Evaporation Technique. I. Effect of Primary Emulsion Stability, Pharmaceutical Research, 11(10):1479-1484 (1994).
Nisisako et al., Controlled formulation of monodisperse double emulsions in a multiple-phase microluidic system, Sot Matter, 1:23-27 (2005).
Nisisako et al., Formation of droplets using branch channels in a microfluidic circuit, Proceedings of the SICE Annual Conference. International Session Papers 1262-1264 (2002).
Nisisako et al., Microstructured Devices for Preparing Controlled Multiple Emulsions. Chem. Eng. Technol 31 (8):1091-1098 (2008).
Nisisako, Takasi et al., Droplet Formation in a MicroChannel NetWork, Lab on a Chip, vol. 2, 2002, pp. 24-26.
Nissim, A. et al., Antibody fragments from a single pot phage display library as immunochemical reagents, Embo J, 13:692-8 (1994).
Nof and Shea, Drug-releasing scaffolds fabricated from drug-loaded microspheres, J. Biomed Mater Res 59:349-356 (2002).
Norman, A., Flow Cytometry, Med. Phys., 7(6):609-615 (1980).
Oberholzer et al., Enzymatic RNA replication in self-reproducing vesicles: an approach to a minimal cell, Biochem Biophys Res Commun 207(1):250-7 (1995).
Oberholzer et al., Polymerase chain reaction in liposomes, Chem. Biol. 2(10):677-82 (1995).
Elghanian, 1997, Selective colorimetric detection of polynucleotides based on the distance-dependent optical properties of gold nanoparticles, Science, 277(5329):1078-1080.
Ellington, 1990, In vitro selection of RNA molecules that bind specific ligands, Nature, 346:818-822.
Ellman, 1991, Biosynthetic method for introducing unnatural amino acids site-specifically into proteins, Methods Enzymol, 202:301-36.
Endo, 1996, Autocatalytic decomposition of cobalt complexes as an indicator system for the determination of trace amounts of cobalt and effectors, Analyst 121:391-394.
Endo, 1998, Kinetic determination of trace cobalt by visual autocatalytic indication, Talanta 47:349-353.
Engl, 2005, Droplet Traffic at a Simple Junction at Low Capillary Nos. Physical Review Letters, vol. 95, 208304, 1 page.
Eow, 2002, Electrocoalesce-separators for the separation of aqueous drops from a flowing dielectric viscous liquid, Separation and Purification Tech 29:63-77.
Eow, 2002, Electrostatic and hydrodynamic separation of aqueous drops in a flowing viscous oil, Chemical Eng Proc 41:649-657.
Eow, 2002, Electrostatic enhancement of coalescence of water droplets in oil: a review of the technology, Chemical Engineeing Journal 85:357-368.
Eow, 2003, Motion, deformation and break-up of aqueous drops in oils under high electric field strengths, Chemical Eng Proc 42:259-272.
Eow, 2003, The behavior of a liquid-liquid interface and drop-interface coalescence under the influence of an electric field, Colloids and Surfaces A: Physiochern. Eng. Aspects 215:101-123.
Eriksson, 2013, Comparative analysis of measures of viral reservoirs in HIV-1 eradication studies, PLoS Pathogens 9(2):e1003174, 17 pages.
Faca, 2008, A mouse to human search for plasma proteome changes associated with pancreatic tumor development, PLoS Med 5(6):el23:0953-0967.
Fahy, 1991, Self-sustained sequence replication (3SR): an isothermal transcription-based amplification system alternative to PCR, PCR Methods Appl 1:25-33.
Fan, 1994, Micromachining of capillary electrophoresis injectors and separators on glass chips and evaluation of flow at capillary intersections, Anal Chem 66:177-184.
Fan, 2007, Detection of Aneuploidy with Digital PCR, available at https://arxiv.org/ftp/arxiv/papers /0705/0705.1 030.pdf, 16 pages.
Fastrez, 1997, In vivo versus in vitro screening or selection for catalytic activity in enzymes and abzymes, Mol Biotechnol 7(1):37-55.
Fettinger, 1993, Stacked modules for micro flow systems in chemical analysis: concept and studies using an enlarged model, Sens Actuat B. 17:19-25.
Fiedler, 1998, Dielectrophoretic sorting of particles and cells in a microsystem, Anal Chem 70(9):1909-1915.
Field, 1988, Purification of a RAS-responsive adenylyl cyclase complex from Saccharomyces cervisiae by use of an epitope addition method. Mol Cell Biol, 8: 2159-2165.
Fields, 1989, A novel genetic system to detect protein-protein interactions, Nature 340(6230):245-6.
Filella, 1994, TAG-72, CA 19.9 and CEA as tumor markers in gastric cancer, Acta Oncol. 33(7):747-751.
Finch, 1993, Encapsulation and controlled release, Spec Publ R Soc Chem, 138:35, 12 pages.
Fingas, 1997, Studies of Water-In-Oil Emulsions: Stability Studies, Environment Canada, Proceedings of the Twentieth Arctic Marine Oilspill Program Technical Seminer, 1-20.
Fire, 1995, Rolling replication of short DNA circles, PNAS 92(10):4641-5.
Firestine, 2000, Using an AraC-based three hybrid system to detect biocatalysts in vivo, Nat Biotechnol 18: 544-547.
Fisher, 2004, Cell Encapsulation on a Microfluidic Platform, The Eighth International Conference on Miniaturised Systems for Chemistry and Life Scieces, MicroTAS, Malmo, Sweden.
Fletcher, 2002, Micro reactors: principles and applications in organic synthesis, Tetrahedron 58:4735-4757.
Fluri, 1996, Integrated capillary electrophoresis devices with an efficient postcolumn reactor in planar quartz and glass chips, Anal Chem 68:4285-4290.
Fornusek, 1986, Polymeric microspheres as diagnostic tools for cell surface marker tracing, Crit Rev Ther Drug Carrier Syst, 2:137-74.
Fowler, 2002, Enhancement of Mixing By Droplet-Based Microfluidics, Int Conf MEMS 97-100.
Frenz, 2008, Reliable microfluidic on-chip incubation of droplets in delay-lines, Lab on a Chip 9:1344-1348.
Fu, 1999, A microfabricated fluorescence-activated cell sorter, Nature Biotechnology, 17(11):1109-1111.
Fu, 2002, An Integrated Microfabricated Cell Sorter, Anal. Chem., 74: 2451-2457.
Fulton, 1997, Advanced multiplexed analysis with the FlowMetrix system, Clin Chem 43:1749-1756.
Fulwyler, 1965, Electronic Separation of Biological Cells by vol. Science 150(3698):910-911.
Galan, 2010, A 454 multiplex sequencing method for rapid and reliable genotyping of highly polymorphic genes in large-scale studies., BMC Genomics 11(296):1-15.
Gallarate, 1999, On the stability of ascorbic acid in emulsified systems for topical and cosmetic use, Int J Pharm 188 (2):233-241.
Ganan-Calvo, 1998, Generation of Steady Liquid Microthreads and Micron-Sized Monodisperse Sprays and Gas Streams, Phys Rev Lett 80(2):285-288.
Ganan-Calvo, 2001, Perfectly Monodisperse Microbubbling by Capillary Flow Focusing, Phys Rev Lett 87(27): 274501-1-4.
Garcia-Ruiz, 1994, Investigation on protein crystal growth by the gel acupuncture method, Acta, Cryst., D50, 99. pp. 484-490.
Garcia-Ruiz, 2001, A super-saturation wave of protein crystallization, J. Crystal Growth, 232:149-155.
Garstecki, 2004, Formation of monodisperse bubbles in a microfiuidic flow-focusing device, Appl Phys Lett 85 (13):2649-2651.
Gasperlin, 1994, The structure elucidation of semisolid w/o emulsion systems containing silicone surfactant, Intl J Pharm, 107:51-6.
Gasperlin, 2000, Viscosity prediction of lipophillic semisolid emulsion systems by neural network modeling, Intl J Pharm, 196:37-50.
Gelderblom, 2008, Viral complemntation allows HIV-1 replication without integration, Retrovirology 5:60.
Georgiou, 1997, Display of heterologous proteins on the surface of microorganisms: from the screenign of combinatiorial libraires to live recombinant vaccines. Nat Biotechnol 15(1), 29-34.
Georgiou, 2000, Analysis of large libraries of protein mutants using flow cytometry, Adv Protein Chem, 55: 293-315.
Gerdts, 2004, A Synthetic Reaction NetWork: Chemical Amplification Using Nonequilibrium Autocatalytic Reactions Coupled in Time, J. Am. Chem. Soc 126:6327-6331.
Ghadessy, 2001, Directed Evolution of Polymerase Function by Compartmentalized Self-Replication, PNSAS 98(8): 4552-4557.
Trolier-Mckinstry, 2004, Thin Film Piezoelectric for MEMS, Journal of Electroceramics 12:7-17.
Tsuchiya, 2007, On-chip polymerase chain reaction microdevice employing a magnetic droplet-manipulation system, Sens Actuators B 130:583-588.
Tuzel, 2006, Region Covariance: A Fast Descriptor for Detection and Classification, European Conference on Computer Vision (ECCV), 14 pages.
Umbanhowar, 2000, Monodisperse Emulsion Generation via Drop Break Off in a Coflowing Stream, Langmuir 16 (2):347-351.
Unger, 2000, Monolithic microfabricated valves and pumps by multylayer soft lithography, Science 288(5463):113-116.
Utada, 2005, Monodisperse double emulsions generated from a microcapillary device, Science, 308:537-541.
Vainshtein, 1996, Peptide rescue of an N-terminal truncation of the stoffel fragment of Taq DNA polymerase, Protein Science, 5:1785-92.
Van der Sluis, 2013, Dendritic Cell-induced Activation of Latent HIV-1 Provirus in Actively Proliferating Primary T Lymphocytes, PLOS Pathog. 9(3): 16 pages.
Van Dilla, 1968, The fluorescent cell photometer: a new method for the rapid measurement of biological cells stained with fluorescent dyes, Annual Report of the Los Alamos Scientific Laboratory of the University of California (Los Alamos, NM), Biological and Medical Research Groupp (H-4) of the Health Division, Compiled by D. G. Ott, pp. 100-105.
Van Dilla, 1969, Cell Microfluorometry: A Method for Rapid Fluorescence Measurement, Science 163(3872):1213-1214.
Vanhooke, 1996, Three-dimensional structure of the zinc-containing phosphotrieesterase with the bound substrate analog diethy 4-methylbenzylphosphonate, Biochemistry 35:6020-6025.
Varga, 1991, Mechanism of allergic cross-reactions-I. Multispecific binding of ligands to a mouse monoclonal anti-DNP IgE antibody. Mol Immunol 28(6), 641-54.
Vary, 1987, A homogeneous nucleic acid hybridization assay based on strand displacement, Nucl Acids Res 15 (17):6883-6897.
Venkateswaran, 1992, Production of Anti-Fibroblast Growth Factor Receptor Monoclonal Antibodies by In Vitro Immunization, Hybirdoma, 11(6):729-739.
Verhoeyen, 1988, Reshaping human antibodies: grafting an antilysozyme activity, Science, 239:1534-1536.
Vogelstein, 1999, Digital PCR, PNAS 96(16):9236-9241.
Voss, 1993, Kinetic measurements of molecular interactions by spectrofluorometry, J Mol Recognit, 6:51-58.
Wahler, 2001, Novel methods for biocatalyst screening. Curr Opin Chem Biol, 5: 152-158.
Walde, 1988, Structure and activity of trypsin in reverse micelles, Eur J Biochem, 173(2):401-9.
Walde, 1993, Spectroscopic and kinetic studies of lipases solubilized in reverse micelles, Biochemistry, 32(15):4029-34.
Walde, 1994, Oparin's reactions revisited: enzymatic synthesis of poly(adenylic acid) in micelles and self-reproducing vesicles. J Am Chem Soc, 116: 7541-7547.
Walker, 1992, Isothermal in vitro amplification of DNA by a restriction enzyme/DNA polymerase system, PNAS 89 (1):392-6.
Walker, 1992, Strand displacement amplification-an isothermal, in vitro DNA amplification technique, Nucleic Acid Res, 20(7):1691-6.
Wang, 1989, Quantitation of mRNA by the polymerase chain reaction. Proc natl Acad Sci USA 86(24), 9717-21.
Wang, 1990, Design and synthesis of new fluorogenic HIV protease substrates based on resonance energy transfer, Tetrahedron Lett., 31:6493.
Wang, 2002, Preparation of Titania Particles Utilizing the Insoluble Phase Interface in a MicroChannel Reactor, Chemical Communications 14:1462-1463.
Wang, 2008, DEP actuated nanoliter droplet dispensing using feedback control, Lab on a Chip 9:901-909.
Wang, 2010, Quantifying EGFR Alterations in the Lung Cancer Genome with Nanofluidic Digital PCR Arrays, Clinical Chemistry 56:4.
Warburton, 1993, Microcapsules for Multiple Emulsions, Encapsulation and Controlled Release, Spec Publ R Soc Chem, 35-51.
Wasserman, 1989, Structure and reactivity of allyl-siloxane monolayers formed by reaction of allcyltrichlorosilanes on silicon substrates, Langmuir 5:1074-1087.
Weaver, 2010, Taking qPCR to a higher level: Analysis of CNV reveals the power of high throughput qPCR to enhance quantitative resolution, Methods 50, 271-276.
Weil, 1979, Selective and accurate initiation of transcription at the Ad2 major late promotor in a soluble system dependent on purified RNA polymerase Il and DNA, Cell, 18(2):469-84.
Werle, 1994, Convenient single-step, one tube purification of PCR products for direct sequencing, Nucl Acids Res 22 (20):4354-4355.
Wetmur, 2005, Molecular haplotyping by linking emulsion PCR: analysis of paraoxonase 1 haplotypes and phenotypes, Nucleic Acids Res 33(8):2615-2619.
White, 2009, Digital PCR provides sensitive and absolute calibration for high throughput sequencing, BMC Genomics 10:116.
Wick, 1996, Enzyme-containing liposomes can endogenously produce membrane-constituting lipids, Chem Biol 3 (4):277-85.
Wiggins, 2004, Foundations of chaotic mixing, Philos Transact A Math Phys Eng Sci 362(1818):937-70.
Williams, 1979, Methotrexate, a high-affinity pseudosubstrate of dihydrofolate reductase, Biochemistry, 18(12):2567-73.
Williams, 2006, Amplification of complex gene libraries by emulsion PCR, Nature Methods 3(7):545-550.
Wilson, 1999, In vitro selection of functional nucleic acids, Ann. Rev. Biochem. 68: 611-647.
Wittrup, 2001, Protein engineering by cell-surface display. Curr Opin Biotechnology, 12: 395-399.
Wittwer, 1989, Automated polymerase chain reaction in capillary tubes with hot air, Nucleic Acids Res., 17(11) 4353-4357.
Wittwer, 1990, Minimizing the Time Required for DNA Amplification by Efficient Heat Transfer to Small Samples, Anal. Biochem., 186, 328-331.
Wolff, 2003, Integrating advanced functionality in a microfabricated high-throughput fluorescent-activated cell sorter, Lab Chip, 3(1): 22-27.
Woolley, 1994, Ultra-high-speed DNA fragment separations using microfabricated capillary array electrophoresis chips. Proc. Natl. Acad. Sci. USA, 91, 11348-11352.
Woolley, 1996, Functional Integration of PCR Amplification and Capillary Electrophoresis in a Microfabricated DNA Analysis Device, Anal. Chem. 68, 4081-4086.
Wronski, 2002, Two-color, fluorescence-based microplate assay for apoptosis detection. Biotechniques, 32:666-668.
Wu, 1989, The ligation amplification reaction (LAR)-amplification of specific DNA sequences using sequential rounds of template dependent ligation, Genomics 4(4):560-9.
Wyatt, 1991, Synthesis and purification of large amounts of RNA oligonucleotides, Biotechniques 11(6):764-9.
Xia, 1998, Soft Lithography, Angew. Chem. Int. Ed. 37:550-575.
Sano, 1992, Immuno-PCR: very sensitive antigen-detection by means of sepcific Ab-DNA conjugates, Science 258 (5079):120-122.
Santalucia, 1998, A unified view of polymer, dumbbell, and oligonucleotide DNA nearest-neighbor thermodynamics, PNAS 95(4):1460-5.
Santra, 2006, Fluorescence lifetime measurements to determine the core-shell nanostructure of FITC-doped silica nanoparticles, J Luminescence 117(1):75-82.
Sawada, 1996, Synthesis and surfactant properties of novel fluoroalkylated amphiphilic oligomers, Chem Commun 2:179-190.
Schatz, 1996, Screening of peptide libraries linked to lac repressor, Meth Enzymol 267:171-91.
Schneegass, 2001, Miniaturized flow-through PCR with different template types in a silicone chip thermocycler, Lab on a Chip 1:42-9.
Schopman, 2012, Selective packaging of cellular miRNAs in HIV-1 particles, Virus Res 169(2):438-47.
Schubert, 2002, Designer Capsules, Nat Med 8:1362.
Schweitzer, 2000, Immunoassays with rolling circle DNA amplification, PNAS 97(18):10113-10119.
Schweitzer, 2001, Combining nucleic acid amplification and detection. Curr Opin Biotechnol 12(1):21-7.
Scott, 1948, The solubility of fluorocarbons, J Am Chem Soc 70:4090-4093.
Sedlak, 2013, Viral diagnostics in the era of digital polymerase chain reaction, Diag Microb Inf Dis 75(1):1-4.
Seethala, 1997, Homogeneous fluorescence polarization assay for Src-Family tyrosine kinases, Anal Biochem 253(2):210-218.
Seiler, 1993, Planar glass chips for capillary electrophoresis: repetitive sample injection, quantitation, and separation efficiency. Anal Chem 65(10):1481-1488.
Selwyn, 1965, A simple test for inactivation of an enzyme during assay, Biochim Biophys Acta 105:193-195.
Seo, 2007, Microfluidic consecutive flow-focusing droplet generators, Soft Matter 3:986-992.
Seong, 2002, Efficient mixing and reactions within microfluidic channels using microbead-supported catalysts, J Am Chem Soc 124(45):13360-1.
Seong, 2002, Fabrication of microchambers defined by photopolymerized hydrogels and weirs within microfluidic systems, Anal Chem 74(14):3372-3377.
Sepp, 2002, Microbead display by in vitro compartmentalisation: selection for binding using flow cytometry, FEBS Letters 532:455-58.
Serpersu, 1985, Reversible and irreversible modification of erythrocyte membrane permeability by electric field, Biochim Biophys Acta 812(3):779-785.
Shapiro, 1983, Multistation multiparameter flow cytometry: a critical review and rationale, Cytometry 3: 227-243.
Shastry, 2006, Directing droplets using microstructured surfaces, Langmuir 22:6161-6167.
Shen, 2006, Eigengene-based linear discriminant model for tumor classification using gene expression microarray data, Bioinformatics 22(21):2635-2642.
Shestopalov, 2004, Multi-step synthesis of nanoparticles performed on millisecond time scale in a microfluidic droplet- based system, Royal Soc Chem 4:316-321.
Shim, 2007, Using microfluidics to decouple nucleation and growth of protein crystals, Cryst Growth Des 7 (11):2192-2194.
Shimizu, 1995, Encapsulation of biologically active proteins in a multiple emulsion, Biosci Biotech Biochem 59 (3):492-496.
Shtern, 1996, Hysteresis in swirling jets, J Fluid Mech 309:1-44.
Sia, 2003, Microfluidic devices fabricated in poly(dimethylsiloxane) for biological studies, Electrophoresis 24 (21):3563-3576.
Siemering, 1996, Mutations that suppress the thermosensitivity of green fluorescent protein, Curr Biol 6:1653-1663.
Silva-Cunha, 1998, W/O/W multiple emulsions of insulin containing a protease inhibitor and an absorption enhancer: biological activity after oral administration to normal and diabetic rats, Int J Pharm 169:33-44.
Sims, 2000, Immunopolymerase chain reaction using real-time polymerase chain reaction for detection, Anal. Biochem. 281(2):230-2.
Sista, 2007, Development of a Digital Microfluidic Lab-on-a-Chip for Automated Immunoassay with Magnetically Responsive Beads, Doctoral Thesis, Florida State University, 128 pages.
Sista, 2008, Development of a digital microfluidic platform for point care testing, Lab on a Chip 8:2091-2104.
Siwy, 2003, Electro-responsive asymmetric nanopores in polyimide with stable ion-current signal, Appl Phys A: Mat Sci Proc 76:781-785.
Slappendel, 1994, Normal cations and abnormal membrane lipids in the red blood cells of dogs with familial stomatocytosis hypertrophic gastritis, Blood 84:904-909.
Slob, 1997, Structural identifiability of PBPK models: practical consequences for modeling strategies and study designs, Crit Rev Toxicol. 27(3):261-72.
Smith, 1985, The synthesis of oligonucleotides containing an aliphatic amino group at the 5′ terminus: synthesis of fluorescent DNA primers for use in DNA sequence analysis, Nucl Acid Res 13:2399-2412.
Smith, 1986, Fluorescence detection in automated DNA sequence analysis, Nature 321:674-679.
Smith, 1989, Absolute displacement measurements using modulation of the spectrum of white light in a Michelson Interferometer, Applied Optics, 28(16)-3339-3342.
Smith, 1992, Direct mechanical measurements of the elasticity of single DNA molecules by using magnetic beads, Science 258(5085):1122-1126.
Smith, 2010, Highly-multiplexed barcode sequencing: an efficient method for parallel analysis of pooled samples, Nucleic Acids Res 38(13):e142.
Smyth, 2000, Markers of apoptosis: methods for elucidating the mechanism of apoptotic cell death from the nervous system, Biotechniques 32:648-665.
Sohn, 2000, Capacitance cytometry: Measuring biological cells one by one, PNAS 97(20):10687-10690.
Sola, 2014, Fabrication of a microfluidic cell made of thiolene for microarray applications, 18th Int Conf Miniaturized Systems for Chem and Life Sciences, MicroTAS, San Antonio, TX 1719-1721.
Somasundaram, 1999, Gain studies of Rhodamine 6G dye doped polymer laser, J Photochem Photobiol 125 (1-3):93-98.
Song, 2002, Experimental test of scaling of mixing by chaotic advection in droplets moving through microfluidic Channels, App Phy Lett 83(22):4664-4666.
Song, 2003, A microfluidic system for controlling reaction networks in time, Angew Chem Int Ed 42(7):768-772.
Song, 2003, Millisecond kinetics on a microluidic chip using nanoliters of reagents, J Am Chem Soc 125:14613-14619.
Song, 2006, Reactions in droplets in microfluidic channels, Angew chem Int ed 45(44):7336-7356.
Soni, 2007, Progress toward ultrafast DNA sequencing using solid-state nanopores, Clin Chem 53:1996-2001.
Luft, 20001, Detection of integrated papillomavirus sequences by ligation-mediaated PCR (DIPS-PCR) and molecular characterization in cervical cancer cells, In J Cancer 92:9-17.
Luisi, 1987, Activity and conformation of enzymes in reverse micellar solutions, Meth Enzymol 136:188-216.
Lund, 1988, Assesment of methods for covalent binding of nucleic acids to magnetic beads, Dynabeads, and the characteristics of the bound nucleic acids in hybridization reactions, Nucleic Acids Res 16(22):10861-10880.
Lunderberg, 1995, Solid-phase technology: magnetic beads to improve nucleic acid detection and analysis, Biotech Ann Rev 1:373-401.
Lundstrom, 2002, Breakthrough in cancer therapy: Encapsulation of drugs and viruses, Curr Drug Disc 19-23.
Lyne, 2002, Structure-based virtual screening: an overview, Drug Disc Tod 7(20):1047-1055.
Ma, 1993, In vitro protein engineering using synthetic tRNA(Ala) with different anticodons, Biochemistry 32(31):7939-45.
Mackenzie, 1985, IABS Symposium on Reduction of Animal Usage in the Development and Control of Biological Products, London, UK, 16 pages.
Mackenzie, 1986, The application of flow microfluorimetry to biomedical research and diagnosis: a review, Dev Biol Stand 64:181-193.
Maclean, 1999, Glossary of terms used in combinatorial chemistry, Pure Appl. Chem. 71(12):2349-2365.
Magdassi, 1984, Multiple Emulsions: HLB Shift Caused by Emulsifier Migration to External Interface, J. Colloid Interface Sci 97:374-379.
Mahajan, 1998, Bcl-2 and Bax Interactions in Mitochondria Probed with Green Florescent Protein and Fluorescence Resonance Energy Transfer, Nat. Biotechnol. 16(6): 547-552.
Mahjoob, 2008, Rapid microfluidic thermal cycler for polymerase chain reaction nucleic acid amplification. Int J HeatMass Transfer,51:2109-22.
Manafi, 2000, New developments in chromogenic and fluorogenic culture media, 2000, International Journal of Food Microbiology, 60, 205-218.
Manley, 1983, In vitro transcription: whole cell extract, Methods Enzymol, 101:568-82.
Manz, 1991, Micromachining of monocrystalline silicon and glass for chemical analysis systems A look into next century's technology or just a fashionable craze, Trends in Analytical Chemistry 10(5):144-149.
Mao, 1991, Substrate effects on the enzymatic activity of alphachymotrypsin in reverse micelles, Biochem Biophys Res Commun, 178(3):1105-12.
Mao, 1992, Kinetic behaviour of alpha-chymotrypsin in reverse micelles: a stopped-flow study, Eur J Biochem 208 (1):165-70.
Mardis, 2008, The impact of next-generation sequencing technology on genetics, Trends Genet 24:133-141.
Margulies, 2005, Genome sequencing in microfabricated high-density picolitre reactors, Nature 437(7057):376-380.
Marks, 1992, Bypassing immunization: building high affinity human antibodies by chain shuffling, BioTechnol 10:779-783.
Marques, 1996, Porous Flow within Concentric Cylinders, Bull Am Phys Soc Div Fluid Dyn 41:1768, 1 page.
Maruno, 1991, Fluorine containing optical adhesives for optical communications systems, J. Appl. Polymer. Sci. 42:2141-2148.
Mason, 1997, Shear Rupturing of Droplets in Complex Fluids, Langmuir, 13(17):4600-4613.
Mastrobattista, 2005, High-throughput screening of enzyme libraries: in vitro evolution of a beta-galactosidase by fluorescence-activated sorting of double emulsions, Chem. Biol. 12(12): 1291-1300.
Masui, 1998, Probing of DNA-Binding Sites of Escherichia coli RecA Protein Utilizing 1-anilinonaphthalene-8-Sulfonic Acid, Biochem 37(35) 12133-12143.
Matayoshi, 1990, Novel fluorogenic substrates for assaying retroviral proteases by resonance energy transfer, Science 247:954.
Matsubara, 2003, Detection of Single Nucleotide Substitution by Competitive Allele-Specific Short Oligonucleotide Hybridization (CASSOH) With Ummunochromatographic Strip, Human Mutation 22:166-172.
Mattheakis, 1994, An in vitro polysome display system for identifying ligands from very large peptide libraries, PNAS 91:9022-6.
Mayr, 2008, The Future of High-Throughput Screening, JBiomol Screen 13:443-448.
Mazutis, 2009, Droplet-Based Microfluidic Systems for High-Throughput Single DNA Molecule Isothermal Amplification and Analysis, Anal Chem 81(12):4813-4821.
Mazutis, 2009, Multi-step microfluidic droplet processing: kinetic analysis of an in vitro translated enzyme, Lab Chip 9:2902-2908.
McDonald, 2000, Fabrication of microfluidic systems in poly(dimethylsiloxane), Electrophoresis 21(1):27-40.
McDonald, 2002, Poly(dimethylsiloxane) as a material for fabricating microfluidic devices, Account Chem. Res. 35:491-499.
Melton, 1984, Efficient in vitro synthesis of biologically active RNA and RNA hybridization probes from plasmids containing a bacteriophage SP6 promoter, Nucl. Acids Res. 12(18):7035-7056.
Mendel, 1995, Site-Directed Mutagenesis with an Expanded Genetic Code, Annu Rev Biophys Biomol Struct, 24:435-62.
Mendieta, 1996, Complementary sequence correlations with applications to reflectometry studies, Instrumentation and Development 3(6):37-46.
Metzker, 2010, Sequencing Technologies - the next generation, Nature Reviews, vol. 11, pp. 31-46.
Meylan, 1995, Atom/fragment contribution method for estimating octanol-water partition coefficients, J Pharm Sci. 84 (1):83-92.
Michalatos-Beloin, 1996, Molecular haplotyping of genetic markers 10 kb apart by allele-specific long-range PCR, Nucleic Acids Research, 24:4841-4843.
Miele, 1983, Autocatalytic replication of a recombinant RNA, J Mol Biol, 171:281-95.
Milstein, 1983, Hybrid hybridomas and their use in immunohistochemistry, Nature 305:537-540.
Mindlin, 1936, A force at a point of a semi-infinite solid, Physics, 7:195-202.
Minshuil, 1999, Protein evolution by molecular breeding, Curr Opin Chem Biol 3(3): 284-90.
Miroux, 1996, Over-production of proteins in Escherichia coli: mutant hosts that allow synthesis of some membrane proteins and globular proteins at high levels, J of Mol Biol 260(3):289-98.
Miyawaki, 1997, Fluorescent Indicators for Ca2+ Based on Green Fluorescent Proteins and Calmodulin, Nature, 388: 882-887.
Mize, 1989, Dual-enzyme cascade—an amplified method for the detection of alkaline phosphatase, Anal Biochem 179 (2): 229-35.
Mock, 1985, A fluorometric assay for the biotin-avidin interaction based on displacement of the fluorescent probe 2- anilinonaphthalene-6-sulfonic acid, Anal Biochem, 151:178-81.
Moldavan, 1934, Photo-electric technique for the counting of microscopical cells, Science 80:188-189.
Monie, 2005, A Novel Assay Allows Genotyping of the Latent Reservoir for Human Imnunodefi ciency Virus Type 1 in the Resting CD4+ T Cells of Viremic Patients, Journal of Virology, 79(8):5185-5202.
Boder et al., Yeast surface display for screening combinatorial polypeptide libraries, Nat Biotechnol 15(6):553-7 (1997).
Bougueleret, L. et al., Characterization of the gene coding for the EcoRV restriction and modification system of Scherichia coli, Nucleic Acids Res, 12(8):3659-76 (1984).
Boyum, A., Separation of leukocytes from blood and bone marrow. Introduction, Scand J Clin Lab Invest Suppl 97:7 (1968).
Branebjerg et al., Fast mixing by lamination, MEMS Proceedings 9th Ann Workshop, San Diego, Feb. 11-15, 1996, 9:441-446 (1996).
Braslavsky et al., Sequence information can be obtained from single DNA molecules, PNAS 100(7):3960-3964 (2003).
Bringer et al., Microfluidic Systems for Chemical Kinetics That Rely on Chaotic Mixing in Droplets, Philos Transact A Math Phys Eng Sci 362:1-18 (2004).
Brody et al., A self-assembled microlensing rotational probe, Applied Physics Letters, 74:144-46 (1999).
Brown et al., Chemical synthesis and cloning of a tyrosine tRNA gene, Methods Enzymol 68:109-151 (1979).
Bru, R. et al., Catalytic activity of elastase in reverse micelles, Biochem Mol Bio Int, 31(4):685-92 (1993).
Bru, R. et al., Product inhibition of alpha-chymotrypsin in reverse micelles. Eur J Biochem 199(1):95-103 (1991).
Brummelkamp et al., A system for stable expression of short interfering RNAs in mammalian cells, Science 296 (5567):550-3 (2002).
Buckpitt et al.,Hepatic and pulmonary microsomal metabolism of naphthalene to glutathione adducts: factors affecting the relative rates of conjugate formation, J. Pharmacol. Exp. Ther. 231:291-300 (1984).
Buican et al., Automated single-cell manipulation and sorting by light trapping, Applied Optics 26(24):5311-5316 (1987).
Burbaum, J., Miniaturization technologies in HTS: how fast, how small, how soon Drug Discov Today 3:313-322 (1998).
Burns et al., Microfabricated structures for integrated DNA analysis, Proc. Natl. Acad. Sci. USA, 93:5556-5561(1996).
Burns, J.R. et al., The Intensification of Rapid Reactions in Multiphase Systems Using Slug Flow in Capillaries, Lab on a Chip, 1:10-15 (2001).
Burns, Mark et al., An Integrated Nanoliter DNA Analysis Device, Science, 282:484-487(1998).
Byrnes, P.J. et al., Sensitive fluorogenic substrates for the detection of trypsin-like proteases and pancreatic elastase, Anal Biochem, 126:447 (1982).
Cahill et al., Polymerase chain reaction and Q beta replicase amplification, Clin Chem 37(9):1482-5 (1991).
Caldwell, S.R. et al., Limits of diffusion in the hydrolysis of substrates by the phosphodiesterase from Pseudomonas diminuta, Biochemistry, 30: 7438-7444 (1991).
Calvert, P., Inkjet printing for materials and devices, Chem Mater 13: 3299-3305 (2001).
Caruccio et al., Nextura Technology for NGS DNA Library Preparation: Simulaneous Fragmentation and Tagging by in Vitro Transposition. [online] Oct. 2009 [retrieved on Aug. 2, 2019] retrieved from http://www.epibio.com/tech- support/newsletter-archives. (2009).
Chakrabarti, A.C. et al., Production of RNA by a polymerase protein encapsulated within phospholipid vesicles, J Mol Evol, 39(6):555-9 (1994).
Chamberlain and Ring, Characterization of T7-specific ribonucleic acid polymerase. 1. General properties of the enzymatic reaction and the template specificity of the enzyme, J Biol Chem 248:2235-44 (1973).
Chan, Emory M. et al., Size-Controlled Growth of CdSe Nanocrystals in Microfluidic Reactors, Nano Letters, 3 (2):199-201(2003).
Chang and Su, Controlled double emulsification utilizing 3D Pdms microchannels, Journal of Micromechanics and Microengineering 18:1-8 (2008).
Chang, T.M., Recycling of NAD(P) by multienzyme systems immobilized by microencapsulation in artifical cells, Methods Enzymol, 136(67):67-82 (1987).
Chao et al., Control of Concentration and vol. Gradients in Microfluidic Droplet Arrays for Protein Crystallization Screening, 26th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, San Francisco, California September 1-5, (2004).
Chao et al., Droplet Arrays in Microfluidic Channels for Combinatorial Screening Assays, Hilton Head 2004: A Solid State Sensor, Actuator and Microsystems Workshop, Hilton Head Island, South Carolina, Jun. 6-10, (2004).
Chapman et al., In vitro selection of catalytic RNAs, Curr. op. Struct. Biol., 4:618-22 (1994).
Chayen, Crystallization with oils: a new dimension in macromolecular crystal growth Journal of Crystal Growth, 196:434-441(1999).
Chen et al., Capturing a Photoexcited Molecular Structure Through Time-Domain X-ray Absorption Fine Structure, Science 292(5515):262-264 (2001).
Chen et al., Microfluidic Switch for Embryo and Cell Sorting The 12th International Conference on Solid State Sensors, Actuators, and Microsystems, Boston, MA Jun. 8-12, 2003 Transducers, 1: 659-662 (2003).
Chen-Goodspeed et al., Structural Determinants of the substrate and stereochemical specificity of phosphotriesterase, Biochemistry, 40(5):1325-31 (2001).
Chen-Goodspeed, M. et al., Enhancement, relaxation, and reversal of the stereoselectivity for phosphotriesterase by rational evolution of active site residues, Biochemistry, 40: 1332-1339 (2001b).
Cheng, Z.,et al, Electro flow focusing inmicrofluidic devices, Microfluidics Poster, presented at DBAS, Frontiers in Nanoscience, presented Apr. 10, 2003.
Chetverin and Spirin, Replicable RNA vectors: prospects for cell-free gene amplification, expression, and cloning, Prog Nucleic Acid Res Mol Biol, 51:225-70 (1995).
Chiang, C.M. et al., Expression and purification of general transcription factors by FLAG epitope-tagging and peptide elution, Pept Res, 6:62-64 (1993).
Chiba et al., Controlled protein delivery from biodegradable tyrosino containing poly(anhydride-co-imide) microspheres, Biomaterials, 18(13):893-901 (1997).
Chiou et al., A closed-cycle capillary polymerase chain reaction machine, Analytical Chemistry, American Chamical Society, 73:2018-21 (2001).
Chiu et al., Chemical transformations in individual ultrasmall biomimetic containers, Science, 283:1892-1895 (1999).
Chou et al., A microfabricated device for sizing and sorting DNA molecules 96:11-13(1998).
Clackson, T. et al., In vitro selection from protein and peptide libraries, Trends Biotechnol, 12:173-84 (1994).
Clausell-Tormos et al., Droplet-based microfluidic platforms for the encapsulation and screening of Mammalian cells and multicellular organisms, Chem Biol 15(5):427-437 (2008).
Cohen, S. et al., Controlled delivery systems for proteins based on poly(lactic/glycolic acid) microspheres, Pharm Res, 3(6):713-720 (1991).
Collins et al., Optimization of Shear Driven Droplet Generation in a Microluidic Device, ASME International Mechanical Engineering Congress and R&D Expo, Washington (2003).
Collins, J. et al., Microfluidic flow transducer based on the measurements of electrical admittance, Lab on a Chip, 4:7-10 (2004).
Compton, J., Nucleic acid sequence-based amplification, Nature, 350(6313):91-2 (1991).
Cormack, B.P. et al., FACS-optimized mutants of the green fluorescent protein (GFP), Gene 173(1):33-38 (1996).
Obukowicz, M.G et al., Secretion and export of IGF-1 in Escerichia coli strain JM101, Mol Gen Genet, 215:19-25 (1988).
Office Action for U.S. Appl. No. 11/246,911 dated Feb. 8, 2011.
Office Action for U.S. Appl. No. 11/360,845 dated Apr. 26, 2011.
Office Action for U.S. Appl. No. 11/360,845 dated Aug. 4, 2010.
Office Action for U.S. Appl. No. 11/698,298, dated Jun. 29, 2011.
Office Action issued in U.S. Appl. No. 13/774,437, dated Jun. 20, 2014.
Ogura, Y., Catalase activity at high concentrations of hydrogen peroxide, Archs Biochem Biophys, 57: 288-300 (1955).
Oh et al., Distribution of Macropores in Silica Particles Prepared by Using Multiple Emulsions, Journal of Colloid and Interface Science, 254(1): 79-86 (2002).
Okushima et al. Controlled production of monodisperse double emulsions by two -step droplet breakup in microfluidic devices, Langmuir 20(23): 9905-8 (2004).
Olsen et al., Function-based isolation of novel enzymes from a large library, Nat Bioteoltnol 13(10):1071-4 (2000).
Omburo, G.A et al., Characterization of the zinc binding site of bacterial phosphotriesterase, J of Biological Chem, 267:13278-83 (1992).
Oroskar et al., Detection of immobilized amplicons by ELISA-like techniques, Clin. Chem. 42:1547-1555 (1996).
Ostermeier, M. et al., A combinatorial approach to hybrid enzymes independent of DNA homology, Nat Biotechnol, 17 (12):1205-9 (1999).
Ouelette, A new wave of microfluidic devices, Indust Physicist pp. 14-17 (2003).
Pabit et al., Laminar-Flow Fluid Mixer for Fast Fluorescence Kinetics Studies, Biophys J 83:2872-2878 (2002).
Paddison et al., Stable suppression of gene expression by RNAi in mammalian cells, PNAS 99(3):1443-1448 (2002).
Pannacci et al., Equilibrium and Nonequilibrium States in Microluidic Double Emulsions Physical Review Leters, 101 (16):164502 (2008).
Park et al., Cylindrical compact thermal-cycling device for continuous-flow polymeras chain reaction, Anal Chem, ACS, 75:6029-33 (2003).
Park et al., Model of Formation of Monodispersed Colloids, J. Phys. Chem. B 105:11630-11635 (2001).
Parker et al., Development of high throughput screening assays using fluorescence polarization: nuclear receptor- ligand-binding and kinase/phosphatase assays, J Biomol Screen, 5(2): 77-88 (2000).
Parmley et al., Antibody-selectable filamentous fd phage vectors: affinity purification of target genes. Gene 73 (2):305-18 (1988).
Pedersen et al., A method for directed evolution and functional cloning of enzymes, PNAS 95(18):10523-8 (1998).
Pelham and Jackson, An efficient mRNA-dependent translation system from reticulocyte lysates, Eur J Biochem 67:247-56 (1976).
Pelletier et al., An in vivo library-versus-library selection of optimized protein-protein interactions, Nature Biotechnology, 17:683-90 (1999).
Peng et al., Controlled Production of Emulsions Using a Crossflow Membrane, Particle & Particle Systems Characterization 15:21-25 (1998).
Perelson et al., Theorectical studies of clonal selection: minimal antibody repertoire size and relaibility of self-non-self discrimination. J Theor Biol 81(4):645-70 (1979).
Perez-Gilabert et al., Application of active-phase plot to the kinetic analysis of lipoxygenase in reverse micelles, Biochemistry J. 288:1011-1015 (1992).
Perrin, J., Polarisation de la lumiere de fluorescence vie moyenne des molecules dans letat excite, J. Phys. Rad. 1:390-401 (1926).
Petrounia, I.P et al., Designed evolution of enzymatic properties, Curr Opin Biotechnol, 11:325-330 (2000).
Piemi et al., Transdermal delivery of glucose through hairless rat skin in vitro: effect of multiple and simple emulsions, Int J Pharm, 171:207-215 (1998).
Pirrung et al., A General Method for the Spatially Defined Immobilization of Biomolecules on Glass Surfaces Using Caged' Biotin, Bioconjug Chem 7: 317-321 (1996).
Ploem, in Fluorescent and Luminescent Probes for Biological Activity Mason, T. G. Ed., Academic Press, Landon, pp. 1-11, 1993.
Pluckthun, A. et al., In vitro selection and evolution of proteins, Adv Protein Chem, 55: 367-403 (2000).
Pollack et al., Electrowetting-based actuation of droplets for integrated microfluidics, Lab Chip 2:96-101 (2002).
Pollack et al., Selective chemical catalysis by an antibody, Science 234(4783): 1570-3 (1986).
Pons et al, Synthesis of Near-Infrared-Emitting, Water-Soluble CdTeSe/CdZnS Core/Shell Quantum Dots, Chemistry of Materials 21(8):1418-1424 (2009).
Posner et al., Engineering specificity for folate into dihydrofolate reductase from Escherichia coli, Biochemistry, 35: 1653-63 (1996).
Poulin and Theil, “A priori” prediction of tissue: plasma partition coefficients of drugs to facilitate the use of physiologically-based pharmokinetic models in drug discovery, J Pharm Sci 89(1):16-35 (2000).
Priest, et al. Generation of Monodisperse Gel Emulsions in a Microfluidic Device, Applied Physics Letters, 88:024106 (2006).
Qi et al., Acid Beta-Glucosidase: Intrinsic Fluorescence and Conformational Changes Induced by Phospholipids and Saposin C, Biochem., 37(33): 11544-11554 (1998).
Raghuraman et al., Emulston Liquid Membranes for Wastewater Treatment: Equillibrium Models for Some Typical Metal-Extractant Systems,Environ. Sci. Technol 28:1090-1098 (1994).
Ralhan, Discovery and Verification of Head-and-neck Cancer Biomarkers by Differential Protein Expression Analysis Jsing iTRAQ Labeling, Multidimensional Liquid Chromatography, and Tandem Mass Spectrometry, Mol Cell Proteomics 7(6):1162-1173 (2008).
Ramsey, J.M., The burgeoning power of the shrinking laboratory, Nat Biotechnol 17(11):1061-2 (1999).
Ramstrom and Lehn, Drug discovery by dynamic combinatorial libraries, Nat Rev Drug Discov 1:26-36 (2002).
Raushel, F.M. et al., Phosphotriesterase: an enzyme in search of its natural substrate, Adv Enzymol Relat Areas Mol Biol, 74: 51-93 (2000).
Rech et al., Introduction of a yeast artificial chromosome vector into Sarrachomyeces cervesia by electroporation, Nucleic Acids Res 18:1313 (1990).
Reyes et al., Micro Total Analysis Systems. 1. Introduction, Theory and Technology, Anal Chem 74(12):2623-2636 (2002).
Riess, J.S., Fluorous micro- and nanophases with a biomedical perspective, Tetrahedron 58(20):4113-4131 (2002).
Roach et al., Controlling nonspecific protein adsorption in a plug-based microfluidic system by controlling inteifacial chemistry using fluorous-phase surfactants, Anal. Chem. 77:785-796 (2005).
Roberts & Ja, In vitro selection of nucleic acids and proteins: What are we learning, Curr Opin Struct Biol 9(4): 521-9 (1999).
Gibbs, 1989, Detection of single DNA base differences by competitive oligonucleotide priming, Nucleic Acids Res. 17 (7): 2437-48.
Gilliland, 1990, Analysis of cytokine mRNA and DNA: Detection and quantitation by competitive polymerase chain reaction, PNAS, 87(7):2725-9.
Giusti, 1993, Synthesis and characterization of 5′ fluorescent dye labeled oligonucleotides, Genome Res 2:223-227.
Glass, 1995, Development of primer sets designed for use with the PCR to amlify conserved genes from filamentous ascomycetes, Applied and Environmental Microbiology, vol. 6, pp. 1323-1330.
Gold, 1995, Diversity of Oligonucleotide Functions Annu Rev Biochem, 64: 763-97.
Gong, 2015, Simple method to prepare oligonucleotide conjugated antibodies and its applicaiotn in multiplex protein detection in single cells, Bioconjugate Chm 27(1):271-225.
Goodall, 1998, Operation of Mixed-Culture Immobilized Cell Reactors for the Metabolism of Meta- and Para-Nitrobenzoate by Comamonas Sp. JS46 and Comamonas Sp. JS47, Biotechnology and Bioengineering, 59 (1): 21-27.
Gordon, 1999, Solid phase synthesis—designer linkers for combinatorial chemistry: a review, J. Chem. Technol. Biotechnol., 74(9):835-851.
Grasland-Mongrain, 2003, Droplet coalescence in microfluidic devices, 30 pages, From internet: http://www.eleves.ens.fr/home/grasland/rapports/stage4.pdf.
Gray, 1987, High speed crhomosome sorting, Science 238(4825):323-329.
Green, 1992, Selection of a Ribozyme That Functions as a Superior Template in a Self Copying Reaction, Science, 258: 1910-5.
Gregoriadis, 1976, Enzyme entrapment in liposomes, Methods Enzymol 44:218-227.
Griffiths, 2000, Man-made enzymes-from design to in vitro compartmentalisation, Curr Opin Biotechnol 11:338-353.
Griffiths, 2003, Directed evolution of an extremely fast phosphotriesterase by in vitro compartmentalization, Embo J, 22:24-25.
Griffiths, 2006, Miniaturising the laboratory in emulsion droplets, Trend Biotech 24(9):395-402.
Grinwood, 2004, The DNA sequence and biology of human chromosome 19, Nature 428:529-535.
Grothues, 1993, PCR amplification of megabase DNA with tagged random primers (T-PCR), Nucl. Acids Res vol. 21 (5):1321-1322.
Grund, 2010, Analysis of biomarker data:logs, odds, ratios and ROC curves, Curr Opin Hiv Aids 5(6):473-479.
Guatelli, 1990, Isothermal, in vitro amplification of nucleic acids by a multienzyme reaction modeled after retroviral replication, PNAS, 87(5):1874-8.
Guixe, 1998, Ligand-Induced Conformational Transitions in Escherichia Coli Phosphofructokinase 2: Evidence for an Allosteric Site for MgATP2n, Biochem., 37: 13269-12375.
Gupta, 1991, A general method for the synthesis of 3'-sulfhydryl and phosphate group containing oligonucleotides, Nucl Acids Res 19 (11): 3019-3026.
Haber, 1993, Activity and spectroscopic properties of bovine liver catalase in sodium bis(2-ethylhexyl) sulfosuccinate/sooctane reverse micelles, Eur J Biochem 217(2): 567-73.
Habig, 1981, Assays for differentiation of glutathione S-transferases, Methods in Enzymology, 77: 398-405.
Hadd, 1997, Microchip Device for Performing Enzyme Assays, Anal. Chem 69(17): 3407-3412.
Haeberle, 2007, Microfluidic platforms for lab-on-a-chip applications, Lab on a Chip 7:1081-1220.
Hagar, 1992, The effect of endotoxemia on concanavalin A induced alterations in cytoplasmic free calcium in rat spleen cells as determined with Fluo-3, Cell Calcium 13:123-130.
Hai, 2004, Investigation on the release of fluorescent markers from the w/o/w emulsions by fluorescence-activated cell sorter, J Control Release, 96(3): 393-402.
Haies, 1981, Morphometric study of rat lung cells. I. Numerical and dimensional characteristics of parenchymal cell population, Am. Rev. Respir. Dis. 123:533-54.
Hall, 2003, The EBG system of E. coli: origin and evolution of a novel beta-galactosidase for the metabolism of lactose, Genetica 118(2-3):143-56.
Hamady, 2008, Error-correcting barcoded primers for pyrosequencing hundreds of samples in multiplex. Nature Nethods vol. 5, No. 3, p. 235-237.
Han, 2001, Quantum-dot-tagged Microbeads for Multiplexed Optical Coding of Biomolecules, Nat Biotech 19(7): 631-635.
Handen, 2002, High-throughput screening- challenges for the future, Drug Discov World, 47-50.
Handique, 2001, On-Chip Thermopneumatic Pressure for Discrete Drop Pumping, Analytical Chemistry, 73:1831-1838.
Hanes, 1997, In vitro selection and evolution of functional proteins by using ribosome display, PNAS 94:4937-42.
Hanes, 1998, Degradation of porous poly(anhydide-co-imide) microspheres and implication for controlled macromolecule delivery, Biomaterials, 19(1-3): 163-172.
Hansen, 2002, A robust and scalable microfluidic metering method that allows protein crystal growth by free interface diffusion, PNAS 99(26):16531-16536.
Harada, 1993, Monoclonal antibody G6K12 specific for membrane-associated differentiation marker of human stratified squamous epithelia and squamous cell carcinoma, J. Oral Pathol. Med 22(4):145-152.
Harder, 1994, Characterization and kinetic analysis of the intracellular domain of human protein tyrosine phosphatase beta (HPTP beta) using synthetic phosphopeptides, Biochem J 298 (Pt 2): 395-401.
Harries, 2006, A Numerical Model for Segmented Flow in a Microreactor, Int J of Heat and Mass Transfer, 46:3313-3322.
Harris, 2008, Single-molecule DNA sequencing of a viral genome, Science 320(5872):106-109.
Harrison, 1993, Micromachining a miniaturized capillary electrophoresis-based chemical analysis system on a chip, Science 261(5123):895-897.
Hasina, 2003, Plasminogen activator inhibitor-2: a molecular biomarker for head and neck cancer progression, Cancer Research 63:555-559.
Haynes, 2012, Digital PCR: A Technology Primer, Principles of Digital PCR and Measurement Issues: The certification of Cytomegalovirus Standard Reference Material (SRM 2366) as a model for future SRMs, National Institute of Standards and Tecnology, San Diego, CA, 4 pages.
Hayward, 2006, Dewetting Instability during the Formation of Polymersomes from BloceCopolymer-Stabilized Double Emulsions, Langmuir, 22(10): 4457-4461.
He, 2005, Selective encapsulation of single cells and subcellular organelles into picoliter- and femtoliter-volume droplets, Anal Chem 77(6): 1539-1544.
Head, 2014, Library construction for next generation sequencing, Biotech Rap Disp 56(2):61.
Heim, 1996, Engineering Green Fluorescent Protein for Improved Brightness, Longer Wavelengths and Fluorescence Response Energy Transfer, Carr. Biol, 6(2): 178-182.
Hellman, 2009, Differential tissue-specific protein markers of vaginal carcinoma, Br J Cancer, 100(8): 1303-131.
Henrich, 2012, Low-level detection and quantitation of cellular HIV-1 Dna and 2-ILTR circles using droplet dPCR, J Virol Meth 186(1-2):68-72.
Hergenrother, 2000, Small-Molecule Microarrays: Covalent Attachment and Screening of Alcohol-Containing Small Molecules on Glass Slides, J. Am. Chem. Soc, 122: 7849-7850.
Joo, 1999, Laboratory evolution of peroxide-mediated cytochrome P450 hydroxylaion, Nature 399:670.
Joos, 1997, Covalent attachment of hybridizable oligonucleotides to glass supports, Analytical Biochemistry 247:96-101.
Joyce, 1994, In vitro Evolution of Nucleic Acids, Curr. Opp. Structural Biol, 4: 331-336.
Kadir, 1990, Haem binding to horse spleen ferritin, Febs Lett, 276: 81-4.
Kallen, 1966, The mechanism of the condensation of formaldehyde with tetrahydrofolic acid, J. Biol. Chem., 241:5851-63.
Kambara, 1988, Optimization of Parameters in a DNA Sequenator Using Fluorescence Detection, Nature Biotechnology 6:816-821.
Kamensky, 1965, Spectrophotometer: new instrument for ultrarapid cell analysis, Science 150(3696):630-631.
Kanouni, 2002, Preparation of a stable double emulsion (W1/0/W2): role of the interfacial films on the stability of the system, Adv. Collid. Interf. Sci., 99(3): 229-254.
Karapatis, 1998, Direct rapid tooling a review of current research, Rapid Prototyping Journal, 4(2):77-89.
Katanaev, 1995, Viral Q beta RNA as a high expression vector for mRNA translation in a cell-free system, Febs Lett, 359:89-92.
Katsura, 2001, Indirect micromanipulation of single molecules in water-in-oil emulsion, Electrophoresis, 22:289-93.
Kawakatsu, 1997, Regular-sized cell creation in microchannel emulsification by visual microprocessing method, Journal of the American Oil ChemistS Society, 74:317-21.
Keana, 1990, New reagents for photoaffinity labeling: synthesis and photolysis of functionalized perfluorophenyl azides, J. Org. Chem.55(11):3640-3647.
Keefe, 2001, Functional proteins from a random-sequence library, Nature, 410: 715-718.
Keij, 1994, High-speed photodamage cell sorting: An evaluation of the ZAPPER prototype, Methods in cell biology, 42: 371-358.
Kelly, 2005, Detection of Vascular Adhesion Molecule-1 Expression Using a Novel Multimodal Nanoparticle, Circulation Research 96:327-336.
Kelly, 2007, Miniaturizing chemistry and biology in microdroplets, Chem Commun 18:1773-1788.
Kerker, 1983, Elastic and inelastic light scattering in flow cytometry, Cytometry, 4:1-10.
Khandjian, 1986, UV crosslinking of RNA to nylon membrane enhances hybridization signals, Mol. Bio. Rep. 11: 107-115.
Kheir, 2012, Oxygen Gas-Filled Microparticles Provide Intravenous Oxygen Delivery, Science Translational Medicine 4 (140):140ra88 (10 pages).
Kim, 2003, Type II quantum dots: CdTe/CdSe (core/shell) and CdSe/ZnTe (core/shell) heterostructures, J. Am Chem Soc. 125:11466-11467.
Kim, 2004, Comparative study on sustained release of human growth hormone from semi-crystalline poly(L-lactic acid) and amorphous poly(D,L-lactic-co-glycolic acid) microspheres: morphological effect on protein release, Journal of Controlled Release, 98(1):115-125.
Kircher, 2010, High-throughput DNA sequencing-concepts and limitations, Bioessays 32(6):524-536.
Kiss, 2008, High-throughput quantitative polymerase chain reaction in picoliter droplets, Anal. Chem 80:8975-8981.
Kitagawa, 1995, Manipulation of a single cell with microcapillary tubing based on its electrophoretic mobility, Electrophoresis 16:1364-1368.
Klug, 1994, All you wanted to know about selex, Molecular Biology Reports, 20:97-107.
Klug, 1995, Gene Regulatory Proteins and Their Interaction with DNA, Ann NY Acad Sci, 758: 143-60.
Klug, 1995, Protein motifs 5. Zinc fingers, Faseb J 9(8):597-604.
Knaak, 1995, Development of partition coefficients, Vmax and Km values, and allometric relationships, Toxicol Lett. 79 (1-3):87-98.
Knight, 1998, Hydrodynamic Focusing on a Silicon Chip: Mixing Nanoliters in Microseconds, Physical Review Lett 80 (17):3863-3866.
Koeller, 2001, Enzymes for chemical synthesis, Nature 409:232-240.
Kohler, 1975, Continuous cultures of fused cells secreting antibody of predefined specificity, Nature, 256:495-7.
Kojima, 2005, PCR amplification from single DNA molecules on magnetic beads in emulsion: application for high- throughput screening of transcription factor targets. Nucleic Acids Res. 33:e150, 9 pages.
Kolb, 1995, Cotranslational folding of proteins, Biochem Cell Biol, 73:1217-20.
Komatsu, 2001, Roles of cytochromes P450 1A2, 2A6, and 2C8 in 5-fluorouracil formation rom tegafur, an anticancer prodrug, in human liver microsomes. Drug Met. Disp., 28:1457-1463.
Kopp, 1998, Chemical amplification: continuous flow PCR on a chip, Science, 280:1046-48.
Koster, 2008, Drop-based microfluidic devices for encapsulation of single cells, Lab on a Chip 8:1110-1115.
Kowalczykowski, 1994, Biochemistry of homologous recombination in Escherichia coli, Microbiol Rev 58(3):401-65.
Kozbor, 1984, A human hybrid myeloma for production of human monoclonal antibodies, J. Immunol., 133:3001-3005.
Krafft, 1991, Synthesis and preliminary data on the biocompatibility and emulsifying properties of perfluoroalkylated phosphoramidates as injectable surfactants, Eur. J. Med. Chem., 26:545-550.
Krafft, 2001, Fluorocarbons and fluorinated amphiphiles in drug delivery and biomedical research, Adv Rev Drug Disc 47:209-228.
Krafft, 2003, Emulsions and microemulsions with a fluorocarbon phase, Colloid and Interface Science 8(3):251-258.
Kralj, 2005, Surfactant-enhanced liquid-liquid extraction in microfluidic channels with inline electric-field enhanced coalescence, Lab Chip 5:531-535.
Kricka, 1996, Micromachining: a new direction for clinical analyzers, Pure and Applied Chemistry 68(10):1831-1836.
Kricka, 2003, Microchip PCR, Anal Bioanal Chem 377(5):820-825.
Kritikou, 2005, “It's cheaper in the Picolab,” Nature, September, vol. 6, 1 page.
Krumdiek, 1980, Solid-phase synthesis of pteroylpolyglutamates, Methods Enzymol, 524-29.
Kruth, 2003, Lasers and materials in selective laser sintering, Assembly Automation, 23(4):357-371.
Kumagai, 1994, Ablation of polymer films by a femtosecond high-peak-power Ti:sapphire laser at 798 nm, Applied Physics Letters, 65(14):1850-1852.
Kumar, 1989, Activity and kinetic characteristics of glutathione reductase in vitro in reverse micellar waterpool, Biochem Biophys Acta, 996(1-2):1-6.
Roberts et al., Simian virus 40 DNA directs synthesis of authentic viral polypeptides in a linked transcription-translation cell-free system 72(5):1922-1926 (1975).
Roberts, et al., RNA-peptide fusion for the in vitro selection of peptides and proteins, PNAS 94:12297-302 (1997).
Roberts, J.W., Termination factor for RNA synthesis, Nature, 224: 1168-74 (1969).
Roberts, R.W. Totally in vitro protein selection using mRNA-protein fusions and ribosome display. Curr Opin Chem Biol 3(3), 268-73 (1999).
Roche (454 Sequencing System Guidelines for Amplicon Experimental Design, attached, May 2011).
Rodriguez-Antona et al., Quantitative RT-PCR measurement of human cytochrome P-450s: application to drug Induction studies. Arch. Biochem. Biophys., 376:109-116 (2000).
Rolland et al., Fluorescence Polarization Assay by Flow Cytometry, J. Immunol. Meth., 76(1): 1-10 (1985).
Rosenberg et al., Termination of transcription in bacteriophage lambda, J Biol Chem, 250: 4755-64 (1975).
Rosenberry, T.L., Acetylcholinesterase, Adv Enzymol Relat Areas Mol Biol, 43: 103-218 (1975).
Rotman, Measurement of activities of single molecules of beta-galactosidase, PNAS, 47:1981-91 (1961).
Russon et al., Single-nucleotide polymorphism analysis by allele-specific extension of fluorescently labeled nucleotides in a microfluidic flow-through device, Electrophoresis, 24:158-61 (2003).
Sadtler et al., Achieving stable, reverse water-in-fluorocarbon emulsions. Angew Chem Int Ed 35:1976-1978 (1996).
Saiki, R.K, et al., Primer directed enzymatic amplification of DNA with a thermostable DNA polymerase. Science 239 (4839):487-91 (1988).
Sakamoto, Rapid and simple quantification of bacterial cells by using a microfluidic device, Appl Env Microb. 71:2 (2005).
Sano, T. et al., Immuno-PCR-Very sensitive antigen-detection by means of sepcific antibody-DNA conjugates. Science 258(5079), 120-122 (1992).
Santalucia, A unified view of polymer, dumbbell, and oligonucleotide DNA nearest-neighbor thermodynamics, PNAS 95(4):1460-5 (1998).
Santra et al., Fluorescence lifetime measurements to determine the core-shell nanostructure of FITC-doped silica hanoparticles: An optical approach to evaluate nanoparticle photostability, J Luminescence 117(1):75-82 (2006).
Schatz et al., Screening of peptide libraries linked to lac repressor, Methods Enzymol 267: 171-91 (1996).
Schneegass et al., Miniaturized flow-through PCR with different template types in a silicone chip thermocycler, Lab on a Chip, Royal Soc of Chem, 1:42-9 (2001).
Schubert et al., Designer Capsules, Nat Med 8:1362 (2002).
Schweitzer et al., Immunoassays with rolling circle DNA amplification: A versatile platform for ultrasensitive antigen detection, PNAS 97(18), 10113-10119 (2000).
Schweitzer, B. et al., Combining nucleic acid amplification and detection. Curr Opin Biotechnol 12(1):21-7 (2001).
Scott, R.L., The Solubility of Fluorocarbons, J. Am. Chem. Soc, 70: 4090-4093 (1948).
Seethala and Menzel, Homogeneous, Fluorescence Polarization Assay for Src-Family Tyrosine Kinases, Anal Biochem 253(2):210-218 (1997).
Seiler et al., Planar glass chips for capillary electrophoresis: repetitive sample injection, quantitation, and separation efficiency, Anal Chem 65(10):1481-1488 (1993).
Selwyn M. J., A simple test for inactivation of an enzyme during assay, Biochim Biophys Acta 105:193-195 (1965).
Seo et al., Microfluidic consecutive flow-focusing droplet generators, Soft Matter, 3:986-992 (2007).
Seong and Crooks, Efficient Mixing and Reactions Within Microfluidic Channels Using Microbead-Supported Catalysts, J Am Chem Soc 124(45):13360-1 (2002).
Seong et al., Fabrication of Microchambers Defined by Photopolymerized Hydrogels and Weirs Within Microfluidic Systems: Application to DNA Hybridization, Analytical Chem 74(14):3372-3377 (2002).
Sepp et al., Microbead display by in vitro compartmentalisation: selection for binding using flow cytometry, FEBS Letters 532:455-58 (2002).
Serpersu et al., Reversible and irreversible modification of erythrocyte membrane permeability by electric field, Biochim Biophys Acta 812(3):779-785 (1985).
Shapiro, H.M., Multistation multiparameter flow cytometry: a critical review and rationale, Cytometry 3: 227-243 (1983).
Shestopalov et al., Multi-Step Synthesis of Nanoparticles Performed on Millisecond Time Scale in a Microfluidic Droplet-Based System, The Royal Society of Chemistry 4:316-321(2004).
Shtern V, and Hussain F., Hysteresis in swirling jets, J. Fluid Mech. 309:1-44 (1996).
Sia & Whitesides, Microfluidic devices fabricated in poly(dimethylsiloxane) for biological studies, Electrophoresis 24 (21):3563-3576 (2003).
Sidhu, S.S., Phage display in pharmaceutical biotechnology, Curr Opin Biotech 11:610-616 (2000).
Siemering et al., Mutations that suppress the thermosensitivity of green fluorescent protein, Current Biology 6:1653-1663 (1996).
Silva-Cunha et al., W/O/W multiple emulsions of insulin containing a protease inhibitor and an absorption enhancer: biological activity after oral administration to normal and diabetic rats, Int J Pharm 169:33-44 (1998).
Sims et al., Immunopolymerase chain reaction using real-time polymerase chain reaction for detection, Anal. Biochem. 281(2):230-2 (2000).
Slappendel et al., Normal cations and abnormal membrane lipids in the red blood cells of dogs with familial stomatocytosis hypertrophic gastritis, Blood 84:904-909 (1994).
Slob et al., Structural identifiability of PBPK models: practical consequences for modeling strategies and study designs. Crit Rev Toxicol. 27(3):261-72 (1997).
Smith et al., 2010, “Highly-multiplexed barcode sequencing: an efficient method for parallel analysis of pooled samples,” Nucleic Acids Research, vol. 38, No. 13, e142, pp. 1-7.
Smith et al., Direct mechanical measurements of the elasticity of single DNA molecules by using magnetic beads, Science 258(5085):1122-1126 (1992).
Smith et al., Fluorescence detection in automated DNA sequence analysis, Nature 321:674-679 (1986).
Smith et al., Phage display, Chemical Reviews 97(2), 391-410 (1997).
Smith et al., The synthesis of oligonucleotides containing an aliphatic amino group at the 5′ terminus: synthesis of fluorescent DNA primers for use in DNA sequence analysis, Nucl. Acid Res. 13:2399-2412 (1985).
Smith G.P., Filamentous fusion phage: novel expression vectors that display cloned antigens on the virion surface, Science 228(4705): 1315-7(1985).
Smyth et al., Markers of apoptosis: methods for elucidating the mechanism of apoptotic cell death from the nervous system, Biotechniques 32:648-665 (2000).
Sohn, et al., Capacitance cytometry: Measuring biological cells one by one, PNAS 97(20):10687-10690 (2000).
Somasundaram and Ramalingam, Gain studies of Rhodamine 6G dye doped polymer laser, J Photochem Photobiol 125(1-3):93-98 (1999).
Joyce, G.F., In vitro Evolution of Nucleic Acids, Curr. Opp. Structural Biol, 4: 331-336 (1994).
Kadir and Moore, Haem binding to horse spleen ferritin, Febs Lett, 276: 81-4 (1990).
Kallen, R.G. et al., The mechanism of the condensation of formaldehyde with tetrahydrofolic acid, J. Biol. Chem., 241:5851-63 (1966).
Kambara et al., Optimization of Parameters in a DNA Sequenator Using Fluorescence Detection, Nature Biotechnology 6:816-821 (1988).
Kamensky et al., Spectrophotometer: new instrument for ultrarapid cell analysis, Science 150(3696):630-631 (1965).
Kanouni et al., Preparation of a stable double emulsion (W1/0/W2): role of the interfacial films on the stability of the system, Adv. Collid. Interf. Sci., 99(3): 229-254 (2002).
Katanaev et al., Viral Q beta RNA as a high expression vector for mRNA translation in a cell-free system, Febs Lett, 359:89-92 (1995).
Katsura et al., Indirect micromanipulation of single molecules in water-in-oil emulsion, Electrophoresis, 22:289-93 (2001).
Kawakatsu et al., Regular-sized cell creation in microchannel emulsification by visual microprocessing method, Journal of the American Oil ChemistS Society, 74:317-21 (1997).
Keana J. & Cai, S. X., New reagents for photoaffinity labeling: synthesis and photolysis of functionalized perfluorophenyl azides, J. Org. Chem.55(11):3640-3647 (1990).
Keefe, A.D et al., Functional proteins from a random-sequence library, Nature, 410: 715-718 (2001).
Keij et al., High-Speed Photodamage Cell Selection Using a Frequency-Doubled Argon Ion Laser, Cytometry, 19(3): 209-216 (1995).
Keij, J.F., et al., High-speed photodamage cell sorting: An evaluation of the ZAPPER prototype, Methods in cell biology, 42: 371-358 (1994).
Kelly et al., Miniaturizing chemistry and biology in microdroplets, Chem Commun 18:1773-1788 (2007).
Kerker, M., Elastic and inelastic light scattering in flow cytometry, Cytometry, 4:1-10 (1983).
Khandjian, UV crosslinking of RNA to nylon membrane enhances hybridization signals, Mol. Bio. Rep. 11: 107-115 (1986).
Kim et al., Comparative study on sustained release of human growth hormone from semi-crystalline poly(L-lactic acid) and amorphous poly(D,L-lactic-co-glycolic acid) microspheres: morphological effect on protein release, Journal of Controlled Release, 98(1):115-125 (2004).
Kim S et al., Type II quantum dots: CdTe/CdSe (core/shell) and CdSe/ZnTe (core/shell) heterostructures, J. Am Chem Soc. 125:11466-11467 (2003).
Kircher et al., High-throughput DNA sequencing-concepts and limitations, Bioessays 32(6):524-536 (2010).
Kiss et al., High-throughput quantitative polymerase chain reaction in picoliter droplets, Anal. Chem 80:8975-8981 (2008).
Kitagawa et al., Manipulation of a single cell with microcapillary tubing based on its electrophoretic mobility, lectrophoresis 16:1364-1368 (1995).
Klug and Famulok, All you wanted to know about selex, Molecular Biology Reports, 20:97-107 (1994).
Klug and Schwabe, Protein motifs 5. Zinc fingers, FASEB J 9(8):597-604 (1995).
Klug, A., Gene Regulatory Proteins and Their Interaction with DNA, Ann NY Acad Sci, 758: 143-60 (1995).
Knaak et al., Development of partition coefficients, Vmax and Km values, and allometric relationships, Toxicol Lett. 79 (1-3):87-98 (1995).
Knight, James B., Hydrodynamic Focusing on a Silicon Chip: Mixing Nanoliters in Microseconds, Physical Review Lett 30(17):3863-3866 (1998).
Kojima et al. PCR amplification from single DNA molecules on magnetic beads in emulsion: application for high- throughput screening of transcription factor targets. Nucleic Acids Res. 33:e150 (2005).
Kolb et al., Cotranslational folding of proteins, Biochem Cell Biol, 73:1217-20 (1995).
Komatsu et al., Roles of cytochromes P450 1A2, 2A6, and 2C8 in 5-fluorouracil formation rom tegafur, an anticancer prodrug, in human liver microsomes. Drug Met. Disp., 28:1457-1463 (2001).
Kopp et al., Chemical amplification: continuous flow PCR on a chip, Science, 280:1046-48 (1998).
Koster et al., Drop-based microfluidic devices for encapsulation of single cells, Lab on a Chip 8:1110-1115 (2008).
Kowalczykowski et al., Biochemistry of homologous recombination in Escherichia coli, Microbiol Rev 58(3):401-65 (1994).
Krafft et al., Emulsions and microemulsions with a fluorocarbon phase, Colloid and Interface Science 8(3):251-258 (2003).
Krafft et al., Synthesis and preliminary data on the biocompatibility and emulsifying properties of perfluoroalkylated phosphoramidates as injectable surfactants, Eur. J. Med. Chem., 26:545-550 (1991).
Kralj et al., Surfactant-enhanced liquid-liquid extraction in microfluidic channels with inline electric-field enhanced coalescence, Lab Chip 5:531-535 (2005).
Kricka and Wilding, Microchip PCR, Anal Bioanal Chem 377(5):820-825 (2003).
Kricka and Wilding, Micromachining: a new direction for clinical analyzers, Pure and Applied Chemistry 68 (10):1831-1836 (1996).
Krumdiek, C.L et al., Solid-phase synthesis of pteroylpolyglutamates, Methods Enzymol, 524-29 (1980).
Kumar, A. et al., Activity and kinetic characteristics of glutathione reductase in vitro in reverse micellar waterpool, Biochem Biophys Acta, 996(1-2):1-6 (1989).
Lage et al., Whole genome analysis of genetic alterations in small DNA samples using hyperbranched strand displacement amplification and array-CGH. Genome Res. 13: 294-307 (2003).
Lamprecht et al., pH-sensitive microsphere delivery increases oral bioavailability of calcitonin, Journal of Controlled Release, 98(1): 1-9(2004).
Lancet, D. et al., Probability model for molecular recognition in biuological receptor repertoirs: significance to the olfactory system, PNAS, 90(8):3715-9 (1993).
Landergren et al., A ligase mediated gene detection technique. Science 241(4869):1077-80 (1988).
Lasheras, et al., Breakup and Atomization of a Round Water Jet by a High Speed Annular Air Jet, J Fluid Mechanics 357:351-379 (1998).
Leary et al., Application of Advanced Cytometric and Molecular Technologies to Minimal Residual Disease Monitoring, Proceedings of SPIE 3913:36-44 (2000).
Lee et al., Investigating the target recognition of DNA cytosine-5 methyltransferase Hhal by library selection using in vitro compartmentalisation (IVC), Nucleic Acids Res 30:4937-4944 (2002).
Lee et al., Circulating flows inside a drop under time-periodic non-uniform electric fields, Phys Fuilds 12(8):1899-1910 (2000).
Lee, et al., Effective Formation of Silicone-in-Fluorocarbon-in-Water Double Emulsions: Studies on Droplet Morphology and Stability, Journal of Dispersion Sci Tech 23(4):491-497(2002).
Lee, et al., Preparation of Silica Particles Encapsulating Retinol Using O/W/O Multiple Emulsions, Journal of Colloid and Interface Science, 240(1): 83-89 (2001).
Lemof, et al., An AC Magnetohydrodynamic Microfluidic Switch for Micro Total Analysis Systems, Biomedical Microdevices, 5(I):55-60 (2003).
Eow et al., Electrostatic enhancement of coalescence of water droplets in oil: a review of the technology, Chemical Engineeing Journal 85:357-368 (2002).
Eow et al., Motion, deformation and break-up of aqueous drops in oils under high electric field strengths, Chemical Eng Proc 42:259-272 (2003).
Eow et al., The behavior of a liquid-liquid interface and drop-interface coalescence under the influence of an electric field, Colloids and Surfaces A: Physiochern. Eng. Aspects 215:101-123 (2003).
Eow, et al. Electrostatic and hydrodynamic separation of aqueous drops in a flowing viscous oil, Chemical Eng Proc 41:649-657 (2002).
Extended European Search Report and Written Opinion for EP 17195627.9, dated Jan. 29, 2018 (7 pages).
Extended European Search Report for Application No. 12746483.2 dated Nov. 26, 14 (10 pages).
Extended European Search Report for Application No. 12746483.2 dated Nov. 26, 2014 (10 pages).
Extended European Search Report for EP 10181911.8 dated Jun. 1, 2011 (7 pages).
Extended European Search Report for EP 10184514.7 dated Dec. 20, 2010 (5 pages).
Faca et al., A mouse to human search for plasma proteome changes associated with pancreatic tumor development, PLoS Med 5(6):el23 (2008).
Fahy et al., Self-sustained sequence replication (3SR): an isothermal transcription-based amplification system alternative to PCR, PCR Methods Appl 1:25-33 (1991).
Fan and Harrison, Micromachining of capillary electrophoresis injectors and separators on glass chips and evaluation of flow at capillary intersections, Anal Chem 66:177-184 (1994).
Fastrez, J., In vivo versus in vitro screening or selection for catalytic activity in enzymes and abzymes, Mol Biotechnol 7(1):37-55 (1997).
Fettinger et al., Stacked modules for micro flow systems in chemical analysis: concept and studies using an enlarged model, Sens Actuat B. 17:19-25 (1993).
Fiedler et al., Dielectrophoretic sorting of particles and cells in a microsystem, Anal Chem 70(9):1909-1915 (1998).
Field, J. et al., Purification of a RAS-responsive adenylyl cyclase complex from Saccharomyces cervisiae by use of an epitope addition method. Mol Cell Biol, 8: 2159-2165 (1988).
Fields, S. and Song, O., A novel genetic system to detect protein-protein interactions, Nature 340(6230):245-6 (1989).
Filella et al., TAG-72, CA 19.9 and CEA as tumor markers in gastric cancer, Acta Oncol. 33(7):747-751 (1994).
Finch, C.A., Encapsulation and controlled release, Spec Publ R Soc Chem, 138:35 (1993).
Finch, C.A., Industrial Microencapsulation: Polymers for Microcapsule Walls, 1-12 in Encapsulation and Controlled Release, Woodhead Publishing (1993).
Fire & Xu, Rolling replication of short DNA circles, PNAS 92(10):4641-5 (1995).
Firestine, S.M. et al., Using an AraC-based three hybrid system to detect biocatalysts in vivo, Nat Biotechnol 18: 644-547 (2000).
Fisch et al., A strategy of exon shuffling for making large peptide repertoires displayed on filamentous bacteriophage, PNAS 93:7761-6 (1996).
Fisher et al., Cell Encapsulation on a Microfluidic Platform, The Eighth International Conference on Miniaturised Systems for Chemistry and Life Scieces, MicroTAS 2004, Sept. 26-30, Malmo, Sweden.
Fletcher et al., Micro reactors: principles and applications in organic synthesis, Tetrahedron 58:4735-4757 (2002).
Fluri et al., Integrated capillary electrophoresis devices with an efficient postcolumn reactor in planar quartz and glass chips, Anal Chem 68:4285-4290 (1996).
Fornusek, L. et al., Polymeric microspheres as diagnostic tools for cell surface marker tracing, Crit Rev Ther Drug Carrier Syst, 2:137-74 (1986).
Fowler, Enhancement of Mixing By Droplet-Based Microfluidics, Int Conf MEMS 97-100 (2002).
Freese, E., The specific mutagenic effect of base analogues on Phage T4, J Mol Biol, 1: 87 (1959).
Frenz et al., Reliable microfluidic on-chip incubation of droplets in delay-lines, Lab on a Chip 9:1344-1348 (2008).
Fu et al., A microfabricated fluorescence-activated cell sorter, Nature Biotechnology, 17(11):1109-1111 (1999).
Fu et al., An Integrated Microfabricated Cell Sorter, Anal. Chem., 74: 2451-2457 (2002).
Fulton et al., Advanced multiplexed analysis with the FlowMetrix system, Clin Chem 43:1749-1756 (1997).
Fulwyler, Electronic Separation of Biological Cells by vol. Science 150(3698):910-911 (1965).
Galan et al., 2010, “A 454 multiplex sequencing method for rapid and reliable genotyping of highly polymorphic genes in large-scale studies.”, BMC Genomics 11(296):1-15.
Gallarate et al., On the stability of ascorbic acid in emulsified systems for topical and cosmetic use, Int J Pharm 188 (2):233-241 (1999).
Ganan-Calvo, A.M., Perfectly Monodisperse Microbubbling by Capillary Flow Focusing, Phys Rev Lett 87(27): 274501-1-4 (2001).
Ganan-Calvo, Generation of Steady Liquid Microthreads and Micron-Sized Monodisperse Sprays and Gas Streams, Phys Rev Lett 80(2):285-288 (1998).
Garcia-Ruiz et al. A super-saturation wave of protein crystallization, J. Crystal Growth, 232:149-155(2001).
Garcia-Ruiz et al., Investigation on protein crystal growth by the gel acupuncture method, Acta, Cryst., 1994, D50, 99. pp. 484-490.
Garstecki, et al., Formation of monodisperse bubbles in a microfiuidic flow-focusing device, Appl Phys Lett 85 (13):2649-2651 (2004).
Gasperlin et al., The structure elucidation of semisolid w/o emulsion systems containing silicone surfactant, Intl J Pharm, 107:51-6 (1994).
Gasperlin et al., Viscosity prediction of lipophillic semisolid emulsion systems by neural network modeling, Intl J Pharm, 196:37-50 (2000).
Georgiou et al., Display of heterologous proteins on the surface of microorganisms: from the screenign of combinatiorial libraires to live recombinant vaccines. Nat Biotechnol 15(1), 29-34 (1997).
Georgiou, G., Analysis of large libraries of protein mutants using flow cytometry, Adv Protein Chem, 55: 293-315 (2000).
Gerdts et al., A Synthetic Reaction NetWork: Chemical Amplification Using Nonequilibrium Autocatalytic Reactions Coupled in Time, J. Am. Chem. Soc 126:6327-6331 (2004).
Ghadessy et al., Directed Evolution of Polymerase Function by Compartmentalized Self-Replication, PNSAS 98(8): 4552-4557 (2001).
Gibbs et al., Detection of single DNA base differences by competitive oligonucleotide priming, Nucleic Acids Res. 17 (7): 2437-48 (1989).
Gilliland, G., Analysis of cytokine mRNA and DNA: Detection and quantitation by competitive polymerase chain reaction, PNAS, 87(7):2725-9 (1990).
Giusti et al., Synthesis and characterization of 5' fluorescent dye labeled oligonucleotides, Genome Res 2:223-227 1993).
Kohara, 2002, DNA probes on beads arrayed in a capillary, 'Beadarray'-exhibited high hybridization performance, 30, 987, pp. 1-7.
Meng, 2015, Self-assembling amphiphilic poly(propargyl methacrylate) grafted DNA copolymers into multi-strand helices, Soft Matter 11(28):5610-5613.
Poon, 2002, Differential DNA Methylation between Fetus and Mother as a Strategy for Detecting Fetal DNA in Maternal Plasma, Clinical Chemistry, 48:35-41.
Balomon, 2019, Droplet-based single cell RNAseq tools: a practical guide, Lab on a Chip 19:1706-1727.
Thompson, L.F., Introduction to Lithography, ACS Symposium Series 219:1-13, (1983).
Thorsen et al., Dynamic pattern formation in a vesicle-generating microfluidic device, Phys Rev Lett 86(18):4163-4166 (2001).
Thorsen et al., Microfluidic Large-Scale Integration, Science 298:580-584 (2002).
Tice et al., Effects of viscosity on droplet formation and mixing in microfluidic channels, Analytica Chimica Acta 607:73-77 (2004).
Tice et al., Formation of droplets and mixing in multiphase microfluidics at low values of the reynolds and the capillary Nos. Langmuir 19:9127-9133 (2003).
Titomanlio et al., Capillary experiments of flow induced crystallization of HOPE, AIChe Journal, 36(1):13-18(1990).
Tleugabulova et al., Evaluating formation and growth mechanisms of silica particles using fluorescence anisotropy decay analysis, Langmuir 20(14):5924-5932 (2004).
Tokatlidis et al., Nascent chains: folding and chaperone intraction during elongation on ribosomes, Philos Trans R Soc ond B Biol Sci, 348:89-95 (1995).
Tokeshi et al., Continuous-Flow Chemical Processing on a Microchip by Combining Microunit Operations and a Multiphase Flow NetWork, Anal Chem 74(7):1565-1571 (2002).
Tokumitsu, H. et al., Preparation of gadopentetic acid-loaded chitosan microparticles for gadolinium neutron-capture therapy of cancer by a novel emulsion-droplet coalescence technique, Chem and Pharm Bull 47(6):838-842 (1999).
Tramontano, A., Catalytic antibodies, Science 234(4783):1566-70 (1986).
Trindade, T., Nanocrystalline semiconductors: synthesis, properties, and perspectives, Chem. Mat. 13:3843-3858 (2001).
Tripet, B. et al., Engineering a de novo-designed coiled-coil heterodimerization domain off the rapid detection, purification and characterization of recombinantly expressed peptides and proteins, Protein Engng., 9:1029-42 (1996).
Tsuchiya et al., 2007, “On-chip polymerase chain reaction microdevice employing a magnetic droplet-manipulation system”, Sensors and Actuators B 130:583-588.
Tuerk, C. and Gold, L., Systematic Evolution of Ligands by Exponentid Enrichment: RNA Ligands to Bacteriophage T4 Dna Polymerase, Science, 249:505-10 (1990).
Umbanhowar et al., Monodisperse Emulsion Generation via Drop Break Off in a Coflowing Stream, Langmuir 16 (2):347-351 (2000).
Unger et al., Monolithic microfabricated valves and pumps by multylayer soft lithography, Science 288(5463):113-116 (2000).
Utada, A. et al., Monodisperse double emulsions generated from a microcapillary device, Science, 308:537-541 (2005).
Vainshtein et al., Peptide rescue of an N-terminal truncation of the stoffel fragment of Taq DNA polymerase, Protein Science, 5:1785-92 (1996).
Van Bockstaele et al., Prognostic markers in chronic lymphocytic leukemia: a comprehensive review, Blood Rev 23 1):25-47 (2009).
Van Dilla et al., Cell Microfluorometry: A Method for Rapid Fluorescence Measurement, Science 163(3872):1213-1214 1969).
Van Dilla et al., The fluorescent cell photometer: a new method for the rapid measurement of biological cells stained with fluorescent dyes, Annual Report of the Los Alamos Scientific Laboratory of the University of California (Los Alamos, NM), Biological and Medical Research Groupp (H-4) of the Health Division, Compiled by D. G. Ott, pp. 100-105, distributed Jan. 23, 1968.
Vanhooke et al., Three-dimensional structure of the zinc-containing phosphotrieesterase with the bound substrate analog diethy 4-methylbenzylphosphonate, Biochemistry 35:6020-6025 (1996).
Varga, J.M. et al., Mechanism of allergic cross-reactions-I. Multispecific binding of ligands to a mouse monoclonal anti- DNP IgE antibody. Mol Immunol 28(6), 641-54 (1991).
Vary, A. homogeneous nucleic acid hybridization assay based on strand displacement, Nucl Acids Res 15 (17):6883-6897 (1987).
Venkateswaran et al., Production of Anti-Fibroblast Growth Factor Receptor Monoclonal Antibodies by In Vitro Immunization, Hybirdoma, 11(6):729-739 (1992).
Venter et al., The sequence of the human genome, Science 291(5507):1304-51 (2001).
Vogelstein et al., Digital Pcr, Pnas 96(16):9236-9241 (1999).
Voss, E.W., Kinetic measurements of molecular interactions by spectrofluorometry, J Mol Recognit, 6:51-58 (1993).
Wahler, D. et al., Novel methods for biocatalyst screening. Curr Opin Chem Biol, 5: 152-158 (2001).
Walde, P. et al., Oparin's reactions revisited: enzymatic synthesis of poly(adenylic acid) in micelles and self- reproducing vesicles. J Am Chem Soc, 116: 7541-7547 (1994).
Walde, P. et al., Spectroscopic and kinetic studies of lipases solubilized in reverse micelles, Biochemistry, 32 (15):4029-34 (1993).
Walde, P. et al., Structure and activity of trypsin in reverse micelles, Eur J Biochem, 173(2):401-9 (1988).
Walker et al., Isothermal in vitro amplification of DNA by a restriction enzyme/DNA polymerase system, PNAS 89 (1):392-6 (1992).
Walker et al., Strand displacement amplification-an isothermal, in vitro DNA amplification technique, Nucleic Acid Res, 20(7):1691-6 (1992).
Wang et al., DEP actuated nanoliter droplet dispensing using feedback control, Lab on a Chip 9:901-909 (2008).
Wang et al., Preparation of Titania Particles Utilizing the Insoluble Phase Interface in a MicroChannel Reactor, Chemical Communications 14:1462-1463 (2002).
Wang, A.M. et al., Quantitation of mRNA by the polymerase chain reaction. Proc natl Acad Sci USA 86(24), 9717-21 (1989).
Wang, G.T. et al., Design and synthesis of new fluorogenic HIV protease substrates based on resonance energy transfer, Tetrahedron Lett., 31:6493 (1990).
Warburton, B., Microcapsules for Multiple Emulsions, Encapsulation and Controlled Release, Spec Publ R Soc Chem, 35-51 (1993).
Wasserman et al., Structure and reactivity of allyl- siloxane monolayers formed by reaction of allcyltrichlorosilanes on silicon substrates, Langmuir 5:1074-1087 (1989).
Weil et al., Selective and accurate initiation of transcription at the Ad2 major late promotor in a soluble system dependent on purified RNA polymerase II and DNA, Cell, 18(2):469-84 (1979).
Werle et al., Convenient single step, one tube purification of PCR products for direct sequencing, Nucl Acids Res 22 (20):4354-4355 (1994).
Wetmur et al., Molecular haplotyping by linking emulsion PCR: analysis of paraoxonase 1 haplotypes and phenotypes, Nucleic Acids Res 33(8):2615- 2619 (2005).
White et al., 2009, Digital PCR provides sensitive and absolute calibration for high throughput sequencing, BMC Genomics 10:116.
Wick et al., Enzyme-containing liposomes can endogenously produce membrane-constituting lipids, Chem Biol 3 (4):277-85 (1996).
Widersten and Mannervik, Glutathione Transferases with Novel Active Sites Isolated by Phage Display from a Library of Random Mutants, J Mol Biol 250(2):115-22 (1995).
Wiggins et al., Foundations of chaotic mixing, Philos Transact A Math Phys Eng Sci 362(1818):937-70 (2004).
Williams et al., Amplification of complex gene libraries by emulsion PCR, Nature Methods 3(7):545-550 (2006).
Williams et al., Methotrexate, a high-affinity pseudosubstrate of dihydrofolate reductase, Biochemistry, 18(12):2567-73 (1979).
Holmes et al., Reagents for Combinatorial Organic Synthesis: Development of a New O-Nitrobenzyl Photolabile Linder for Solid Phase Synthesis, J. OrgChem., 60: 2318-2319(1995).
Hong, S.B. et al., Stereochemical constraints on the substrate specificity of phosphodiesterase, Biochemistry, 38: 1159-1165 (1999).
Hoogenboom et al., Multi-subunit proteins on the surface of filamentous phage: methodologies for displaying antibody (Fab) heavy and light chains, Nucl Acids Res., 91: 4133-4137 (1991).
Hoogenboom, H.R., Designing and optimizing library selection strategies for generating high-affinity antibodies, Trends Biotechnol, 15:62-70 (1997).
Topfinger & Lasheras, Explosive Breakup of a Liquid Jet by a Swirling Coaxial Jet, Physics of Fluids 8(7):1696-1700 1996).
Topman et al., Rapid synthesis of biotin-, digoxigenin-, trinitrophenyl-, and fluorochrome-labeled tyramides and their application for In situ hybridization using CARD amplification, J of Histochem and Cytochem, 46(6):771-77 (1998).
Horton et al., Engineering hybrid genes without the use of restriction enzymes: gene splicing by overlap extension, Gene 77(1):61-8 (1989).
Hosokawa, Kazuo et al., Handling of Picoliter Liquid Samples in a Poly(dimethylsiloxane)-Based Microfluidic Device, Analytical Chemistry, 71(20):4781-4785 (1999).
Hisu et al., Comparison of process parameters for microencapsulation of plasmid DNA in poly(D, L-lactic-co-glycolic acid microspheres, J Drug Target, 7:313-23 (1999).
Huang L. R. et al., Continuous particle separation through deterministic lateral displacement, Science 304 (5673) 987-990 (2004).
Huang, Z. et al., A sensitive competitive ELISA for 2,4-dinitrophenol using 3,6-fluorescein diphosphate as a fluorogenic substrate, J Immunol Meth, 149:261 (1992).
Tuang, Z.J., Kinetic assay of fluorescein mono-beta-D-galactosidase hydrolysis by beta-galactosidase: a front-face measurement for strongly absorbing fluorogenic substrates, Biochemistry, 30:8530-4 (1991).
Hubert et al. Data Concordance from a Comparison between Filter Binding and Fluorescence Polarization Assay Formats for Identification of RUOCK-Il Inhibitors, J biomol Screen 8(4):399-409 (2003).
Huebner, A. et al., Quantitative detection of protein expression in single cells using droplet microfluidics, Chem Com 12:1218-1220 (2007).
Hung et al., Optimization of Droplet Generation by controlling PDMS Surface Hydrophobicity, 2004 ASME International Mechanical Engineering Congress and RD&D Expo, Nov. 13-19, Anaheim, CA (2004).
Hung, et al., Controlled Droplet Fusion in Microfluidic Devices, MicroTAS 2004, Sept. 26-30, Malmo, Sweden (2004).
Hutchison et al., Cell-free cloning using Phi29 polymerase, PNAS 102(48):17332-17336 (2005).
Ibrahim, S.F. et al., High-speed cell sorting: fundamentals and recent advances, Curr Opin Biotchnol, 14(1):5-12 (2003).
Keda et al., Bioactivation of tegafur to 5-fluorouracil is catalyzed by cytochrome p. 450 2A6 in human liver microsomes In vitro, Clin Cancer Res 6(11):4409-4415 (2000).
Illumina (Genomic Sequencing, data Sheet, attached, 2010).
Nai et al., Immunohistochemical detection of an enamel protein-related epitope in rat bone at an early stage of osteogenesis, Histochemistry 99(5):335-362 (1993).
International Preliminary Report of Patentability for PCTU.S. Pat. No. 2010061741 Mailed Sep. 16, 11(4 pages).
International Preliminary Report on Patentability mailed Sep. 20, 2007, for PCT/US2006/007772 (11 pages).
International Search Report and Written Opinion for PCT/US11/54353 Mailed Apr. 20, 12 (34 pages).
International Search Report and Written Opinion for PCT/US12/024745 Mailed May 11, 12 (21 pages).
International Search Report and Written Opinion for PCT/US12/24741 Mailed Jun. 12, 12 (12 pages).
International Search Report and Written Opinion for PCT/US12/5499 Mailed May 29, 12 (10 pages).
International Search Report and Written Opinion for PCT/US2009/050931 Mailed Nov. 26, 2009 (3 pages).
International Search Report and Written Opinion in PCT/EP2010/065188 Mailed Jan. 12, 2011 (7 pages).
International Search Report and Written Opinion in PCT/US11/24615 Mailed Jul. 25, 11 (37 pages).
International Search Report and Written Opinion in PCT/US2004/010903 Mailed Dec. 20, 2004 (16 pages).
International Search Report and Written Opinion in PCT/US2006/021286 Mailed Sep. 14, 2007 (16 pages).
International Search Report and Written Opinion in PCT/US2007/002063 Mailed Nov. 15, 07 (20 pages).
International Search Report in PCT/US01/18400 Mailed Jan. 28, 2005 (37 pages).
Invitrogen (2008) Specification sheet for Dynabeads@ Oligo (dT)25, http://www.invitrogen.com.
Smagilov, Integrated Microfluidic Systems, Angew. Chem. Int. Ed 42:4130-4132 (2003).
Janda, et al., Chemical selection for catalysis in combinatorial antibody libraries, Science, 275:945-948 (1997).
Jang et al., Controllable delivery of non-viral DNA from porous scaffold, J Controlled Release 86(1):157-168 (2003).
Japanese Office Action for JP 2006-509830 mailed Jun. 1, 2011 (4 pages).
Jermutus et al., Recent advances in producing and selecting functional proteins by using cell-free translation, Curr Opin Biotechnol 9(5): 534-48 (1998).
Jestin et al., A Method for the Selection of Catalytic Activity Using Phage Display and Proximity Coupling, Agnew. Chem. Int. Ed. Engi. 38(8):1124-1127 (1999).
Jo, et al., Encapsulation of Bovine Serum Albumin in Temperature-Programmed Shell-in-Shell Structures, Macromol. Rapid Comm 24:957-962 (2003).
Joerger et al., Analyte detection with DNA-labeled antibodies and polymerase chain reaction, Clin. Chem. 41(9):1371-7 1995).
Johannsson et al., Amplification by Second Enzymes, In ELISA and Other Solid Phase Immunoassays, Kemeny et al. (ed.), Chapter 4, pp. 85-106 John Wiley (1988).
Johannsson, A., Heterogeneous Enzyme Immunoassays, In Principles and Practice of Immunoassay, pp. 295-325 Stockton Press (1991).
Johnson, T.O. et al., Protein tyrosine phosphatase 1B inhibitors for diabetes, Nature Review Drug Discovery 1, 696-709 (2002).
Jones et al. Glowing jellyfish, luminescence and a molecule called coelenterazine, Trends Biotechnol. 17(12):477-81 (1999).
Jones, L.J. et al., Quenched BODIPY dye-labeled casein substrates for the assay of protease activity by direct fluorescence measurement, Anal Biochem, 251:144 (1997).
Joo et al., Laboratory evolution of peroxide-mediated cytochrome P450 hydroxylaion, Nature 399:670 (1999).
Joos et al., Covalent attachment of hybridizable oligonucleotides to glass supports, Analytical Biochemistry 247:96-101 (1997).
Song et al., A microfluidic system for controlling reaction networks in time, Angew. Chem. Int. Ed. 42(7):768-772 (2003).
Song et al., Experimental Test of Scaling of Mixing by Chaotic Advection in Droplets Moving Through Microfluidic Channels, App Phy Lett 83(22):4664-4666 (2003).
Song, H. and Ismagilov, R.F., Millisecond kinetics on a microluidic chip using nanoliters of reagents, J Am Chem Soc. 125: 14613-14619 (2003).
Soni and Meller, Progress toward ultrafast DNA sequencing using solid-state nanopores, Clin Chem 53:1996-2001 (2007).
Soumillion et al., Novel concepts for the selection of catalytic activity. Curr Opin Biotechnol 12:387-394 (2001).
Soumillion et al., Selection of B-lactomase on filamentous bacteriophage by catalytic activity, J Mol Biol, 237:415-22 (1994).
Sproat et al., The synthesis of protected 5'-mercapto-2',5'-dideoxyribonucleoside-3'-0-phosphorainidites, uses of 5'- mercapto-oligodeoxyribonucleotides, Nucleic Acids Res 15:4837-4848 (1987).
Stauber, et a., Rapid generation of monoclonal antibody-secreting hybridomas against African horse sickness virus by In vitro immunization and the fusion/cloning technique, J. Immunol. Meth 161(2):157-168 (1993).
Stemmer, W.P., Dna shuffling by random fragmentation and reassembly: in vitro recombination for molecular evolution. PNAS 91(22):10747-51(1994).
Stemmer, W.P., Rapid evolution of a protein in vitro by DNA shuffling, Nature 370(6488):389-91 (1994).
Stober et al., Controlled growth of monodisperse silica spheres in the micron size range, J Colloid and Interface Sci 26 (1):62-69 (1968).
Stofko, H.R et al., A single step purification for recombinant proteins. Characterization of microtube associated protein (MAP2) fragment which associates with the type II cAMP-dependent protein kinase, Febs Lett 302: 274-278 (1992).
Stone et al., Engineering flows in small devices: Microfluidics toward a lab-on-a-chip, Ann. Rev. Fluid Mech. 36:381-441 (2004).
Strizhkov et al., PCR amplification on a microarray of gel-immobilized oligonucleotides: Detection of bacterial toxin- and drug- resistant genes and their mutations, BioTechniques 29(4):844-857 (2000).
Stroock et al., Chaotic mixer for microchannels, Science 295(5555):647-651 (2002).
Studer et al., Fluorous Synthesis: A Fluorous-Phase Strategy for Improving Separation Efficiency in Organic Synthesis, Science 275: 823-826 (1997).
Sugiura et al., Effect of Channel Structure on MicroChannel Emuisification, Langmuir 18:5708-5712 (2002).
Sugiura et al., Interfacial tension driven monodispersed droplet formation from mtcrofabricated channel array angmuir, 17: 5562-5566 (2001).
Sundberg et al., Spatially-Addressable Immobilisation of Macromolecules on Solid Supports, J. Am. Chem. Soc, 117:12050-12057 (1995).
Sung et al. Chip-based microfluidic devices coupled with electrospray ionization-mass spectrometry, Electrophoresis 26:1783-1791 (2005).
Suzuki et al., Random mutagenesis of thermus aquaticus DNA polmerase I: concordance of immutable sites in vivo with the crystal structure, Pnas USA, 93:96701-9675 (1996).
Tabatabai and Faghri, A New Two-Phase Flow Map and Transition Boundary Accounting for Surface Tension Effects In Horizontal Miniature and Micro Tubes, J Heat Transfer 123:958-968 (2001).
Tabatabai et al., Economic feasability study of polyelectrolyte-enhanced ultrafiltration (PEUF) for water softening, J Membrane Science 100(3):193-207 (1995).
Tabatabai et al., Reducing Surfactant Adsorption on Carbonate Reservoirs, SPE Resenroir Engineering 8(2):117-122 (1993).
Tabatabai, Water Softening Using polyelectrolyte-enhanced ultrafiltration, Separation Science Technology 30 (2):211-224 (1995).
Takayama et al., Patterning Cells and Their Environments Using Multiple Laminar Fluid Flows in Capillary NetWO rks, PNAS 96:5545-5548 (1999).
Takeuchi et al., An Axisymmetric Flow-Focusing Microfluidic Device, Adv. Mater 17(8):1067-1072 (2005).
Taly et al., Droplets as Microreactors for High-Throughput Biology, Chembiochem 8(3):263-272 (2007).
Tan et al., Controlled Fission of Droplet Emulsions in Bifurcating Microfluidic Channels, Transducers Boston (2003).
Tan et al., Design of microluidic channel geometries for the control of droplet vol. chemical concentration, and sorting, Lab Chip, 4(4): 292-298 (2004).
Tan et al., Monodispersed microfluidic droplet generation by shear focusing microfluidic device, Sensors and Actuators 114:350-356 (2006).
Tan, Y.C., Microfluidic Liposome Generation from Monodisperse Droplet Emulsion-Towards the Realization of Artificial Cells, Summer Bioengineering Conference, Florida (2003).
Tan, Y.C., Monodisperse Droplet Emulsions in Co-Flow Microfluidic Channels, Micro TAS, Lake Tahoe (2003).
Tanaka et al., Ethanol Production from Starch by a Coimmobilized Mixed Culture System of Aspergillus awamori and Zymomonas mobilis, Biotechnol Bioeng XXVII:1761-1768 (1986).
Tang et al., A multi-color fast-switching microfluidic droplet dye laser, Lab Chip 9:2767-2771 (2009).
Taniguchi et al., Chemical Reactions in Microdroplets by Electrostatic Manipulation of Droplets in Liquid Media, Lab on a Chip 2:19-23 (2002).
Tawfik et al., catELISA: a facile general route to catalytic antibodies, PNAS 90(2):373-7 (1993).
Tawfik et al., Efficient and selective p-nitrophenyl-ester=hydrolyzing antibodies elicited by a p-nitrobenzyl phosphonate hapten, Eur J Biochem, 244:619-26 (1997).
Tawfik et al., Man-made cell-like compartments for molecular evolution, Nature Biotechnology, 7(16):652-56 (1998).
Tawfik, D.S. et al., 1,8-diabycyclo[5.4.0]undecane mediated transesterification of p-nitrophenyl phosphonates- a novel route to phosphono esters, Synthesis-Stuttgart, 10: 968-972 (1993).
Taylor et al., Characterization of chemisorbed monolayers by surface potential measurments, J. Phys. D. Appl. Phys. 24:1443 (1991).
Taylor, The formation of emulsions in definable field of flow, Proc R Soc London A 146(858):501-523 (1934).
Tchagang et al., Early detection of ovarian cancer using group biomarkers, Mol Cancer Ther 7:27-37 (2008).
Tencza et al., Development of a Fluorescence Polarization-Based Diagnostic Assay for Equine Infectious Anemia Virus, J Clinical Microbiol 38(5):1854-185 (2000).
Terray et al., Microfluidic Control Using Colloidal Devices, Science, 296(5574):1841-1844 (2002).
Terray, et al., Fabrication of linear colloidal structures for microfluidic applications, Applied Phys Lett 81(9):1555-1557 (2002).
Tewhey et al., Microdroplet-based PCR amplification for large scale targeted sequencing, Nat Biotechnol 27 (11):1025-1031 (2009).
Tewhey et al., Microdroplet-based PCR enrichment for large scale targeted sequencing, Nature Biotechnology, 2009, vol. 27 (11) p. 1025-1031.
Theberge et al., Microdroplets in Microfluidics: An Evolving Platform for Discoveries in Chemistry and Biology, Angew. Chem. Int. Ed 49(34):5846-5868 (2010).
Patel, 2003, Formation of Fluorinated Nonionic Surfactant Microemulsions in Hydrfuorocarbon 134a, Journal of Colloid and Interface Science, 258, 345-353.
Pedersen, 1998, A method for directed evolution and functional cloning of enzymes, PNAS 95(18):10523-8.
Pekin, 2011, Quantitative and sensitive detection of rare mutations using droplet-based microfluidics, Lab on a Chip 11 (13):2156-2166.
Pelham, 1976, An efficient mRNA-dependent translation system from reticulocyte lysates, Eur J Biochem 67:247-56.
Pelletier, 1999, An in vivo library-versus-library selection of optimized protein-protein interactions, Nature Biotechnology, 17:683-90.
Peng, 1998, Controlled Production of Emulsions Using a Crossflow Membrane, Particle & Particle Systems Characterization 15:21-25.
Pepe, 2004, Limitations of the odds ratio in gauging the performance of a diagnostic, prognostic, or screening marker, American Journal of Epidemiology 159(9):882-890.
Perelson, 1979, Theorectical studies of clonal selection: minimal antibody repertoire size and relaibility of self-non-self discrimination. J Theor Biol 81(4):645-70.
Perez-Gilabert, 1992, Application of active-phase plot to the kinetic analysis of lipoxygenase in reverse micelles, Biochemistry J. 288:1011-1015.
Petrounia, 2000, Designed evolution of enzymatic properties, Curr Opin Biotechnol, 11:325-330.
Pirrung, 1996, A General Method for the Spatially Defined Immobilization of Biomolecules on Glass Surfaces Using Caged' Biotin, Bioconjug Chem 7: 317-321.
Ploem, 1993, in Fluorescent and Luminescent Probes for Biological Activity Mason, T. G. Ed., Academic Press, andon, pp. 1-11.
Pluckthun, 2000, In vitro selection and evolution of proteins, Adv Protein Chem, 55: 367-403.
Pollack, 1986, Selective chemical catalysis by an antibody, Science 234(4783):1570-3.
Pollack, 2002, Electrowetting-based actuation of droplets for integrated microfluidics, Lab Chip 2:96-101.
Pons, 2009, Synthesis of Near-Infrared-Emitting, Water-Soluble CdTeSe/CdZnS Core/Shell Quantum Dots, Chemistry of Materials 21(8):1418-1424.
Posner, 1996, Engineering specificity for folate into dihydrofolate reductase from Escherichia coli, Biochemistry, 35: 1653-63.
Priest, 2006, Generation of Monodisperse Gel Emulsions in a Microfluidic Device, Applied Physics Letters, 88:024106, 3 pages.
Qi, 1998, Acid Beta-Glucosidase: Intrinsic Fluorescence and Conformational Changes Induced by Phospholipids and Saposin C, Biochem., 37(33): 11544-11554.
Raghuraman, 1994, Emulston Liquid Membranes for Wastewater Treatment: Equillibrium Models for Some Typical Metal-Extractant Systems,Environ. Sci. Technol 28:1090-1098.
Ralhan, 2008, Discovery and Verification of Head-and-neck Cancer Biomarkers by Differential Protein Expression Analysis Using iTRAQ Labeling, Multidimensional Liquid Chromatography, and Tandem Mass Spectrometry, Mol Cell Proteomics 7(6):1162-1173.
Ramanan, 2016, Algae-bacteria interactions, Biotech ADv 34:14-29.
Ramsey, 1999, The burgeoning power of the shrinking laboratory, Nat Biotechnol 17(11):1061-2.
Ramstrom, 2002, Drug discovery by dynamic combinatorial libraries, Nat Rev Drug Discov 1:26-36.
Rasmussen, 2013, Comparison of HDAC inhibitors in clinical development, Human Vacc Immunother 9(5):993-1001.
Raushel, 2000, Phosphotriesterase: an enzyme in search of its natural substrate, Adv Enzymol Relat Areas Mol Biol, 74: 51-93.
Rech, 1990, Introduction of a yeast artificial chromosome vector into Sarrachomyeces cervesia by electroporation, Nucleic Acids Res 18:1313.
Reyes, 2002, Micro Total Analysis Systems. 1. Introduction, Theory and Technology, Anal Chem 74(12):2623-2636.
Riechmann, 1988, Reshaping human antibodies for therapy, Nature, 332:323-327.
Riess, 2002, Fluorous micro- and nanophases with a biomedical perspective, Tetrahedron 58(20):4113-4131.
Roach, 2005, Controlling nonspecific protein adsorption in a plug-based microfluidic system by controlling inteifacial chemistry using fluorous-phase surfactants, Anal. Chem. 77:785-796.
Roberts, 1969, Termination factor for RNA synthesis, Nature, 224: 1168-74.
Roberts, 1975, Simian virus 40 DNA directs synthesis of authentic viral polypeptides in a linked transcription- translation cell-free system 72(5):1922-1926.
Roberts, 1997, RNA-peptide fusion for the in vitro selection of peptides and proteins, PNAS 94:12297-302.
Roberts, 1999, In vitro selection of nucleic acids and proteins: What are we learning, Curr Opin Struct Biol 9(4): 521-9.
Roberts, 1999, Totally in vitro protein selection using mRNA-protein fusions and ribosome display. Curr Opin Chem Biol 3(3), 268-73.
Roche, 2011, 454 Sequencing System Guidelines for Amplicon Experimental Design, 50 pages.
Rodriguez-Antona, 2000, Quantitative RT-PCR measurement of human cytochrome p. 450s: application to drug induction studies. Arch. Biochem. Biophys., 376:109-116.
Rogers, 2005, Closing bacterial genoimc sequence gaps with adaptor-PCR, BioTechniques 39(1):1-3.
Rolland, 1985, Fluorescence Polarization Assay by Flow Cytometry, J. Immunol. Meth., 76(1): 1-10.
Rosenberg, 1975, Inhibition of Human Factor IX by Human Antithrombin, J Biol Chem, 250: 4755-64.
Rosenberry, 1975, Acetylcholinesterase, Adv Enzymol Relat Areas Mol Biol, 43: 103-218.
Rotman, 1961, Measurement of activities of single molecules of beta-galactosidase, PNAS, 47:1981-91.
Rouzioux, 2013, How to best measure HIV reservoirs, Curr Op Hiv Aids 8(3):170-175.
Russon et al., Single-nucleotide polymorphism analysis by allele-specific extension of fluorescently labeled nucleotides n a microfluidic flow-through device, Electrophoresis, 24:158-61 (2003).
Saarela, 2006, Re-usable multi-inlet PDMS fluidic connector, Sensors Actuators B 114(1):552-57.
Sadtler, 1996, Achieving stable, reverse water-in-fluorocarbon emulsions, Angew Chem Int Ed 35(17):1976-1978.
Sadtler, 1999, Reverse water-In-fluorocarbon emulsions as a drug delivery system: an in vitro study, Colloids & Surfaces A: Phys Eng Asp 147:309-315.
Saiki, 1988, Primer directed enzymatic amplification of DNA with a thermostable DNA polymerase, Science 239 (4839):487-91.
Bakamoto, 2005, Rapid and simple quantification of bacterial cells by using a microfluidic device, Appl Env Microb 71:2.
Kia, 1998, Soft Lithography, Ann. Rev. Mat. Sci. 28:153-184.
Xiao, 2007, Rapid DNA mapping by fluorescent single molecule detection, Nucleic Acids Research 35:1-12.
King, 2011, Novel structurally related compounds reactivate latent HIV-1 in a bcl-2-transduced primary CD4+ T cell model without inducing global T cell activation, Journal of Antimicrobial Chemotherapy, 67(2):398-403.
Ku, 2005, Generation of monodisperse particles by using microfluidics: control over size, shape, and composition, Angew. Chem. Int. Ed. 44:724-728.
Ku, 2009, Design of 240, 000 orthogonal 25mer DNA barcode probes, PNAS, 106(7) p. 2289-2294.
Yamagishi, 1990, Mutational analysis of structure-activity relationships in human tumor necrosis factor-alpha, Protein Eng, 3:713-9.
Yamaguchi, 2002, Insulin-loaded biodegradable PLGA microcapsules: initial burst release controlled by hydrophilic additives, Journal of Controlled Release, 81(3): 235-249.
Yelamos, 1995, Targeting of non-Ig sequences in place of the V segment by somatic hypermutation. Nature 376 (6537) 225-9.
Yershov, 1996, DNA analysis and diagnostics on oligonucleotide microchips, PNAS 93(10):4913-4918.
Yonezawa, 2003, DNA display for in vitro selection of diverse peptide libraries, Nucleic Acids Research, 31(19): e118, 6 pages.
Yu, 1997, Specific inhibition of PCR by non-extendable oligonucleotides using a 5' to 3' exonuclease- deficient DNA polymerase, Biotechniques 23(4):714-6, 718-20.
Yu, 2001, Responsive biomimetic hydrogel valve for microfluidics. Appl. Phys. Lett 78:2589-2591.
Yu, 2002, Environmental Carcinogenic Polycyclic Aromatic Hydrocarbons: Photochemisrty and Phototoxicity, J Environ Scie Health C Environ Carcinog Exotoxicol Rev, 20(2), 1-43.
Yu, 2007, Quantum dot and silica nanoparticle doped polymer optical fibers, Optics Express 15(16):9989-9994.
Zaccolo, 1996, An approach to random mutagenesis of DNA using mixtures of triphosphate derivatives of nucleoside analogues. J Mol Biol 255(4):589-603.
Zakrzewski, 1980, Preparation of tritiated dihydrofolic acid of high specific activity, Methods Enzymol, 529-533.
Zaug, 1986, The intervening sequence RNA of Tetrahymena is an enzyme, Science 231(4737):470-5.
Zaug, 1986, The Tetrahymena intervening sequence ribonucleic acid enzyme is a phosphotransferase and an acid phosphatase, Biochemistry 25(16):4478-82.
Zaug, 1986, The Tetrahymena ribozyme acts like an RNA restriction endonuclease, Nature 324(6096):429-33.
Zhang, 1993, Substrate specificity of the protein tyrosine phosphatases, PNAS 90: 4446-4450.
Zhang, 1999, A Simple Statistical Parameter for Use in Evaluation and Validation of High Throughput Screening Assays, Journal of Biomolecular Screening, 4(2): 67-73.
Zhao, 1998, Molecular evolution by staggered extension process (StEP) in vitro recombination. Nat Biotechnol 16 (3):258-61.
Zhao, 2002, Control and Applications of Immiscible Liquids in Microchannels, J. Am. Chem. Soc, vol. 124:5284-5285.
Zheng, 2003, Screening of Protein Crystallization Conditions on a Microfluidic Chip Using Nanoliter-Size Droplets, J Am Chem Soc 125(37):11170-11171.
Zheng, 2004, A Droplet-Based, Composite PDMS/Glass Capillary Microfluidic System for Evaluating Protein Crystallization Conditions by Microbatch and Vapor-Diffusion Methods with On-Chip X-Ray Diffraction, Angew. Chem., 116:1-4.
Zheng, 2004, Formation of Droplets of Alternating Composition in Microfluidic Channels and Applications to Indexing of Concentrations in Droplet-Based /Assays, Anal. Chem., 76: 4977-4982.
Zheng, 2005, A Microiuidic Approach for Screening Submicroliter vols. against Multiple Reagents by Using Performed Arrays of Nanoliter Plugs in a Three-Phase Liquid/Liquid/Gas Flow, Angew. Chem. Int. Ed., 44(17): 2520-2523.
Zhong, 2011, Multiplex digital PCR: breaking the one target per color barrier of quantitative PCR, Lab on a Chip 11 (13):2167-2174.
Zimmermann, 1974, Dielectric Breakdown of Cell Membranes, Biophys J 14(11):881-889.
Zimmermann, 1992, Microscale Production of Hybridomas by Hypo-Osmolar Electrofusion, Hum. Antibod. Hybridomas, 3(1): 14-18.
Zimmermann, 2008, Digital PCR: a powerful new tool for noninvasive prenatal diagnosis?, Prenat Diagn 28, 1087-1093.
Zubay, 1973, In vitro synthesis of protein in microbial systems, Annu Rev Genet, 7: 267-87.
Zubay, 1980, The isolation and properties of CAP, the catabolite gene activator, Methods Enzymol, 65: 856-77.
Zuckermann, 1987, Efficient Methods for Attachment of Thiol-Specific Probes to the 3-end of Synthetic Oligodeoxyribonucleotides, Nucleic Acids Res. 15:5305-5321.
Cortesi et al., Production of lipospheres as carriers for bioactive compounds, Biomateials, 23(11): 2283-2294 (2002).
Courrier et al., Reverse water-in-fluorocarbon emulsions and microemulsions obtained with a fluorinated surfactant, Colloids and Surfaces A: Physicochem. Eng. Aspects 244:141-148 (2004).
Craig, D. et al., Fluorescence-based enzymatic assay by capillary electrophoresis laser-induced fluoresence detection for the determinination of a few alpha-galactosidase molecules, Anal. Biochem. 226:147 (1995).
Creagh, A.L. et al., Structural and catalytic properties of enzymes in reverse micelles, Enzyme Microb Technol 15 (5):383-92 (1993).
Crosland-Taylor, A Device for Counting Small Particles suspended in a Fluid through a Tube, Nature 171:37-38 (1953).
Crowley, J. M., Electrical breakdown of bimolecular lipid membranes as an electromechanical instability, Biophys J. 13 (7):711-724 (1973).
Cull, M.G. et al., Screening for receptor ligands using large libraries of peptides linked to the C terminus of the lac repressor, PNAS 89:1865-9 (1992).
Curran, D.P., Strategy-level separations in organic synthesis: from planning to practice. Angew Chem Int Ed, 37:1174-11-96 (1998).
Czarnik, A.W., Encoding methods for combinatorial chemistry, Curr Opin Chem Biol 1:60-66 (1997).
Dankwardt et al., Combinatorial synthesis of small-molecule libraries using 3-amino-5-hydroxybenzoic acid, 1:113-120 (1995).
Davis, J.A. et al., Deterministic hydrodynamics: Taking blood apart, PNAS 103:14779-14784 (2006).
Davis, S.S. et al., Multiple emulsions as targetable delivery systems, Methods in Enzymology, 149:51-64 (1987).
De Gans, B.J. et al., Inkjet printing of polymers: state of the art and future developments, Advanced materials, 16: 203-213 (2004).
De-Bashan, L. E. et al., Removal of ammonium and phosphorus ions from synthetic wastewater by the microalgae Chlorella vulgaris coimmobilized in alginate beads with the microalgae growth-promoting bacterium Azospirillum brasilense, Water Research 36:2941-2948 (2002).
Delagrave, S. et al., Red-shifted excitation mutants of the green fluorescent protein, Biotechnology 13(2):151-4 (1995).
Delraso, In vitro methodologies for enhanced toxicity testing, Toxicol. Lett. 68:91-99 (1993).
Demartis et al., A strategy for the isolation of catalytic activities from repertoires of enzymes displayed on phage, J. Mol. Biol 286:617-633 (1999).
Dickinson, E., Emulsions and droplet size control, Wedlock, D.J., Ed., in Controlled Particle Droplet and Bubble Formulation, ButterWorth-Heine-mann, 191-257 (1994).
Dimatteo, et al., Genetic conversion of an SMN2 gene to SMN1: A novel approach to the treatment of spinal muscular atrophy, Exp Cell Res. 314(4):878-886 (2008).
Dinsmore et al., Colioidosomes: Selectively Permeable Capsules Composed of Colloidal Particles, Science 298 (5595):1006-1009. (2002).
Dittrich et al., A new embedded process for compartmentalized cell-free protein expression and on-line detection in microfluidic devices, Chembiochem 6(5):811-814 (2005).
Doi et al., In vitro selection of restriction endonucleases by in vitro compartmentilization, Nucleic Acids Res, 32(12): 295 (2004).
Doi, N. and Yanagawa, H. Stable: protein-DNA fusion system for screening of combinatorial protein libraries in vitro, FEBS Lett., 457: 227-230 (1999).
Doman, T.N. et al., Molecular docking and high-throughput screening for novel inhibitors of protein tyrosine phosphatase-1B, J Med Chem, 45: 2213-2221 (2002).
Domling A., Recent advances in isocyanide-based multicomponent chemistry, Curr Opin Chem Biol, 6(3):306-13 (2002).
Domling and Ugi, Multicomponent Reactions with Isocyanides, Angew Chem Int Ed 39(18):3168-3210 (2000).
Dove et al., In Brief, Nature Biotechnology 20:1213 (2002).
Dower et al., High efficiency transformation of E. coli by high voltage electroporation, Nucleic Acids Res 16:6127-6145 (1988).
Dressman et al., Transforming single DNA molecules into fluorescent magnetic particles for detection and enumeration of genetic variations, PNAS 100:8817-22 (2003).
Dreyfus et al., Ordered and disordered patterns in two phase flows in microchannels, Phys Rev Lett 90 (14):144505-1-144505-4 (2003).
Drmanac, 1992, Sequencing by hybridization: towards an automated sequencing of one million M13 clones arrayed on membranes, Elctrophoresis 13:566-573.
Dubertret et al., In vivo imaging of quantum dots encapsulated in phospholipid micelles, Science, 298: 1759-1762 (2002).
Duffy et al., Rapid Protyping of Microfluidic Systems and Polydimethylsiloxane, Anal Chem 70:474-480 (1998).
Duggleby, R. G. Analysis of Enzyme Progress Curves by Nonlinear Regression, Pt D. Academic Press 249:61-90 (1995).
Dumas, D.P., Purification and properties of the phosphotriesterase from Psuedomonas diminuta, J Biol Chem 264: 19659-19665 (1989).
Eckert and Kunkel, DNA polymerase fidelity and the polymerase chain reaction, Genome Res 1:17-24 (1991).
Edd et al., Controlled encapsulation of single-cells into monodisperse picolitre drops, Lab Chip 8(8):1262-1264 (2008).
Del, Joshua B et al., Microfluidic Routes to the Controlled Production of Nanopaticles, Chemical Communications, 1136-1137 (2002).
Edris et al., Encapsulation of orange oil in a spray dried double emulsion, Nahrung/Food, 45(2):133-137 (2001).
Effenhauser et al., Glass chips for high-speed capillary electrophoresis separations with submicrometer plate heights, Anal Chem 65:2637-2642 (1993).
Eggers, Jens et al., Coalescence of Liquid Drops, J. Fluid Mech., 401:293-310 (1999).
Ehrig, T. et al., Green-fluorescent protein mutants with altered fluorescence excitation spectra, Febs Lett, 367 (2):163-66 (1995).
Eigen et al., Hypercycles and compartments: compartments assists - but does not replace - hypercyclic organization of early genetic information, J Theor Biol, 85:407-11 (1980).
Eigen et al., The hypercycle: coupling of RNA and protein biosynthesis in the infection cycle of an RNA bacteriophage, Biochemistry, 30:11005-18 (1991).
Eigen, Wie entsteht information Prinzipien der selbstorganisation in der biologie, Berichte der punsen-gesellschaft fur physikalische chemi, 80:1059-81 (1976).
Ellington and Szostak, In vitro selection of RNA molecules that bind specific ligands, Nature, 346:818-822 (1990).
Ellman et al., Biosynthetic method for introducing unnatural amino acids site-specifically into proteins, Methods Enzymol, 202:301-36 (1991).
Endo et al. Kinetic determination of trace cobalt by visual autocatalytic indication, Talanta 47:349-353 (1998).
Endo et al., Autocatalytic decomposition of cobalt complexes as an indicator system for the determination of trace amounts of cobalt and effectors, Analyst 121:391-394 (1996).
Eow et al., Electrocoalesce-separators for the separation of aqueous drops from a flowing dielectric viscous liquid, Separation and Purification Tech 29:63-77 (2002).
Wilson, D.S. and Szostak, J.W., In vitro selection of functional nucleic acids, Ann. Rev. Biochem. 68: 611-647 (1999).
Winter et al., Making antibodies by phage display technology, Annu Rev Immunol 12:433-55 (1994).
Wittrup, K.D., Protein engineering by cell-surface display. Curr Opin Biotechnology, 12: 395-399 (2001).
Wolff et al., Integrating advanced functionality in a microfabricated high-throughput fluorescent-activated cell sorter, ab Chip, 3(1): 22-27 (2003).
Wronski et al., Two-color, fluorescence-based microplate assay for apoptosis detection. Biotechniques, 32:666-668 (2002).
Wu et al., The ligation amplification reaction (LAR)-amplification of specific DNA sequences using sequential rounds of template-dependent ligation, Genomics 4(4):560-9 (1989).
Wyatt et al., Synthesis and purification of large amounts of RNA oligonucleotides, Biotechniques 11(6):764-9 (1991).
Kia and Whitesides, Soft Lithography, Angew. Chem. Int. Ed. 37:550-575 (1998).
Kia and Whitesides, Soft Lithography, Ann. Rev. Mat. Sci. 28:153-184 (1998).
Ku et al., 2009, Design of 240,000 orthogonal 25mer DNA barcode probes, PNAS, Feb. 17, 2009, 106(7), pp. 2289-2294.
Xu, S. et al., Generation of monodisperse particles by using microfluidics: control over size, shape, and composition, Angew. Chem. Int. Ed. 44:724-728 (2005).
Yamagishi, J. et al., Mutational analysis of structure-activity relationships in human tumor necrosis factor-alpha, Protein Eng, 3:713-9 (1990).
Yamaguchi et al., Insulin-loaded biodegradable PLGA microcapsules: initial burst release controlled by hydrophilic additives, Journal of Controlled Release, 81(3): 235-249 (2002).
Yelamos, J. et al., Targeting of non-Ig sequences in place of the V segment by somatic hypermutation. Nature 376 (6537):225-9 (1995).
Yershov et al., DNA analysis and diagnostics on oligonucleotide microchips, PNAS 93(10):4913-4918 (1996).
Yu et al. Responsive biomimetic hydrogel valve for microfluidics. Appl. Phys. Lett 78:2589-2591 (2001).
Yu et al., Quantum dot and silica nanoparticle doped polymer optical fibers, Optics Express 15(16):9989-9994 (2007).
Yu et al., Specific inhibition of PCR by non-extendable oligonucleotides using a 5′ to 3′ exonuclease- deficient DNA polymerase, Biotechniques 23(4):714-6, 718-20 (1997).
Zaccolo, M. et al., An approach to random mutagenesis of DNA using mixtures of triphosphate derivatives of nucleoside analogues. J Mol Biol 255(4):589-603 (1996).
Zakrzewski, S.F., Preparation of tritiated dihydrofolic acid of high specific activity, Methods Enzymol, 539 (1980).
Zaug and Cech, The intervening sequence RNA of Tetrahymena is an enzyme, Science 231(4737):470-5 (1986).
Zaug and Cech, The Tetrahymena intervening sequence ribonucleic acid enzyme is a phosphotransferase and an acid phosphatase, Biochemistry 25(16):4478-82 (1986).
Zaug et al., The Tetrahymena ribozyme acts like an RNA restriction endonuclease, Nature 324(6096):429-33 (1986).
Zhang et al., A Simple Statistical Parameter for Use in Evaluation and Validation of High Throughput Screening Assays, Journal of Biomolecular Screening, 4(2): 67-73 (1999).
Zhang, Z.Y., Substrate specificity of the protein tyrosine phosphatases, PNAS 90: 4446-4450 (1993).
Zhao, B. et al., Control and Applications of Immiscible Liquids in Microchannels, J. Am. Chem. Soc, vol. 124:5284-5285 (2002).
Zhao, H. et al., Molecular evolution by staggered extension process (StEP) in vitro recombination. Nat Biotechnol 16 (3):258-61 (1998).
Zheng et al., A Droplet-Based, Composite PDMS/Glass Capillary Microfluidic System for Evaluating Protein Crystallization Conditions by Microbatch and Vapor-Diffusion Methods with On-Chip X-Ray Diffraction, Angew. Chem., 116:1-4, (2004).
Zheng et al., A Microiuidic Approach for Screening Submicroliter vols. against Multiple Reagents by Using Performed Arrays of Nanoliter Plugs in a Three-Phase Liquid/Liquid/Gas Flow, Angew. Chem. Int. Ed., 44(17): 2520-2523 (2005).
Zheng et al., Formation of Droplets of Alternating Composition in Microfluidic Channels and Applications to Indexing of Concentrations in Droplet-Based /Assays, Anal. Chem., 76: 4977-4982 (2004).
Zheng et al., Screening of Protein Crystallization Conditions on a Microfluidic Chip Using Nanoliter-Size Droplets, J Am Chem Soc 125(37):11170-11171 (2003).
Zimmermann et al., Dielectric Breakdown of Cell Membranes, Biophys J 14(11):881-889 (1974).
Zimmermann et al., Microscale Production of Hybridomas by Hypo-Osmolar Electrofusion, Hum. Antibod. Hybridomas, 3(1): 14-18 (1992).
Zubay, G., In vitro synthesis of protein in microbial systems, Annu Rev Genet, 7: 267-87 (1973).
Zubay, G., The isolation and properties of CAP, the catabolite gene activator, Methods Enzymol, 65: 856-77 (1980).
Zuckermann, R et al., Efficient Methods for Attachment of Thiol-Specific Probes to the 3-end of Synthetic Oligodeoxyribonucleotides, Nucleic Acids Res. 15:5305-5321 (1987).
Cooper, 2000, The Central Role of Enzymes as Biological Catalysts, The Cell: A Molecular Approach, 2nd Edition, pp. 1-6.
Cormack, 1996, FACS-optimized mutants of the green fluorescent protein (GFP), Gene 173(1):33-38.
Cortesi, 2002, Production of lipospheres as carriers for bioactive compounds, Biomateials, 23(11): 2283-2294.
Courrier, 2004, Reverse water-in-fluorocarbon emulsions and microemulsions obtained with a fluorinated surfactant, Colloids and Surfaces A: Physicochem. Eng. Aspects 244:141-148.
Craig, 1995, Fluorescence-based enzymatic assay by capillary electrophoresis laser-induced fluoresence detection for the determinination of a few alpha-galactosidase molecules, Anal. Biochem. 226:147.
Creagh, 1993, Structural and catalytic properties of enzymes in reverse micelles, Enzyme Microb Technol 15 (5):383-92.
Crosland-Taylor, 1953, A Device for Counting Small Particles suspended in a Fluid through a Tube, Nature 171:37-38.
Crowley, 1973, Electrical breakdown of bimolecular lipid membranes as an electromechanical instability, Biophys J. 13 (7):711-724.
Cull, 1992, Screening for receptor ligands using large libraries of peptides linked to the C terminus of the lac repressor, PNAS 89:1865-9.
Curran, 1998, Strategy-level separations in organic synthesis: from planning to practice. Angew Chem Int Ed, 37:1174-11-96.
Czamik, 1997, Encoding methods for combinatorial chemistry, Curr Opin Chem Biol 1:60-66.
Dankwardt, 1995, Combinatorial synthesis of small-molecule libraries using 3-amino-5-hydroxybenzoic acid, 1:113-120.
David, 1974, Protein iodination with solid-state lactoperoxidase, Biochemistry 13:1014-1021.
Davis, 1987, Multiple emulsions as targetable delivery systems, Meth Enzymol 149:51-64.
Davis, 2006, Deterministic hydrodynamics: Taking blood apart, PNAS 103:14779-14784.
De Gans, 2004, Inkjet printing of polymers: state of the art and future developments, Advanced materials, 16: 203-213.
De Wildt, 2002, Isolation of receptor-ligand pairs by capture of long-lived multivalent interaction complexes, Proceedings of the National Academy of Sciences of the United States, 99, 8530-8535.
Delraso, 1993, In vitro methodologies for enhanced toxicity testing, Toxicol. Lett. 68:91-99.
Deng, 2008, Design and analysis of mismatch probes for long oligonucleotide microarrays, BMC Genomics; 9:491, 13 pages.
Dickinson, 1992, Interfacial interactions and the stability of oil-in-water emulsions, Pure Appl Chem 64(11):1721-1724.
Dickinson, 1994, Emulsions and droplet size control, Wedlock, D.J., Ed., in Controlled Particle Droplet and Bubble Formulation, ButterWorth-Heine-mann, 191-257.
Dimatteo, 2008, Genetic conversion of an SMN2 gene to SMN1: A novel approach to the treatment of spinal muscular atrophy, Exp Cell Res. 314(4):878-886.
Ding, 2001, Scheduling of microfluidic operations for reconfigurable two-dimensional electrowetting arrays, IEEE Trans CADICS 20(12):1463-1468.
Ding, 2003, Direct molecular haplotyping of long-range genomic DNA with M1-PCR, Proc. Natl. Acad. Sci. USA, 100 (33):7449-7453.
Dinsmore, 2002, Colioidosomes: Selectively Permeable Capsules Composed of Colloidal Particles, Science 298 (5595):1006-1009.
Dittrich, 2005, A new embedded process for compartmentalized cell-free protein expression and on-line detection in microfluidic devices, Chembiochem 6(5):811-814.
Doi, 1999, STABLE: protein-DNA fusion system for screening of combinatorial protein libraries in vitro, FEBS Lett., 457: 227-230.
Doi, 2004, In vitro selection of restriction endonucleases by in vitro compartmentilization, Nucleic Acids Res, 32(12): e95.
Doman, 2002, Molecular docking and high-throughput screening for novel inhibitors of protein tyrosine phosphatase-1B, J Med Chem, 45: 2213-2221.
Domling, 2000, Multicomponent Reactions with Isocyanides, Angew Chem Int Ed 39(18):3168-3210.
Domling, 2002, Recent advances in isocyanide-based multicomponent chemistry, Curr Opin Chem Biol, 6(3):306-13.
Dorfman, 2005, Contamination-free continuous flow microfluidic polymerase chain reaction for quantitative and clinical applications, Anal Chem 77:3700-3704.
Dove, 2002, Research News Briefs, Nature Biotechnology 20:1213, 1 page.
Dower, 1988, High efficiency transformation of E. coli by high voltage electroporation, Nucleic Acids Res 16:6127-6145.
Dressman, 2003, Transforming single DNA molecules into fluorescent magnetic particles for detection and enumeration of genetic variations, PNAS 100:8817-22.
Dreyfus, 2003, Ordered and disordered patterns in two phase flows in microchannels, Phys Rev Lett 90 (14):144505-1-144505-4.
Ormanac, 1992, Sequencing by hybridization: towards an automated sequencing of one million M13 clones arrayed on membranes, Elctrophoresis 13:566-573.
Du, 2009, SlipChip, Lab Chip, 9, 2286-2292.
Dubertret, 2002, In vivo imaging of quantum dots encapsulated in phospholipid micelles, Science, 298: 1759-1762.
Duffy, 1998, Rapid Protyping of Microfluidic Systems and Polydimethylsiloxane, Anal Chem 70:474-480.
Duggleby, 1995, Analysis of Enzyme Progress Curves by Nonlinear Regression, Pt D. Academic Press 249:61-90.
Dumas, 1989, Purification and properties of the phosphotriesterase from Psuedomonas diminuta, J Biol Chem 264: 19659-19665.
Eckert, 1991, DNA polymerase fidelity and the polymerase chain reaction, Genome Res 1:17-24.
Ecole Polytech Federale de Lausanne, 2014, Tracing water channels in cell surface receptors, PhysOrg News (2 pages).
Edel, 2002, Microfluidic Routes to the Controlled Production of Nanopaticles, Chemical Communications, 1136-1137.
Edris, 2001, Encapsulation of orange oil in a spray dried double emulsion, Nahrung/Food, 45(2):133-137.
Effenhauser, 1993, Glass chips for high-speed capillary electrophoresis separations with submicrometer plate heights, Anal Chem 65:2637-2642.
Eggers, 1999, Coalescence of Liquid Drops, J Fluid Mech 401:293-310.
Ehrig, 1995, Green-fluorescent protein mutants with altered fluorescence excitation spectra, Febs Lett, 367(2):163-66.
Eigen, 1980, Hypercycles and compartments: compartments assists - but does not replace - hypercyclic organization of early genetic information, J Theor Biol, 85:407-11.
Leng et al., 2010, “Agarose droplet microfluidics for highly parallel and efficient single molecule emulsion PCR,” Lab Chip, vol. 10, pp. 2841-2843.
Lesley et al., Use of in vitro protein synthesis from PCR-generated templates to study interaction of E coli transcription factors with core RNA polymerase, J Biol Chem 266(4):2632-8 (1991).
Lesley, S.A., Preparation and use of E. coli S-30 extracts, Methods Mol Biol, 37:265-78 (1995).
Leung et al., A method for random mutagenesis of a defined DNA segment using a modified polymerase chain reaction. Technique 1:11-15 (1989).
Li and Harrison, Transport, Manipulation, and Reaction of Biological Cells On-Chip Using Electrokinetic Effects, Analytical Chemistry 69(8): 1564-1568 (1997).
Li et al., 2005, “Multiplexed detection of pathogen DNA with DNA-based fluorescence nanobarcodes” , Nature Biotechnology 23(7):885-889.
Li et al., Nanoliter microfluidic hybrid method for simultaneous screening and optimization validated with crystallization of membrane proteins, PNAS 103: 19243-19248 (2006).
Li et al., Single-step procedure for labeling DNA strand breaks with fllourescein-or BODIPY-conjugated deoxynucleotides: detection of apoptosis and bromodeoxyuridine incorporation. Cytometry 20:172-180 (1995).
Liao et al., Isolation of a thermostable enzyme variant by cloning and selection in a thermophile, PNAS 83:576-80 1986).
Lim et al., Microencapsulated islets as bioartificial endocrine pancreas, Science 210(4472):908-10 (1980).
Lin et al., 2007, Self-Assembled Combinatorial Encoding Nanoarrays for Multiplexed Biosensing, Nano Letters, vol. 7, No. 2, pp. 507-512.
Link et al., Geometrically Mediated Breakup of Drops in Microfluidic Devices, Phys. Rev. Lett., 92(5): 054503-1 thru 054503-4 (2004).
Link et al., Electric control droplets in microfluidic devices, Angew Chem Int Ed 45:2556-2560 (2006).
Lipinski et al., Experimental and Computational Approaches to Estimate Solubility and Permeability in Drug Discovery and Development Settings ,Adv. Drug Deliv. Rev., 46:3-26 (2001).
Lipkin et al., Biomarkers of increased susceptibility to gastreointestinal cancer: new application to studies of cancer prevention in human subjects, Cancer Research 48:235-245 (1988).
Liu et al., Fabrication and characterization of hydrogel-based microvalves, Mecoelectromech. Syst. 11:45-53 (2002).
Liu et al., Passive Mixing in a Three-Dimensional Serpentine MicroChannel, J Mems 9(2):190-197 (2000).
Lizardi et al., Mutation detection and single-molecule counting using isothermal rolling-circle amplification. Nat Genet 19(3):225-32 (1998).
Loakes and Brown, 5-Nitroindole as a universal base analogue. Nucleic Acids Res 22: 4039-4043 (1994).
Loakes et al., Stability and structure of DNA oligonucleotides containing non-specific base analogues. J. Mol. Biol 270:426-435 (1997).
Loeker et al., Colloids and Surfaces A: Physicochem. Eng. Aspects 214:143-150, (2003).
Lopez-Herrera, et al., Coaxial jets generated from electrified Taylor cones. Scaling laws, Aerosol Science, 34:535-552 (2003).
Lopez-Herrera, et al., One-Dimensional Simulation of the Breakup of Capillary Jets of Conducting Liquids Application to .H.D. Spraying, Aerosol. Set, 30 (7): 895-912 (1999).
Lopez-Herrera, et al., The electrospraying of viscous and non-viscous semi-insulating liquids. Scalilng laws, Bulletin of the American Physical Society,40 (12):2041(1995).
Lorenceau et al., Generation of Polymerosomes from Double-Emulsions, Langmuir, 21(20): 9183-9186 (2005).
Lorenz et al., Isolation and expression of a cDNA encoding Renilla reniformis luciferase, PNAS 88(10):4438-42 (1991).
Loscertales, et al., Micro/Nano Encapsulation via Electrified Coaxial Liquid Jets, Science, 295(5560): 1695-1698 (2002).
Low N.M et al., Mimicking somatic hypermutaion: affinity maturation of antibodies displayed on bacteriophage using a bacterila mutator strain. J Mol Biol 260(3), 359-68 (1996).
Lowe, K.C., Perfluorochemical respiratory gas carriers: benefits to cell culture systems, J Fluorine Chem 118:19-26 (2002).
Lowman et al., Selecting high affinity binding proteins by monovalent phage display, Biochemistry 30(45):10832-8 1991).
Lu et al., Robust fluorescein-doped silica nanoparticles via dense-liquid treatment, Colloids and Surfaces A Physicachemical and Engineering Aspects, 303(3):207-210 (2007).
Luisi et al., Activity and Conformation of Enzymes in Reverse Micellar Solutions, Meth. Enzymol 136:188-216 (1987).
Lund et al., Assesment of methods for covalent binding of nucleic acids to magnetic beads, Dynabeads, and the characteristics of the bound nucleic acids in hybridization reactions, Nucleic Acids Research, Oxford University Press, 16(22) (1998).
Lunderberg et al., Solid-phase technology: magnetic beads to improve nucleic acid detection and analysis, Biotechnology Annual Review, 1:373-401 (1995).
Lndstrom, et al., Breakthrough in cancer therapy: Encapsulation of drugs and viruses, www.currentdrugdiscovery.com. 19-23, Nov. 2002.
Lyne, P.D., Structure-Based Virtual Screening: An Overview, Drug Discov. Today, 7(20):1047-1055 (2002).
Ma, C. et al., In vitro protein engineering using synthetic tRNA(Ala) with different anticodons, Biochemistry 32 (31):7939-45 (1993).
Mackenzie et al., The application of flow microfluorimetry to biomedical research and diagnosis: a review, Dev Biol Stand 64:181-193 (1986).
Mackenzie, IABS Symposium on Reduction of Animal Usage in the Development and Control of Biological Products, ondon, UK, 1985.
Maclean, D. et al., Glossary of terms used in combinatorial chemistry, Pure Appl. Chem. 71(12):2349-2365 (1999).
Magdassi et al., Multiple Emulsions: HLB Shift Caused by Emulsifier Migration to External Interface, J. Colloid Interface Sci 97:374-379 (1984).
Mahajan et al., Bcl-2 and Bax Interactions in Mitochondria Probed with Green Florescent Protein and Fluorescence Resonance Energy Transfer, Nat. Biotechnol. 16(6): 547-552 (1998).
Manley et al., In vitro transcription: whole cell extract, Methods Enzymol, 101:568-82 (1983).
Manz et al., Micromachining of monocrystalline silicon and glass for chemical analysis systems A look into next century's technology or just a fashionable craze, Trends in Analytical Chemistry 10(5):144-149 (1991).
Mao et al., Kinetic behaviour of alpha-chymotrypsin in reverse micelles: a stopped-flow study, Eur J Biochem 208 (1):165-70 (1992).
Mao, Q. et al., Substrate effects on the enzymatic activity of alphachymotrypsin in reverse micelles, Biochem Biophys Res Commun, 178(3):1105-12 (1991).
Mardis, E.R., The impact of next-generation sequencing technology on genetics, Trends Genet 24:133-141 (2008).
Margulies, M. et al., Genome sequencing in microfabricated high-density picolitre reactors, Nature 437(7057):376-380 (2005).
Marques et al., Porous Flow within Concentric Cylinders, Bull Am Phys Soc Div Fluid Dyn 41:1768 (1996).
Mason, T.J. and Bibette, J. Shear Rupturing of Droplets in Complex Fluids, Langmuir, 13(17):4600-4613 (1997).
Cantor, 2003, Direct molecular haplotyping of long-range genomic DNA with M1-PCR; Pnas 100(13):7449-7453.
Finettie, 2015, Thesis, Novel Functional Hydrophilic Polymers and Hydrogels for Microanalytical Systems, Universita Degli Studi Di Milano, 203 pages.
Segawa, 1992, Selective amplification of cDNA sequence from total RNA by cassette ligation mediated polymerase chain reaction (PCR): Application to sequencing 6-5 kb genome segment of hantavirus strain B-1, Molecular and Cellular Probes, 6:467-475.
Lee, 2003, Miniaturization of polymerase chain reacton, Biotechnology and Bioprocess Engineering, 8.4:213-220.
Maenaka, 2008, Continuous and size-dependent sorting of emulsion droplets using hydrodynamics in pinched microchannels, Langmuir, 24.8:4405-4410.
Mueller, 1992, Thermotropic Aqueous Gels and Solutions of N,N-Dimethylacrylamide-acrylate Copolymers, Polymer, 33(1):3470-3476.
Pamme, 2007, Continuous flow separations in microfluidic devices, Lab on a Chip, 1644-1659.
Pooley, 2010, Hydrogels From Acrylic Acid with N,N-Dimethylacrylamide: Synthesis, Characterization, and Water Absorption Properties, J. Chil. Chem. Soc. 55(1):19-24.
Smith, 1996, Environmental Degradation of Polyacrylamides, 1. Effects of Artificial Environmental Conditions: Temperature, Light and pH, Ecotoxicology and Environmental Safety, 35:121-135.
Takagi, 2005, Continuous particle separation in a microchannel having asymmetrically arranged multiple branches, lab on a Chip, 5.7:778-784.
Tan, 2005, Microfluidic separation of satellite droplets as the basis of a monodispersed micron and submicron emulsification system, Lab on a Chip, 5.10, 1178-1183.
Wang, 2010, Single cell analysis: the new frontier in ‘omics’, Trends Biotech 28:281-290.
Zhou, 2001, Counting alleles reveals a connection between chromosome 18q loss and vascular invasion, Nat Biotechnol 19(1):78-81.
Curcio, 2003, Continuous Segmented-Flow Polymerase Chain Reaction for High-Throughput Miniaturized DNA Amplification, Anal Chem 75(1):1-7.
Flanagan, 2004, Fab Antibody Fragments: Some Applications in Clinical Toxicology, Drug Safety, 27(14):1115-1133.
Hutter, 2005, Detection of proteinases in Saccharomyces cervisiae by flow cytometry, J Inst Brewing 111(1):26-32.
Kohara, 2002, DNA probes on beads arrayed in a capillary, Nucleic Acids Research 30:e87.
Kuhlmann, 2009, Fixation of biological specimens, Division of Radiooncology, Germany, 12 pages.
Obeid, 2003, Continuous-flow DNA and RNA amplification chip combined with laser-induced fluorescence detection, Anal Chimica Acta 494(1-2):1-9.
Viswanathan, 2019, DNA Analysis by Restriction Enzyme (DARE) enables concurrent genomic and epigenomic characterization of single cells, Nucleic Acids Research, 47(19), e122.
Weaver, 1997, Gel microdrop technology for rapid isolation of rare and high producer cells, Nat Med 3(5):583-585.
Related Publications (1)
Number Date Country
20200270600 A1 Aug 2020 US
Provisional Applications (2)
Number Date Country
61476714 Apr 2011 US
61444612 Feb 2011 US
Continuations (4)
Number Date Country
Parent 16400858 May 2019 US
Child 16795467 US
Parent 14995744 Jan 2016 US
Child 16400858 US
Parent 14874553 Oct 2015 US
Child 14995744 US
Parent 13398677 Feb 2012 US
Child 14874553 US