Patent Application
20200392567
The present application is filed with a Sequence Listing in electronic ASCII format. The Sequence Listing is provided as a file entitled “2020-06-23_01149-0013-00US_Seq_List_ST25.txt” created on Jun. 23, 2020, which is 40,960 bytes in size. The information in the electronic ASCII format of the sequence listing is incorporated herein by reference in its entirety.
Developing general cell-based functional assays for small and large molecule screening is highly challenging. Cell-based functional assays typically rely upon the use of fluorescence or luminescence so that the cells can be screened using handling platforms and high content imaging or luminescence readouts. Generally, the functional assays seek to test the effect of a perturbation on how cells react or function. The perturbation is typically a library of small molecule agents or a large molecule biologics, and the assay typically involves measure signaling pathway changes, enzyme kinetics, cell growth or various other types of cellular function. Measuring changes in a signaling pathway or gene network is usually accomplished by building a surrogate reporter cell line that turns on or off a luciferase or fluorescent molecule when a specific pathway is activated, thus signaling a certain function. Building such a reporter cell line is very time consuming and is hard to generalize, and thus a unique set of cells must be built for each function tested.
Measuring changes in mRNA gene networks or proteins by RNA-seq, microarray, PCR, in situ hybridization or “in cell RNA-seq” in response to a perturbation would be an ideal generalized method. The advent of genome amplification techniques and next generation sequencing methods have led to breakthroughs in our ability to sequence the genome and transcriptome of individual biological cells and small populations of cells. These breakthroughs provide us with new tools for studying cellular behavior, providing for functional assays that rely upon analysis of transcriptome and/or genome sequencing results. To date, such methods are not routinely used because the cost of reagents is prohibitively high. For example, building an RNA-seq library is very costly from a reagent standpoint when testing a set of 1000s, 10,000s, 100,000s, or 1,000,000s of molecules/perturbation agents. Thus, a need exists for general cell-based functional assays that are not excessively costly.
Disclosed herein are methods for assaying a biological cell, e.g., to detect changes in transcription following contacting the cell with a test agent. In one aspect, the methods comprise contacting a biological cell with a test agent for a period of time, wherein the biological cell is disposed within a sequestration pen located within an enclosure of a microfluidic device; lysing said biological cell and allowing RNA molecules released from said lysed biological cell to be captured by a plurality of capture oligonucleotides, wherein: the capture oligonucleotides are comprised by a comprised by a capture object disposed within said sequestration pen, and each capture oligonucleotide of the plurality comprises: a priming sequence that binds a primer, and a capture sequence; wherein the capture oligonucleotides are configured to become covalently associated with a plurality of cDNAs upon transcription of the captured RNA molecules. The methods may further comprise transcribing said captured RNA molecules, thereby producing a plurality of cDNAs decorating said capture object, each cDNA comprising an oligonucleotide sequence complementary to a corresponding one of said captured RNA molecules, wherein the complementary oligonucleotide sequence is covalently linked to one of said plurality of capture oligonucleotides. The methods may further comprise comprising generating sequence from said plurality of cDNAs decorating said capture object. The methods may further comprise analyzing said generated sequence to detect a change in transcription of one or more genes of said biological cell associated with contacting said biological cell with said test substance for said period of time.
In another aspect, the methods comprise disposing a biological cell within a sequestration pen located within an enclosure of a microfluidic device; contacting the biological cell with a test agent for a period of time; disposing a capture object within the sequestration pen, the capture object having a plurality of capture oligonucleotides, each having a capture sequence and a priming sequence that binds a primer; lysing the biological cell and allowing RNA molecules released from the lysed biological cell to be captured by the capture oligonucleotides of the capture object; transcribing the captured RNA molecules to produce a plurality of cDNAs attached to the capture object, each cDNA having an oligonucleotide sequence complementary to a corresponding one of the captured RNA molecules, with the complementary oligonucleotide sequence being covalently linked to one of the plurality of capture oligonucleotides; generating sequence from the plurality of cDNAs decorating the capture object; and analyzing the generated sequence to detect a change in transcription of one or more genes of the biological cell associated with contacting the biological cell with the test substance for the period of time.
In certain embodiments, analyzing the generated sequence to detect a change in transcription includes comparing the generated sequence to sequence obtained from one or more control biological cells.
In another aspect, one of the methods for assaying a biological cell using sequence data derived from a cDNA library (RNA-seq), as disclosed herein, is combined with phenotypic data obtained from the biological cell while it is resident in the microfluidic device (e.g., a sequestration pen of the microfluidic device). The phenotypic data can be secretion data (e.g., cytokine secretion data), cell-surface staining, live/dead staining, DNA and/or chromosomal staining, and the like.
In another aspect, a combination of a first capture object and a second capture object is provided, wherein: the first capture object comprises a first plurality of cDNAs decorating the capture object, each cDNA of the first plurality comprising an oligonucleotide sequence complementary to a captured RNA molecule from a first cell; the second capture object comprises a second plurality of cDNAs decorating the capture object, each cDNA of the second plurality comprising an oligonucleotide sequence complementary to a captured RNA molecule from a second cell; the first cell was contacted with a test agent under a first condition before preparing cDNA therefrom; the second cell was, before preparing cDNA therefrom: (i) not contacted with the test agent or (ii) contacted with the test agent under a second condition different from the first condition; and the level of at least one cDNA differs in the first plurality of cDNAs and the second plurality of cDNAs.
In certain embodiments, the one or more genes that are analyzed for (or detected as having) a change in transcription, or the at least one cDNA differs in the first plurality of cDNAs and the second plurality of cDNAs, include one or more oncogenes and/or one or more tumor suppressor genes, or cDNAs thereof. In other embodiments, the one or more genes that are analyzed for (or detected as having) a change in transcription, or the at least one cDNA differs in the first plurality of cDNAs and the second plurality of cDNAs, include one or more genes involved in cell cycle progression and/or circadian rhythms, or cDNAs thereof. In other embodiments, one or more genes that are analyzed for (or detected as having) a change in transcription, or the at least one cDNA differs in the first plurality of cDNAs and the second plurality of cDNAs, include one or more genes involved in programmed cell death, or cDNAs thereof. In other embodiments, one or more genes that are analyzed for (or detected as having) a change in transcription, or the at least one cDNA differs in the first plurality of cDNAs and the second plurality of cDNAs, include one or more genes involved in maintaining developmental plasticity, or cDNAs thereof. In still other embodiments, one or more genes that are analyzed for (or detected as having) a change in transcription, or the at least one cDNA differs in the first plurality of cDNAs and the second plurality of cDNAs, include one or more genes comprise one or more genes involved in cellular differentiation, such as neural differentiation, endothelial differentiation, cardiac differentiation, muscle differentiation, liver differentiation, fat differentiation, bone differentiation, bone marrow differentiation, immunological differentiation, skin differentiation, gut differentiation, or the like; or cDNAs thereof.
In certain embodiments, the biological cell is from a cell line. In other embodiments, the biological cell is a primary cell. For example, the biological cell can be an immune cell, a cancer cell, a stem cell, a progenitor cell, or an embryonic cell. With respect to the disclosed combinations of capture objects, the first and second cells may be any of the foregoing. In certain embodiments, the biological cell is a single biological cell (e.g., a single biological cell in a sequestration pen). In other embodiments, disposing the biological cell within the sequestration pen includes disposing a plurality (e.g., 2 or more, 2 to 10, 3 to 8, 4 to 6, or the like) of biological cells within the sequestration pen.
These and other features and advantages of the disclosed methods will be set forth or will become more fully apparent in the description that follows and in the appended claims. The features and advantages may be realized and obtained by means of the objects and combinations particularly pointed out in the appended examples, partial listing of embodiments, and claims. Furthermore, the features and advantages of the described methods may be learned by the practice or will be obvious from the description, as set forth hereinafter.
This specification describes exemplary embodiments and applications of the disclosure. The disclosure, however, is not limited to these exemplary embodiments and applications or to the manner in which the exemplary embodiments and applications operate or are described herein. Moreover, the figures may show simplified or partial views, and the dimensions of elements in the figures may be exaggerated or otherwise not in proportion. In addition, as the terms “on,” “attached to,” “connected to,” “coupled to,” or similar words are used herein, one element (e.g., a material, a layer, a substrate, etc.) can be “on,” “attached to,” “connected to,” or “coupled to” another element regardless of whether the one element is directly on, attached to, connected to, or coupled to the other element or there are one or more intervening elements between the one element and the other element. Also, unless the context dictates otherwise, directions (e.g., above, below, top, bottom, side, up, down, under, over, upper, lower, horizontal, vertical, “x,” “y,” “z,” etc.), if provided, are relative and provided solely by way of example and for ease of illustration and discussion and not by way of limitation. In addition, where reference is made to a list of elements (e.g., elements a, b, c), such reference is intended to include any one of the listed elements by itself, any combination of less than all of the listed elements, and/or a combination of all of the listed elements. Section divisions in the specification are for ease of review only and do not limit any combination of elements discussed.
Where dimensions of microfluidic features are described as having a width or an area, the dimension typically is described relative to an x-axial and/or y-axial dimension, both of which lie within a plane that is parallel to the substrate and/or cover of the microfluidic device. The height of a microfluidic feature may be described relative to a z-axial direction, which is perpendicular to a plane that is parallel to the substrate and/or cover of the microfluidic device. In some instances, a cross sectional area of a microfluidic feature, such as a channel or a passageway, may be in reference to a x-axial/z-axial, a y-axial/z-axial, or an x-axial/y-axial area.
It should be noted that, as used in this specification and the appended claims, the singular form “a”, “an” and “the” include plural references unless the context clearly dictates otherwise. Thus, for example, reference to “a cDNA” includes a plurality of cDNAs, reference to “a cell” includes a plurality of cells, and the like.
Numeric ranges are inclusive of the numbers defining the range. Measured and measurable values are understood to be approximate, taking into account significant digits and the error associated with the measurement. Also, the use of “comprise”, “comprises”, “comprising”, “contain”, “contains”, “containing”, “include”, “includes”, and “including” are not intended to be limiting. It is to be understood that both the foregoing general description and detailed description are exemplary and explanatory only and are not restrictive of the teachings.
Unless specifically noted in the above specification, embodiments in the specification that recite “comprising” various components are also contemplated as “consisting of” or “consisting essentially of” the recited components; embodiments in the specification that recite “consisting of” various components are also contemplated as “comprising” or “consisting essentially of” the recited components; and embodiments in the specification that recite “consisting essentially of” various components are also contemplated as “consisting of” or “comprising” the recited components (this interchangeability does not apply to the use of these terms in the claims).
The section headings used herein are for organizational purposes only and are not to be construed as limiting the desired subject matter in any way. In the event that any literature incorporated by reference contradicts any term defined in this specification, this specification controls.
As used herein, “substantially” means sufficient to work for the intended purpose. The term “substantially” thus allows for minor, insignificant variations from an absolute or perfect state, dimension, measurement, result, or the like such as would be expected by a person of ordinary skill in the field but that do not appreciably affect overall performance. When used with respect to numerical values or parameters or characteristics that can be expressed as numerical values, “substantially” means within ten percent.
The term “ones” means more than one.
“Or” is used in the inclusive sense, i.e., equivalent to “and/or,” unless the context requires otherwise.
As used herein, the term “plurality” can be 2, 3, 4, 5, 6, 7, 8, 9, 10, or more.
As used herein: μm means micrometer, μm3 means cubic micrometer, pL means picoliter, nL means nanoliter, and μL (or uL) means microliter.
As used herein, the term “disposed” encompasses within its meaning “located”; and the term “disposing” encompasses within its meaning “placing.”
As used herein, a “microfluidic device” or “microfluidic apparatus” is a device that includes one or more discrete microfluidic circuits configured to hold a fluid, each microfluidic circuit comprised of fluidically interconnected circuit elements, including but not limited to region(s), flow path(s), channel(s), chamber(s), and/or pen(s), and at least one port configured to allow the fluid (and, optionally, micro-objects suspended in the fluid) to flow into and/or out of the microfluidic device. Typically, a microfluidic circuit of a microfluidic device will include a flow region, which may include a microfluidic channel, and at least one chamber, and will hold a volume of fluid of less than about 1 mL, e.g., less than about 750, 500, 250, 200, 150, 100, 75, 50, 25, 20, 15, 10, 9, 8, 7, 6, 5, 4, 3, or 2 μL. In certain embodiments, the microfluidic circuit holds about 1-2, 1-3, 1-4, 1-5, 2-5, 2-8, 2-10, 2-12, 2-15, 2-20, 5-20, 5-30, 5-40, 5-50, 10-50, 10-75, 10-100, 20-100, 20-150, 20-200, 50-200, 50-250, or 50-300 μL. The microfluidic circuit may be configured to have a first end fluidically connected with a first port (e.g., an inlet) in the microfluidic device and a second end fluidically connected with a second port (e.g., an outlet) in the microfluidic device.
As used herein, a “nanofluidic device” or “nanofluidic apparatus” is a type of microfluidic device having a microfluidic circuit that contains at least one circuit element configured to hold a volume of fluid of less than about 1 μL, e.g., less than about 750, 500, 250, 200, 150, 100, 75, 50, 25, 20, 15, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1 nL or less. A nanofluidic device may comprise a plurality of circuit elements (e.g., at least 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 50, 75, 100, 150, 200, 250, 300, 400, 500, 600, 700, 800, 900, 1000, 1500, 2000, 2500, 3000, 3500, 4000, 4500, 5000, 6000, 7000, 8000, 9000, 10,000, or more). In certain embodiments, one or more (e.g., all) of the at least one circuit elements is configured to hold a volume of fluid of about 100 pL to 1 nL, 100 pL to 2 nL, 100 pL to 5 nL, 250 pL to 2 nL, 250 pL to 5 nL, 250 pL to 10 nL, 500 pL to 5 nL, 500 pL to 10 nL, 500 pL to 15 nL, 750 pL to 10 nL, 750 pL to 15 nL, 750 pL to 20 nL, 1 to 10 nL, 1 to 15 nL, 1 to 20 nL, 1 to 25 nL, or 1 to 50 nL. In other embodiments, one or more (e.g., all) of the at least one circuit elements are configured to hold a volume of fluid of about 20 nL to 200 nL, 100 to 200 nL, 100 to 300 nL, 100 to 400 nL, 100 to 500 nL, 200 to 300 nL, 200 to 400 nL, 200 to 500 nL, 200 to 600 nL, 200 to 700 nL, 250 to 400 nL, 250 to 500 nL, 250 to 600 nL, or 250 to 750 nL.
A microfluidic device or a nanofluidic device may be referred to herein as a “microfluidic chip” or a “chip”; or “nanofluidic chip” or “chip”.
A “microfluidic channel” or “flow channel” as used herein refers to flow region of a microfluidic device having a length that is significantly longer than both the horizontal and vertical dimensions. For example, the flow channel can be at least 5 times the length of either the horizontal or vertical dimension, e.g., at least 10 times the length, at least 25 times the length, at least 100 times the length, at least 200 times the length, at least 500 times the length, at least 1,000 times the length, at least 5,000 times the length, or longer. In some embodiments, the length of a flow channel is about 100,000 microns to about 500,000 microns, including any value therebetween. In some embodiments, the horizontal dimension is about 100 microns to about 1000 microns (e.g., about 150 to about 500 microns) and the vertical dimension is about 25 microns to about 200 microns, (e.g., from about 40 to about 150 microns). It is noted that a flow channel may have a variety of different spatial configurations in a microfluidic device, and thus is not restricted to a perfectly linear element. For example, a flow channel may be, or include one or more sections having, the following configurations: curve, bend, spiral, incline, decline, fork (e.g., multiple different flow paths), and any combination thereof. In addition, a flow channel may have different cross-sectional areas along its path, widening and constricting to provide a desired fluid flow therein. The flow channel may include valves, and the valves may be of any type known in the art of microfluidics. Examples of microfluidic channels that include valves are disclosed in U.S. Pat. Nos. 6,408,878 and 9,227,200, each of which is herein incorporated by reference in its entirety.
As used herein, the term “obstruction” refers generally to a bump or similar type of structure that is sufficiently large so as to partially (but not completely) impede movement of target micro-objects between two different regions or circuit elements in a microfluidic device. The two different regions/circuit elements can be, for example, the connection region and the isolation region of a microfluidic sequestration pen.
As used herein, the term “constriction” refers generally to a narrowing of a width of a circuit element (or an interface between two circuit elements) in a microfluidic device. The constriction can be located, for example, at the interface between the isolation region and the connection region of a microfluidic sequestration pen of the instant disclosure.
As used herein, the term “transparent” refers to a material which allows visible light to pass through without substantially altering the light as is passes through.
As used herein, the term “micro-object” refers generally to any microscopic object that may be isolated and/or manipulated in accordance with the present disclosure. Non-limiting examples of micro-objects include: inanimate micro-objects such as microparticles; microbeads (e.g., polystyrene beads, Luminex™ beads, or the like); magnetic beads; microrods; microwires; quantum dots, and the like; biological micro-objects such as cells; biological organelles; vesicles, or complexes; synthetic vesicles; liposomes (e.g., synthetic or derived from membrane preparations); lipid nanorafts, and the like; or a combination of inanimate micro-objects and biological micro-objects (e.g., microbeads attached to cells, liposome-coated micro-beads, liposome-coated magnetic beads, or the like). Beads may include moieties/molecules covalently or non-covalently attached, such as detectable labels, proteins, carbohydrates, antigens, small molecule signaling moieties, or other chemical/biological species capable of use in an assay. Lipid nanorafts have been described, for example, in Ritchie et al. (2009) “Reconstitution of Membrane Proteins in Phospholipid Bilayer Nanodiscs,” Methods Enzymol., 464:211-231.
As used herein, the term “cell” is used interchangeably with the term “biological cell.” Non-limiting examples of biological cells include eukaryotic cells, plant cells, animal cells, such as mammalian cells, reptilian cells, avian cells, fish cells, or the like, prokaryotic cells, bacterial cells, fungal cells, protozoan cells, or the like, cells dissociated from a tissue, such as muscle, cartilage, fat, skin, liver, lung, neural tissue, and the like, immunological cells, such as T cells, B cells, natural killer cells, macrophages, and the like, embryos (e.g., zygotes), oocytes, ova, sperm cells, hybridomas, cultured cells, cells from a cell line, cancer cells, infected cells, transfected and/or transformed cells, reporter cells, and the like. A mammalian cell can be, for example, from a human, a mouse, a rat, a horse, a goat, a sheep, a cow, a primate, or the like.
A colony of biological cells is “clonal” if all of the living cells in the colony that are capable of reproducing are daughter cells derived from a single parent cell. In certain embodiments, all the daughter cells in a clonal colony are derived from the single parent cell by no more than 10 divisions. In other embodiments, all the daughter cells in a clonal colony are derived from the single parent cell by no more than 14 divisions. In other embodiments, all the daughter cells in a clonal colony are derived from the single parent cell by no more than 17 divisions. In other embodiments, all the daughter cells in a clonal colony are derived from the single parent cell by no more than 20 divisions. The term “clonal cells” refers to cells of the same clonal colony.
As used herein, a “colony” of biological cells refers to 2 or more cells (e.g. about 2 to about 20, about 4 to about 40, about 6 to about 60, about 8 to about 80, about 10 to about 100, about 20 to about 200, about 40 to about 400, about 60 to about 600, about 80 to about 800, about 100 to about 1000, or greater than 1000 cells).
As used herein, the term “maintaining (a) cell(s)” refers to providing an environment comprising both fluidic and gaseous components and, optionally a surface, that provides the conditions necessary to keep the cells viable and/or expanding.
As used herein, the term “expanding” when referring to cells, refers to increasing in cell number.
A “component” of a fluidic medium is any chemical or biochemical molecule present in the medium, including solvent molecules, ions, small molecules, antibiotics, nucleotides and nucleosides, nucleic acids, amino acids, peptides, proteins, sugars, carbohydrates, lipids, fatty acids, cholesterol, metabolites, or the like.
As used herein, “capture moiety” is a chemical or biological species, functionality, or motif that provides a recognition site for a micro-object. A selected class of micro-objects may recognize the in situ-generated capture moiety and may bind or have an affinity for the in situ-generated capture moiety. Non-limiting examples include antigens, antibodies, and cell surface binding motifs.
As used herein, “B” used to denote a single nucleotide, is a nucleotide selected from G (guanosine), C (cytidine) and T (thymidine) nucleotides but does not include A (adenine).
As used herein, “H” used to denote a single nucleotide, is a nucleotide selected from A, C and T, but does not include G.
As used herein, “D” used to denote a single nucleotide, is a nucleotide selected from A, G, and T, but does not include C.
As used herein, “V” used to denote a single nucleotide, is a nucleotide selected from A, G, and C, and does not include T.
As used herein, “N” used to denote a single nucleotide, is a nucleotide selected from A, C, G, and T.
As used herein, “S” used to denote a single nucleotide, is a nucleotide selected from G and C.
As used herein, “Y” used to denote a single nucleotide, is a nucleotide selected from C and T.
As used herein, A, C, T, G followed by “*” indicates phosophorothioate substitution in the phosphate linkage of that nucleotide.
As used herein, IsoG is isoguanosine; IsoC is isocytidine; IsodG is a isoguanosine deoxyribonucleotide and IsodC is a isocytidine deoxyribonucleotide. Each of the isoguanosine and isocytidine ribo- or deoxyribo-nucleotides contain a nucleobase that is isomeric to the guanine nucleobase or cytosine nucleobase, respectively, usually incorporated within RNA or DNA.
As used herein, rG denotes a ribonucleotide included within a nucleic acid otherwise containing deoxyribonucleotides. A nucleic acid containing all ribonucleotides may not include labeling to indicated that each nucleotide is a ribonucleotide, but is made clear by context.
As used herein, a “priming sequence” is an oligonucleotide sequence which is part of a larger oligonucleotide and, when separated from the larger oligonucleotide such that the priming sequence includes a free 3′ end, can function as a primer in a DNA (or RNA) polymerization reaction.
As used herein, “antibody” refers to an immunoglobulin (Ig) and includes both polyclonal and monoclonal antibodies; primatized (e.g., humanized); murine; mouse-human; mouse-primate; and chimeric; and may be an intact molecule, a fragment thereof (such as scFv, Fv, Fd, Fab, Fab′ and F(ab)′2 fragments), or multimers or aggregates of intact molecules and/or fragments; and may occur in nature or be produced, e.g., by immunization, synthesis or genetic engineering. An “antibody fragment,” as used herein, refers to fragments, derived from or related to an antibody, which bind antigen and which in some embodiments may be derivatized to exhibit structural features that facilitate clearance and uptake, e.g., by the incorporation of galactose residues. This includes, e.g., F(ab), F(ab)′2, scFv, light chain variable region (VL), heavy chain variable region (VH), and combinations thereof.
An antigen, as referred to herein, is a molecule or portion thereof that can bind with specificity to another molecule, such as an Ag-specific receptor. Antigens may be capable of inducing an immune response within an organism, such as a mammal (e.g., a human, mouse, rat, rabbit, etc.), although the antigen may be insufficient to induce such an immune response by itself. An antigen may be any portion of a molecule, such as a conformational epitope or a linear molecular fragment, and often can be recognized by highly variable antigen receptors (B-cell receptor or T-cell receptor) of the adaptive immune system. An antigen may include a peptide, polysaccharide, or lipid. An antigen may be characterized by its ability to bind to an antibody's variable Fab region. Different antibodies have the potential to discriminate among different epitopes present on the antigen surface, the structure of which may be modulated by the presence of a hapten, which may be a small molecule.
In some embodiments, an antigen is a cancer cell-associated antigen. The cancer cell-associated antigen can be simple or complex; the antigen can be an epitope on a protein, a carbohydrate group or chain, a biological or chemical agent other than a protein or carbohydrate, or any combination thereof; the epitope may be linear or conformational.
The cancer cell-associated antigen can be an antigen that uniquely identifies cancer cells (e.g., one or more particular types of cancer cells) or is upregulated on cancer cells as compared to its expression on normal cells. Typically, the cancer cell-associated antigen is present on the surface of the cancer cell, thus ensuring that it can be recognized by an antibody. The antigen can be associated with any type of cancer cell, including any type of cancer cell that can be found in a tumor known in the art or described herein. In particular, the antigen can be associated with lung cancer, breast cancer, melanoma, and the like. As used herein, the term “associated with a cancer cells,” when used in reference to an antigen, means that the antigen is produced directly by the cancer cell or results from an interaction between the cancer cell and normal cells.
As used herein in reference to a fluidic medium, “diffuse” and “diffusion” refer to thermodynamic movement of a component of the fluidic medium down a concentration gradient.
The phrase “flow of a medium” means bulk movement of a fluidic medium primarily due to any mechanism other than diffusion. For example, flow of a medium can involve movement of the fluidic medium from one point to another point due to a pressure differential between the points. Such flow can include a continuous, pulsed, periodic, random, intermittent, or reciprocating flow of the liquid, or any combination thereof. When one fluidic medium flows into another fluidic medium, turbulence and mixing of the media can result.
The phrase “substantially no flow” refers to a rate of flow of a fluidic medium that, averaged over time, is less than the rate of diffusion of components of a material (e.g., an analyte of interest) into or within the fluidic medium. The rate of diffusion of components of such a material can depend on, for example, temperature, the size of the components, and the strength of interactions between the components and the fluidic medium.
As used herein in reference to different regions within a microfluidic device, the phrase “fluidically connected” means that, when the different regions are substantially filled with fluid, such as fluidic media, the fluid in each of the regions is connected so as to form a single body of fluid. This does not mean that the fluids (or fluidic media) in the different regions are necessarily identical in composition. Rather, the fluids in different fluidically connected regions of a microfluidic device can have different compositions (e.g., different concentrations of solutes, such as proteins, carbohydrates, ions, or other molecules) which are in flux as solutes move down their respective concentration gradients and/or fluids flow through the microfluidic device.
As used herein, a “flow path” refers to one or more fluidically connected circuit elements (e.g. channel(s), region(s), chamber(s) and the like) that define, and are subject to, the trajectory of a flow of medium. A flow path is thus an example of a swept region of a microfluidic device. Other circuit elements (e.g., unswept regions) may be fluidically connected with the circuit elements that comprise the flow path without being subject to the flow of medium in the flow path.
As used herein, “isolating a micro-object” confines a micro-object to a defined area within the microfluidic device.
A microfluidic (or nanofluidic) device can comprise “swept” regions and “unswept” regions. As used herein, a “swept” region is comprised of one or more fluidically interconnected circuit elements of a microfluidic circuit, each of which experiences a flow of medium when fluid is flowing through the microfluidic circuit. The circuit elements of a swept region can include, for example, regions, channels, and all or parts of chambers. As used herein, an “unswept” region is comprised of one or more fluidically interconnected circuit element of a microfluidic circuit, each of which experiences substantially no flux of fluid when fluid is flowing through the microfluidic circuit. An unswept region can be fluidically connected to a swept region, provided the fluidic connections are structured to enable diffusion but substantially no flow of media between the swept region and the unswept region. The microfluidic device can thus be structured to substantially isolate an unswept region from a flow of medium in a swept region, while enabling substantially only diffusive fluidic communication between the swept region and the unswept region. For example, a flow channel of a microfluidic device is an example of a swept region while an isolation region (described in further detail below) of a microfluidic device is an example of an unswept region.
Transcription, as referred to herein, includes reverse transcription and is the process in which a particular segment of a nucleic acid molecule such as DNA or RNA is used by an enzyme (RNA polymerase in the case of DNA, or reverse transcriptase for RNA) as a template to synthesize a complementary sequence with a different backbone. During transcription of DNA, a DNA sequence is read by RNA polymerase, resulting in the production of complementary, anti-parallel RNA strand that includes the nucleotide uracil in place of thymine. During reverse transcription of RNA, an RNA sequence is read by reverse transcriptase resulting in the synthesis of a complementary DNA or cDNA.
Provided herein are methods of assaying a biological cell. In some embodiments, the methods comprise contacting a biological cell with a test agent for a period of time. The cell may be disposed within a sequestration pen located within an enclosure of a microfluidic device. In some embodiments, the methods comprise disposing the biological cell within a sequestration pen located within an enclosure of a microfluidic device. The biological cell, test agent, time period (and optionally other conditions), sequestration pens, and microfluidic devices may be any of those described herein.
In some embodiments, the methods comprise disposing a capture object within the sequestration pen, wherein the capture object comprises a plurality of capture oligonucleotides. In some embodiments, each capture oligonucleotide of the plurality comprises a priming sequence that binds a primer. In some embodiments, each capture oligonucleotide of the plurality comprises a capture sequence. In some embodiments, the methods comprise lysing the biological cell. In some embodiments, the methods comprise allowing RNA molecules released from the lysed biological cell to be captured by a plurality of capture oligonucleotides, e.g., comprised by a capture object. The capture object, capture oligonucleotides, priming sequence, capture sequence, and lysis procedures may be any of those described herein.
In some embodiments, the methods comprise transcribing RNA molecules captured by capture oligonucleotides. In some embodiments, a plurality of cDNAs decorating a capture object is produced. In some embodiments, each cDNA of such a plurality comprises an oligonucleotide sequence complementary to a corresponding captured RNA molecule, wherein the complementary oligonucleotide sequence is covalently linked to one of the plurality of capture oligonucleotides. Transcribing RNA molecules may be performed according to any appropriate procedure described herein.
In some embodiments, the methods comprise generating sequence from a plurality of cDNAs decorating a capture object. In some embodiments, the methods comprise analyzing the generated sequence to detect a change in transcription of one or more genes of the biological cell associated with contacting the biological cell with the test substance for the period of time. Generating and/or analyzing sequence may be performed according to any appropriate procedure described herein.
Where applicable, the disposing of the capture object, identifying of the barcode of the capture object, disposing the biological cell, lysing/transcribing/sequencing, and identifying the barcode sequence based upon the read sequence of methods disclosed herein can be performed in the order in which they are written or in other orders, with the limitation that the rearrangement of the order of these activities does not violate logical order (e.g., transcribing before lysing, and so on). As an example, in situ identification of the barcode sequence can be performed after introducing the biological cell into the sequestration pen, after lysing the biological cell, or after transcribing the captured nucleic acids. Likewise, the step of introducing the capture object into the sequestration pen can be performed after introducing the at least one biological cell into the sequestration pen.
Combinations of first and second capture objects are provided herein, e.g., which may be generated by certain embodiments of the methods of assaying a biological cell described herein. In some embodiments, the first capture object comprises a first plurality of cDNAs decorating the capture object, each cDNA of the first plurality comprising an oligonucleotide sequence complementary to a captured RNA molecule from a first biological cell. In some embodiments, the first cell was contacted with a test agent under a first condition before preparing cDNA therefrom. In some embodiments, the second capture object comprises a second plurality of cDNAs decorating the capture object, each cDNA of the second plurality comprising an oligonucleotide sequence complementary to a captured RNA molecule from a second biological cell. In some embodiments, the second cell was, before preparing cDNA therefrom: (i) not contacted with the test agent or (ii) contacted with the test agent under a second condition different from the first condition. The first and second biological cells, test agent, first condition, and second condition may be any of those described herein.
In various embodiments, the biological cell may be a single biological cell. Alternatively, the biological cell can be a plurality of biological cells, such as a clonal population. Biological cells include eukaryotic cells, plant cells, animal cells, such as mammalian cells, reptilian cells, avian cells, fish cells, or the like, or prokaryotic cells, bacterial cells, fungal cells, protozoan cells, or the like.
In some embodiments involving first and second biological cells, the first and second biological cells are of the same cell type (e.g., differentiation status). In some embodiments, the first and second biological cells are of the same biological species. In some embodiments, the first and second biological cells are isolated from the same subject, sample, or cell line. In some embodiments, the first and second biological cells are members of the same clonal population.
In some embodiments, the biological cell is from a cell line.
In some embodiments, the biological cell is a primary cell isolated from a tissue, such as blood, muscle, cartilage, fat, skin, liver, lung, neural tissue, and the like.
In some embodiments, the biological cell may be an immune cell, for example a T cell, B cell, NK cell, macrophage, dendritic cell, and the like.
In some embodiments, the biological cell may be a cancer cell, such as a melanoma cancer cell, breast cancer cell, neurological cancer cell, etc.
In other embodiments, the biological cell may be a stem cell (e.g., embryonic stem cell, induced pluripotent (iPS) stem cell, etc.) or a progenitor cell.
In yet other embodiments, the biological cell is an embryo (e.g., a zygote, a 2 to 200 cell embryo, a blastula, etc.), an oocyte, ovum, sperm cell, hybridoma, cultured cell, infected cell, transfected and/or transformed cell, or reporter cell.
In some embodiments, the biological cell may be contacted with labeled antibody prior to lysing. Such an antibody may specifically bind to surface antigens that are broadly expressed across multiple cell types (for example, CD45 marks leukocytes generally) or to a surface antigen that is cell-type specific (for example, CD19 marks B lymphocytes, CD8 marks cytotoxic T lymphocytes, and CD14 marks blood monocytes).
In some embodiments, the biological cell may be contacted with labeled antibody prior to lysing. The label may be a nucleic acid, for example RNA or DNA, that is covalently conjugated to the antibody. In some embodiments, the bond is labile or susceptible to breaking during the lysing step. Release of the label permits its capture on a capture object, and it can contribute to sequence data subsequently generated from captured material. As such, labeled antibodies specific for a given marker can provide signals about cells from which sequence data is generated, e.g., that the cell was positive for a given marker that was bound by the antibody. Alternatively or in addition, antibodies labeled with RNA or DNA can also be used to supply a barcode that is incorporated into sequencing data.
To examine the effect of a test agent on a biological cell, the biological cell is exposed to a test agent. The test agent may comprise a small molecule agent (e.g., molecular weight less than about 2000 Da or less than about 1000 Da) or a large molecule, such as a polynucleotide, polypeptide, lipid nanoparticle, liposome, a combination thereof, or the like. In some embodiments, the test agent is a drug or drug candidate. In some embodiments, the test agent is a signaling molecule, e.g., an agonist or antagonist of a receptor (which may be, e.g., a surface receptor or a nuclear receptor), a hormone, a chemokine, a cytokine, an interleukin, an interferon, or the like. In some embodiments, the test agent is an antigen, e.g., a viral antigen, a bacterial antigen, a fungal antigen, an autoantigen, or a tumor or cancer cell antigen. In some embodiments, the test agent is provided in solution, e.g., in or diluted in medium that is compatible with the biological cell used in the assay. The medium may or may not be supplemented with serum and other supplements if required by the biological cell.
In some embodiments, the biological cell is contacted with the test agent is added to the biological cell disposed within a sequestration pen for a period of time. The period of time may be, for example, 0.1-0.2 minutes, 0.2-0.5 minutes, 0.5-1 minutes, 1-2 minutes, 2-5 minutes, 5-10 minutes, 10-30 minutes, 30-60 minutes, 1-2 hours, 2-5 hours, 5-12 hours, 12-18 hours, 18-24 hours, 1-1.5 days, 1.5-2 days, 2-3 days, 3-5 days, 5-10 days, or 10-20 days. The effect of the test agent on the biological cell may then be interrogated by disposing a capture object within the sequestration pen to capture RNA from the biological cell and lysing the biological cell. RNA captured in this way can be reverse transcribed and sequenced. The generated sequence is analyzed to measure transcription of one or more genes of the biological cell in response to the test agent. In certain embodiments, analyzing the generated sequence to detect a change in transcription includes comparing the generated sequence to sequence obtained from one or more control biological cells, e.g., biological cells not treated with the test agent, treated with a control agent, or treated with the test agent under a control condition, such as a different concentration and/or different time period.
Other conditions such as the temperature during the contacting of the biological cell with the test agent; the atmospheric levels, for example, the level of CO2 or nitrogen in the environment; the pH; the percentage of serum or other supplements in the medium, including serum starvation and the like can be varied.
A. Capture Objects
A capture object may be of any suitable size, as long as it is small enough to pass through the flow channel(s) of the flow region and into/out of a sequestration pen of the microfluidic device with which it is being used, e.g., any microfluidic device as described herein. Further, the capture object may be selected to have a sufficiently large number of capture oligonucleotides linked thereto, such that nucleic acid may be captured in sufficient quantity to generate a nucleic acid library useful for sequencing. In some embodiments, the capture object may be a spherical or partially spherical bead and have a diameter greater than about 5 microns and less than about 40 microns. In some embodiments, the spherical or partially spherical bead may have a diameter of about 5, about 7, about 8, about 10, about 12, about 14, about 16, about 18, about 20, about 22, about 24, or about 26 microns.
In some embodiments, the capture object has a composition such that it is amenable to movement using a dielectrophoretic (DEP) force, such as a negative DEP force. For example, the capture object can be a bead (or similar object) having a core that includes a paramagnetic material, a polymeric material and/or glass. The polymeric material may be polystyrene or any other plastic material which may be functionalized to link the capture oligonucleotide. The core material of the capture object may be coated to provide a suitable material to attach linkers to the capture oligonucleotide, which may include functionalized polymers, although other arrangements are possible. The linkers used to link the capture oligonucleotides to the capture object may be any suitable linker as is known in the art. The linker may include hydrocarbon chains, which may be unsubstituted or substituted, or interrupted or non-interrupted with functional groups such as amide, ether or keto-groups, which may provide desirable physicochemical properties. The linker may have sufficient length to permit access by processing enzymes to priming sites near the end of the capture oligonucleotide linked to the linker. The capture oligonucleotides may be linked to the linker covalently or non-covalently, as is known in the art. A nonlimiting example of a non-covalent linkage to the linker may be via a biotin/streptavidin pair.
In some embodiments, capture objects comprise capture oligonucleotides, which comprise a priming sequence, a capture sequence, and optionally a barcode sequence as discussed in detail below. Some exemplary, but not limiting capture objects are illustrated in Table 2, where only one capture oligonucleotide is shown, for clarity. Capture objects including a priming sequence, a barcode, a UMI and a capture sequence for capturing RNA may be a capture object having SEQ ID No. 97, SEQ ID No. 98, SEQ ID No. 99, or SEQ ID No. 100. A capture object including a priming sequence, a barcode, a UMI, a Not1 sequence, and a capture sequence for capturing RNA may be a capture object having SEQ ID NO. 101 or SEQ ID NO. 102.
A plurality of capture objects. A plurality of capture objects is provided for use in multiplex nucleic acid capture. Each capture object of the plurality is a capture object according to any capture object described herein, where, for each capture object of the plurality, each capture oligonucleotide of that capture object has the same barcode sequence, and wherein the barcode sequence of the capture oligonucleotides of each capture object of the plurality is different from the barcode sequence of the capture oligonucleotides of every other capture object of the plurality. In some embodiments, the plurality of capture objects may include at least 256 capture objects. In other embodiments, the plurality of capture objects may include at least 10,000 capture objects. A schematic showing the construction of a plurality of capture objects is shown in
Barcode 525 of the capture oligonucleotide is 3′ to the priming sequence, and contains 4 cassetable sequences 435a, 435b, 435c, and 435d, which each are 10 bp in length. Each capture oligonucleotide of the plurality of capture oligonucleotides 550 of on a single capture object 630 has an identical barcode 525, and the barcode 525 for the plurality of capture objects are different for each of the capture object 630 of the plurality. The diversity of the barcodes 525 for each of the capture objects may be obtained by making the selection for the cassetable oligonucleotides from defined sets of oligonucleotides as described below. In this example, 10, 000 different barcodes can be made by choosing one of each of the four defined sets of oligonucleotides, each of which contain 10 different possible choices.
Method for producing a capture object. A method is also provided for producing a capture object having a plurality of capture oligonucleotides, including: chemically linking each of the plurality of capture oligonucleotides to the capture object, wherein each capture oligonucleotide of the plurality includes: a priming sequence which binds to a primer; a capture sequence (e.g., configured to hybridize with a target nucleic acid); and a barcode sequence, wherein the barcode sequence includes three or more cassetable oligonucleotide sequences, each cassetable oligonucleotide sequence being non-identical to the other cassetable oligonucleotide sequences of the barcode sequence; and wherein each capture oligonucleotide of the plurality comprises the same barcode sequence.
In various embodiments, the capture object may be a bead. For example, the capture object can be a bead (or similar object) having a core that includes a paramagnetic material, a polymeric material and/or glass. The polymeric material may be polystyrene or any other plastic material which may be functionalized to link the capture oligonucleotide. The core material of the capture object may be coated to provide a suitable material to attach linkers to the capture oligonucleotide, which may include functionalized polymers, although other arrangements are possible.
In various embodiments, linking may include covalently linking each of the plurality of capture oligonucleotides to the capture object. Alternatively, each of the plurality of capture oligonucleotides may be non-covalently linked to the bead, which may be via a streptavidin/biotin linkage. The barcoded beads may be synthesized in any suitable manner as is known in the art. The priming sequence/Unique molecular identifier tag/Cell Barcode/primer sequence may be synthesized by total oligonucleotide synthesis, split and pool synthesis, ligation of oligonucleotide segments of any length, or any combination thereof.
Each capture oligonucleotide of the plurality may include a 5′-most nucleotide and a 3′-most nucleotide, where the priming sequence may be adjacent to or comprises the 5′-most nucleotide, where the capture sequence may be adjacent to or comprises the 3′-most nucleotide, and where the barcode sequence may be located 3′ to the priming sequence and 5′ to the capture sequence.
In various embodiments, the three or more cassetable oligonucleotide sequences of each barcode sequence may be linked in tandem without any intervening oligonucleotide sequences. In some other embodiments, the one or more of the cassetable oligonucleotides may be linked to another cassetable oligonucleotide sequence via intervening one or two nucleotides to permit linking via ligation chemistry.
In various embodiments, the method may further include: introducing each of the three or more cassetable oligonucleotide sequences into the capture oligonucleotides of the plurality via a split and pool synthesis.
In various embodiments of the method of producing a capture object, each cassetable oligonucleotide sequence may include about 6 to 15 nucleotides, and may include about 10 nucleotides.
In various embodiments, the method may further include: selecting each of the three or more cassetable oligonucleotide sequences of each barcode sequence from a set of 12 to 100 non-identical cassetable oligonucleotide sequences. In some embodiments, the method may include selecting each of the three or more cassetable oligonucleotides sequences of each barcode sequence from SEQ ID NOs: 1-40.
In some embodiments, the cell-associated barcode sequence may include four cassetable oligonucleotide sequences. In various embodiments, the method may include selecting: a first cassetable oligonucleotide sequence from any one of SEQ ID NOs: 1-10; selecting a second cassetable oligonucleotide sequence from any one of SEQ ID NOs: 11-20; selecting a third cassetable oligonucleotide sequence from any one of SEQ ID NOs: 21-30; and selecting a fourth cassetable oligonucleotide sequence from any one of SEQ ID NOs: 31-40.
In various embodiments of the method of producing a capture object, the when separated from said capture oligonucleotide, primes a DNA polymerase. In some embodiments, the DNA polymerase is a reverse transcriptase. In some embodiments, the priming sequence comprises a sequence of a P7 or P5 primer.
In some embodiments, the method may further include: introducing a unique molecule identifier (UMI) sequence into each capture oligonucleotide of the plurality, such that each capture oligonucleotide of the plurality includes a different UMI. The UMI may be an oligonucleotide sequence comprising 5 to 20 nucleotides (e.g., 8 to 15 nucleotides).
In various embodiments of the method of producing a capture object, the capture sequence may include a poly-dT sequence, a random hexamer, or a mosaic end sequence.
In various embodiments of the method of producing a capture object, the method may further include: introducing the primer sequence into each capture oligonucleotide of the plurality near a 5′ end of the capture oligonucleotide; and, introducing the capture sequence into each capture oligonucleotide of the plurality near a 3′ end of the capture oligonucleotide. In some embodiments, the method may further include: introducing the barcode sequence into each capture oligonucleotide of the plurality after introducing the priming sequence and before introducing the capture sequence.
In some embodiments, the method may further include: introducing the UMI into each capture oligonucleotide of the plurality after introducing the priming sequence and before introducing the capture sequence. In yet other embodiments, the method may further include: introducing a sequence comprising a Not1 restriction site into each capture oligonucleotide of the plurality. In some embodiments, the method may further include: introducing the sequence comprising the Not1 restriction site after introducing the barcode sequence and before introducing the capture sequence.
In various embodiments of the method of producing a capture object, the method may further include: introducing one or more adapter sequences into each capture oligonucleotide of the plurality.
B. Capture Oligonucleotides
In various embodiments, the capture object may include a plurality of capture oligonucleotides. Each of said plurality may include: a priming sequence, e.g., which is a primer binding sequence; and a capture sequence. Each capture oligonucleotide comprises a 5′-most nucleotide and a 3′-most nucleotide. In various embodiments, the priming sequence may be adjacent to or comprises said 5′-most nucleotide. In various embodiments, the capture sequence may be adjacent to or comprises said 3′-most nucleotide. In some embodiments, the capture oligonucleotide comprises a barcode sequence. In some embodiments, the barcode sequence is located 3′ to the priming sequence and 5′ to the capture sequence. In some embodiments, the barcode sequence comprises a plurality of (e.g., three or more) cassetable oligonucleotide sequences, each cassetable oligonucleotide sequence being non-identical to the other cassetable oligonucleotide sequences of barcode sequence.
In some embodiments, each capture oligonucleotide attached to a capture object has the same barcode sequence, and in many embodiments, each capture object has a unique barcode sequence. Using capture beads having unique barcodes on each capture bead permits unique identification of the sequestration pen into which the capture object is placed. In experiments where a plurality of cells is placed within sequestration pens, often singly, a plurality of capture objects are also delivered and placed into the occupied sequestration pens, one capture bead per sequestration. Each of the plurality of capture beads has a unique barcode, and the barcode is non-identical to any other barcode of any other capture present within the microfluidic device. As a result, the cell (or, in some embodiments, cells) within the sequestration pen, will have a unique barcode identifier incorporated within its sequencing library.
In another embodiment, a capture oligonucleotide sequence may be used to capture nucleic acid released from a cell, by shepherding recognizable end sequences through recombinase/polymerase directed strand extension to effectively “capture” appropriately tagged released nucleic acid, to thereby add sequencing adaptors, barcodes, and indices. Examples of this type of capture oligonucleotide sequence includes a mosaic end (ME) sequence or other tagmentation insert sequence, as is known in the art. A mosaic end insert sequence is a short oligonucleotide that is easily recognized by transposons and can be used to provide priming/tagging to nucleic acid fragments. A suitable oligonucleotide sequence for this purpose may contain about 8 nucleotides to about 50 nucleotides. In some embodiments, ME plus additional insert sequence may be about 33 nucleotides long, and may be inserted by use of commercially available tagmentation kits, such as Nextera DNA Library Prep Kit, Illumina, Cat. #15028212, and the like. Nextera kits were designed to prepare libraries from genomic DNA; however, with minor modifications, the technology can be adapted for cDNA library preparation. For example, a random-primed method is used to synthesize first-strand cDNA from polyadenylated (poly(A)+) mRNA. Following second-strand synthesis, double-strand (ds) cDNA is used as input for the Nextera “tagmentation” (fragmentation and tagging) reaction. In this embodiment, the capture performed by the capture sequence is not a hybridization event but a shepherding and directing interaction between the capture oligonucleotide, the tagged cDNA, and the recombinase/polymerase machinery to the priming sequence(s), barcode sequence and any other indices, adaptors, or functional sites such as, but not limited to a Not1 restriction site sequence (as discussed below), onto the tagmented cDNA fragment. The shepherding and directing interaction provides an equivalent product to the cDNA product described above using a hybridization interaction to capture released nucleic acids. In both cases, an augmented nucleic acid fragment is provided from the released nucleic acid, which now includes at least sequencing adaptor(s) and the barcode, permitting amplification, further sequencing library adaptation, and the ability to obtain sequenced barcode and sample nucleic acid reads.
C. Priming and Other/Additional Sequences
The capture oligonucleotide of the capture object has a priming sequence, and the priming sequence may be adjacent to or comprises the 5′-most nucleotide of the capture oligonucleotide(s). The priming sequence may be a generic or a sequence-specific priming sequence. The priming sequence may bind to a primer that, upon binding, primes a reverse transcriptase or a polymerase. In some embodiments, the generic priming sequence may bind to a P7 (5′-CAAGCAGAAGACGGCATACGAGAT-3′ (SEQ ID. NO 107)) or a P5 (5′-CAAGCAGAAGACGGCATACGAGAT-3′ (SEQ ID NO. 108)) primer.
In other embodiments, the generic priming sequence may bind to a primer having a sequence of one of the following:
Additional priming and/or adaptor sequences. The capture oligonucleotide(s) may optionally have one or more additional priming/adaptor sequences, which either provide a landing site for primer extension or a site for immobilization to complementary hybridizing anchor sites within a massively parallel sequencing array or flow cell.
Optional oligonucleotide sequences. Each capture oligonucleotide of the plurality of capture oligonucleotides may optionally further include a unique molecule identifier (UMI) sequence. Each capture oligonucleotide of the plurality may have a different UMI from the other capture oligonucleotides of a capture object, permitting identification of unique captures as opposed to numbers of amplified sequences. In some embodiments, the UMI may be located 3′ to the priming sequence and 5′ to the capture sequence. The UMI sequence may be an oligonucleotide having about 5 to about 20 nucleotides. In some embodiments, the oligonucleotide sequence of the UMI sequence may have about 10 nucleotides.
In some embodiments, each capture oligonucleotide of the plurality of capture oligonucleotides may also include a Not1 restriction site sequence (GCGGCCGC, SEQ ID NO. 160). The Not1 restriction site sequence may be located 5′ to the capture sequence of the capture oligonucleotide. In some embodiments, the Not1 restriction site sequence may be located 3′ to the barcode sequence of the capture oligonucleotide.
In other embodiments, each capture oligonucleotide of the plurality of capture oligonucleotides may also include additional indicia such as a pool Index sequence. The Index sequence is a sequence of 4 to 10 oligonucleotides which uniquely identify a set of capture objects belonging to one experiment, permitting multiplex sequencing combining sequencing libraries from several different experiments to save on sequencing run cost and time, while still permitting deconvolution of the sequencing data, and correlation back to the correct experiment and capture objects associated therein.
D. Primers
The capture oligonucleotide of the capture object has a priming sequence, and the priming sequence may be adjacent to or comprises the 5′-most nucleotide of the capture oligonucleotide(s). The priming sequence may be a generic or a sequence-specific priming sequence. The priming sequence may bind to a primer that, upon binding, primes reverse transcriptase.
In other embodiments, the generic priming sequence may bind to a primer having a sequence of one of the following:
E. Capture Sequences
The capture oligonucleotide includes a capture sequence configured to capture RNA. The capture sequence is an oligonucleotide sequence having from about 6 to about 50 nucleotides. In some embodiments, the capture oligonucleotide sequence captures RNA by hybridizing to RNA released from a cell of interest. One non-limiting example includes polyT sequences, (having about 30 to about 40 nucleotides) which can capture and hybridize to RNA fragments having PolyA at their 3′ ends. The polyT sequence may further contain two nucleotides VN at its 3′ end. Other examples of capture oligonucleotides include random hexamers (“randomers”) which may be used in a mixture to hybridize to and thus capture complementary nucleic acids. Alternatively, complements to gene specific sequences may be used for targeted capture of nucleic acids, such as B cell receptor or T cell receptor sequences.
In some embodiments, the capture sequence of one or more (which can be each) of the plurality of capture oligonucleotides may include an oligo-dT primer sequence. In other embodiments, the capture sequence of one or more (e.g., each) of the plurality of capture oligonucleotides may include a gene-specific primer sequence. In some embodiments, the gene-specific primer sequence may target (or may bind to) an mRNA sequence encoding a T cell receptor (TCR) (e.g., a TCR alpha chain or TCR beta chain, particularly a region of the mRNA encoding a variable region or a region of the mRNA located 3′ but proximal to the variable region). In other embodiments, the gene-specific primer sequence may target (or may bind to) an mRNA sequence encoding a B-cell receptor (BCR) (e.g., a BCR light chain or BCR heavy chain, particularly a region of the mRNA encoding a variable region or a region of the mRNA located 3′ but proximal to the variable region).
In various embodiments, the capture sequence of one or more (e.g., all or substantially all) of the plurality of capture oligonucleotides may bind to one of the released RNA and primes the released RNA, thereby allowing a polymerase (e.g., reverse transcriptase) to transcribe the captured RNA.
F. Barcode Sequence.
The barcode sequence may include two or more (e.g., 2, 3, 4, 5, or more) cassetable oligonucleotide sequences, each of which is non-identical to the other cassetable oligonucleotide sequences of the barcode sequence. A barcode sequence is “non-identical” to other barcode sequences in a set when the n (e.g., three or more) cassetable oligonucleotide sequences of any one barcode sequence in the set of barcode sequences do not completely overlap with the n′ (e.g., three or more) cassetable oligonucleotide sequences of any other barcode sequence in the set of barcode sequences; partial overlap (e.g., up to n−1) is permissible, so long as each barcode sequence in the set is different from every other barcode sequence in the set by a minimum of 1 cassetable oligonucleotide sequence. In certain embodiments, the barcode sequence consists of (or consists essentially of) two or more (e.g., 2, 3, 4, 5, or more) cassetable oligonucleotide sequences. As used herein, a “cassetable oligonucleotide sequence” is an oligonucleotide sequence that is one of a defined set of oligonucleotide sequences (e.g., a set of 12 or more oligonucleotide sequences) wherein, for each oligonucleotide sequence in the defined set, the complementary oligonucleotide sequence (which can be part of a hybridization probe, as described elsewhere herein) does not substantially hybridize to any of the other oligonucleotide sequences in the defined set of oligonucleotide sequences. In certain embodiments, all (or substantially all) of the oligonucleotide sequences in the defined set will have the same length (or number of nucleotides). For example, the oligonucleotides sequences in the defined set can all have a length of 10 nucleotides. However, other lengths are also suitable for use in the present invention, ranging from about 6 nucleotides to about 15 nucleotides. Thus, for example, each oligonucleotide sequence in the defined set, for substantially all oligonucleotide sequences in the defined set, can have a length of 6 nucleotides, 7 nucleotides, 8 nucleotides, 9 nucleotides, 10 nucleotides, 11 nucleotides, 12 nucleotides, 13 nucleotides, 14 nucleotides, or 15 nucleotides. Alternatively, each or substantially all oligonucleotide sequences in the defined set may have length of 6-8, 7-9, 8-10, 9-11, 10-12, 11-12, 12-14, or 13-16 nucleotides.
Each oligonucleotide sequence selected from the defined set of oligonucleotide sequences (and, thus, in a barcode sequence) can be said to be “non-identical” to the other oligonucleotide sequences in the defined set (and thus, the barcode sequence) because each oligonucleotide sequence can be specifically identified as being present in a barcode sequence based on its unique nucleotide sequence, which can be detected both by (i) sequencing the barcode sequence, and (ii) performing a hybridization reaction with a probe (e.g., hybridization probe) that contains an oligonucleotide sequence that is complementary to the cassetable oligonucleotide sequence.
In some embodiments, the three or more cassetable oligonucleotide sequences of the barcode sequence are linked in tandem without any intervening oligonucleotide sequences. In other embodiments, the three or more cassetable oligonucleotide sequences may have one or more linkage between one of the cassetable oligonucleotides and its neighboring cassetable oligonucleotide that is not a direct linkage. Such linkages between any of the three or more cassetable oligonucleotide sequences may be present to facilitate synthesis by ligation rather than by total synthesis. In various embodiments, however, the oligonucleotide sequences of the cassetable oligonucleotides are not interrupted by any other of the other oligonucleotide sequences forming one or more priming sequences, optional index sequences, optional Unique Molecular Identifier sequences or optional restriction sites, including but not limited to Not1 restriction site sequences.
As used herein in connection with cassetable oligonucleotide sequences and their complementary oligonucleotide sequences (including hybridization probes that contain all or part of such complementary oligonucleotide sequences), the term “substantially hybridize” means that the level of hybridization between a cassetable oligonucleotide sequence and its complementary oligonucleotide sequence is above a threshold level, wherein the threshold level is greater than and experimentally distinguishable from a level of cross-hybridization between the complementary oligonucleotide sequence and any other cassetable oligonucleotide sequence in the defined set of oligonucleotide sequences. As persons skilled in the art will readily understand, the threshold for determining whether a complementary oligonucleotide sequence does or does not substantially hybridize to a particular cassetable oligonucleotide sequence depends upon a number of factors, including the length of the cassetable oligonucleotide sequences, the components of the solution in which the hybridization reaction is taking place, the temperature at which the hybridization reaction is taking place, and the chemical properties of the label (which may be attached to the complementary oligonucleotide sequence) used to detect hybridization. Applicants have provided exemplary conditions that can be used to defined sets of oligonucleotide sequences that are non-identical, but persons skilled in the art can readily identify additional conditions that are suitable.
Each of the three or more cassetable oligonucleotide sequences may be selected from a set of at least 12 cassetable oligonucleotide sequences. For example, the set can include at least 12, 15, 16, 18, 20, 21, 24, 25, 27, 28, 30, 32, 33, 35, 36, 39, 40, 42, 44, 45, 48, 50, 51, 52, 54, 55, 56, 57, 60, 63, 64, 65, 66, 68, 69, 70, 72, 75, 76, 78, 80, 81, 84, 85, 87, 88, 90, 92, 93, 95, 96, 99, 100, or more, including any number in between any of the foregoing.
A set of forty cassetable oligonucleotide sequences SEQ ID. Nos. 1-40 as shown in Table 1 has been designed for use in the in-situ detection methods, using 10-mer oligonucleotides, which optimally permits fluorophore probe hybridization during detection. At least 6 bases of the 10mer are differentiated to prevent mis-annealing in the detection methods. The set was designed using the barcode generator python script from the Comai lab: (http://comailab.genomecenter.ucdavis.edu/index.php/Barcode generator), and further selection to the sequences shown, was based on selecting for sequences having a Tm (Melting Temperature) of equal to or greater than 28° C. The Tm calculation was performed using the IDT OligoAnalyzer 3.1 (https://www.idtdna.com/calc/analyzer).
In various embodiments, each of the three or more cassetable oligonucleotides sequences of a barcode sequence has a sequence of any one of SEQ ID NOs: 1-40, wherein none of the three or more cassetable oligonucleotides are identical. The cassetable sequences may be presented within the capture oligonucleotide in any order; the order does not change the in-situ detection and the sequences of each of the cassetable oligonucleotide sequences can be deconvoluted from the sequencing reads. In some embodiments, the barcode sequence may have four cassetable oligonucleotide sequences.
In some embodiments, a first cassetable oligonucleotide sequence of a barcode has a sequence selected from a first sub-set of SEQ ID Nos. 1-40; a second cassetable sequence of a barcode has a sequence selected from a second sub-set of SEQ ID Nos. 1-40; a third cassetable sequence of a barcode has a sequence selected from a third sub-set of SEQ ID Nos. 1-40; and a fourth cassetable sequence of a barcode has a sequence selected from a fourth sub-set of SEQ ID Nos. 1-40.
In some embodiments, a first cassetable oligonucleotide sequence of a barcode has a sequence of any one of SEQ ID NOs: 1-10; a second cassetable oligonucleotide sequence of the barcode has a sequence of any one of SEQ ID NOs: 11-20; a third cassetable oligonucleotide sequence of the barcode has a sequence of any one of SEQ ID NOs: 21-30; and a fourth cassetable oligonucleotide sequence of the barcode has a sequence of any one of SEQ ID NOs: 31-40. In some embodiments, when a first cassetable oligonucleotide sequence of a barcode has a sequence of any one of SEQ ID NOs: 1-10; a second cassetable oligonucleotide sequence of the barcode has a sequence of any one of SEQ ID NOs: 11-20; a third cassetable oligonucleotide sequence of the barcode has a sequence of any one of SEQ ID NOs: 21-30; and a fourth cassetable oligonucleotide sequence of the barcode has a sequence of any one of SEQ ID NOs: 31-40, each of the first, second, third and fourth cassetable oligonucleotide sequences are located along the length of the capture oligonucleotide in order, 5′ to 3′ of the barcode sequence, that is, the first cassetable oligonucleotide will be 5′ to the second cassetable oligonucleotide sequence, which is in turn located 5′ to the third cassetable oligonucleotide sequence, which is located 5′ to the fourth cassetable oligonucleotide sequence. This is shown schematically in
Set of barcode sequences. A set of barcode sequences is provided, which includes at least 64 non-identical barcode sequences, each barcode sequence of the set having a structure according to any barcode as described herein. As used herein, a barcode sequence is “non-identical” to other barcode sequences in a set when the n (e.g., three or more) cassetable oligonucleotide sequences of any one barcode sequence in the set of barcode sequences do not completely overlap with the n′ (e.g., three or more) cassetable oligonucleotide sequences of any other barcode sequence in the set of barcode sequences; partial overlap (e.g., up to n−1) is permissible, so long as each barcode sequence in the set is different from every other barcode sequence in the set by a minimum of 1 cassetable oligonucleotide sequence. In some embodiments, the set of barcode sequences may consist essentially of 64, 81, 100, 125, 216, 256, 343, 512, 625, 729, 1000, 1296, 2401, 4096, 6561, or 10,000 barcode sequences.
G. Hybridization Probes.
Also disclosed are hybridization probes which have an oligonucleotide sequence which is complementary to a cassetable oligonucleotide sequence; and a detectable label. The detectable label can be, for example, a fluorescent label, such as, but not limited to a fluorescein, a cyanine, a rhodamine, a phenyl indole, a coumarin, or an acridine dye. Some non-limiting examples include Alexa Fluor dyes such as Alexa Fluor® 647, Alexa Fluor® 405, Alexa Fluor® 488; Cyanine dyes such as Cy® 5 or Cy® 7, or any suitable fluorescent label as known in the art. Any set of distinguishable fluorophores may be selected to be present on hybridization probes flowed into the microfluidic environment for detection of the barcode, as long as each dye's fluorescent signal is detectable distinguishable. Alternatively, the detectable label can be luminescent agent such as a luciferase reporter, lanthanide tag or an inorganic phosphor, a Quantum Dot, which may be tunable and may include semiconductor materials. Other types of detectable labels may be incorporated such as FRET labels which can include quencher molecules along with fluorophore molecules. FRET labels can include dark quenchers such as Black Hole Quencher® (Biosearch); Iowa Black™ or dabsyl. The FRET labels may be any of TaqMan® probes, hairpin probes, Scorpion® probes, Molecular Beacon probes and the like.
Further details of the hybridization conditions are described below, and one of skill may determine other variations of such conditions suitable to gain binding specificity for a range of barcodes and their hybridization probe pairs.
H. Hybridization Probe
A hybridization probe is provided including an oligonucleotide sequence having a sequence of any one of SEQ ID NOs: 41 to 80 (See Table 1); and a detectable label. The detectable label may be a rhodamine, cyanine or fluorescein fluorescent dye label. In various embodiments, the oligonucleotide sequence of the hybridization probe consists essentially of one sequence of any one of SEQ ID Nos. 41-80, and has no other nucleotides forming part of the hybridization probe.
I. Hybridization Reagent.
A hybridization reagent is provided, including a plurality of hybridization probes, where each hybridization probe of the plurality is a hybridization probe as described herein, and where each hybridization probe of the plurality (i) comprises an oligonucleotide sequence which is non-identical to the oligonucleotide sequence of every other hybridization probe of the plurality and (ii) comprises a detectable label which is spectrally distinguishable from the detectable label of every other hybridization probe of the plurality. Also disclosed are reagents that comprise a plurality of (e.g., 2, 3, 4, 5, or more) hybridization probes. The hybridization probes can be any of the hybridization probes disclosed herein. The reagent can be a liquid, such as a solution. Alternatively, the reagent can be a solid, such as a lyophilized powder. When provided as a solid, the addition of an appropriate volume of water (or a suitable solution) can be added to generate a liquid reagent suitable for introduction into a microfluidic device.
In some embodiments, the plurality of hybridization probes consists of two to four hybridization probes. In some embodiments of the plurality of hybridization probes, a first hybridization probe of the plurality includes a sequence selected from a first subset of SEQ ID NOs: 41-80, and a first detectable label; and a second hybridization probe of the plurality includes a sequence selected from a second subset of SEQ ID NOs: 41-80, and a second detectable label which is spectrally distinguishable from the first detectable label, and where the first and second subsets of SEQ ID NOs: 41-80 are non-overlapping subsets.
The first hybridization probe can include a sequence that comprises all or part (e.g., 8 to 10 nucleotides) of one of the sequences set forth in SEQ ID NOs: 41-80, or a subset of sequences thereof. In certain embodiments, the first hybridization probe can include a sequence that consists of (or consists essentially of) all or part (e.g., 8 to 10 nucleotides) of one of the sequences set forth in SEQ ID NOs: 41-80, or a subset of sequences thereof. The second hybridization probe can include a sequence that comprises all or part (e.g., 8 to 10 nucleotides) of one of the sequences set forth in SEQ ID NOs: 41-80, or a subset of sequences thereof (e.g., a subset that does not include the sequence present in the first hybridization probe, or a subset that is non-overlapping with the subset from which the sequence present in the first hybridization probe is selected). In certain embodiments, the second hybridization probe can include a sequence that consists of (or consists essentially of) all or part (e.g., 8 to 10 nucleotides) of one of the sequences set forth in SEQ ID NOs: 41-80, or a subset of sequences thereof (e.g., a subset that does not include the sequence present in the first hybridization probe, or a subset that is non-overlapping with the subset from which the sequence present in the first hybridization probe is selected). The third hybridization probe (if present) can include a sequence that comprises all or part (e.g., 8 to 10 nucleotides) of one of the sequences set forth in SEQ ID NOs: 41-80, or a subset of sequences thereof (e.g., a subset that does not include the sequences present in the first and second hybridization probes, or a subset that is non-overlapping with the subsets from which the sequences present in the first and second hybridization probes are selected). In certain embodiments, the third hybridization probe (if present) can include a sequence that consists of (or consists essentially of) all or part (e.g., 8 to 10 nucleotides) of one of the sequences set forth in SEQ ID NOs: 41-80, or a subset of sequences thereof (e.g., a subset that does not include the sequences present in the first and second hybridization probes, or a subset that is non-overlapping with the subsets from which the sequences present in the first and second hybridization probes are selected). The fourth hybridization probe (if present) can include a sequence that comprises all or part (e.g., 8 to 10 nucleotides) of one of the sequences set forth in SEQ ID NOs: 41-80, or a subset of sequences thereof (e.g., a subset that does not include the sequences present in the first, second, and third hybridization probes, or a subset that is non-overlapping with the subsets from which the sequences present in the first, second, and third hybridization probes are selected). In certain embodiments, the fourth hybridization probe (if present) can include a sequence that consists of (or consists essentially of) all or part (e.g., 8 to 10 nucleotides) of one of the sequences set forth in SEQ ID NOs: 41-80, or a subset of sequences thereof (e.g., a subset that does not include the sequences present in the first, second, and third hybridization probes, or a subset that is non-overlapping with the subsets from which the sequences present in the first, second, and third hybridization probes are selected). As will be evident to persons skilled in the art, the reagent could include fifth, sixth, etc. hybridization probes, which can have properties analogous to the first, second, third, and fourth hybridization probes.
In some embodiments, the third hybridization probe of the plurality may include a sequence selected from a third subset of SEQ ID NOs: 41-80, and a third detectable label which is spectrally distinguishable from each of the first and second detectable labels, wherein the first, second, and third subsets of SEQ ID NOs: 41-80 are non-overlapping subsets.
In yet other embodiments, the reagent may further include a fourth hybridization probe of the plurality, wherein the fourth hybridization probe may include a sequence selected from a fourth subset of SEQ ID NOs: 41-80, and a fourth detectable label which is spectrally distinguishable from each of the first, second, and third detectable labels, wherein the first, second, third, and fourth subsets of SEQ ID NOs: 41-80 are non-overlapping subsets.
In various embodiments of the hybridization reagent, each subset of SEQ ID NOs: 41-80 may include at least 10 sequences. In various embodiments of the hybridization reagent, the first subset contains SEQ ID NOs: 41-50, the second subset contains SEQ ID NOs: 51-60, the third subset contains SEQ ID NOs: 61-70, and the fourth subset contains SEQ ID NOs: 71-80.
In some embodiments, the method may further include disposing one or more biological cells within the one or more sequestration pens of the microfluidic device. In some embodiments, each one of the one or more biological cells may be disposed in a different one of the one or more sequestration pens. The one or more biological cells may be disposed within the isolation regions of the one or more sequestration pens of the microfluidic device. In some embodiments of the method, at least one of the one or more biological cells may be disposed within a sequestration pen having one of the one or more capture objects disposed therein. In some embodiments, the one or more biological cells may be a plurality of biological cells from a clonal population. In various embodiments of the method, disposing the one or more biological cells may be performed before disposing the one or more capture objects.
In various embodiments, the capture object may be any capture object as described herein. In some embodiments, the capture object may include a magnetic component (e.g., a magnetic bead). Alternatively, the capture object can be non-magnetic.
In some embodiments, a single biological cell is disposed in a sequestration pen. In some embodiments, a plurality of biological cells, for example, 2 or more, 2 to 10, 3 to 8, 4 to 6, or the like, are disposed within said sequestration pen.
In various embodiments, disposing the biological cell may further include marking the biological cell (e.g., with a marker for nucleic acids, such as Dapi or Hoechst stain.
In some embodiments, disposing said biological cell within said sequestration pen is performed before disposing said capture object within said sequestration pen. In some embodiments, disposing said capture object within said sequestration pen is performed before disposing said biological cell within said sequestration pen.
In some embodiments, said enclosure of said microfluidic device comprises at least one coated surface. In some embodiments, the coated surface comprises a covalently linked surface. In some embodiments, the coated surface comprises a hydrophilic or a negatively charged coated surface. The coated surface can be coated with Tris and/or a polymer, such as a PEG-PPG block co-polymer. In yet other embodiments, the enclosure of the microfluidic device may include at least one conditioned surface.
The at least one conditioned surface may include a covalently bound hydrophilic moiety or a negatively charged moiety. A covalently bound hydrophilic moiety or negatively charged moiety can be a hydrophilic or negatively charged polymer.
In some embodiments, said enclosure of the microfluidic device further comprises a dielectrophoretic (DEP) configuration, and wherein disposing said biological cell and/or disposing said capture object is performed by applying a dielectrophoretic (DEP) force on or proximal to said biological cell and/or said capture object.
In some embodiments, said microfluidic device further comprises a plurality of sequestration pens. Optionally, the method further comprises disposing a plurality of said biological cells within said plurality of sequestration pens.
A plurality of said biological cells disposed within said plurality of sequestration pens may have substantially only one biological cell disposed within sequestration pens of said plurality. Thus, each sequestration pen of the plurality having a biological cell disposed therein will generally contain a single biological cell. For example, less than 10%, 7%, 5%, 3% or 1% of sequestration pens occupied by a cell may contain more than one biological cell. In some embodiments, the plurality of biological cells may be a clonal population of biological cells.
A plurality of said capture objects disposed within said plurality of sequestration pens may have substantially only one capture object disposed within sequestration pens of said plurality. Thus, each sequestration pen of the plurality having a capture object disposed therein will generally contain a single capture object. For example, less than 10%, 7%, 5%, 3% or 1% of sequestration pens occupied by a capture object may contain more than one capture object.
A plurality of said biological cells and a plurality of capture objects disposed within said plurality of sequestration pens may have substantially only one biological cell and substantially only one capture object disposed within sequestration pens of said plurality. Thus, each sequestration pen of the plurality having a biological cell and a capture object disposed therein will generally contain a single biological cell and a single capture object. For example, less than 10%, 7%, 5%, 3% or 1% of sequestration pens occupied by a cell and a capture object may contain more than one biological cell or more than one capture object. In some embodiments, the plurality of biological cells may be a clonal population of biological cells.
A. In Situ Identification of Barcode Sequences in Sequestration Pens
In some embodiments, the barcode sequence of the plurality of capture oligonucleotides of the capture object can be identified in situ, while the capture object is located within said sequestration pen. In situ identification of the barcode sequence can be performed after introducing the biological cell into the sequestration pen, after lysing the biological cell, or after transcribing the captured nucleic acids.
In some embodiments, identifying the barcode is performed using a method that allows the in-situ identification of one or more capture objects within a microfluidic device. An exemplary method comprises disposing a single capture object of said one or more capture objects into each of one or more sequestration pens located within an enclosure of said microfluidic device. Each capture object comprises a plurality of capture oligonucleotides, and wherein each capture oligonucleotide of said plurality comprises: a priming sequence; a capture sequence; and a barcode sequence, wherein said barcode sequence comprises three or more cassetable oligonucleotide sequences, each cassetable oligonucleotide sequence being non-identical to the other cassetable oligonucleotide sequences of said barcode sequence. The method further comprises flowing a first reagent solution comprising a first set of hybridization probes into a flow region within said enclosure of said microfluidic device, wherein said flow region is fluidically connected to each of said one or more sequestration pens. Each hybridization probe of said first set comprises an oligonucleotide sequence complementary to a cassetable oligonucleotide sequence comprised by any of said barcode sequences of any of said capture oligonucleotides of any of said one or more capture objects, wherein said complementary oligonucleotide sequence of each hybridization probe in the first set is non-identical to every other complementary oligonucleotide sequence of said hybridization probes in said first set; and a fluorescent label selected from a set of spectrally distinguishable fluorescent labels, wherein the fluorescent label of each hybridization probe in said first set is different from the fluorescent label of every other hybridization probe in said first set of hybridization probes.
The method further comprises hybridizing said hybridization probes of said first set to corresponding cassetable oligo-nucleotide sequences in any of said barcode sequences of any of said capture oligonucleotides of any of said one or more capture objects. The method further comprises detecting, for each hybridization probe of said first set of hybridization probes, a corresponding fluorescent signal associated with any of said one or more capture objects. The method further comprises generating a record, for each capture object disposed within one of said one or more sequestration pens, comprising (i) a location of the sequestration pen within said enclosure of said microfluidic device, and (ii) an association or non-association of said corresponding fluorescent signal of each hybridization probe of said first set of hybridization probes with said capture object, wherein said record of associations and non-associations constitute a barcode which links said capture object with said sequestration pen.
The one or more capture objects, as used in this method, may each be any capture object as described herein. Generally, all of the barcode sequences will have the same number of cassetable oligonucleotide sequences, and each capture oligonucleotide of the plurality of capture oligonucleotide that are comprised by a particular capture object will have the same barcode sequence. As discussed above, the three or more cassetable oligonucleotide sequences of each barcode sequence are selected from a set of non-identical cassetable oligonucleotide sequences. The set of cassetable oligonucleotides sequences can, for example, include 12 to 100 (or more) non-identical oligonucleotide sequences. Thus, the set of cassetable oligonucleotide sequences can comprise a number of cassetable oligonucleotide sequences greater than the number of spectrally distinguishable labels in the set of spectrally distinguishable labels, which can include 2 or more (e.g., 2 to 5) spectrally distinguishable labels.
The number of hybridization probes in the first (or subsequent) set can be identical to the number of cassetable oligonucleotides in each barcode sequence. However, these numbers do not have to be the same. For example, the number of hybridization probes in the first (or any subsequent) set can be greater than the number of cassetable oligonucleotides in each barcode sequence.
Detecting each hybridization probe (or class of label) comprises identifying distinguishing spectral characteristics of each hybridization probe (or label) of the first set of hybridization probes. Furthermore, detecting a given hybridization probe generally requires detection of a level of the distinguishing spectral characteristic(s) that exceeds a background or threshold level associated with the system (e.g., optical train) used to detect the distinguishing spectral characteristic(s). Following such identification, any detected label can be correlated with the presence of a cassetable oligonucleotide sequence which is complementary to the oligonucleotide sequence of the hybridization probe. The detectable label can be, for example, a fluorescent label, such as, but not limited to a fluorescein, a cyanine, a rhodamine, a phenyl indole, a coumarin, or an acridine dye. Some non-limiting examples include Alexa Fluor dyes such as Alexa Fluor® 647, Alexa Fluor® 405, Alexa Fluor® 488; Cyanine dyes such as Cy® 5 or Cy® 7, or any suitable fluorescent label as known in the art. Any set of distinguishable fluorophores may be selected to be present on hybridization probes flowed into the microfluidic environment for detection of the barcode, as long as each dye's fluorescent signal is detectable distinguishable. Alternatively, the detectable label can be luminescent agent such as a luciferase reporter, lanthanide tag or an inorganic phosphor, a Quantum Dot, which may be tunable and may include semiconductor materials. Other types of detectable labels may be incorporated such as FRET labels which can include quencher molecules along with fluorophore molecules. FRET labels can include dark quenchers such as Black Hole Quencher® (Biosearch); Iowa Black™ or dabsyl. The FRET labels may be any of TaqMan® probes, hairpin probes, Scorpion® probes, Molecular Beacon probes and the like.
Detecting and/or generating a record can be automated, for example, by means of a controller.
In some embodiments, such a method of in situ identification further comprises flowing an nth reagent solution comprising an nth set of hybridization probes into said flow region of said microfluidic device, wherein each hybridization probe of said nth set comprises an oligonucleotide sequence complementary to a cassetable oligonucleotide sequence comprised by any of said barcode sequences of any of said capture oligonucleotides of any of said one or more capture objects, wherein said complementary oligonucleotide sequence of each hybridization probe in the nth set is non-identical to every other complementary oligonucleotide sequence of said hybridization probes in said nth set and any other set of hybridization probes flowed into said flow region of said microfluidic device; and a fluorescent label selected from a set of spectrally distinguishable fluorescent labels, wherein the fluorescent label of each hybridization probe in said nth set is different from the fluorescent label of every other hybridization probe in said nth set of hybridization probes. The method further comprises hybridizing said hybridization probes of said nth set to corresponding cassetable oligo-nucleotide sequences in any of said barcode sequences of any of said capture oligonucleotides of any of said one or more capture objects; detecting, for each hybridization probe of said nth set of hybridization probes, a corresponding fluorescent signal associated with any of said one or more capture objects; and supplementing said record, for each capture object disposed within one of said one or more sequestration pens, with an association or non-association of said corresponding fluorescent signal of each hybridization probe of said nth set of hybridization probes with said capture object, wherein n is a set of positive integers having values of {2, . . . , m}, wherein m is a positive integer having a value of 2 or greater, and wherein the foregoing steps of flowing said nth reagent, hybridizing said nth set of hybridization probes, detecting said corresponding fluorescent signals, and supplements said records are repeated for each value of n in said set of positive integers {2, . . . , m}.
In some embodiments, m has a value greater than or equal to 3 and less than or equal to 20 (e.g., greater than or equal to 5 and less than or equal to 15). In some embodiments, m has a value greater than or equal to 8 and less than or equal to 12 (e.g., 10). Flowing said first reagent solution and/or said nth reagent solution into said flow region may further comprise permitting said first reagent solution and/or said nth reagent solution to equilibrate by diffusion into said one or more sequestration pens.
Detecting the corresponding fluorescent signal associated with any of the one or more capture objects may further include: flowing a rinsing solution having no hybridization probes through the flow region of the microfluidic device; and equilibrating by diffusion the rinsing solution into the one or more sequestration pens, thereby allowing unhybridized hybridization probes of the first set or any of the nth sets to diffuse out of the one or more sequestration pens. In some embodiments, the flowing of the rinsing solution may be performed before detecting the fluorescent signal.
In some embodiments of the method of in-situ detection, each barcode sequence of each capture oligonucleotide of each capture object may include three cassetable oligonucleotide sequences. In some embodiments, the first set of hybridization probes and each of the nth sets of hybridization probes may include three hybridization probes.
In various embodiments of the method of in-situ detection, each barcode sequence of each capture oligonucleotide of each capture object may include four cassetable oligonucleotide sequences. In some embodiments, the first set of hybridization probes and each of the nth sets of hybridization probes comprise four hybridization probes.
Disposing each of the one or more capture objects may include disposing each of the one or more capture objects within an isolation region of the one or more sequestration pens within the microfluidic device.
In some embodiments, the method may further include disposing one or more biological cells within the one or more sequestration pens of the microfluidic device. In some embodiments, each one of the one or more biological cells may be disposed in a different one of the one or more sequestration pens. The one or more biological cells may be disposed within the isolation regions of the one or more sequestration pens of the microfluidic device. In some embodiments of the method, at least one of the one or more biological cells may be disposed within a sequestration pen having one of the one or more capture objects disposed therein. In some embodiments, the one or more biological cells may be a plurality of biological cells from a clonal population. In various embodiments of the method, disposing the one or more biological cells may be performed before disposing the one or more capture objects.
In various embodiments of the method of in-situ detection, the enclosure of the microfluidic device may further include a dielectrophoretic (DEP) configuration, and disposing the one or more capture objects into one or more sequestration pens may be performed using dielectrophoretic (DEP) force. In various embodiments of the method of in-situ detection, the enclosure of the microfluidic device may further include a dielectrophoretic (DEP) configuration, and disposing the one or more biological cells within the one or more sequestration pens may be performed using dielectrophoretic (DEP) forces. The microfluidic device can be any microfluidic device disclosed herein. For example, the microfluidic device can comprise at least one coated surface (e.g., a covalently bound surface). The at least one coated surface can comprise a hydrophilic or a negatively charged coated surface.
In various embodiments of the method of in-situ identification, at least one of the plurality of capture oligonucleotides of each capture object may further include a target nucleic acid captured thereto by the capture sequence.
Turning to
In some embodiments, barcodes of capture objects may be identified or deconvolved as follows. Capture objects are initially detected by brightfield imaging. Fluorescence is then measured in a plurality of fluorescence channels (e.g., two, three, or four channels, such as channels corresponding to two, three, or four of FITC, Cy5, DAPI, and Texas red (TRED)) with a plurality of measurements being taken in each channel. The plurality of measurements taken in each channel will generally comprise measurements taken for at least two flow conditions, e.g., three or four flow conditions.
Each flow condition for a given channel comprises providing in the flow a different hybridization probe labeled with a dye that fluoresces in that channel, such as the dyes noted above. Each hybridization probe has a sequence corresponding to a segment of sequence (e.g., a cassetable oligonucleotide sequence) that occurs in some but not all possible barcodes. In some embodiments, the sequences of the hybridization probes with the label corresponding to a given channel are such that only one of them will substantially bind to a given barcode. In some embodiments, the plurality of measurements also comprises a measurement for a pre-flow condition, which can be used to obtain a reference intensity value for the capture object in each fluorescence channel. In some embodiments, relative fluorescence units or arbitrary fluorescence units are used for measurements of brightness/fluorescence intensity.
For each flow condition, a signal value is determined based at least in part on the fluorescence intensity of the capture object in that flow condition. In some embodiments, the signal value is determined by subtracting a reference intensity, such as from a pre-flow measurement, from an intensity corresponding to the flow condition. In some embodiments, the reference intensity is the difference between a raw intensity (e.g., median raw intensity) measured at the position of the capture object and a background intensity (e.g., a median background intensity) under the pre-flow condition; and/or the intensity corresponding to the flow condition is the difference between a raw intensity (e.g., median raw intensity) measured at the position of the capture object and a background intensity (e.g., a median background intensity) under the flow condition.
Optionally, the signal value may be subjected to a noise suppression step, e.g., in which signal values below a pre-determined minimum threshold are set to a pre-determined floor value. The pre-determined floor value may be greater than or equal to the pre-determined minimum threshold. The pre-determined floor value may be, for example, a median signal value for flow conditions in which the hybridization probe does not substantially hybridize to a barcode, or a value corresponding to 50-1000% thereof. In some embodiments, the pre-determined minimum threshold is a value corresponding to 500-1000% of the pre-determined floor value.
For each channel, the signal values for each flow condition are analyzed to determine whether binding of the hybridization probe to the barcode sequence occurred. In some embodiments, this is done by determining which flow condition gave the greatest relative increase (e.g., percentage increase) relative to the previous flow condition. For the first flow condition, the signal value from the pre-flow condition may be used as the previous flow condition. Alternatively, the pre-determined floor value may be used, or the signal value from the final flow condition may be used. The results for the plurality of channels can be expressed as one or more data strings, e.g., a binary string for each channel, where the first, second, etc., bit of the binary string corresponds, respectively, to the first, second, etc., flow condition. For example, where the number of flow conditions is four, the binary string 1000 indicates that binding occurred in the first flow condition, while 0010 indicates that binding occurred in the third flow condition. For each fluorescence channel, each binary string can correspond to a short barcode text string, which may also serve as the designation of a cassetable oligonucleotide sequence that occurs in barcodes. For example, in the Cy5 channel, the binary strings 1000, 0100, 0010, and 0001 can correspond to barcode strings C1, C2, C3, and C4, respectively. For the DAPI channel, the binary strings 1000, 0100, 0010, and 0001 can correspond to barcode strings D11, D12, D13, and D14, respectively. For the FITC channel, the binary strings 1000, 0100, 0010, and 0001 can correspond to barcode strings F21, F22, F23, and F24, respectively. For the TRED channel, the binary strings 1000, 0100, 0010, and 0001 can correspond to barcode strings T31, T32, T33, and T34, respectively. Thus, upon determination for a capture object of binary strings in four channels, the binary strings can be deconvolved into a single data string which is, e.g., a four-part barcode text string that identifies four cassetable oligonucleotides of the barcode. For example, where the binary strings are 1000 (Cy5), 0010 (DAPI), 0010 (FITC), and 0010 (TRED), the deconvolved barcode string can be determined as C1D13F23T33. See Example 8 below for an exemplification of an embodiment of this deconvolution procedure.
The capture object in Pen #12 has a barcode having a sequence of:
The capture object in Pen #126 has a barcode having a sequence of:
The capture object in Pen #260 has a barcode having a sequence of:
The first reagent flow 820 includes four hybridization probes having sequences and detectable labels as follows; a first probe 440a-1 having a sequence of TTTTTTTTTT (SEQ ID 85)(for this illustration, the choice of sequence is only for explication, and does not represent a probe sequence used in combination with a capture sequence of PolyT) having a first detectable label selected from a set of four distinguishable labels (represented as a circle having pattern 1; a second probe 440b-1 having a sequence of AAAAAAAAAA (SEQ ID NO. 86), having a second detectable label selected from the set of distinguishable labels (represented as the circle having pattern 2); a third probe 440c-1 having a sequence of CCCCCCCCCC (SEQ ID No. 87) and a third detectable label selected from the set of distinguishable labels (represented as the circle having pattern 3); and a fourth probe 440d-1, having a sequence of GGGGGGGGGG (SEQ ID NO. 88, and a fourth detectable label selected from the set of distinguishable labels (represented as the circle having pattern 4).
After the first flow 810 has been permitted to diffuse into the sequestration pens, and the probes have hybridized to any target cassetable oligonucleotide sequences present in any of the barcodes, flushing with probe-free medium is performed to remove unhybridized probes, while retaining hybridized probes in place. This is accomplished by use of medium that does not dissociate hybridized pairs of probes from their target, such as use of DPBS or Duplex buffer, as described below in the Experimental section. After the excess, unhybridized probe containing medium has been flushed, excitation with the appropriate excitation wavelengths permit detection of the detectable labels on the probes still hybridized to their targets. In this example, it is observed that for Pen #84, a signal is observed for the wavelength of the second distinguishable detection, and no other. This is notated with the patterned circle next to Pen #84 indicating pattern 2 was observed in Flow 1 (810). For Pen #12, signals in all four distinguishable detection wavelengths is observed, and notated with the corresponding patterns 1-4. For Pen #126, no detectable signal observed, and the circles along the figure so notate. Last, Pen #260, three of the probes, 440b-1, 440c-1 and 440d-1 bind, and notation of the detectable signals observed is made showing pattern 2, 3, and 4.
It can be seen that not all cassetable oligonucleotide sequences have been detected, so a second flow 815 is then performed as shown in
The same process of flowing the reagent flow 2 (815) in, permitting diffusion and binding, flushing unhybridized probes and then detecting in each of the four distinguishable wavelengths is performed. As shown in
Returning to the analysis from detection of the second flow 815, the capture object in Pen #84 is noted to having signal in the first, third and fourth detectable signal wavelength channel, and notated with the first, third and fourth pattern. The capture object in Pen #126 has all four probes binding, so is notated with the first, second, third and fourth pattern. The capture object in Pen #260 is notated as having signal in the first detectable label signal wavelength channel, and notated with the first pattern. The results can be tabulated as in
The sequence of each barcode on a capture object in a specific sequestration pen can be derived as shown, matching the detected signal pattern to the complementary sequence of each cassetable oligonucleotide as the sequence of the hybridization probe is known. The sequence of the capture object can then be assigned as shown, where the barcode of the capture object in Pen #12 is determined by the in-situ method of detection to have a sequence of SEQ ID NO. 90; the barcode of the capture object in Pen #84 to have a sequence of SEQ ID NO. 89; the barcode of the capture object in Pen #126 to have a sequence of SEQ ID No. 91, and the barcode of the capture object in Pen #260 to have a sequence of SEQ ID NO. 92.
In various embodiments, the detectable labels used may include Alexa Fluor® 647, which is detected in the Cy®5 fluorescent channel of the optical system that used to excite, observe and record events within the microfluidic device; Alexa Fluor® 405, which is detectable in the Dapi fluorescent channel of the optical system; Alexa Fluor® 488 which is detectable in the FITC fluorescent channel of the optical system; and Alexa Fluor® 594, which is detectable in the Texas Red fluorescent channel of the optical system. The fluorophores may be attached to the hybridization probe as is suitable for synthesis and can be at the 5′ or the 3′ end of the probe. Hybridization of two probes, one labeled at the 5′ end and one labeled at the 3′ end, was found to be unaffected by the presence of adjacent labels (data not shown).
In various embodiments of the method of in-situ detection, the enclosure of the microfluidic device may further include a dielectrophoretic (DEP) configuration, and disposing the one or more capture objects into one or more sequestration pens may be performed using dielectrophoretic (DEP) force. In various embodiments of the method of in-situ detection, the enclosure of the microfluidic device may further include a dielectrophoretic (DEP) configuration, and disposing the one or more biological cells within the one or more sequestration pens may be performed using dielectrophoretic (DEP) forces. The microfluidic device can be any microfluidic device disclosed herein. For example, the microfluidic device can comprise at least one coated surface (e.g., a covalently bound surface). The at least one coated surface can comprise a hydrophilic or a negatively charged coated surface.
B. Microfluidic Devices and Systems for Operating and Observing Such Devices.
As generally illustrated in
The support structure 104 can be at the bottom and the cover 110 at the top of the microfluidic circuit 120 as illustrated in
The support structure 104 can comprise one or more electrodes (not shown) and a substrate or a plurality of interconnected substrates. For example, the support structure 104 can comprise one or more semiconductor substrates, each of which is electrically connected to an electrode (e.g., all or a subset of the semiconductor substrates can be electrically connected to a single electrode). The support structure 104 can further comprise a printed circuit board assembly (“PCBA”). For example, the semiconductor substrate(s) can be mounted on a PCBA.
The microfluidic circuit structure 108 can define circuit elements of the microfluidic circuit 120. Such circuit elements can comprise spaces or regions that can be fluidly interconnected when microfluidic circuit 120 is filled with fluid, such as flow regions (which may include or be one or more flow channels), chambers, pens, traps, and the like. In the microfluidic circuit 120 illustrated in
The microfluidic circuit material 116 can be patterned with cavities or the like to define circuit elements and interconnections of the microfluidic circuit 120. The microfluidic circuit material 116 can comprise a flexible material, such as a flexible polymer (e.g. rubber, plastic, elastomer, silicone, polydimethylsiloxane (“PDMS”), or the like), which can be gas permeable. Other examples of materials that can compose microfluidic circuit material 116 include molded glass, an etchable material such as silicone (e.g. photo-patternable silicone or “PPS”), photo-resist (e.g., SU8), or the like. In some embodiments, such materials—and thus the microfluidic circuit material 116—can be rigid and/or substantially impermeable to gas. Regardless, microfluidic circuit material 116 can be disposed on the support structure 104 and inside the frame 114.
The cover 110 can be an integral part of the frame 114 and/or the microfluidic circuit material 116. Alternatively, the cover 110 can be a structurally distinct element, as illustrated in
In some embodiments, the cover 110 can comprise a rigid material. The rigid material may be glass or a material with similar properties. In some embodiments, the cover 110 can comprise a deformable material. The deformable material can be a polymer, such as PDMS. In some embodiments, the cover 110 can comprise both rigid and deformable materials. For example, one or more portions of cover 110 (e.g., one or more portions positioned over sequestration pens 124, 126, 128, 130) can comprise a deformable material that interfaces with rigid materials of the cover 110. In some embodiments, the cover 110 can further include one or more electrodes. The one or more electrodes can comprise a conductive oxide, such as indium-tin-oxide (ITO), which may be coated on glass or a similarly insulating material. Alternatively, the one or more electrodes can be flexible electrodes, such as single-walled nanotubes, multi-walled nanotubes, nanowires, clusters of electrically conductive nanoparticles, or combinations thereof, embedded in a deformable material, such as a polymer (e.g., PDMS). Flexible electrodes that can be used in microfluidic devices have been described, for example, in U.S. 2012/0325665 (Chiou et al.), the contents of which are incorporated herein by reference. In some embodiments, the cover 110 can be modified (e.g., by conditioning all or part of a surface that faces inward toward the microfluidic circuit 120) to support cell adhesion, viability and/or growth. The modification may include a coating of a synthetic or natural polymer. In some embodiments, the cover 110 and/or the support structure 104 can be transparent to light. The cover 110 may also include at least one material that is gas permeable (e.g., PDMS or PPS).
The electrical power source 192 can provide electric power to the microfluidic device 100 and/or tilting device 190, providing biasing voltages or currents as needed. The electrical power source 192 can, for example, comprise one or more alternating current (AC) and/or direct current (DC) voltage or current sources. The imaging device (part of imaging module 164, discussed below) can comprise a device, such as a digital camera, for capturing images inside microfluidic circuit 120. In some instances, the imaging device further comprises a detector having a fast frame rate and/or high sensitivity (e.g. for low light applications). The imaging device can also include a mechanism for directing stimulating radiation and/or light beams into the microfluidic circuit 120 and collecting radiation and/or light beams reflected or emitted from the microfluidic circuit 120 (or micro-objects contained therein). The emitted light beams may be in the visible spectrum and may, e.g., include fluorescent emissions. The reflected light beams may include reflected emissions originating from an LED or a wide spectrum lamp, such as a mercury lamp (e.g. a high pressure mercury lamp) or a Xenon arc lamp. As discussed with respect to
System 150 further comprises a tilting device 190 (part of tilting module 166, discussed below) configured to rotate a microfluidic device 100 about one or more axes of rotation. In some embodiments, the tilting device 190 is configured to support and/or hold the enclosure 102 comprising the microfluidic circuit 120 about at least one axis such that the microfluidic device 100 (and thus the microfluidic circuit 120) can be held in a level orientation (i.e. at 0° relative to x- and y-axes), a vertical orientation (i.e. at 90° relative to the x-axis and/or the y-axis), or any orientation therebetween. The orientation of the microfluidic device 100 (and the microfluidic circuit 120) relative to an axis is referred to herein as the “tilt” of the microfluidic device 100 (and the microfluidic circuit 120). For example, the tilting device 190 can tilt the microfluidic device 100 at 0.1°, 0.2°, 0.3°, 0.4°, 0.5°, 0.6°, 0.7°, 0.8°, 0.9°, 1°, 2°, 3°, 4°, 5°, 10°, 15°, 20°, 25°, 30°, 35°, 40°, 45°, 50°, 55°, 60°, 65°, 70°, 75°, 80°, 90° relative to the x-axis or any degree therebetween. The level orientation (and thus the x- and y-axes) is defined as normal to a vertical axis defined by the force of gravity. The tilting device can also tilt the microfluidic device 100 (and the microfluidic circuit 120) to any degree greater than 90° relative to the x-axis and/or y-axis, or tilt the microfluidic device 100 (and the microfluidic circuit 120) 180° relative to the x-axis or the y-axis in order to fully invert the microfluidic device 100 (and the microfluidic circuit 120). Similarly, in some embodiments, the tilting device 190 tilts the microfluidic device 100 (and the microfluidic circuit 120) about an axis of rotation defined by flow path 106 or some other portion of microfluidic circuit 120.
In some instances, the microfluidic device 100 is tilted into a vertical orientation such that the flow path 106 is positioned above or below one or more sequestration pens. The term “above” as used herein denotes that the flow path 106 is positioned higher than the one or more sequestration pens on a vertical axis defined by the force of gravity (i.e. an object in a sequestration pen above a flow path 106 would have a higher gravitational potential energy than an object in the flow path). The term “below” as used herein denotes that the flow path 106 is positioned lower than the one or more sequestration pens on a vertical axis defined by the force of gravity (i.e. an object in a sequestration pen below a flow path 106 would have a lower gravitational potential energy than an object in the flow path).
In some instances, the tilting device 190 tilts the microfluidic device 100 about an axis that is parallel to the flow path 106. Moreover, the microfluidic device 100 can be tilted to an angle of less than 90° such that the flow path 106 is located above or below one or more sequestration pens without being located directly above or below the sequestration pens. In other instances, the tilting device 190 tilts the microfluidic device 100 about an axis perpendicular to the flow path 106. In still other instances, the tilting device 190 tilts the microfluidic device 100 about an axis that is neither parallel nor perpendicular to the flow path 106.
System 150 can further include a media source 178. The media source 178 (e.g., a container, reservoir, or the like) can comprise multiple sections or containers, each for holding a different fluidic medium 180. Thus, the media source 178 can be a device that is outside of and separate from the microfluidic device 100, as illustrated in
The master controller 154 can comprise a control module 156 and a digital memory 158. The control module 156 can comprise, for example, a digital processor configured to operate in accordance with machine executable instructions (e.g., software, firmware, source code, or the like) stored as non-transitory data or signals in the memory 158. Alternatively, or in addition, the control module 156 can comprise hardwired digital circuitry and/or analog circuitry. The media module 160, motive module 162, imaging module 164, tilting module 166, and/or other modules 168 can be similarly configured. Thus, functions, processes acts, actions, or steps of a process discussed herein as being performed with respect to the microfluidic device 100 or any other microfluidic apparatus can be performed by any one or more of the master controller 154, media module 160, motive module 162, imaging module 164, tilting module 166, and/or other modules 168 configured as discussed above. Similarly, the master controller 154, media module 160, motive module 162, imaging module 164, tilting module 166, and/or other modules 168 may be communicatively coupled to transmit and receive data used in any function, process, act, action or step discussed herein.
The media module 160 controls the media source 178. For example, the media module 160 can control the media source 178 to input a selected fluidic medium 180 into the enclosure 102 (e.g., through an inlet port 107). The media module 160 can also control removal of media from the enclosure 102 (e.g., through an outlet port (not shown)). One or more media can thus be selectively input into and removed from the microfluidic circuit 120. The media module 160 can also control the flow of fluidic medium 180 in the flow path 106 inside the microfluidic circuit 120. For example, in some embodiments media module 160 stops the flow of media 180 in the flow path 106 and through the enclosure 102 prior to the tilting module 166 causing the tilting device 190 to tilt the microfluidic device 100 to a desired angle of incline.
The motive module 162 can be configured to control selection, trapping, and movement of micro-objects (not shown) in the microfluidic circuit 120. As discussed below with respect to
The imaging module 164 can control the imaging device. For example, the imaging module 164 can receive and process image data from the imaging device. Image data from the imaging device can comprise any type of information captured by the imaging device (e.g., the presence or absence of micro-objects, droplets of medium, accumulation of detectable label, such as fluorescent label, etc.). Using the information captured by the imaging device, the imaging module 164 can further calculate the position of objects (e.g., micro-objects, droplets of medium) and/or the rate of motion of such objects within the microfluidic device 100.
The tilting module 166 can control the tilting motions of tilting device 190. Alternatively, or in addition, the tilting module 166 can control the tilting rate and timing to optimize transfer of micro-objects to the one or more sequestration pens via gravitational forces. The tilting module 166 is communicatively coupled with the imaging module 164 to receive data describing the motion of micro-objects and/or droplets of medium in the microfluidic circuit 120. Using this data, the tilting module 166 may adjust the tilt of the microfluidic circuit 120 in order to adjust the rate at which micro-objects and/or droplets of medium move in the microfluidic circuit 120. The tilting module 166 may also use this data to iteratively adjust the position of a micro-object and/or droplet of medium in the microfluidic circuit 120.
In the example shown in
The microfluidic circuit 120 may comprise any number of microfluidic sequestration pens. Although five sequestration pens are shown, microfluidic circuit 120 may have fewer or more sequestration pens. As shown, microfluidic sequestration pens 124, 126, 128, and 130 of microfluidic circuit 120 each comprise differing features and shapes which may provide one or more benefits useful for maintaining, isolating, assaying or culturing biological micro-objects. In some embodiments, the microfluidic circuit 120 comprises a plurality of identical microfluidic sequestration pens.
In the embodiment illustrated in
In some instances, microfluidic circuit 120 comprises a plurality of parallel channels 122 and flow paths 106, wherein the fluidic medium 180 within each flow path 106 flows in the same direction. In some instances, the fluidic medium within each flow path 106 flows in at least one of a forward or reverse direction. In some instances, a plurality of sequestration pens is configured (e.g., relative to a channel 122) such that the sequestration pens can be loaded with target micro-objects in parallel.
In some embodiments, microfluidic circuit 120 further comprises one or more micro-object traps 132. The traps 132 are generally formed in a wall forming the boundary of a channel 122, and may be positioned opposite an opening of one or more of the microfluidic sequestration pens 124, 126, 128, 130. In some embodiments, the traps 132 are configured to receive or capture a single micro-object from the flow path 106. In some embodiments, the traps 132 are configured to receive or capture a plurality of micro-objects from the flow path 106. In some instances, the traps 132 comprise a volume approximately equal to the volume of a single target micro-object.
The traps 132 may further comprise an opening which is configured to assist the flow of targeted micro-objects into the traps 132. In some instances, the traps 132 comprise an opening having a height and width that is approximately equal to the dimensions of a single target micro-object, whereby larger micro-objects are prevented from entering into the micro-object trap. The traps 132 may further comprise other features configured to assist in retention of targeted micro-objects within the trap 132. In some instances, the trap 132 is aligned with and situated on the opposite side of a channel 122 relative to the opening of a microfluidic sequestration pen, such that upon tilting the microfluidic device 100 about an axis parallel to the microfluidic channel 122, the trapped micro-object exits the trap 132 at a trajectory that causes the micro-object to fall into the opening of the sequestration pen. In some instances, the trap 132 comprises a side passage 134 that is smaller than the target micro-object in order to facilitate flow through the trap 132 and thereby increase the likelihood of capturing a micro-object in the trap 132.
In some embodiments, dielectrophoretic (DEP) forces are applied across the fluidic medium 180 (e.g., in the flow path and/or in the sequestration pens) via one or more electrodes (not shown) to manipulate, transport, separate and sort micro-objects located therein. For example, in some embodiments, DEP forces are applied to one or more portions of microfluidic circuit 120 in order to transfer a single micro-object from the flow path 106 into a desired microfluidic sequestration pen. In some embodiments, DEP forces are used to prevent a micro-object within a sequestration pen (e.g., sequestration pen 124, 126, 128, or 130) from being displaced therefrom. Further, in some embodiments, DEP forces are used to selectively remove a micro-object from a sequestration pen that was previously collected in accordance with the embodiments of the current disclosure. In some embodiments, the DEP forces comprise optoelectronic tweezer (OET) forces.
In other embodiments, optoelectrowetting (OEW) forces are applied to one or more positions in the support structure 104 (and/or the cover 110) of the microfluidic device 100 (e.g., positions helping to define the flow path and/or the sequestration pens) via one or more electrodes (not shown) to manipulate, transport, separate and sort droplets located in the microfluidic circuit 120. For example, in some embodiments, OEW forces are applied to one or more positions in the support structure 104 (and/or the cover 110) in order to transfer a single droplet from the flow path 106 into a desired microfluidic sequestration pen. In some embodiments, OEW forces are used to prevent a droplet within a sequestration pen (e.g., sequestration pen 124, 126, 128, or 130) from being displaced therefrom. Further, in some embodiments, OEW forces are used to selectively remove a droplet from a sequestration pen that was previously collected in accordance with the embodiments of the current disclosure.
In some embodiments, DEP and/or OEW forces are combined with other forces, such as flow and/or gravitational force, so as to manipulate, transport, separate and sort micro-objects and/or droplets within the microfluidic circuit 120. For example, the enclosure 102 can be tilted (e.g., by tilting device 190) to position the flow path 106 and micro-objects located therein above the microfluidic sequestration pens, and the force of gravity can transport the micro-objects and/or droplets into the pens. In some embodiments, the DEP and/or OEW forces can be applied prior to the other forces. In other embodiments, the DEP and/or OEW forces can be applied after the other forces. In still other instances, the DEP and/or OEW forces can be applied at the same time as the other forces or in an alternating manner with the other forces.
Examples of microfluidic devices having pens in which biological micro-objects can be placed, cultured, and/or monitored have been described, for example, in US 2014/0116881 (application Ser. No. 14/060,117, filed Oct. 22, 2013), US 2015/0151298 (application Ser. No. 14/520,568, filed Oct. 22, 2014), and US 2015/0165436 (application Ser. No. 14/521,447, filed Oct. 22, 2014), each of which is incorporated herein by reference in its entirety. U.S. application Ser. Nos. 14/520,568 and 14/521,447 also describe exemplary methods of analyzing secretions of cells cultured in a microfluidic device. Each of the foregoing applications further describes microfluidic devices configured to produce dielectrophoretic (DEP) forces, such as optoelectronic tweezers (OET) or configured to provide opto-electro wetting (OEW). For example, the optoelectronic tweezers device illustrated in FIG. 2 of US 2014/0116881 is an example of a device that can be utilized in embodiments of the present disclosure to select and move an individual biological micro-object or a group of biological micro-objects.
Microfluidic device motive configurations. As described above, the control and monitoring equipment of the system can comprise a motive module for selecting and moving objects, such as micro-objects or droplets, in the microfluidic circuit of a microfluidic device. The microfluidic device can have a variety of motive configurations, depending upon the type of object being moved and other considerations. For example, a dielectrophoresis (DEP) configuration can be utilized to select and move micro-objects in the microfluidic circuit. Thus, the support structure 104 and/or cover 110 of the microfluidic device 100 can comprise a DEP configuration for selectively inducing DEP forces on micro-objects in a fluidic medium 180 in the microfluidic circuit 120 and thereby select, capture, and/or move individual micro-objects or groups of micro-objects. Alternatively, the support structure 104 and/or cover 110 of the microfluidic device 100 can comprise an electrowetting (EW) configuration for selectively inducing EW forces on droplets in a fluidic medium 180 in the microfluidic circuit 120 and thereby select, capture, and/or move individual droplets or groups of droplets.
One example of a microfluidic device 200 comprising a DEP configuration is illustrated in
As seen in
In certain embodiments, the microfluidic device 200 illustrated in
With the power source 212 activated, the foregoing DEP configuration creates an electric field gradient in the fluidic medium 180 between illuminated DEP electrode regions 214a and adjacent dark DEP electrode regions 214, which in turn creates local DEP forces that attract or repel nearby micro-objects (not shown) in the fluidic medium 180. DEP electrodes that attract or repel micro-objects in the fluidic medium 180 can thus be selectively activated and deactivated at many different such DEP electrode regions 214 at the inner surface 208 of the region/chamber 202 by changing light patterns 218 projected from a light source 216 into the microfluidic device 200. Whether the DEP forces attract or repel nearby micro-objects can depend on such parameters as the frequency of the power source 212 and the dielectric properties of the medium 180 and/or micro-objects (not shown).
The square pattern 220 of illuminated DEP electrode regions 214a illustrated in
In some embodiments, the electrode activation substrate 206 can comprise or consist of a photoconductive material. In such embodiments, the inner surface 208 of the electrode activation substrate 206 can be featureless. For example, the electrode activation substrate 206 can comprise or consist of a layer of hydrogenated amorphous silicon (a-Si:H). The a-Si:H can comprise, for example, about 8% to 40% hydrogen (calculated as 100*the number of hydrogen atoms/the total number of hydrogen and silicon atoms). The layer of a-Si:H can have a thickness of about 500 nm to about 2.0 μm. In such embodiments, the DEP electrode regions 214 can be created anywhere and in any pattern on the inner surface 208 of the electrode activation substrate 206, in accordance with the light pattern 218. The number and pattern of the DEP electrode regions 214 thus need not be fixed, but can correspond to the light pattern 218. Examples of microfluidic devices having a DEP configuration comprising a photoconductive layer such as discussed above have been described, for example, in U.S. Pat. No. RE 44,711 (Wu et al.) (originally issued as U.S. Pat. No. 7,612,355), the entire contents of which are incorporated herein by reference.
In other embodiments, the electrode activation substrate 206 can comprise a substrate comprising a plurality of doped layers, electrically insulating layers (or regions), and electrically conductive layers that form semiconductor integrated circuits, such as is known in semiconductor fields. For example, the electrode activation substrate 206 can comprise a plurality of phototransistors, including, for example, lateral bipolar phototransistors, each phototransistor corresponding to a DEP electrode region 214. Alternatively, the electrode activation substrate 206 can comprise electrodes (e.g., conductive metal electrodes) controlled by phototransistor switches, with each such electrode corresponding to a DEP electrode region 214. The electrode activation substrate 206 can include a pattern of such phototransistors or phototransistor-controlled electrodes. The pattern, for example, can be an array of substantially square phototransistors or phototransistor-controlled electrodes arranged in rows and columns, such as shown in
Examples of microfluidic devices having electrode activation substrates that comprise phototransistors have been described, for example, in U.S. Pat. No. 7,956,339 (Ohta et al.) (see, e.g., device 300 illustrated in
In some embodiments of a DEP configured microfluidic device, the top electrode 210 is part of a first wall (or cover 110) of the enclosure 102, and the electrode activation substrate 206 and bottom electrode 204 are part of a second wall (or support structure 104) of the enclosure 102. The region/chamber 202 can be between the first wall and the second wall. In other embodiments, the electrode 210 is part of the second wall (or support structure 104) and one or both of the electrode activation substrate 206 and/or the electrode 210 are part of the first wall (or cover 110). Moreover, the light source 216 can alternatively be used to illuminate the enclosure 102 from below.
With the microfluidic device 200 of
In other embodiments, the microfluidic device 200 can have a DEP configuration that does not rely upon light activation of DEP electrodes at the inner surface 208 of the electrode activation substrate 206. For example, the electrode activation substrate 206 can comprise selectively addressable and energizable electrodes positioned opposite to a surface including at least one electrode (e.g., cover 110). Switches (e.g., transistor switches in a semiconductor substrate) may be selectively opened and closed to activate or inactivate DEP electrodes at DEP electrode regions 214, thereby creating a net DEP force on a micro-object (not shown) in region/chamber 202 in the vicinity of the activated DEP electrodes. Depending on such characteristics as the frequency of the power source 212 and the dielectric properties of the medium (not shown) and/or micro-objects in the region/chamber 202, the DEP force can attract or repel a nearby micro-object. By selectively activating and deactivating a set of DEP electrodes (e.g., at a set of DEP electrodes regions 214 that forms a square pattern 220), one or more micro-objects in region/chamber 202 can be trapped and moved within the region/chamber 202. The motive module 162 in
As yet another example, the microfluidic device 200 can have an electrowetting (EW) configuration, which can be in place of the DEP configuration or can be located in a portion of the microfluidic device 200 that is separate from the portion which has the DEP configuration. The EW configuration can be an opto-electrowetting configuration or an electrowetting on dielectric (EWOD) configuration, both of which are known in the art. In some EW configurations, the support structure 104 has an electrode activation substrate 206 sandwiched between a dielectric layer (not shown) and the bottom electrode 204. The dielectric layer can comprise a hydrophobic material and/or can be coated with a hydrophobic material, as described below. For microfluidic devices 200 that have an EW configuration, the inner surface 208 of the support structure 104 is the inner surface of the dielectric layer or its hydrophobic coating.
The dielectric layer (not shown) can comprise one or more oxide layers, and can have a thickness of about 50 nm to about 250 nm (e.g., about 125 nm to about 175 nm). In certain embodiments, the dielectric layer may comprise a layer of oxide, such as a metal oxide (e.g., aluminum oxide or hafnium oxide). In certain embodiments, the dielectric layer can comprise a dielectric material other than a metal oxide, such as silicon oxide or a nitride. Regardless of the exact composition and thickness, the dielectric layer can have an impedance of about 10 kOhms to about 50 kOhms.
In some embodiments, the surface of the dielectric layer that faces inward toward region/chamber 202 is coated with a hydrophobic material. The hydrophobic material can comprise, for example, fluorinated carbon molecules. Examples of fluorinated carbon molecules include perfluoro-polymers such as polytetrafluoroethylene (e.g., TEFLON®) or poly(2,3-difluoromethylenyl-perfluorotetrahydrofuran) (e.g., CYTOP™). Molecules that make up the hydrophobic material can be covalently bonded to the surface of the dielectric layer. For example, molecules of the hydrophobic material can be covalently bound to the surface of the dielectric layer by means of a linker such as a siloxane group, a phosphonic acid group, or a thiol group. Thus, in some embodiments, the hydrophobic material can comprise alkyl-terminated siloxane, alkyl-termination phosphonic acid, or alkyl-terminated thiol. The alkyl group can be long-chain hydrocarbons (e.g., having a chain of at least 10 carbons, or at least 16, 18, 20, 22, or more carbons). Alternatively, fluorinated (or perfluorinated) carbon chains can be used in place of the alkyl groups. Thus, for example, the hydrophobic material can comprise fluoroalkyl-terminated siloxane, fluoroalkyl-terminated phosphonic acid, or fluoroalkyl-terminated thiol. In some embodiments, the hydrophobic coating has a thickness of about 10 nm to about 50 nm. In other embodiments, the hydrophobic coating has a thickness of less than 10 nm (e.g., less than 5 nm, or about 1.5 to 3.0 nm).
In some embodiments, the cover 110 of a microfluidic device 200 having an electrowetting configuration is coated with a hydrophobic material (not shown) as well. The hydrophobic material can be the same hydrophobic material used to coat the dielectric layer of the support structure 104, and the hydrophobic coating can have a thickness that is substantially the same as the thickness of the hydrophobic coating on the dielectric layer of the support structure 104. Moreover, the cover 110 can comprise an electrode activation substrate 206 sandwiched between a dielectric layer and the top electrode 210, in the manner of the support structure 104. The electrode activation substrate 206 and the dielectric layer of the cover 110 can have the same composition and/or dimensions as the electrode activation substrate 206 and the dielectric layer of the support structure 104. Thus, the microfluidic device 200 can have two electrowetting surfaces.
In some embodiments, the electrode activation substrate 206 can comprise a photoconductive material, such as described above. Accordingly, in certain embodiments, the electrode activation substrate 206 can comprise or consist of a layer of hydrogenated amorphous silicon (a-Si:H). The a-Si:H can comprise, for example, about 8% to 40% hydrogen (calculated as 100*the number of hydrogen atoms/the total number of hydrogen and silicon atoms). The layer of a-Si:H can have a thickness of about 500 nm to about 2.0 μm. Alternatively, the electrode activation substrate 206 can comprise electrodes (e.g., conductive metal electrodes) controlled by phototransistor switches, as described above. Microfluidic devices having an opto-electrowetting configuration are known in the art and/or can be constructed with electrode activation substrates known in the art. For example, U.S. Pat. No. 6,958,132 (Chiou et al.), the entire contents of which are incorporated herein by reference, discloses opto-electrowetting configurations having a photoconductive material such as a-Si:H, while U.S. Patent Publication No. 2014/0124370 (Short et al.), referenced above, discloses electrode activation substrates having electrodes controlled by phototransistor switches.
The microfluidic device 200 thus can have an opto-electrowetting configuration, and light patterns 218 can be used to activate photoconductive EW regions or photoresponsive EW electrodes in the electrode activation substrate 206. Such activated EW regions or EW electrodes of the electrode activation substrate 206 can generate an electrowetting force at the inner surface 208 of the support structure 104 (i.e., the inner surface of the overlaying dielectric layer or its hydrophobic coating). By changing the light patterns 218 (or moving microfluidic device 200 relative to the light source 216) incident on the electrode activation substrate 206, droplets (e.g., containing an aqueous medium, solution, or solvent) contacting the inner surface 208 of the support structure 104 can be moved through an immiscible fluid (e.g., an oil medium) present in the region/chamber 202.
In other embodiments, microfluidic devices 200 can have an EWOD configuration, and the electrode activation substrate 206 can comprise selectively addressable and energizable electrodes that do not rely upon light for activation. The electrode activation substrate 206 thus can include a pattern of such electrowetting (EW) electrodes. The pattern, for example, can be an array of substantially square EW electrodes arranged in rows and columns, such as shown in
Regardless of the configuration of the microfluidic device 200, a power source 212 can be used to provide a potential (e.g., an AC voltage potential) that powers the electrical circuits of the microfluidic device 200. The power source 212 can be the same as, or a component of, the power source 192 referenced in
C. Sequestration Pens
Non-limiting examples of generic sequestration pens 224, 226, and 228 are shown within the microfluidic device 230 depicted in
The sequestration pens 224, 226, and 228 of
The microfluidic channel 122 can thus be an example of a swept region, and the isolation regions 240 of the sequestration pens 224, 226, 228 can be examples of unswept regions. As noted, the microfluidic channel 122 and sequestration pens 224, 226, 228 can be configured to contain one or more fluidic media 180. In the example shown in
As is known, a flow 242 of fluidic medium 180 in a microfluidic channel 122 past a proximal opening 234 of sequestration pen 224 can cause a secondary flow 244 of the medium 180 into and/or out of the sequestration pen 224. To isolate micro-objects 246 in the isolation region 240 of a sequestration pen 224 from the secondary flow 244, the length Lcon of the connection region 236 of the sequestration pen 224 (i.e., from the proximal opening 234 to the distal opening 238) should be greater than the penetration depth Dp of the secondary flow 244 into the connection region 236. The penetration depth Dp of the secondary flow 244 depends upon the velocity of the fluidic medium 180 flowing in the microfluidic channel 122 and various parameters relating to the configuration of the microfluidic channel 122 and the proximal opening 234 of the connection region 236 to the microfluidic channel 122. For a given microfluidic device, the configurations of the microfluidic channel 122 and the opening 234 will be fixed, whereas the rate of flow 242 of fluidic medium 180 in the microfluidic channel 122 will be variable. Accordingly, for each sequestration pen 224, a maximal velocity Vmax for the flow 242 of fluidic medium 180 in channel 122 can be identified that ensures that the penetration depth Dp of the secondary flow 244 does not exceed the length Lcon of the connection region 236. As long as the rate of the flow 242 of fluidic medium 180 in the microfluidic channel 122 does not exceed the maximum velocity Vmax, the resulting secondary flow 244 can be limited to the microfluidic channel 122 and the connection region 236 and kept out of the isolation region 240. The flow 242 of medium 180 in the microfluidic channel 122 will thus not draw micro-objects 246 out of the isolation region 240. Rather, micro-objects 246 located in the isolation region 240 will stay in the isolation region 240 regardless of the flow 242 of fluidic medium 180 in the microfluidic channel 122.
Moreover, as long as the rate of flow 242 of medium 180 in the microfluidic channel 122 does not exceed Vmax, the flow 242 of fluidic medium 180 in the microfluidic channel 122 will not move miscellaneous particles (e.g., microparticles and/or nanoparticles) from the microfluidic channel 122 into the isolation region 240 of a sequestration pen 224. Having the length Lcon of the connection region 236 be greater than the maximum penetration depth Dp of the secondary flow 244 can thus prevent contamination of one sequestration pen 224 with miscellaneous particles from the microfluidic channel 122 or another sequestration pen (e.g., sequestration pens 226, 228 in
Because the microfluidic channel 122 and the connection regions 236 of the sequestration pens 224, 226, 228 can be affected by the flow 242 of medium 180 in the microfluidic channel 122, the microfluidic channel 122 and connection regions 236 can be deemed swept (or flow) regions of the microfluidic device 230. The isolation regions 240 of the sequestration pens 224, 226, 228, on the other hand, can be deemed unswept (or non-flow) regions. For example, components (not shown) in a first fluidic medium 180 in the microfluidic channel 122 can mix with a second fluidic medium 248 in the isolation region 240 substantially only by diffusion of components of the first medium 180 from the microfluidic channel 122 through the connection region 236 and into the second fluidic medium 248 in the isolation region 240. Similarly, components (not shown) of the second medium 248 in the isolation region 240 can mix with the first medium 180 in the microfluidic channel 122 substantially only by diffusion of components of the second medium 248 from the isolation region 240 through the connection region 236 and into the first medium 180 in the microfluidic channel 122. In some embodiments, the extent of fluidic medium exchange between the isolation region of a sequestration pen and the flow region by diffusion is greater than about 90%, 91%, 92%, 93%, 94% 95%, 96%, 97%, 98%, or greater than about 99% of fluidic exchange. The first medium 180 can be the same medium or a different medium than the second medium 248. Moreover, the first medium 180 and the second medium 248 can start out being the same, then become different (e.g., through conditioning of the second medium 248 by one or more cells in the isolation region 240, or by changing the medium 180 flowing through the microfluidic channel 122).
The maximum penetration depth Dp of the secondary flow 244 caused by the flow 242 of fluidic medium 180 in the microfluidic channel 122 can depend on a number of parameters, as mentioned above. Examples of such parameters include: the shape of the microfluidic channel 122 (e.g., the microfluidic channel can direct medium into the connection region 236, divert medium away from the connection region 236, or direct medium in a direction substantially perpendicular to the proximal opening 234 of the connection region 236 to the microfluidic channel 122); a width Wch (or cross-sectional area) of the microfluidic channel 122 at the proximal opening 234; and a width Wcon (or cross-sectional area) of the connection region 236 at the proximal opening 234; the velocity V of the flow 242 of fluidic medium 180 in the microfluidic channel 122; the viscosity of the first medium 180 and/or the second medium 248, or the like.
In some embodiments, the dimensions of the microfluidic channel 122 and sequestration pens 224, 226, 228 can be oriented as follows with respect to the vector of the flow 242 of fluidic medium 180 in the microfluidic channel 122: the microfluidic channel width Wch (or cross-sectional area of the microfluidic channel 122) can be substantially perpendicular to the flow 242 of medium 180; the width Wcon (or cross-sectional area) of the connection region 236 at opening 234 can be substantially parallel to the flow 242 of medium 180 in the microfluidic channel 122; and/or the length Lcon of the connection region can be substantially perpendicular to the flow 242 of medium 180 in the microfluidic channel 122. The foregoing are examples only, and the relative position of the microfluidic channel 122 and sequestration pens 224, 226, 228 can be in other orientations with respect to each other.
As illustrated in
As illustrated in
The microfluidic device 250 of
Each sequestration pen 266 can comprise an isolation structure 272, an isolation region 270 within the isolation structure 272, and a connection region 268. From a proximal opening 274 at the microfluidic channel 264 to a distal opening 276 at the isolation structure 272, the connection region 268 fluidically connects the microfluidic channel 264 to the isolation region 270. Generally, in accordance with the above discussion of
As illustrated in
As illustrated in
In various embodiments of sequestration pens (e.g. 124, 126, 128, 130, 224, 226, 228, or 266), the isolation region (e.g. 240 or 270) is configured to contain a plurality of micro-objects. In other embodiments, the isolation region can be configured to contain only one, two, three, four, five, or a similar relatively small number of micro-objects. Accordingly, the volume of an isolation region can be, for example, at least 1×106, 2×106, 4×106, 6×106 cubic microns, or more.
In various embodiments of sequestration pens, the width Wch of the microfluidic channel (e.g., 122) at a proximal opening (e.g. 234) can be about 50-1000 microns, 50-500 microns, 50-400 microns, 50-300 microns, 50-250 microns, 50-200 microns, 50-150 microns, 50-100 microns, 70-500 microns, 70-400 microns, 70-300 microns, 70-250 microns, 70-200 microns, 70-150 microns, 90-400 microns, 90-300 microns, 90-250 microns, 90-200 microns, 90-150 microns, 100-300 microns, 100-250 microns, 100-200 microns, 100-150 microns, or 100-120 microns. In some other embodiments, the width Wch of the microfluidic channel (e.g., 122) at a proximal opening (e.g. 234) can be about 200-800 microns, 200-700 microns, or 200-600 microns. The foregoing are examples only, and the width Wch of the microfluidic channel 122 can be any width within any of the endpoints listed above. Moreover, the Wch of the microfluidic channel 122 can be selected to be in any of these widths in regions of the microfluidic channel other than at a proximal opening of a sequestration pen.
In some embodiments, a sequestration pen has a height of about 30 to about 200 microns, or about 50 to about 150 microns. In some embodiments, the sequestration pen has a cross-sectional area of about 1×104-3×106 square microns, 2×104-2×106 square microns, 4×104-1×106 square microns, 2×104-5×105 square microns, 2×104-1×105 square microns or about 2×105-2×106 square microns.
In various embodiments of sequestration pens, the height Hch of the microfluidic channel (e.g., 122) at a proximal opening (e.g., 234) can be a height within any of the following heights: 20-100 microns, 20-90 microns, 20-80 microns, 20-70 microns, 20-60 microns, 20-50 microns, 30-100 microns, 30-90 microns, 30-80 microns, 30-70 microns, 30-60 microns, 30-50 microns, 40-100 microns, 40-90 microns, 40-80 microns, 40-70 microns, 40-60 microns, or 40-50 microns. The foregoing are examples only, and the height Hch of the microfluidic channel (e.g., 122) can be a height within any of the endpoints listed above. The height Hch of the microfluidic channel 122 can be selected to be in any of these heights in regions of the microfluidic channel other than at a proximal opening of a sequestration pen.
In various embodiments of sequestration pens a cross-sectional area of the microfluidic channel (e.g., 122) at a proximal opening (e.g., 234) can be about 500-50,000 square microns, 500-40,000 square microns, 500-30,000 square microns, 500-25,000 square microns, 500-20,000 square microns, 500-15,000 square microns, 500-10,000 square microns, 500-7,500 square microns, 500-5,000 square microns, 1,000-25,000 square microns, 1,000-20,000 square microns, 1,000-15,000 square microns, 1,000-10,000 square microns, 1,000-7,500 square microns, 1,000-5,000 square microns, 2,000-20,000 square microns, 2,000-15,000 square microns, 2,000-10,000 square microns, 2,000-7,500 square microns, 2,000-6,000 square microns, 3,000-20,000 square microns, 3,000-15,000 square microns, 3,000-10,000 square microns, 3,000-7,500 square microns, or 3,000 to 6,000 square microns. The foregoing are examples only, and the cross-sectional area of the microfluidic channel (e.g., 122) at a proximal opening (e.g., 234) can be any area within any of the endpoints listed above.
In various embodiments of sequestration pens, the length Lon of the connection region (e.g., 236) can be about 1-600 microns, 5-550 microns, 10-500 microns, 15-400 microns, 20-300 microns, 20-500 microns, 40-400 microns, 60-300 microns, 80-200 microns, or about 100-150 microns. The foregoing are examples only, and length Lon of a connection region (e.g., 236) can be in any length within any of the endpoints listed above.
In various embodiments of sequestration pens the width Wcon of a connection region (e.g., 236) at a proximal opening (e.g., 234) can be about 20-500 microns, 20-400 microns, 20-300 microns, 20-200 microns, 20-150 microns, 20-100 microns, 20-80 microns, 20-60 microns, 30-400 microns, 30-300 microns, 30-200 microns, 30-150 microns, 30-100 microns, 30-80 microns, 30-60 microns, 40-300 microns, 40-200 microns, 40-150 microns, 40-100 microns, 40-80 microns, 40-60 microns, 50-250 microns, 50-200 microns, 50-150 microns, 50-100 microns, 50-80 microns, 60-200 microns, 60-150 microns, 60-100 microns, 60-80 microns, 70-150 microns, 70-100 microns, or 80-100 microns. The foregoing are examples only, and the width Wcon of a connection region (e.g., 236) at a proximal opening (e.g., 234) can be different than the foregoing examples (e.g., any value within any of the endpoints listed above).
In various embodiments of sequestration pens, the width Wcon of a connection region (e.g., 236) at a proximal opening (e.g., 234) can be at least as large as the largest dimension of a micro-object (e.g., biological cell which may be a T cell, B cell, or an ovum or embryo) that the sequestration pen is intended for. The foregoing are examples only, and the width Wcon of a connection region (e.g., 236) at a proximal opening (e.g., 234) can be different than the foregoing examples (e.g., a width within any of the endpoints listed above).
In various embodiments of sequestration pens, the width Wpr of a proximal opening of a connection region may be at least as large as the largest dimension of a micro-object (e.g., a biological micro-object such as a cell) that the sequestration pen is intended for. For example, the width Wpr may be about 50 microns, about 60 microns, about 100 microns, about 200 microns, about 300 microns or may be about 50-300 microns, about 50-200 microns, about 50-100 microns, about 75-150 microns, about 75-100 microns, or about 200-300 microns.
In various embodiments of sequestration pens, a ratio of the length Lcon of a connection region (e.g., 236) to a width of the connection region (e.g., 236) at the proximal opening 234 Wcon can be greater than or equal to any of the following ratios: 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, or more. The foregoing are examples only, and the ratio of the length Lcon of a connection region 236 to a width of the connection region 236 at the proximal Wcon opening 234 can be different than the foregoing examples.
In various embodiments of microfluidic devices 100, 200, 23, 250, 280, 290, 300, 700, 800, 1000, Vmax can be set around 0.2, 0.5, 0.7, 1.0, 1.3, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.7, 7.0, 7.5, 8.0, 8.5, 9.0, 10, 11, 12, 13, 14, or 15 microliters/sec.
In various embodiments of microfluidic devices having sequestration pens, the volume of an isolation region (e.g., 240) of a sequestration pen can be, for example, at least 5×105, 8×105, 1×106, 2×106, 4×106, 6×106, 8×106, 1×107, 5×107, 1×108, 5×108, or 8×108 cubic microns, or more. In various embodiments of microfluidic devices having sequestration pens, the volume of a sequestration pen may be about 5×105, 6×105, 8×105, 1×106, 2×106, 4×106, 8×106, 1×107, 3×107, 5×107, or about 8×107 cubic microns, or more. In some other embodiments, the volume of a sequestration pen may be about 1 nanoliter to about 50 nanoliters, 2 nanoliters to about 25 nanoliters, 2 nanoliters to about 20 nanoliters, about 2 nanoliters to about 15 nanoliters, or about 2 nanoliters to about 10 nanoliters.
In various embodiment, the microfluidic device has sequestration pens configured as in any of the embodiments discussed herein where the microfluidic device has about 5 to about 10 sequestration pens, about 10 to about 50 sequestration pens, about 100 to about 500 sequestration pens; about 200 to about 1000 sequestration pens, about 500 to about 1500 sequestration pens, about 1000 to about 2000 sequestration pens, about 1000 to about 3500 sequestration pens, about 3000 to about 7000 sequestration pens, about 5000 to about 10,000 sequestration pens, about 9,000 to about 15,000 sequestration pens, or about 12,000 to about 20,000 sequestration pens. The sequestration pens need not all be the same size and may include a variety of configurations (e.g., different widths, different features within the sequestration pen).
As illustrated in
Typically, the electrical signal generation subsystem 304 will include a waveform generator (not shown). The electrical signal generation subsystem 304 can further include an oscilloscope (not shown) and/or a waveform amplification circuit (not shown) configured to amplify a waveform received from the waveform generator. The oscilloscope, if present, can be configured to measure the waveform supplied to the microfluidic device 320 held by the socket 302. In certain embodiments, the oscilloscope measures the waveform at a location proximal to the microfluidic device 320 (and distal to the waveform generator), thus ensuring greater accuracy in measuring the waveform actually applied to the device. Data obtained from the oscilloscope measurement can be, for example, provided as feedback to the waveform generator, and the waveform generator can be configured to adjust its output based on such feedback. An example of a suitable combined waveform generator and oscilloscope is the Red Pitaya™.
In certain embodiments, the nest 300 further comprises a controller 308, such as a microprocessor used to sense and/or control the electrical signal generation subsystem 304. Examples of suitable microprocessors include the Arduino™ microprocessors, such as the Arduino Nano™. The controller 308 may be used to perform functions and analysis or may communicate with an external master controller 154 (shown in
In some embodiments, the nest 300 can comprise an electrical signal generation subsystem 304 comprising a Red Pitaya™ waveform generator/oscilloscope unit (“Red Pitaya unit”) and a waveform amplification circuit that amplifies the waveform generated by the Red Pitaya unit and passes the amplified voltage to the microfluidic device 100. In some embodiments, the Red Pitaya unit is configured to measure the amplified voltage at the microfluidic device 320 and then adjust its own output voltage as needed such that the measured voltage at the microfluidic device 320 is the desired value. In some embodiments, the waveform amplification circuit can have a +6.5V to −6.5V power supply generated by a pair of DC-DC converters mounted on the PCBA 322, resulting in a signal of up to 13 Vpp at the microfluidic device 100.
As illustrated in
In some embodiments, the nest 300 can include a thermal control subsystem 306 with a feedback circuit that is an analog voltage divider circuit (not shown) which includes a resistor (e.g., with resistance 1 kOhm+/−0.1%, temperature coefficient +/−0.02 ppm/C0) and a NTC thermistor (e.g., with nominal resistance 1 kOhm+/−0.01%). In some instances, the thermal control subsystem 306 measures the voltage from the feedback circuit and then uses the calculated temperature value as input to an on-board PID control loop algorithm. Output from the PID control loop algorithm can drive, for example, both a directional and a pulse-width-modulated signal pin on a Pololu™ motor drive (not shown) to actuate the thermoelectric power supply, thereby controlling the Peltier thermoelectric device.
The nest 300 can include a serial port 324 which allows the microprocessor of the controller 308 to communicate with an external master controller 154 via the interface 310 (not shown). In addition, the microprocessor of the controller 308 can communicate (e.g., via a Plink tool (not shown)) with the electrical signal generation subsystem 304 and thermal control subsystem 306. Thus, via the combination of the controller 308, the interface 310, and the serial port 324, the electrical signal generation subsystem 304 and the thermal control subsystem 306 can communicate with the external master controller 154. In this manner, the master controller 154 can, among other things, assist the electrical signal generation subsystem 304 by performing scaling calculations for output voltage adjustments. A Graphical User Interface (GUI) (not shown) provided via a display device 170 coupled to the external master controller 154, can be configured to plot temperature and waveform data obtained from the thermal control subsystem 306 and the electrical signal generation subsystem 304, respectively. Alternatively, or in addition, the GUI can allow for updates to the controller 308, the thermal control subsystem 306, and the electrical signal generation subsystem 304.
As discussed above, system 150 can include an imaging device. In some embodiments, the imaging device comprises a light modulating subsystem 330 (See
In certain embodiments, the imaging device further comprises a microscope 350. In such embodiments, the nest 300 and light modulating subsystem 330 can be individually configured to be mounted on the microscope 350. The microscope 350 can be, for example, a standard research-grade light microscope or fluorescence microscope. Thus, the nest 300 can be configured to be mounted on the stage 344 of the microscope 350 and/or the light modulating subsystem 330 can be configured to mount on a port of microscope 350. In other embodiments, the nest 300 and the light modulating subsystem 330 described herein can be integral components of microscope 350.
In certain embodiments, the microscope 350 can further include one or more detectors 348. In some embodiments, the detector 348 is controlled by the imaging module 164. The detector 348 can include an eye piece, a charge-coupled device (CCD), a camera (e.g., a digital camera), or any combination thereof. If at least two detectors 348 are present, one detector can be, for example, a fast-frame-rate camera while the other detector can be a high sensitivity camera. Furthermore, the microscope 350 can include an optical train configured to receive reflected and/or emitted light from the microfluidic device 320 and focus at least a portion of the reflected and/or emitted light on the one or more detectors 348. The optical train of the microscope can also include different tube lenses (not shown) for the different detectors, such that the final magnification on each detector can be different.
In certain embodiments, the imaging device is configured to use at least two light sources. For example, a first light source 332 can be used to produce structured light (e.g., via the light modulating subsystem 330) and a second light source 334 can be used to provide unstructured light. The first light source 332 can produce structured light for optically-actuated electrokinesis and/or fluorescent excitation, and the second light source 334 can be used to provide bright field illumination. In these embodiments, the motive module 164 can be used to control the first light source 332 and the imaging module 164 can be used to control the second light source 334. The optical train of the microscope 350 can be configured to (1) receive structured light from the light modulating subsystem 330 and focus the structured light on at least a first region in a microfluidic device, such as an optically-actuated electrokinetic device, when the device is being held by the nest 300, and (2) receive reflected and/or emitted light from the microfluidic device and focus at least a portion of such reflected and/or emitted light onto detector 348. The optical train can be further configured to receive unstructured light from a second light source and focus the unstructured light on at least a second region of the microfluidic device, when the device is held by the nest 300. In certain embodiments, the first and second regions of the microfluidic device can be overlapping regions. For example, the first region can be a subset of the second region. In other embodiments, the second light source 334 may additionally or alternatively include a laser, which may have any suitable wavelength of light. The representation of the optical system shown in
In
In some embodiments, the second light source 334 emits blue light. With an appropriate dichroic filter 346, blue light reflected from the sample plane 342 is able to pass through dichroic filter 346 and reach the detector 348. In contrast, structured light coming from the light modulating subsystem 330 gets reflected from the sample plane 342, but does not pass through the dichroic filter 346. In this example, the dichroic filter 346 is filtering out visible light having a wavelength longer than 495 nm. Such filtering out of the light from the light modulating subsystem 330 would only be complete (as shown) if the light emitted from the light modulating subsystem did not include any wavelengths shorter than 495 nm. In practice, if the light coming from the light modulating subsystem 330 includes wavelengths shorter than 495 nm (e.g., blue wavelengths), then some of the light from the light modulating subsystem would pass through filter 346 to reach the detector 348. In such an embodiment, the filter 346 acts to change the balance between the amount of light that reaches the detector 348 from the first light source 332 and the second light source 334. This can be beneficial if the first light source 332 is significantly stronger than the second light source 334. In other embodiments, the second light source 334 can emit red light, and the dichroic filter 346 can filter out visible light other than red light (e.g., visible light having a wavelength shorter than 650 nm).
D. Coating Solutions, Coating Agents, and Coating Materials for Conditioning or Coating Microfluidic Device Inner Surfaces; Conditioned or Coated Surfaces
Without intending to be limited by theory, maintenance of a biological micro-object (e.g., a biological cell) within a microfluidic device (e.g., a DEP-configured and/or EW-configured microfluidic device) may be facilitated (i.e., the biological micro-object exhibits increased viability, greater expansion and/or greater portability within the microfluidic device) when at least one or more inner surfaces of the microfluidic device have been conditioned or coated so as to present a layer of organic and/or hydrophilic molecules that provides the primary interface between the microfluidic device and biological micro-object(s) maintained therein. In some embodiments, one or more of the inner surfaces of the microfluidic device (e.g. the inner surface of the electrode activation substrate of a DEP-configured microfluidic device, the cover of the microfluidic device, and/or the surfaces of the circuit material) may be treated with or modified by a coating solution and/or coating agent to generate the desired layer of organic and/or hydrophilic molecules.
The coating may be applied before or after introduction of biological micro-object(s), or may be introduced concurrently with the biological micro-object(s). In some embodiments, the biological micro-object(s) may be imported into the microfluidic device in a fluidic medium that includes one or more coating agents. In other embodiments, the inner surface(s) of the microfluidic device (e.g., a DEP-configured microfluidic device) are treated or “primed” with a coating solution comprising a coating agent prior to introduction of the biological micro-object(s) into the microfluidic device.
In some embodiments, at least one surface of the microfluidic device includes a coating material that provides a layer of organic and/or hydrophilic molecules suitable for maintenance and/or expansion of biological micro-object(s) (e.g. provides a conditioned surface as described below). In some embodiments, substantially all the inner surfaces of the microfluidic device include the coating material. The coated inner surface(s) may include the surface of a flow region (e.g., channel), chamber, or sequestration pen, or a combination thereof. In some embodiments, each of a plurality of sequestration pens has at least one inner surface coated with coating materials. In other embodiments, each of a plurality of flow regions or channels has at least one inner surface coated with coating materials. In some embodiments, at least one inner surface of each of a plurality of sequestration pens and each of a plurality of channels is coated with coating materials.
Coating agent/Solution. Any convenient coating agent/coating solution can be used, including but not limited to: serum or serum factors, bovine serum albumin (BSA), polymers, detergents, enzymes, and any combination thereof.
Polymer-based coating materials. The at least one inner surface may include a coating material that comprises a polymer. The polymer may be covalently or non-covalently bound (or may be non-specifically adhered) to the at least one surface. The polymer may have a variety of structural motifs, such as found in block polymers (and copolymers), star polymers (star copolymers), and graft or comb polymers (graft copolymers), all of which may be suitable for the methods disclosed herein.
The polymer may include a polymer including alkylene ether moieties. A wide variety of alkylene ether containing polymers may be suitable for use in the microfluidic devices described herein. One non-limiting exemplary class of alkylene ether containing polymers are amphiphilic nonionic block copolymers which include blocks of polyethylene oxide (PEO) and polypropylene oxide (PPO) subunits in differing ratios and locations within the polymer chain. Pluronic® polymers (BASF) are block copolymers of this type and are known in the art to be suitable for use when in contact with living cells. The polymers may range in average molecular mass Mw from about 2000 Da to about 20 KDa. In some embodiments, the PEO-PPO block copolymer can have a hydrophilic-lipophilic balance (HLB) greater than about 10 (e.g. 12-18). Specific Pluronic® polymers useful for yielding a coated surface include Pluronic® L44, L64, P85, and F127 (including F127NF). Another class of alkylene ether containing polymers is polyethylene glycol (PEG Mw<100,000 Da) or alternatively polyethylene oxide (PEO, Mw>100,000). In some embodiments, a PEG may have an Mw of about 1000 Da, 5000 Da, 10,000 Da or 20,000 Da.
In other embodiments, the coating material may include a polymer containing carboxylic acid moieties. The carboxylic acid subunit may be an alkyl, alkenyl or aromatic moiety containing subunit. One non-limiting example is polylactic acid (PLA). In other embodiments, the coating material may include a polymer containing phosphate moieties, either at a terminus of the polymer backbone or pendant from the backbone of the polymer. In yet other embodiments, the coating material may include a polymer containing sulfonic acid moieties. The sulfonic acid subunit may be an alkyl, alkenyl or aromatic moiety containing subunit. One non-limiting example is polystyrene sulfonic acid (PSSA) or polyanethole sulfonic acid. In further embodiments, the coating material may include a polymer including amine moieties. The polyamino polymer may include a natural polyamine polymer or a synthetic polyamine polymer. Examples of natural polyamines include spermine, spermidine, and putrescine.
In other embodiments, the coating material may include a polymer containing saccharide moieties. In a non-limiting example, polysaccharides such as xanthan gum or dextran may be suitable to form a material which may reduce or prevent cell sticking in the microfluidic device. For example, a dextran polymer having a size about 3 kDa may be used to provide a coating material for a surface within a microfluidic device.
In other embodiments, the coating material may include a polymer containing nucleotide moieties, i.e. a nucleic acid, which may have ribonucleotide moieties or deoxyribonucleotide moieties, providing a polyelectrolyte surface. The nucleic acid may contain only natural nucleotide moieties or may contain unnatural nucleotide moieties which comprise nucleobase, ribose or phosphate moiety analogs such as 7-deazaadenine, pentose, methyl phosphonate or phosphorothioate moieties without limitation.
In yet other embodiments, the coating material may include a polymer containing amino acid moieties. The polymer containing amino acid moieties may include a natural amino acid containing polymer or an unnatural amino acid containing polymer, either of which may include a peptide, a polypeptide or a protein. In one non-limiting example, the protein may be bovine serum albumin (BSA) and/or serum (or a combination of multiple different sera) comprising albumin and/or one or more other similar proteins as coating agents. The serum can be from any convenient source, including but not limited to fetal calf serum, sheep serum, goat serum, horse serum, and the like. In certain embodiments, BSA in a coating solution is present in a concentration from about 1 mg/mL to about 100 mg/mL, including 5 mg/mL, 10 mg/mL, 20 mg/mL, 30 mg/mL, 40 mg/mL, 50 mg/mL, 60 mg/mL, 70 mg/mL, 80 mg/mL, 90 mg/mL, or more or anywhere in between. In certain embodiments, serum in a coating solution may be present in a concentration of about 20% (v/v) to about 50% v/v, including 25%, 30%, 35%, 40%, 45%, or more or anywhere in between. In some embodiments, BSA may be present as a coating agent in a coating solution at 5 mg/mL, whereas in other embodiments, BSA may be present as a coating agent in a coating solution at 70 mg/mL. In certain embodiments, serum is present as a coating agent in a coating solution at 30%. In some embodiments, an extracellular matrix (ECM) protein may be provided within the coating material for optimized cell adhesion to foster cell growth. A cell matrix protein, which may be included in a coating material, can include, but is not limited to, a collagen, an elastin, an RGD-containing peptide (e.g. a fibronectin), or a laminin. In yet other embodiments, growth factors, cytokines, hormones or other cell signaling species may be provided within the coating material of the microfluidic device.
In some embodiments, the coating material may include a polymer containing more than one of alkylene oxide moieties, carboxylic acid moieties, sulfonic acid moieties, phosphate moieties, saccharide moieties, nucleotide moieties, or amino acid moieties. In other embodiments, the polymer conditioned surface may include a mixture of more than one polymer each having alkylene oxide moieties, carboxylic acid moieties, sulfonic acid moieties, phosphate moieties, saccharide moieties, nucleotide moieties, and/or amino acid moieties, which may be independently or simultaneously incorporated into the coating material.
Covalently linked coating materials. In some embodiments, the at least one inner surface includes covalently linked molecules that provide a layer of organic and/or hydrophilic molecules suitable for maintenance/expansion of biological micro-object(s) within the microfluidic device, providing a conditioned surface for such cells.
The covalently linked molecules include a linking group, wherein the linking group is covalently linked to one or more surfaces of the microfluidic device, as described below. The linking group is also covalently linked to a moiety configured to provide a layer of organic and/or hydrophilic molecules suitable for maintenance/expansion of biological micro-object(s).
In some embodiments, the covalently linked moiety configured to provide a layer of organic and/or hydrophilic molecules suitable for maintenance/expansion of biological micro-object(s) may include alkyl or fluoroalkyl (which includes perfluoroalkyl) moieties; mono- or polysaccharides (which may include but is not limited to dextran); alcohols (including but not limited to propargyl alcohol); polyalcohols, including but not limited to polyvinyl alcohol; alkylene ethers, including but not limited to polyethylene glycol; polyelectrolytes (including but not limited to polyacrylic acid or polyvinyl phosphonic acid); amino groups (including derivatives thereof, such as, but not limited to alkylated amines, hydroxyalkylated amino group, guanidinium, and heterocylic groups containing an unaromatized nitrogen ring atom, such as, but not limited to morpholinyl or piperazinyl); carboxylic acids including but not limited to propiolic acid (which may provide a carboxylate anionic surface); phosphonic acids, including but not limited to ethynyl phosphonic acid (which may provide a phosphonate anionic surface); sulfonate anions; carboxybetaines; sulfobetaines; sulfamic acids; or amino acids.
In various embodiments, the covalently linked moiety configured to provide a layer of organic and/or hydrophilic molecules suitable for maintenance/expansion of biological micro-object(s) in the microfluidic device may include non-polymeric moieties such as an alkyl moiety, a substituted alkyl moiety, such as a fluoroalkyl moiety (including but not limited to a perfluoroalkyl moiety), amino acid moiety, alcohol moiety, amino moiety, carboxylic acid moiety, phosphonic acid moiety, sulfonic acid moiety, sulfamic acid moiety, or saccharide moiety. Alternatively, the covalently linked moiety may include polymeric moieties, which may be any of the moieties described above.
In some embodiments, the covalently linked alkyl moiety may comprise carbon atoms forming a linear chain (e.g., a linear chain of at least 10 carbons, or at least 14, 16, 18, 20, 22, or more carbons) and may be an unbranched alkyl moiety. In some embodiments, the alkyl group may include a substituted alkyl group (e.g., some of the carbons in the alkyl group can be fluorinated or perfluorinated). In some embodiments, the alkyl group may include a first segment, which may include a perfluoroalkyl group, joined to a second segment, which may include a non-substituted alkyl group, where the first and second segments may be joined directly or indirectly (e.g., by means of an ether linkage). The first segment of the alkyl group may be located distal to the linking group, and the second segment of the alkyl group may be located proximal to the linking group.
In other embodiments, the covalently linked moiety may include at least one amino acid, which may include more than one type of amino acid. Thus, the covalently linked moiety may include a peptide or a protein. In some embodiments, the covalently linked moiety may include an amino acid which may provide a zwitterionic surface to support cell growth, viability, portability, or any combination thereof.
In other embodiments, the covalently linked moiety may include at least one alkylene oxide moiety, and may include any alkylene oxide polymer as described above. One useful class of alkylene ether containing polymers is polyethylene glycol (PEG Mw<100,000 Da) or alternatively polyethylene oxide (PEO, Mw>100,000). In some embodiments, a PEG may have an Mw of about 1000 Da, 5000 Da, 10,000 Da or 20,000 Da.
The covalently linked moiety may include one or more saccharides. The covalently linked saccharides may be mono-, di-, or polysaccharides. The covalently linked saccharides may be modified to introduce a reactive pairing moiety which permits coupling or elaboration for attachment to the surface. Exemplary reactive pairing moieties may include aldehyde, alkyne or halo moieties. A polysaccharide may be modified in a random fashion, wherein each of the saccharide monomers may be modified or only a portion of the saccharide monomers within the polysaccharide are modified to provide a reactive pairing moiety that may be coupled directly or indirectly to a surface. One exemplar may include a dextran polysaccharide, which may be coupled indirectly to a surface via an unbranched linker.
The covalently linked moiety may include one or more amino groups. The amino group may be a substituted amine moiety, guanidine moiety, nitrogen-containing heterocyclic moiety or heteroaryl moiety. The amino containing moieties may have structures permitting pH modification of the environment within the microfluidic device, and optionally, within the sequestration pens and/or flow regions (e.g., channels).
The coating material providing a conditioned surface may comprise only one kind of covalently linked moiety or may include more than one different kind of covalently linked moiety. For example, the fluoroalkyl conditioned surfaces (including perfluoroalkyl) may have a plurality of covalently linked moieties which are all the same, e.g., having the same linking group and covalent attachment to the surface, the same overall length, and the same number of fluoromethylene units comprising the fluoroalkyl moiety. Alternatively, the coating material may have more than one kind of covalently linked moiety attached to the surface. For example, the coating material may include molecules having covalently linked alkyl or fluoroalkyl moieties having a specified number of methylene or fluoromethylene units and may further include a further set of molecules having charged moieties covalently attached to an alkyl or fluoroalkyl chain having a greater number of methylene or fluoromethylene units, which may provide capacity to present bulkier moieties at the coated surface. In this instance, the first set of molecules having different, less sterically demanding termini and fewer backbone atoms can help to functionalize the entire substrate surface and thereby prevent undesired adhesion or contact with the silicon/silicon oxide, hafnium oxide or alumina making up the substrate itself. In another example, the covalently linked moieties may provide a zwitterionic surface presenting alternating charges in a random fashion on the surface.
Conditioned surface properties. Aside from the composition of the conditioned surface, other factors such as physical thickness of the hydrophobic material can impact DEP force. Various factors can alter the physical thickness of the conditioned surface, such as the manner in which the conditioned surface is formed on the substrate (e.g. vapor deposition, liquid phase deposition, spin coating, flooding, and electrostatic coating). In some embodiments, the conditioned surface has a thickness of about 1 nm to about 10 nm; about 1 nm to about 7 nm; about 1 nm to about 5 nm; or any individual value therebetween. In other embodiments, the conditioned surface formed by the covalently linked moieties may have a thickness of about 10 nm to about 50 nm. In various embodiments, the conditioned surface prepared as described herein has a thickness of less than 10 nm. In some embodiments, the covalently linked moieties of the conditioned surface may form a monolayer when covalently linked to the surface of the microfluidic device (e.g., a DEP configured substrate surface) and may have a thickness of less than 10 nm (e.g., less than 5 nm, or about 1.5 to 3.0 nm). These values are in contrast to that of a surface prepared by spin coating, for example, which may typically have a thickness of about 30 nm. In some embodiments, the conditioned surface does not require a perfectly formed monolayer to be suitably functional for operation within a DEP-configured microfluidic device.
In various embodiments, the coating material providing a conditioned surface of the microfluidic device may provide desirable electrical properties. Without intending to be limited by theory, one factor that impacts robustness of a surface coated with a particular coating material is intrinsic charge trapping. Different coating materials may trap electrons, which can lead to breakdown of the coating material. Defects in the coating material may increase charge trapping and lead to further breakdown of the coating material. Similarly, different coating materials have different dielectric strengths (i.e. the minimum applied electric field that results in dielectric breakdown), which may impact charge trapping. In certain embodiments, the coating material can have an overall structure (e.g., a densely-packed monolayer structure) that reduces or limits that amount of charge trapping.
In addition to its electrical properties, the conditioned surface may also have properties that are beneficial in use with biological molecules. For example, a conditioned surface that contains fluorinated (or perfluorinated) carbon chains may provide a benefit relative to alkyl-terminated chains in reducing the amount of surface fouling. Surface fouling, as used herein, refers to the amount of indiscriminate material deposition on the surface of the microfluidic device, which may include permanent or semi-permanent deposition of biomaterials such as protein and its degradation products, nucleic acids and respective degradation products and the like.
Unitary or Multi-part conditioned surface. The covalently linked coating material may be formed by reaction of a molecule which already contains the moiety configured to provide a layer of organic and/or hydrophilic molecules suitable for maintenance/expansion of biological micro-object(s) in the microfluidic device, as is described below. Alternatively, the covalently linked coating material may be formed in a two-part sequence by coupling the moiety configured to provide a layer of organic and/or hydrophilic molecules suitable for maintenance/expansion of biological micro-object(s) to a surface modifying ligand that itself has been covalently linked to the surface.
Methods of preparing a covalently linked coating material. In some embodiments, a coating material that is covalently linked to the surface of a microfluidic device (e.g., including at least one surface of the sequestration pens and/or flow regions) has a structure of Formula 1 or Formula 2. When the coating material is introduced to the surface in one step, it has a structure of Formula 1, while when the coating material is introduced in a multiple step process, it has a structure of Formula 2.
The coating material may be linked covalently to oxides of the surface of a DEP-configured or EW-configured substrate. The DEP- or EW-configured substrate may comprise silicon, silicon oxide, alumina, or hafnium oxide. Oxides may be present as part of the native chemical structure of the substrate or may be introduced as discussed below.
The coating material may be attached to the oxides via a linking group (“LG”), which may be a siloxy or phosphonate ester group formed from the reaction of a siloxane or phosphonic acid group with the oxides. The moiety configured to provide a layer of organic and/or hydrophilic molecules suitable for maintenance/expansion of biological micro-object(s) in the microfluidic device can be any of the moieties described herein. The linking group LG may be directly or indirectly connected to the moiety configured to provide a layer of organic and/or hydrophilic molecules suitable for maintenance/expansion of biological micro-object(s) in the microfluidic device. When the linking group LG is directly connected to the moiety, optional linker (“L”) is not present and n is 0. When the linking group LG is indirectly connected to the moiety, linker L is present and n is 1. The linker L may have a linear portion where a backbone of the linear portion may include 1 to 200 non-hydrogen atoms selected from any combination of silicon, carbon, nitrogen, oxygen, sulfur and/or phosphorus atoms, subject to chemical bonding limitations as is known in the art. It may be interrupted with any combination of one or more moieties, which may be chosen from ether, amino, carbonyl, amido, and/or phosphonate groups, arylene, heteroarylene, or heterocyclic groups. In some embodiments, the backbone of the linker L may include 10 to 20 atoms. In other embodiments, the backbone of the linker L may include about 5 atoms to about 200 atoms; about 10 atoms to about 80 atoms; about 10 atoms to about 50 atoms; or about 10 atoms to about 40 atoms. In some embodiments, the backbone atoms are all carbon atoms.
In some embodiments, the moiety configured to provide a layer of organic and/or hydrophilic molecules suitable for maintenance/expansion of biological micro-object(s) may be added to the surface of the substrate in a multi-step process, and has a structure of Formula 2, as shown above. The moiety may be any of the moieties described above.
In some embodiments, the coupling group CG represents the resultant group from reaction of a reactive moiety Rx and a reactive pairing moiety Rpx (i.e., a moiety configured to react with the reactive moiety Rx). For example, one typical coupling group CG may include a carboxamidyl group, which is the result of the reaction of an amino group with a derivative of a carboxylic acid, such as an activated ester, an acid chloride or the like. Other CG may include a triazolylene group, a carboxamidyl, thioamidyl, an oxime, a mercaptyl, a disulfide, an ether, or alkenyl group, or any other suitable group that may be formed upon reaction of a reactive moiety with its respective reactive pairing moiety. The coupling group CG may be located at the second end (i.e., the end proximal to the moiety configured to provide a layer of organic and/or hydrophilic molecules suitable for maintenance/expansion of biological micro-object(s) in the microfluidic device) of linker L, which may include any combination of elements as described above. In some other embodiments, the coupling group CG may interrupt the backbone of the linker L. When the coupling group CG is triazolylene, it may be the product resulting from a Click coupling reaction and may be further substituted (e.g., a dibenzocylcooctenyl fused triazolylene group).
In some embodiments, the coating material (or surface modifying ligand) is deposited on the inner surfaces of the microfluidic device using chemical vapor deposition. The vapor deposition process can be optionally improved, for example, by pre-cleaning the cover 110, the microfluidic circuit material 116, and/or the substrate (e.g., the inner surface 208 of the electrode activation substrate 206 of a DEP-configured substrate, or a dielectric layer of the support structure 104 of an EW-configured substrate), by exposure to a solvent bath, sonication or a combination thereof. Alternatively, or in addition, such pre-cleaning can include treating the cover 110, the microfluidic circuit material 116, and/or the substrate in an oxygen plasma cleaner, which can remove various impurities, while at the same time introducing an oxidized surface (e.g. oxides at the surface, which may be covalently modified as described herein). Alternatively, liquid-phase treatments, such as a mixture of hydrochloric acid and hydrogen peroxide or a mixture of sulfuric acid and hydrogen peroxide (e.g., piranha solution, which may have a ratio of sulfuric acid to hydrogen peroxide from about 3:1 to about 7:1) may be used in place of an oxygen plasma cleaner.
In some embodiments, vapor deposition is used to coat the inner surfaces of the microfluidic device 200 after the microfluidic device 200 has been assembled to form an enclosure 102 defining a microfluidic circuit 120. Without intending to be limited by theory, depositing such a coating material on a fully-assembled microfluidic circuit 120 may be beneficial in preventing delamination caused by a weakened bond between the microfluidic circuit material 116 and the electrode activation substrate 206 dielectric layer and/or the cover 110. In embodiments where a two-step process is employed the surface modifying ligand may be introduced via vapor deposition as described above, with subsequent introduction of the moiety configured provide a layer of organic and/or hydrophilic molecules suitable for maintenance/expansion of biological micro-object(s). The subsequent reaction may be performed by exposing the surface modified microfluidic device to a suitable coupling reagent in solution.
In the embodiment shown in
In other embodiments, the coating material 298 used to coat the inner surface(s) 292, 294 of the microfluidic device 290 can include anionic, cationic, or zwitterionic moieties, or any combination thereof. Without intending to be limited by theory, by presenting cationic moieties, anionic moieties, and/or zwitterionic moieties at the inner surfaces of the enclosure 284 of the microfluidic circuit 120, the coating material 298 can form strong hydrogen bonds with water molecules such that the resulting water of hydration acts as a layer (or “shield”) that separates the biological micro-objects from interactions with non-biological molecules (e.g., the silicon and/or silicon oxide of the substrate). In addition, in embodiments in which the coating material 298 is used in conjunction with coating agents, the anions, cations, and/or zwitterions of the coating material 298 can form ionic bonds with the charged portions of non-covalent coating agents (e.g. proteins in solution) that are present in a medium 180 (e.g. a coating solution) in the enclosure 284.
In still other embodiments, the coating material may comprise or be chemically modified to present a hydrophilic coating agent at its enclosure-facing terminus. In some embodiments, the coating material may include an alkylene ether containing polymer, such as PEG. In some embodiments, the coating material may include a polysaccharide, such as dextran. Like the charged moieties discussed above (e.g., anionic, cationic, and zwitterionic moieties), the hydrophilic coating agent can form strong hydrogen bonds with water molecules such that the resulting water of hydration acts as a layer (or “shield”) that separates the biological micro-objects from interactions with non-biological molecules (e.g., the silicon and/or silicon oxide of the substrate).
Further details of appropriate coating treatments and modifications may be found at U.S. application Ser. No. 15/135,707, filed on Apr. 22, 2016, and is incorporated by reference in its entirety.
Additional system components for maintenance of viability of cells within the sequestration pens of the microfluidic device. In order to promote growth and/or expansion of cell populations, environmental conditions conducive to maintaining functional cells may be provided by additional components of the system. For example, such additional components can provide nutrients, cell growth signaling species, pH modulation, gas exchange, temperature control, and removal of waste products from cells.
Methods of loading. Loading of biological micro-objects or micro-objects such as, but not limited to, beads, can involve the use of fluid flow, gravity, a dielectrophoresis (DEP) force, electrowetting, a magnetic force, or any combination thereof as described herein. The DEP force can be generated optically, such as by an optoelectronic tweezers (OET) configuration and/or electrically, such as by activation of electrodes/electrode regions in a temporal/spatial pattern. Similarly, electrowetting force may be provided optically, such as by an opto-electro wetting (OEW) configuration and/or electrically, such as by activation of electrodes/electrode regions in a temporal spatial pattern.
In some embodiments, the method may include lysing the biological cell and allowing nucleic acids released from the lysed biological cell to be captured by the plurality of capture oligonucleotides comprised by the capture object. In some embodiments, lysing the biological cell is performed such that a plasma membrane of the biological cell is degraded, releasing cytoplasmic RNA from the biological cell. In some embodiments, the lysing reagent may include at least one ribonuclease inhibitor.
An exemplary lysis reagent is commercially available in the Single Cell Lysis Kit, Ambion Catalog No. 4458235. This reagent can be flowed into the microfluidic channel of a microfluidic device and permitted to diffuse into sequestration pens, followed by a suitable exposure period (e.g., 10 minutes; shorter or longer periods may be appropriate depending on cell type, temperature, etc.). Lysis can be stopped by flowing in an appropriate stop lysis buffer, e.g., from the Single Cell Lysis Kit, Ambion Catalog No. 4458235 and incubating for an appropriate time. Similar results can be obtained using other lysis buffers, including but not limited to Clontech lysis buffer, Cat #635013, which does not require a stop lysis treatment step. Released mRNA can be captured by a capture object present within the same sequestration pen.
The capture oligonucleotides of the capture object include a capture sequence configured to capture RNA. In some embodiments, the capture sequence is an oligonucleotide sequence having from about 6 to about 50 nucleotides. In some embodiments, the capture oligonucleotide sequence captures a nucleic acid by hybridizing to a nucleic acid released from a cell of interest. For example, PolyT sequences, (having about 30 to about 40 nucleotides) can capture and hybridize to RNA fragments having PolyA at their 3′ ends. The polyT sequence may further contain two nucleotides VN at its 3′ end.
Following capture using a capture object, RNA may be reverse transcribed into cDNA. The method of obtaining cDNA from released nucleic acid may be more fully understood by turning to
Also included in box 0916 is Pool Indexing box 918 where tagmented DNA 940 is acted upon by primers 935a and 935b. A first primer 935a, directed against the tagmentation adaptor 942 introduce a P7 sequencing adaptor 932, having a sequence of: 5′-CAAGCAGAAGACGGCATACGAGAT-3 (SEQ ID NO. 107);
and also introduces optional Pool Index 934. A second primer 935b, having a sequence of: (5′-AATGATACGGCGACCACCGAGATCTACACTCTTTCCCTACACGACGCTCTTC C*G*A*T*C*T-3 (SEQ ID No. 106) has a portion directed against priming sequence 520 and introduces a P5 sequencing adaptor sequence 936. The sized, indexed and adapted sequencing library 950 may be sequenced in the Sequencing box 922, where a first sequencing read 955 (point of sequence read initiation reads the barcode 525 and optional UMI 539. A second sequencing read 960 reads Pool Index 934. A third sequencing read 965 reads a desired number of bp within the DNA library itself, to generate genomic reads.
One or more capture objects decorated with a plurality of cDNA may be provided, e.g., following reverse transcription of captured RNA as discussed above.
In some embodiments, a combination of capture objects is provided wherein a first capture object comprises a first plurality of cDNAs decorating the capture object, each cDNA of the first plurality comprising an oligonucleotide sequence complementary to a captured RNA molecule from a first cell, which was contacted with a test agent under a first condition before preparing cDNA therefrom. The combination of capture objects may comprise a second capture object comprising a second plurality of cDNAs decorating the capture object, each cDNA of the second plurality comprising an oligonucleotide sequence complementary to a captured RNA molecule from a second cell. In some embodiments, the second cell was, before preparing cDNA therefrom: (i) not contacted with the test agent or (ii) contacted with the test agent under a second condition different from the first condition. In some embodiments, the second cell was, before preparing cDNA therefrom, not contacted with the test agent but was contacted with an alternative agent. In some embodiments, the level of at least one cDNA differs in the first plurality and the second plurality. For example, at least 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, or 50 cDNAs may be more abundant in the first plurality than in the second plurality. Alternatively or in addition, at least 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, or 50 cDNAs may be more abundant in the second plurality than in the first plurality. Abundance may be in absolute terms (number of molecules) or relative terms (fraction of total cDNA).
In some embodiments, the at least one cDNA that differs in the first plurality and the second plurality comprises a tumor suppressor cDNA, an oncogene cDNA, a cDNA involved in cell cycle progression and/or circadian rhythms, a cDNA involved in programmed cell death, a cDNA involved in maintaining developmental plasticity differs in the first plurality of cDNAs and the second plurality of cDNAs, or a cDNA involved in cellular differentiation differs in the first plurality of cDNAs and the second plurality of cDNAs. A cDNA is considered to be a tumor suppressor cDNA if it is a cDNA reverse transcribed from a tumor suppressor gene mRNA or a copy thereof. The other types of cDNA referred to above have parallel meanings.
In some embodiments, the method further comprises exporting said capture object from said microfluidic device prior to generating said sequence from said plurality of cDNAs decorating said capture object. Exporting the plurality of the capture objects may include exporting each of the plurality of the capture objects individually. In some embodiments, the method may further include delivering each capture object of the plurality to a separate destination container outside of the microfluidic device. The destination container may be a cell culture flask, dish, petri dish, multi-well plate, or the like.
By way of an introductory overview,
This workflow may also be adapted to PacBio library preparation (SMRT system, Pacific Biosystems) by processing the barcoded cDNA obtained above, and SMRTbell adaptors may be directly ligated to the full length barcoded transcripts.
A. Generating Sequence from cDNA
In some embodiments, methods disclosed herein comprise generating sequence from cDNA associated with capture objects. Based on the workflows described herein, a variety of sequencing libraries may be prepared that will permit correlation of sequence data with the location of the source cell as well as phenotype information observed for that cell. The approaches shown here are adapted for eventual use with Illumina® sequencing by synthesis chemistries, but are not so limited. Any sort of sequencing chemistries may be suitable for use within these methods and may include emulsion PCR, sequencing by synthesis, pyrosequencing and semiconductor detection. One of skill can adapt the methods and construction of the capture oligonucleotides and associated adaptors, primers and the like to use these methods within other massively parallel sequencing platforms and chemistries such as PacBio long read systems (SMRT, Pacific Biosystems), Ion Torrent (ThermoFisher Scientific), Roche 454, Oxford Nanopore, and the like.
A barcoded sequencing library may be prepared, for example, by a method including: amplifying a cDNA library of a capture object or a cDNA library of each of a plurality of the capture objects obtained by any method described herein; and tagmenting the amplified DNA library or the plurality of cDNA libraries, thereby producing one or a plurality of barcoded sequencing libraries. In various embodiments, amplifying the cDNA library or the plurality of cDNA libraries may include introducing a pool index sequence, wherein the pool index sequence comprises 4 to 10 nucleotides. In other embodiments, the method may further include combining a plurality of the barcoded sequencing libraries, wherein each barcoded sequencing library of the plurality comprises a different barcode sequence and/or a different pool index sequence.
In some embodiments, the method described herein can be used to identify changes in gene transcription following the cell being contacted with a test agent as described herein. For example, which genes are upregulated, downregulated, induced, or inhibited in individual biological cells may be determined by comparing the sequence from cells contacted with the test agent to sequence from control cells. For example, this method could be used to detect the effect on transcription of a drug or drug candidate.
In some embodiments control cells have same origin as the test cells. For example, control cells may come from the same cell line. A control cell may also come from the same preparation of primary cells derived from a tissue; or from the same clonal colony. A colony of biological cells is considered “clonal” if all of the living cells in the colony that are capable of reproducing are daughter cells derived from a single parent cell.
In some embodiments, control cells are processed in the same manner as test cells prior to sequencing except control cells are not contacted with test agent. In some embodiments test and control cells may be contacted with first and second labeled antibodies, respectively prior to lysing. The label may be a nucleic acid, for example RNA or DNA, that is covalently conjugated to the antibody, wherein the bond is labile or susceptible to breaking during the lysing step. In some embodiments, the labels on the first and second antibodies are different, e.g., different bar codes.
In certain embodiments, the one or more genes that are analyzed for (or detected as having) a change in transcription comprise one or more oncogenes. An oncogene results from the activation of a normal cellular gene or proto-oncogene, whose gene products function in cellular growth-controlling pathways. In some embodiments, the oncogene is any gene that encodes a protein able to transform cells in culture. In some embodiments, the oncogene is any gene that encodes a protein able to induce cancer in animals. For example, the ras gene is a proto-oncogene that encodes an intracellular signal-transduction protein, and mutations in ras can result in excessive or uncontrolled growth-promoting signal.
In certain embodiments, the one or more genes that are analyzed for (or detected as having) a change in transcription comprise one or more tumor suppressor genes. Normally tumor suppressor genes are involved in DNA repair or apoptosis but when tumor suppressor genes become inactivated, cancer develops. For example, inactivation of the p53 tumor suppressor protein has been detected in several cancers including colon cancer, breast cancer, and lung cancer. Mutations in p53 are present in leukemias, lymphomas, sarcomas, and neurogenic tumors.
In certain embodiments, the one or more genes that are analyzed for (or detected as having) a change in transcription comprise one or more genes involved in cell cycle progression. For example, protein kinases known as the cyclin dependent kinases (cdk) are responsible for initiating the major cell cycle transitions. An example is the gene cdc2 which encodes Cdc2, a protein-serine/threonine kinase that is a key regulator of mitosis in eukaryotic cells.
In certain embodiments, the one or more genes that are analyzed for (or detected as having) a change in transcription comprise one or more genes involved in circadian rhythm. In genes that affect circadian rhythms include genes for transcription factors such as Clock, for enzymes such CK1, nuclear receptors such as Rorγ, and the like.
In certain embodiments, the one or more genes that are analyzed for (or detected as having) a change in transcription comprise one or more genes involved in programmed cell death (including activation or inhibition thereof). Examples of these genes include those encoding initiator caspases (caspase-2, -8, -9, -10), effector or executioner caspases (caspase-3, -6, -7) and inflammatory caspases (caspase-1, -4, -5). Inhibitors of programmed cell death include the genes encoding c-FLIP, Toso, and ICAD.
In certain embodiments, the one or more genes that are analyzed for (or detected as having) a change in transcription comprise one or more genes involved in maintaining developmental plasticity. For example, environmental or developmental mechanisms such as DNA methylation, histone modifications and non-coding RNAs can stably alter gene expression without changing the underlying DNA sequence.
In certain embodiments, the one or more genes that are analyzed for (or detected as having) a change in transcription comprise one or more genes involved in cellular differentiation. Differentiation is the process by which unspecialized cells such as stem cells, become specialized to carry out distinct functions. In order for a cell to differentiate into its specialized form and function, genes (and thus those proteins) that will be expressed, and those that will be silent, are modulated by transcription factors. Examples of differentiation processes include, e.g., neural differentiation, endothelial differentiation, cardiac differentiation, muscle differentiation, liver differentiation, fat differentiation, bone differentiation, bone marrow differentiation, immunological differentiation, skin differentiation, and gut differentiation.
A kit is also provided for use in methods of assaying a biological cell such as any of those disclosed herein. In some embodiments, the kit includes: a microfluidic device comprising an enclosure, where the enclosure includes a flow region and a plurality of sequestration pens opening off of the flow region; and capture objects described herein. In some embodiments, a first plurality and a second plurality of capture objects are provided, wherein the first and second pluralities comprise first and second capture oligonucleotides, respectively, which are configured to generate differentially tagged or barcoded cDNA upon reverse transcription of captured RNA. Further materials that may be included in the kits include DAPI for staining nuclei; lysing reagent; reagents for making cDNA including reverse transcriptase; reagents for tagmentation; and instructions for carrying out a method described herein.
System and Microfluidic device. System and Microfluidic device: Manufactured by Berkeley Lights, Inc. The system included at least a flow controller, temperature controller, fluidic medium conditioning and pump component, light source for light activated DEP configurations, mounting stage for the microfluidic device, and a camera. The microfluidic device was an OptoSelect™ device (Berkeley Lights, Inc.), configured with OptoElectroPositioning (OEP™) technology. The microfluidic device included a microfluidic channel and a plurality of NanoPen™ chambers fluidically connected thereto, with the chambers having a volume of about 7×105 cubic microns.
Priming regime. 250 microliters of 100% carbon dioxide was flowed in at a rate of 12 microliters/sec. This was followed by 250 microliters of a priming medium composed as follows: 1000 ml Iscove's Modified Dulbecco's Medium (ATCC® Catalog No. 30-2005), 200 ml Fetal Bovine Serum (ATCC® Cat. #30-2020), 10 ml penicillin-streptomycin (Life Technologies® Cat. #15140-122), and 10 mL Pluronic F-127 (Life Tech Catalog No. 50-310-494). The final step of priming included 250 microliters of the priming medium, flowed in at 12 microliters/sec. Introduction of the culture medium follows.
Perfusion regime. The perfusion method was either of the following two methods:
1. Perfuse at 0.01 microliters/sec for 2 h; perfuse at 2 microliters/sec for 64 sec; and repeat.
2. Perfuse at 0.02 microliters/sec for 100 sec; stop flow 500 sec; perfuse at 2 microliters/sec for 64 sec; and repeat.
Barcoded nucleic acid capture beads: Beads were either polystyrene (16 micron) or magnetic (22 micron), Spherotech #SVP-150-4 or #SVM-200-4. Beads were modified to include oligonucleotides having a barcode as described herein. The barcoded beads may be synthesized in any suitable manner as is known in the art.
RNA sequencing: The beads were modified to display an oligo(dT) capture sequence/Unique Molecular Identifier sequence/barcode/priming sequence. The barcode was selected to be unique for each bead. The oligo(dT) primer/Unique molecular identifier tag/Cell Barcode/primer sequence may be synthesized by total oligonucleotide synthesis, split and pool synthesis, ligation of oligonucleotide segments of any length, or any combination thereof. The oligo(dT) primer/Unique molecular identifier tag/Cell Barcode/primer sequence may be covalently attached directly or indirectly to the bead or may be attached non-covalently, e.g., via a streptavidin/biotin linker or the like. In this experiment, a fully synthesized oligonucleotide including the capture sequence, UMI, barcode and priming sequence was attached to the bead via a non-covalent biotin/streptavidin linkage.
Cells: OKT3 cells, a murine myeloma hybridoma cell line, were obtained from the ATCC (ATCC® Cat. #CRL-8001™). The cells were provided as a suspension cell line. Cultures were maintained by seeding about 1×105 to about 2×105 viable cells/mL and incubating at 37° C., using 5% carbon dioxide in air as the gaseous environment. Cells were split every 2-3 days. OKT3 cell number and viability were counted and cell density is adjusted to 5×105/ml for loading to the microfluidic device.
Culture medium: 1000 ml Iscove's Modified Dulbecco's Medium (ATCC® Catalog No. 30-2005), 200 ml Fetal Bovine Serum (ATCC® Cat. #30-2020) and 10 ml penicillin-streptomycin (Life Technologies® Cat. #15140-122) were combined to make the culture medium. The complete medium was filtered through a 0.22 μm filter and stored away from light at 4° C. until use.
When perfusing during incubation periods, the culture medium was conditioned continuously with 5% carbon dioxide in air before introduction into the OptoSelect device.
Experiment: A sample of OKT3 cells were introduced into the OptoSelect device at a density of 2E6 in 200 microliters. 250 of the cells were moved by optically actuated dielectrophoretic force to load one cell per NanoPen chamber. Each cell was positioned within the section of the chamber furthest from the opening to the microfluidic channel (e.g., isolation region). A single uniquely barcoded bead was subsequently loaded into each of the occupied chambers. The total number of beads loaded to the NanoPen chambers having single biological cells was 223, and each bead was also positioned within the portion of each chamber that was not subjected to penetrating fluidic flow. In this experiment, 256 uniquely barcoded beads were created, each having a total of 4 cassetable sequences. Diversity was created by selecting by selecting one of four possible sequences in a first position; one of four of a second, different set of four possible sequences in a second position, one of four of a third different set of four possible sequences in a third position and one of four of a fourth different set of four possible sequences in a four position within the barcode.
Lysis reagent (Single Cell Lysis Kit, Ambion Catalog No. 4458235) was flowed into the microfluidic channel and permitted to diffuse into the NanoPen chambers. The individually penned OKT3 cells were exposed to the lysis buffer for 10 minutes. Lysis was stopped by flowing in stop lysis buffer (Single Cell Lysis Kit, Ambion Catalog No. 4458235) and incubating for 2 minutes at room temperature while there was no flow in the microfluidic channel. (Similar results can be obtained using other lysis buffers, including but not limited to Clontech lysis buffer, Cat #635013, which does not require a stop lysis treatment step. Under the conditions used, the nuclear membrane was not disrupted. The released mRNA was captured onto the barcoded bead present within the same NanoPen chamber.
The captured RNA was reverse transcribed to cDNA by flowing in a RT reagent mixture (Thermo Scientific™ Maxima™ H Minus RT (Thermofisher, Catalog No. EP0751: 4 mciroliters of RT buffer; 2 microliters of 10 millimolar each of dNTPs (New England Biolabs Cat #NO447L; 2 microliters of 10 micromolar E5V6 primer (5Me-isodC//iisodG//iMe-isodC/ACACTCTTTCCCTACACGACGCrGrGrG; SEQ ID No. 103); 1 microliter H Minus RT enzyme; 11 microliters of water). Alternatively, a Clontech SMARTscribe™ reverse transcriptase kit (Cat. #639536), including enzyme, buffer and DTT can be used to obtain cDNA from the captured nucleic acid. Diffusion of the reagent mixture into the NanoPen Chamber was permitted during a 20 minute period at 16° C., followed by a reaction period of 90 minutes at 42° C.
After reverse transcription, a blank export of 12 microliters at 3 microliters/sec was performed as negative control. This control was then processed separately but similarly to handling of the export group of beads as described below.
The unique Cell Barcode was then identified for each bead by multiplexed flows of fluorescently labeled hybridization probes as described above. Fluorescently labeled probes (provided in sets of four probes per reagent flow, each probe containing a different fluorophore and a non-identical oligonucleotide sequence from any of the other probes in the flow) were flowed, each group of four probes having distinguishable fluorescent labels, into the microfluidic channel of the microfluidic device at 1 micromolar diluted in 1×DPBS from a 100 mM stock, and permitted to diffuse into the NanoPen chambers at 16° C. over a period of 20 min, and then permitted to hybridize for 90 minutes at 42 C. (Alternatively, a different buffer solution, IDT Duplex buffer Cat. #11-05-01-12 was also used successfully. Use of this buffer, which is nuclease free, and contains 30 mM Hepes, and 100 mM potassium acetate at pH7.5, also facilitated excellent duplex formation under these conditions.) After completion of the hybridization period, fresh medium (DPBS or Duplex buffer) was flowed through the microfluidic device for 20 min (300 microliters, at 0.25 microliter/sec) to flush unassociated hybridization probes out of the flow region of the microfluidic device. The flush period was selected to be long enough for unhybridized hybridization probes to diffuse out of each NanoPen chamber. Each distinguishable fluorescent wavelength (Cy5, FITC, DAPI, and Texas Red channels) was subsequently excited, and identification of which, if any of the NanoPen chambers demonstrated a fluorescent signal. The location and color of the fluorescent label of each probe localized to a NanoPen chamber was noted, and correlated to the known sequence and fluorescent label of the hybridization probes of the first reagent flow, and the identity of the corresponding cassetable sequence of the barcode on the bead was assigned. Successive additional reagent flows of further sets of fluorescently labeled hybridization probes, each having non-identical oligonucleotide sequences to each other and different from the sequences of the first and any other preceding reagent flows were flowed in as above and detection continued. Between each round of reagent flow and detection, flushing was performed using a first flush of 100 microliters of 1×DPBS (Dulbecco's PBS), followed by a second 50 microliter flush of the same medium, both performed at 0.5 microliters/sec. To minimize misidentification of a cassetable sequence in a second or further reagent flow, only the first identified fluorescent signal of each distinguishable fluorophore was used to assign cassetable sequence identity for the barcode. Upon completing reagent flows totaling all of the cassetable sequences used in the barcodes of all the beads within the microfluidic device, the barcodes for all beads in the NanoPen chambers were assigned to each respective single NanoPen chamber. The assigned location of a specific barcode sequence assigned by this method was used to identify from which specific cell the RNA was captured to the bead, e.g., the location of the source nucleic acid within the Nanopen chambers of the microfluidic device.
Optically actuated dielectrophoretic force was then used to export the barcoded beads from the NanoPen chambers into the flow region (e.g., flow channel) in a displacement buffer, 10 micromolar Tris, as shown in
Initial purification of the crude amplification mixture for the export group was performed using 0.6×SPRI (Solid Phase Reversible Immobilization) beads (Agencourt AMPure XP beads (Beckman Coulter, catalog no. A63881) according to supplier instructions. Quantification was performed (Bioanalyzer 2100, Agilent, Inc.) electrophoretically and/or fluorescently (Qubit™, ThermoFisher Scientific) (
Sequencing was performed using a MiSeq Sequencer (Illumina®, Inc.). Initial analysis of sequencing results indicated that data obtained from the blank control export looks different from the export group of DNA bearing beads, and the sequencing reads appear to be related with positive control sequences. (data not shown). Analyzing barcode identity within the blank control export, it was seen that most highly represented barcodes were derived from the positive control beads. (data not shown). Because the barcodes were linkable to a specific NanoPen chamber, comparison of cell barcodes showed that the Cell Barcodes from detected and exported beads (“unpenned”) were far more represented than the Cell Barcodes that were detected but had not been exported from its specific NanoPen chamber location (“not unpenned”). As shown in
Some other analyses were used to evaluate the quality of the sequencing sample library. An off-chip experiment was conducted using 1 ng of extracted total RNA from a pool of the same cells. cDNA was prepared using a mix of beads containing all 256 barcode combinations. The downstream processing was performed as described above, providing a bulk control, requiring no identification of barcodes. Equal amounts of input DNA were sequenced from each of these inputs. Comparison of the sequencing data obtained from these samples is shown in
The microfluidic system, materials and methods were the same as in Experiment 1, except for the following:
Cells: Control cells were human peripheral blood T cells. Sample cells were human T cells derived from a human tumor sample.
Culture medium: RPMI 1640 medium (Gibco, #12633-012), 10% Fetal Bovine Serum (FBS), (Seradigm, #1500-500); 2% Human AB Serum (Zen-bio, #HSER-ABP100 ml), IL-2 (R&D Systems, 202-IL-010) 2 U/ml; IL-7 (PeproTech, #200-07) 10 ng/ml; IL-15 {PeproTech, #200-15) 10 ng/ml, 1×Pluronic F-127 (Life Tech Catalog No. 50-310-494).
Human T cells derived from a human tumor sample were stained with an antigen off-chip then introduced to the microfluidic channel of the OptoSelect device at a density of at a density of 5×E6 cells/ml. Both antigen positive T cells (P-Ag) and antigen negative cells (N-Ag) were moved by optically actuated dielectrophoretic force to isolate a single T cell into an individual NanoPen chamber, forming a plurality of populated NanoPen chambers.
Human peripheral blood T cells were activated in the presence of CD3/28 beads (Dynabeads® Human T-Activator CD2/CD28, ThermoFisher No. Gibco™ #11131D), during a four day culture period (
To each occupied chamber, were added a single barcoded bead which were synthesized via ligation (in this specific experiment). Each bead included a priming sequence, a barcode sequence, a UMI sequence, and a capture sequence as described above. Lysis and capture of RNA followed, as described above. Under the conditions used, the nuclear membrane is not disrupted. The released mRNA was captured onto the barcoded bead present within the same NanoPen chamber.
In
In
RNA release, capture, library prep and sequencing. The protocol described in Example 1 for reverse transcription and barcode reading within the microfluidic environment was performed and identification of the barcode for each NanoPen chamber was recorded. In
Sequencing was performed using a MiSeq Sequencer (Illumina®, Inc.) A first sequencing read sequenced 55 cycles on read 1 to sequence 40 bp of barcode and 10 bp of UMIs. 4 additional cycles were required in between the first two cassetable sequences and the last two cassetable sequences of the full-length barcode as an additional 4 bp were used for barcode ligation in this specific experiment. The last cycle was used for base-calling purposes. A second sequencing read sequenced 8 bp representing the pool index added during the Nextera library preparation, allowing for multiplexing of several experiments on the same sequencing run. Finally, an additional 46 cycles was sequenced on read 2 (paired-end run) that provides sequencing of the cDNA (transcript/gene). Longer reads may be obtained, if desired, but was not used in this experiment.
Apparatus, priming and perfusion regimes, cell source and preparation were used/performed as in the general methods above, unless specifically noted in this example. The media and OptoSelect device were maintained at 37° C., unless otherwise specified.
This experiment demonstrated that Nextera sequencing libraries (Illumina) can be generated with isothermal PCR using one biotinylated priming sequence (carrying a barcode) attached to a bead and one primer free in solution. OKT3 cells (150) were imported into the OptoSelect device, and loaded using optically actuated dielectrophoretic forces into NanoPen chambers.
Lysis. The lysis procedure was performed using an automated sequence, but may be suitably performed via manual control of each step. Lysis buffer was flowed into the OptoSelect device (Buffer TCL (Qiagen, Catalog #1031576) and flow was then stopped for 2 mins to permit buffer diffusion into the pens. Lysis of both the cell membrane and the nuclear membrane was effected. The OptoSelect device was then flushed three times with 50 microliters of culture media, including a 30 second pause after each 50 microliter flush. Proteinase K (Ambion Catalog #AM2546, 20 mg/ml) at a concentration of 800 micrograms/milliliter was introduced to the OptoSelect device and maintained without perfusion for 20 min. Proteinase K diffused into the NanoPen chamber and proteolyzed undesired proteins and disrupted chromatin to permit gDNA extraction. After completion, the OptoSelect device was flushed with three cycles of 50 microliters of PBS including 10 min hold periods after each flow.
Staining with SYBR® Green I stain (ThermoFisher Scientific, Catalog # S7585), at 1:1000 in 1×PBS, was performed to demonstrate that compacted DNA 2510 of the nucleus was present, as shown in
Tagmentation. Tagmentation of DNA with transposase. A protocol for tagmentation was followed by introducing a 15 microliter volume of transposome reagents (Nextera DNA Library Prep Kit, Illumina, Cat. #15028212) including 3.3 microliters of Tagment DNA Buffer (TD); 16 microliters of Tagment DNA enzyme mix (TDE1 Buffer); and 14 microliters of nuclease free H2O (Ambion Cat. #AM9937) into the OptoSelect device. The tagmentation reagents diffused into the Nanopen chambers over a 15 minute period. The OptoSelect device was then flushed extensively, including clearing the inlet and outlet lines with 100 microliters of PBS, and flushing the device itself with 50 microliters of PBS.
DNA capture to beads. Biotinylated 16 micron polystyrene capture beads (Spherotech) were modified by streptavidin labelled oligonucleotides. The oligonucleotides included a priming sequence, a barcode sequence, and a capture sequence (e.g., mosaic sequence), in 5′ to 3′ order. The barcode sequence contained at least one sub-barcode module, permitting identification of the source cell within a specific NanoPen chamber of the OptoSelect device. The priming sequence incorporated within the oligonucleotide was P7 (P7 adaptor sequence), in this experiment. (However, other priming sequences may be utilized such as P5 or a priming sequence specifically designed for compatibility with the recombinase and polymerase of the RPA process. After binding with an excess of SA-oligonucleotide for 15 min in a binding buffer including 1M NaCl, 20 mM TrisHC1, 1 mM EDTA and 0.00002% Triton-X with agitation at speeds up to about 300 rpm (VWR Analog vortex mixer), the beads were washed with three aliquots of fresh binding buffer, followed by 50 microliters of PBS. Freshly prepared beads containing P7 priming sequence (sequencing adaptor)/barcode/capture sequence oligonucleotides were delivered to the NanoPen chambers which had contained cells prior to lysis. This step was performed using an automated sequence including OEP delivery to the NanoPen chambers, but may also be performed manually if desired. In this experiment, the specific automated process used took 1 h to complete. More rapid delivery can be advantageous. Additionally, reduced temperature below 37° C. may be advantageous for effective DNA capture.
Isothermal Amplification. Isothermal amplification of the captured DNA on the beds was performed using a recombinase polymerase amplification (RPA) reaction, (TwistAMP TABA S03, TwistDX,), also including a single-strand DNA (ss-DNA) binding protein which stabilizes displacement loops (D-loops) formed during the process. Also present in the reaction mixture were P5-Mosaic sequence, P7 and P5 primers (IDT). The following mixture: dry enzyme pellet of the TwistDx kit; 27.1 microliters of resuspension buffer; 2.4 microliters of 10 micromolar P5 primer; 2.4 microliters of 10 micromolar P7 primer; and 2.4 microliters of 10 micromolar P5 end index primer (e.g. S521) was added to 2.5 microliters of 280 millimolar magnesium acetate (MgOAc) and vortexed within a microfuge tube. Fifteen microliters of this solubilized and spun solution were imported into the microfluidic channel of the OptoSelect device at a rate of 1 microliter/second, and permitted to diffuse into the NanoPen chambers and contact the captured DNA on the beads for 40 to 60 minutes.
After completion of the isothermal amplification period, 50 microliters of fluidic medium were exported from the OptoSelect device, using PBS. The exported solution (“Immediate Export”) containing amplified DNA that had diffused out of the NanoPen chambers) was cleaned up using 1×AMPure® beads (Agencourt Bioscience), removing primers and other nucleic acid materials of less than 100 bp size.
The OptoSelect Device still containing beads and amplified DNA that did not diffuse into the channel was maintained at 4° C. overnight, and a second export using 50 microliters of PBS was made, capturing amplification product then present in the microfluidic channel, “2nd Export”. The two samples were further separately amplified via PCR for quantitation and size analysis, each using 5 cycles PCT in a 25 microliter reaction with KAPA HiFi Hotstart (KAPA Biosystems), 1 microliter of 10 micromolar P5 primer, and 1 microliter of 10 micromolar P7 primer. Each of the Immediate Export and 2nd Export samples were cleaned up to remove primers by repeating treatment with 1×AMPure® beads. The Immediate Export sample yielded 40 ng total having fragment sizes suitable for sequencing, having an average size of about 312 bp (data not shown). The 2nd Export sample yielded 85 ng total, with an average size of about 760 bp (data not shown), which were not suitable for further sequencing by NGS parallel techniques.
The Immediate Export sample was sequenced within a shared Miseq massively parallel sequencing experiment (Illumina). The coverage was low (mean=0.002731), but reads mapped throughout the mouse genome, as shown in
Source of LCL1 cells: Coriell Institute. Catalog number: GM128781C. Media used for culture is RPMI-1640 (Life Technologies, Cat #11875-127), 10% FBS, 1% Pen/Strep (1000 U/ml), 2 mM Glutamax.
Experiments used either 150 OKT3 cells: 150 Hu LCL1 cells or 75 OKT3 cells:75 Hu LCL1 cells. The cells were specifically delivered to individual NanoPen chambers, one cell to a chamber, using OEP forces such that the locations of each OKT3 and each Hu LCL1 cell was known.
The process of lysis and tagmentation, was performed as in Experiment 3, but with Mosaic End plus insert sequences appended to the fragmented DNA by the transposase having one of the following sequences:
Specific delivery was made of a first set of barcoded beads having a first unique barcode only to the OKT3 cell-containing NanoPens, followed by specific delivery of a second set of barcoded beads having a second unique barcode only to the Hu LCL1 cell-containing NanoPens. This provided specific identifiers for DNA amplified from each set of beads, so that murine DNA reads could be mapped back to murine cells, and Hu LCL1 cell DNA reads could be mapped back to human cells. The beads were delivered to the NanoPen chambers after the tagmentation step. Isothermal amplification was performed as in Experiment 3, yielding 5.67 ng (from 300 cells total) or 2.62 ng (from 150 cells total). Two cycles of PCR, run as described above were performed on each library to ensure the presence of P5, P7 for NGS sequencing, and clean up was similarly performed.
In-situ barcode detection. After export of amplified DNA products, sequential flow of fluorescently labeled hybridization probes as described above identified barcode position.
Without wishing to be bound by theory, the activity of transposon is directed towards double stranded nucleic acids, not single stranded bound oligos. The robustness of the capture beads to these conditions was shown in a corollary experiment. Beads, 20 microliters, as prepared for Experiment 3 were exposed to the tagmentation reaction reagents under the conditions for that same experiment. Both transposon-exposed beads and non-exposed control beads were contacted with 1.4 ng of human standard DNA. 2.4 microliters of each bead set were used in an isothermal amplification, using 2.4 microliters of a paired primer (S521, Illumina) in RPA (S521), and provided substantially similar amounts of amplified DNA. The results show that the capture beads exposed to transposon prior to use in DNA capture yielded reasonably equivalent amounts of amplified product, indicating that transposon did not degrade the capture oligonucleotides on the capture bead.
The step of introduction of the barcoded priming sequence bearing beds was shown to be suitably performed either prior to the tagmentation step or after tagmentation (as in Experiment 3).
Additionally, the step of reading the barcode(s) on barcoded beads placed within the NanoPen chambers may be performed before tagmentation, before isothermal amplification, prior to export of amplified DNA, or after export of amplified DNA (as shown in Exp. 4). Alternatively, beads may be placed within the NanoPen chambers before importation of biological cells. In that embodiment, the barcodes may also be detected before biological cells are brought into the microfluidic environment.
Cells: OKT3 cells, a murine myeloma hybridoma cell line, were obtained from the ATCC (ATCC® Cat. #CRL-800 ™). The cells were provided as a suspension cell line. Cultures were maintained by seeding about 1×105 to about 2×105 viable cells/mL and incubating at 37° C., using 5% carbon dioxide in air as the gaseous environment. Cells were split every 2-3 days. OKT3 cell number and viability were counted and cell density is adjusted to 5×105/ml for loading to the microfluidic device.
OKT8 cells, a murine myeloma hybridoma cell line, were obtained from the ATCC (ATCC® Cat. #CPI-8014™). The cells were provided as a suspension cell line. Cultures were maintained by seeding about 1×105 to about 2×105 viable cells/mL and incubating at 37° C., using 5% carbon dioxide in air as the gaseous environment. Cells were split every 2-3 days. OKT8 cell number and viability were counted and cell density is adjusted to 5×105/ml for loading to the microfluidic device.
Culture medium: Iscove's Modified Dulbecco's Medium (For OKT3; ATCC® Catalog No. 30-2005, for OKT8; ATCC® Catalog No. 30-2005), 10% Fetal Bovine Serum (ATCC® Cat. #30-2020) and 10 ml penicillin-streptomycin (Life Technologies® Cat. #15140-122) were combined to make the culture medium. The complete medium was filtered through a 0.22 μm filter and stored away from light at 4° C. until use.
When perfusing during incubation periods, the culture medium was conditioned continuously with 5% carbon dioxide in air before introduction into the OptoSelect device.
GATGTACACTCTTTCCCTACACGACGCTCTTCCGAT
ATCAGACACTCTTTCCCTACACGACGCTCTTCCGAT
AATGATACGGCGACCACCGAGATCTACACGGATA
AATGATACGGCGACCACCGAGATCTACACCTGGA
Experiment: A sample of OKT3 cells were introduced into the OptoSelect device at a density of 2E6 in 200 microliters. Approximately 150 of the cells were moved by optically actuated dielectrophoretic force to load one cell per NanoPen chamber. Each cell was positioned within the section of the chamber furthest from the opening to the microfluidic channel (e.g., isolation region). The OptoSelect device was then flushed once with 50 microliters of priming medium. A brightfield image was taken of the OptoSelect device for the purpose of identifying the locations of penned OKT3 cells (not shown). A sample of OKT8 cells were introduced into the OptoSelect device at a density of 2E6 in 200 microliters. Approximately 150 of the cells were moved by optically actuated dielectrophoretic force to load one cell per NanoPen chamber in fields of view in which OKT3 cells were not penned. The OptoSelect device was then flushed once with 50 microliters of priming medium. A brightfield image was taken of the OptoSelect device for the purpose of identifying the locations of penned OKT8 cells (not shown). A sample of barcoded beads having capture oligos as described herein (two exemplary, but not limiting sequences are SEQ ID NOs. 101 and 102, see Table 2) were introduced into the OptoSelect device at a density of 2E6 in 200 microliters. A single uniquely barcoded bead was subsequently loaded into each of the occupied chambers. The total number of beads loaded to the NanoPen chambers having single biological cells was 126, with 57 beads assigned to OKT3 cells and 69 beads assigned to OKT8 cells, and each bead was also positioned within the portion of each chamber that was not subjected to penetrating fluidic flow. The OptoSelect device was then flushed once with 50 microliters of 1×DPBS.
Lysis reagent (Single Cell Lysis Kit, Ambion Catalog No. 4458235) was flowed into the microfluidic channel and permitted to diffuse into the NanoPen chambers. The individually penned OKT3 and OKT8 cells were exposed to the lysis buffer for 10 minutes. The OptoSelect device was then flushed once with 30 microliters of 1×DPBS. Lysis was stopped by flowing in stop lysis buffer (Single Cell Lysis Kit, Ambion Catalog No. 4458235) and incubating for 2 minutes at room temperature while there was no flow in the microfluidic channel. Alternatively, a lysis buffer such as 10× Lysis Buffer, Catalog No. 635013, Clontech/Takara can be used to provide similar results, with the advantage of not requiring the use of a stop lysis buffer. The OptoSelect device was then flushed once with 30 microliters of 1×DPBS. Under the conditions used, the nuclear membrane was not disrupted. The released mRNA was captured onto the barcoded bead present within the same NanoPen chamber.
The captured RNA was reverse transcribed to cDNA by flowing in a RT reagent mixture (Thermo Scientific™ Maxima® H Minus RT (Thermofisher, Catalog No. EP0751)) and template switching oligonucleotide (SEQ ID NO. 112). Diffusion of the enzyme into the NanoPen Chamber was permitted during a 20 minute period at 16° C., followed by a reaction period of 90 minutes at 42° C. After reverse transcription, the OptoSelect device was then flushed once with 30 microliters of 1×DPBS.
The unique barcode was then identified for each capture bead by multiplexed flows of fluorescently labeled hybridization probes as described herein. Successive reagent flows of each set of fluorescently labeled probes were flowed into the microfluidic channel of the microfluidic device at 1 micromolar diluted in 1×DPBS (alternatively, IDT Duplex buffer may be used), and permitted to diffuse into the NanoPen chambers. After hybridization background signal was removed by flushing the OptoSelect device with 150 microliters of 1×DPBS. The location of each Cell Barcode so identified (e.g., NanoPen location of the bead labeled with that Cell Barcode) was recorded and was used to identify from which specific cell the BCR sequence was captured to the bead. In
After detection, the chip was washed twice with 10 mM Tris-HCl (200 microliters at 0.5 microliters/sec), prior to export of cDNA decorated capture beads.
Optically actuated dielectrophoretic force was used to export selected barcoded cDNA decorated beads from the NanoPen chambers in a displacement buffer, 10 mM Tris-HCl. One export contained 47 beads from OKT3 assigned wells and 69 beads from OKT8 assigned wells. The beads that had been exported from the NanoPen chambers were subsequently exported out of the microfluidic device using flow and pooled.
After treatment with Exonuclease I (NEB, catalog no. M0293L), the export group of beads was subjected to 22 cycles of DNA amplification (Advantage® 2 PCR kit, Clontech, Catalog #. 639206) using as a primer 5′-ACACTCTTTCCCT ACACGACGC-3′ (SEQ ID NO. 113). Initial purification of the crude amplification mixture for the export group was performed using 1×SPRI (Solid Phase Reversible Immobilization) beads (Agencourt AMPure XP beads (Beckman Coulter, catalog no. A63881) according to supplier instructions.
The crude amplification mixture was then split in two, where the first of the two portions was subject to 18 cycles of PCR with a mixture of BCR specific forward primers for heavy chain (SEQ ID NOs 114-132, Table 6) and where the second portion was subjected to 18 cycles of PCR with a mixture of BCR specific forward primers for light chain (SEQ ID NOs 133-150, Table 6) (Q5® High-Fidelity DNA polymerase, NEB, catalog no. M0491S). Reverse primers (SEQ ID Nos. 151 and 152) added priming sequences with an index assigned to the export group of beads and heavy or light chain. A touchdown PCR protocol (where the annealing temperature is decreased in successive cycles) was used to increase amplification specificity. Initial purification of the BCR sequence containing amplicons was performed using 1×SPRI (Solid Phase Reversible Immobilization) beads (Agencourt AMPure XP beads (Beckman Coulter, catalog no. A63881) according to supplier instructions and subsequently selected by size on a 2% Agarose gel (E-gel™ EX Agarose Gels 2%, Catalog no. G401002, ThermoFisher Scientific). Gel extraction was performed according to supplier instructions (Zymoclean™ Gel DNA Recovery Kit, catalog no. D4001, Zymo Research).
Purified and size-selected BCR sequence containing amplicons were treated with T4 polynucleotide kinase (T4 polynucleotide kinase, NEB, catalog no. M0201) then the reaction was purified with using 1×SPRI (Solid Phase Reversible Immobilization) beads (Agencourt AMPure XP beads (Beckman Coulter, catalog no. A63881) according to supplier instructions. Quantification was performed fluorescently (Qubit™, ThermoFisher Scientific).
Purified T4 polynucleotide kinase-treated BCR sequence containing amplicons using less than or equal to 10 ng of the BCR amplicons were then self-ligated to create circularized DNA molecules (T4 DNA Ligase, Catalog no. EL0011, ThermoFisher Scientific). Any amount of DNA over the limit of detection, roughly about 0.5 ng will be sufficient to the circularization reaction. Not exceeding about 10 ng is useful to drive to self circularization rather than cross-ligating to another molecule of amplicon.
The ligation reaction was purified with using 1×SPRI (Solid Phase Reversible Immobilization) beads (Agencourt AMPure XP beads (Beckman Coulter, catalog no. A63881) according to supplier instructions and the circularized DNA molecules subsequently selected by position on a 2% Agarose gel (E-gel™ EX Agarose Gels 2%, Catalog no. G401002, ThermoFisher Scientific). Gel extraction was performed according to supplier instructions (Zymoclean™ Gel DNA Recovery Kit, catalog no. D4001, Zymo Research).
Purified circularized DNA molecules were then re-linearized by performing a Not1 restriction enzyme digest (Not1-HF, NEB, Catalog no. R3189S) according to manufacturer's directions, and subsequently inactivating the reaction. The re-linearized DNA was purified using 1×SPRI (Solid Phase Reversible Immobilization) beads (Agencourt AMPure XP beads (Beckman Coulter, catalog no. A63881) according to supplier instructions.
The re-linearized DNA was subject to PCR 16 cycles with a P7 adaptor sequence forward primer (SEQ ID NO. 153, Table 6) and a BCR constant region primer (SEQ ID NO. 154, Table 6) containing the P5 adaptor sequence (KAPA HiFi HotStart ReadyMix, KK2601, KAPA Biosystems/Roche). The amplified DNA molecule was purified using 1×SPRI (Solid Phase Reversible Immobilization) beads (Agencourt AMPure XP beads (Beckman Coulter, Catalog #A63881) according to supplier instructions. The amplified DNA product was then subject to PCR, 7 cycles for heavy chain and 6 cycles for light chain, with P7 and P5 adaptor sequence primers (SEQ ID NOs. 153 and 155, Table 6) (KAPA HiFi HotStart ReadyMix, KK2601, KAPA Biosystems/Roche). The resulting sequencing library was purified using 1×SPRI (Solid Phase Reversible Immobilization) beads (Agencourt AMPure XP beads (Beckman Coulter, catalog no. A63881) according to supplier instructions and subsequently selected by size (550-750 bp) on a 2% Agarose gel (E-gel™ EX Agarose Gels 2%, Catalog no. G401002, ThermoFisher Scientific). Gel extraction was performed according to supplier instructions (Zymoclean™ Gel DNA Recovery Kit, catalog no. D4001, Zymo Research).
Quantification of the purified sequencing library was performed fluorescently (Qubit™, ThermoFisher Scientific). Sequencing was performed using a MiSeq Sequencer (Illumina®, Inc.).
Sequencing results were de-plexed to generate FASTQ files of sequence data separate for each pool (including heavy or light chain) via the index included in the read 1 and read 2 primer, and for each cell as identified by the unique barcode sequence. Known CDR3 BCR sequences, containing a critical sub-region, directed to antigen biding sites, of the variable region for the OKT3 and OKT8 cell lines were aligned to the read data for each cell and used to identify the reads as coming from either OKT3 or OKT8 cells. The right hand column within
Reads from cells 9-12 matched OKT8 sequence identity (SEQ ID 159, having a CDR2 sequence of:
The barcodes for each cell was also determined by sequencing and is shown for each of cells 1-12. Matching the barcodes determined by sequencing to the barcodes determined by the reagent flow methods described above, permitted unequivocal correlation between cell and genome. For example, the barcode determined above for NanoPen chamber 1451 via flow reagent matched to Cell 1, having a CDR3 sequence matching the phenotype for OKT3 cells. The other barcode described above, for NanoPen 3441, matched the barcode for Cell 9, having a CDR3 sequence matching the phenotype for OKT8. As this was a proof of principle experiment, it was known which type of cell was disposed within a specific NanoPen chamber, and the sequencing results showed that the barcode flow reagent detection tied perfectly to the barcode determined by sequencing and with the expected CDR3 sequence. This demonstrated that BCR sequence data was linkable to the physical location of the source cell.
A capture object (bead) comprising a plurality of capture oligonucleotides, each capture oligonucleotide comprising the same barcode, was loaded into a microfluidic device. The barcode comprised four cassetable oligonucleotide sequences.
The capture object position was identified in a brightfield image (OEP). For each of FITC, Cy5, DAPI, and Texas Red (TRED) fluorescence channels, fluorescence intensity was measured in arbitrary fluorescence units under a pre-flow condition and four flow conditions. Fluorescence intensity was measured as the difference between median bead brightness and median background brightness. The pre-flow condition measurement was used as a reference intensity. In each of the four flow conditions, a different hybridization probe having a label corresponding to the fluorescence channel was flowed into the microfluidic chip. Each flow condition was maintained for a sufficient amount of time so as to ensure that the capture object was contacted with the hybridization probes, then fluorescence images were taken and capture object fluorescence was measured. In total, four pre-flow fluorescent images (one for each fluorescent channel) and 16 flow condition fluorescent images (4 flow conditions×4 channels) were taken. Fluorescence images and accompanying brightfield images are shown in
Signal values for each flow condition-fluorescent channel combination were determined as the difference between the fluorescence intensity measured for that combination and the reference intensity for that channel. Signal values are shown in
The relative change in signal value from one flow condition to the next was determined as a percentage increase or decrease. The signal value for flow condition 1 was compared to the pre-flow reference intensity (or a minimum floor value of 20000) for the corresponding fluorescent channel. Hybridization probe binding was determined to have occurred in the flow condition that showed the greatest percentage increase relative to the preceding pre-flow/flow condition, and this determined flow condition was assigned a binary value of 1, as shown in
Gene expression variation associated with different cell cycle stages (G1, S, G2, and M) are investigated at the single-cell level using a microfluidic device and methods as described herein, allowing for cell culture and live imaging to collect phenotypic data which can be linked to transcription data from the same cells. Individual cells that are synchronized at a certain cell cycle stage by a cell cycle inhibitor (e.g., using a double thymidine block; see Chen et al., “Cell Synchronization by Double Thymidine Block,” Bio-protocol 8(17): e2994 (2018), DOI: 10.21769/BioProtoc.2994, for detailed information) are isolated in sequestration pens, allowing transcriptional data from a single cell to be matched with the cell's phenotypic data and an investigation into the heterogeneity of gene expression levels in single cells at the same cell cycle stage.
Sample Preparation and Off-Chip Experiments.
HeLa S3 cells are plated (2×106 cells) in 150-mm tissue culture dishes in DMEM with 10% fetal bovine serum and 100 U of penicillin-streptomycin (Invitrogen, Carlsbad, Calif.). Cells are arrested in S phase by adding thymidine (Sigma-Aldrich, catalog number: T9250) to a final concentration of 2 mM. Cells are collected at 0, 4, 6, and 8 hours after the treatment with the double thymine block. Cells are stained with propidium iodide (PI) and flow cytometry analysis of PI-stained cells is performed to analyze synchrony. Cell cycle inhibition is optionally further verified by detecting cell cycle marker protein expression. For example: anti-Cyclin A (Abcam, catalog number: ab38), anti-Cyclin D (Santa Cruz Biotechnology, catalog number: sc-753), and/or anti-β-Actin (Santa Cruz Biotechnology, catalog number: sc-58673) can be measured by Western blot.
Next, the optimal thymidine concentration for on-chip cell cycle inhibition is determined. Individual cells are introduced to the microfluidic chips described herein and load one cell per sequestration pen. Various thymine concentrations of 0.5, 1, 1.5, and 2 mM are introduced into respective microfluidic chips, and the cells inside the chambers are stained with PI (or any other staining that discriminates live from dead cells) to confirm cell viability after the treatment and to determine optimal thymidine concentration.
On-Chip Experiments.
Phenotypic data regarding the cell cycle: HeLa S3 cells are loaded into each of two microfluidic chips; in one chip, the cells are treated with a double thymidine block using the above-determined optimal concentration and, in the other chip, the cells are not treated. The cells are further treated by staining with PI, DAPI to quantify DNA amount, and/or one or more cell cycle markers suitable for assessing cell cycle status. Imaging of the cells is performed, e.g., essentially as described above in Example 2.
Transcription data regarding the cell cycle: RNA is captured from individual cells at different stages of the cell cycle on capture objects comprising capture oligonucleotides and barcodes, as described herein. The barcodes of the capture objects are determined in situ, e.g., essentially as described in Example 8. The captured RNA is reverse transcribed to provide barcoded cDNA that is tagged so as to distinguish nucleic acid corresponding to different cells, and sequenced according to a method disclosed herein (see, e.g., Example 1 above). Various analyses of single-cell RNA-sequencing data thus obtained are performed as follows: first, initial quality control is performed using cellity to identify and filter low quality cells from the scRNA-seq data (available at bioconductor.org/packages/release/bioc/html/cellity.html, the content of which is incorporated here by reference in its entirety). Then, reduction of dimensionality to look at clustering (all genes and top 500 genes) is performed. The top 500 genes are examined to check if they match the preexisting data (e.g., from microarray experiments), if available. A differential expression analysis and a pathway overdispersion analysis are performed with the SCDE package (available at hms-dbmi.github.io/scde/pagoda.html, the content of which is incorporated here by reference in its entirety). Cell cycle scoring and regression are performed by calculating cell cycle phase scores based on canonical markers, and regressing these out of the data using Seurat (available at satijalab.org/seurat/cell cycle vignette.html, the content of which is incorporated here by reference in its entirety).
In this experiment, the gene expression profile of cells was used to cluster them into groups (confirmed by prior knowledge about the cell type). Briefly, human T cells from the same donor (test cells) were activated in different protocols alongside non-activated T cells (control cells), and our RNA-Seq assay data was used to group the test cells into functionally distinguishable groups.
Cell treatments. 1) T cells (“Non-activated”) were cultured with 5 ng/ml IL-7, 50 IU/ml IL-2 (R&D Systems) in CTL media (Advanced RPMI [ThermoFisher 12633020], 1× Glutamax [ThermoFisher 35050079], 10% Human Serum [ThermoFisher MT35060CI], 50 uM β-Mercaptoethanol [ThermoFisher 31350010]); 2) T cells (“Activated”) were cultured for 4 days in the presence of beads coupled with anti-CD3 and anti-CD28 antibodies (Thermo Fisher, #11131D) in CTL media supplemented with 5 ng/ml IL-7 (R&D Systems, 207-IL-005) and 10 ng/ml IL-15 (R&D Systems, 202-IL-010); and 3) T cells (“PMA treated”) were cultured the same as the Activated T cells, then additionally treated for 3 hrs 50 min with PMA/ionomycin (eBioscience, 00-4970-03).
Cell loading and manipulation. Microfluidic cellular manipulations and observations were performed using an OptoSelect™ microfluidic chip (Berkeley Lights, Inc.) controlled by a BEACON® instrument (Berkeley Lights, Inc.). Prior to import into the microfluidic chip, the cells from each condition were washed 3× with ice cold PBS (200G for 2 min to pellet cells, remove supernatant, add PBS) and then resuspended in 100 ul PBS. The cells were then imported and loaded into sequestration pens (“penned”) as single cells across the same nanofluidic device, and their respective locations recorded; the locations were determined by field of view (FOV) under a 10× objective. Non-activated cells were penned in FOV 5 through 9, Activated cells were penned in FOV 11 through 14, 18 and 19, and PMA treated cells were penned in FOV 0 through 4. A mixture of Non-activated and activated cells were penned together in FOV 15, 16, 20 and 21.
Barcoded RNA capture beads were imported into the microfluidic chip and loaded into sequestration pens containing cells. Additional barcoded RNA capture beads were penned independently (not paired with a cell) as negative controls in FOV 17. Inside the microfluidic chip, the beads and cells were washed, then the RNA was freed from the cell via lysis, allowing it to be captured onto a single bead with a barcode. Reverse transcription reagents were imported to the nanofluidic device and the RNA was reverse transcribed to cDNA, thereby joining a pen barcode to the cDNA. The pen barcode was elucidated by a series of hybridization events utilizing fluorophores attached to known complementary DNA sequences. Beads were then exported (in a series of 23 exports) from the microfluidic chip and placed in an Eppendorf 96 well plate. The exports had variable number of beads and represented different conditions, as are described in Table 7, below. The foregoing steps, including lysis, mRNA capture, reverse transcription, barcode elucidation, and capture bead export were performed essentially as described in the Examples above and elsewhere herein.
The exported beads were treated with ExonucleaseI followed by PCR amplification of the cDNA. PCR was performed for 25 cycles. The reactions were then cleaned using the Agencourt AMPure XP system (NC9959336) and the amplified cDNA was prepared for Illumina sequencing by using NexteraXT tagmentation and amplification (Illumina, FC-131-1024) to add the P7 index, as described in the Examples above and elsewhere herein. Each of the 23 exports, containing 6 to 55 beads, were assigned a different P7 index for the amplification (Illumina FC-131-2001 and FC-131-2002), which was recorded in the sequencing sample sheet. The samples were sequenced on a NextSeq 500 instrument with a 150 bp v2 sequencing kit (Illumina, FC-404-2002) 55 bp read 1, Index read 1 and 100 bp read 2.
Sequence analysis. A bioinformatics pipeline aimed at detecting the right barcodes and assigning the genomic information to the corresponding sequestration pen/phenotypic information was applied to the resulting sequence data. Briefly, the bcl files from Illumina Nextseq were demultiplexed using the bcl2fastq tool (v2.20.0.422). First the data was demultiplexed by the P7 index assigned to each export and the data separated into fastq files, which were run for each export in the following analysis. The read 1 (R1) contained information about the 44 bp barcode and a 10 bp high variability sequence region (HVSR), while read 2 (R2) captured approximately 100 bp of sequence derived from the mRNA molecules. The barcodes were corrected for sequencing errors using a custom script and grouped according to their closest match to the database of 256 barcode sequences used in this experiment. The R2 fastq was modified to include the barcode names and HVSR as the read names for further analysis. An aligner called STAR (version 2.5.0a) performed splicing-aware alignment of reads to the genome (version 20201). Htseq count (version 0.9.1) was used to count how many reads map to each gene feature. The htseq counts were grouped, PCR duplicates were grouped together, and counts of the unique molecules per gene were performed. This gave a unique gene hit count for each barcode. These hit counts were transferred to a matrix with column names specifying the export number and row names for each human gene. These counts, representing gene expression data per cell, were clustered with t-Distributed Stochastic Neighbor Embedding (t-SNE), a technique for dimensionality reduction that is particularly well suited for the visualization of high-dimensional datasets. The t-SNE generation was run using RtSNE in R (version 3.5.1). The plot (
Results. The tSNE plot shown in
In this experiment, the data clusters gene expression profiles from different populations of cells, in this case single human T cells that have been activated in two different protocols and non-activated T cells from the same donor. Notably, the two different activation protocols produced a different profile. In this case, we had prior knowledge of the cell conditions, which we used to label the clusters that were observed in the data, thereby confirming our ability to detect differences in gene expression profiles related to the functional properties of the cells.
Profiles or representations of gene expression data that have been captured from the BLI RNA-Seq workflow could also be stored for use in subsequent experiments. In addition, marker genes—genes that are expressed in one condition but not others—could be used to further annotate the clusters generated. Control cells of a known origin, treatment or cell type could be included in experiments alongside unknown cells, to act as a reference profile, and if data from the unknown cells clusters with the controls or shares a subset of characteristics in the gene expression then the unknown cells can be assigned the control cell identity.
Some uses of this method include: analyzing mixtures of cells of unknown origin to determine their origin; defining characteristics of cells of known or unknown type or displaying a specific phenotype; and identifying cells that have been responsive or unresponsive to a treatment protocol. In some cases, a treatment protocol may remove certain subset(s) of cells and this method could be used to identify those the cells that have survived.
The method described in Example 10, above, has also been used in combination with an IFNy secretion assay. T cells were directed to either a TH1 or TH2 subtype by culture with different cytokines. Specifically, TH1 cells were cultured in AIM-V media (ThermoFisher, 12055091) with 10 ng/ml of IL12 (R&D Systems 219-IL-005) and 5 ug/ml anti-hIL4 antibody (In vivoMab Cat #BE0240), and the TH2 cells were cultured in AIM-V media (ThermoFisher, 12055091) with 10 ng/ml of IL4 (R&D Systems 204-IL-010) and 5 ug/ml anti-hlFNgamma antibody (In vivoMab Cat #BE0245). These cells were imported sequentially into the nanofluidic device, single cells were penned into sequestration pens, and an IFNgamma assay was performed (as described in BL002402-PRV, U.S. Ser. No. 62/754,107, filed Nov. 1, 2018, the entire contents of which are incorporated herein by reference). The RNA-Seq assay was performed subsequently, essentially as described in the examples above and elsewhere herein.
Briefly, IFN gamma capture beads were loaded on a microfluidic chip together with TH1 CD4+ T cells or TH2 CD4+ T cells, in different areas of the chip. Then, AIM-V media supplemented with 1× stimulation cocktail (eBioscience, 00-4970-03) was perfused for 6 hours with pulses of 4 ul per minute. After incubation, an antibody against human IFN gamma, fluorescently labeled with Phycoerytrin (PE, Cat. #506507 Biolegend), was flowed in the chip and perfused for 25 minutes with pulses of 4 ul per minute, to allow diffusion of the fluorescent antibody inside the pens and binding to the capture beads coated with secreted IFN gamma. After perfusion, unbound antibody was removed by perfusing FACS buffer for 30 minutes in the chip. Bright field images were obtained for the microfluidic device with different T cell populations and presence of IFN gamma on beads was detected using the TXRED fluorescent filter.
Each of the barcodes was traced back to individual pens with custom export list and the barcodes called by a series of fluorphore imaging steps. The cells were thus identified by the sequestration pen from which they originated, and thereby associated with their phenotypes in the IFNGamma assay. On the Beacon® instrument, a .csv file is generated containing a sequestration pen ID number and the capture object barcode elucidated from the imaging results. A .csv file is also generated reporting the sequestration pen ID number for beads included in each sequential export of multiple beads (in this case 24 exports were generated with 23-36 beads included in each export). The two .csv files were merged to identify the expected sequestration pen barcodes in each export. Barcodes in the sequencing data that were not expected were not considered for further analysis. Gene counts for gene expression profiles were obtained for the remaining cells that could be assigned to specific sequestration pens and associated data (cell type and IFNgamma assay result) on the microfluidc chip. As expected, example TH1 cells that were positive for the IFNgamma phenotyping showed higher gene counts for IGNgamma than TH2 cells that were not positive in the assay (see Table 8).
This experiment demonstrates a linking phenotypic data from BLI technology to gene expression data. In some instances, this could be informative for annotated new gene expression profiles, or providing additional weight to experimental conclusions through inclusion of multiple supporting data readouts.
In addition to any previously indicated modification, numerous other variations and alternative arrangements may be devised by those skilled in the art without departing from the spirit and scope of this description, and appended claims are intended to cover such modifications and arrangements. Thus, while the information has been described above with particularity and detail in connection with what is presently deemed to be the most practical and preferred aspects, it will be apparent to those of ordinary skill in the art that numerous modifications, including, but not limited to, form, function, manner of operation, and use may be made without departing from the principles and concepts set forth herein. Also, as used herein, the examples and embodiments, in all respects, are meant to be illustrative only and should not be construed to be limiting in any manner. Furthermore, where reference is made herein to a list of elements (e.g., elements a, b, c), such reference is intended to include any one of the listed elements by itself, any combination of less than all of the listed elements, and/or a combination of all of the listed elements. Also, as used herein, the terms a, an, and one may each be interchangeable with the terms at least one and one or more. It should also be noted, that while the term step is used herein, that term may be used to simply draw attention to different portions of the described methods and is not meant to delineate a starting point or a stopping point for any portion of the methods, or to be limiting in any other way.
Exemplary embodiments provided in accordance with the presently disclosed subject matter include, but are not limited to, the claims and the following embodiments:
1. A capture object comprising a plurality of capture oligonucleotides, wherein each capture oligonucleotide of said plurality comprises: a priming sequence; a capture sequence; and a barcode sequence comprising three or more cassetable oligonucleotide sequences, each cassetable oligonucleotide sequence being non-identical to the other cassetable oligonucleotide sequences of said barcode sequence.
2. The capture object of embodiment 1, wherein each capture oligonucleotide of said plurality comprises the same barcode sequence.
3. The capture object of embodiment 1 or 2, wherein each capture oligonucleotide of said plurality comprises a 5′-most nucleotide and a 3′-most nucleotide, wherein said priming sequence is adjacent to or comprises said 5′-most nucleotide, wherein said capture sequence is adjacent to or comprises said 3′-most nucleotide, and wherein said barcode sequence is located 3′ to said priming sequence and 5′ to said capture sequence.
4. The capture object of any one of embodiments 1 to 3, wherein each of said three or more cassetable oligonucleotide sequences comprises 6 to 15 nucleotides.
5. The capture object of any one of embodiments 1 to 4, wherein each of said three or more cassetable oligonucleotide sequences comprises 10 nucleotides.
6. The capture object of any one of embodiments 1 to 5, wherein the three or more cassetable oligonucleotide sequences of said barcode sequence are linked in tandem without any intervening oligonucleotide sequences.
7. The capture object of any one of embodiments 1 to 6, wherein each of said three or more cassetable oligonucleotide sequences of said barcode sequence is selected from a plurality of 12 to 100 cassetable oligonucleotide sequences.
8. The capture object of any one of embodiments 1 to 7, wherein each of said three or more cassetable oligonucleotides sequences of said barcode sequence has a sequence of any one of SEQ ID NOs: 1-40.
9. The capture object of any one of embodiments 1 to 8, wherein said barcode sequence comprises four cassetable oligonucleotide sequences.
10. The capture object of embodiment 9, wherein a first cassetable oligonucleotide sequence has a sequence of any one of SEQ ID NOs: 1-10; a second cassetable oligonucleotide sequence has a sequence of any one of SEQ ID NOs: 11-20; a third cassetable oligonucleotide sequence has a sequence of any one of SEQ ID NOs: 21-30; and a fourth cassetable oligonucleotide sequence has a sequence of any one of SEQ ID NOs: 31-40.
11. The capture object of any one of embodiments 1 to 10, wherein said priming sequence, when separated from said capture oligonucleotide, primes a polymerase.
12. The capture object of embodiment 11, wherein said priming sequence comprises a sequence of a P7 or P5 primer.
13. The capture object of any one of embodiments 1 to 12, wherein each capture oligonucleotide of said plurality further comprises a unique molecule identifier (UMI) sequence.
14. The capture object of embodiment 13, wherein each capture oligonucleotide of said plurality comprises a different UMI sequence.
15. The capture object of embodiment 13 or 14, wherein said UMI is located 3′ to said priming sequence and 5′ to said capture sequence.
16. The capture object of any one of embodiments 13 to 15, wherein said UMI sequence is an oligonucleotide sequence comprising 5 to 20 nucleotides.
17. The capture object of any one of embodiments 13 to 15, wherein said oligonucleotide sequence of said UMI comprises 10 nucleotides.
18. The capture object of any one of embodiments 1 to 17, wherein each capture oligonucleotide further comprises a Not1 restriction site sequence.
19. The capture object of embodiment 18, wherein said Not1 restriction site sequence is located 5′ to said capture sequence.
20. The capture object of embodiment 18 or 19, wherein said Not1 restriction site sequence is located 3′ to said barcode sequence.
21. The capture object of any one of embodiments 1 to 20, wherein each capture oligonucleotide further comprises one or more adapter sequences.
22. The capture object of any one of embodiments 1 to 19, wherein said capture sequence comprises a poly-dT sequence, a random hexamer sequence, or a mosaic end sequence.
23. A plurality of capture objects, wherein each capture object of said plurality is a capture object according to any one of embodiments 1 to 22, wherein, for each capture object of said plurality, each capture oligonucleotide of said capture object comprises the same barcode sequence, and wherein the barcode sequence of the capture oligonucleotides of each capture object of said plurality is different from the barcode sequence of the capture oligonucleotides of every other capture object of said plurality.
24. The plurality of capture objects of embodiment 23, wherein said plurality comprises at least 256 capture objects.
25. The plurality of capture objects of embodiment 23, wherein said plurality comprises at least 10,000 capture objects.
26. A cassetable oligonucleotide sequence comprising an oligonucleotide sequence that comprises a sequence of any one of SEQ ID NOs: 1 to 40.
27. A barcode sequence comprising three or more cassetable oligonucleotide sequences, wherein each of said three or more cassetable oligonucleotides sequences of said barcode sequence has a sequence of any one of SEQ ID NOs: 1-40, and wherein each cassetable oligonucleotide sequence of said barcode sequence is non-identical to the other cassetable oligonucleotide sequences of said barcode sequence.
28. The barcode sequence of embodiment 27 comprising three or four cassetable oligonucleotide sequences.
29. The barcode sequence of embodiment 27 or 28, wherein said three or more cassetable oligonucleotide sequences are linked in tandem without any intervening oligonucleotide sequences.
30. A set of barcode sequences comprising at least 64 non-identical barcode sequences, each barcode sequence of said set having a structure according to any one of embodiments 27 to 29.
31. The set of barcode sequences of embodiment 30, wherein the set consists essentially of 64, 81, 100, 125, 216, 256, 343, 512, 625, 729, 1000, 1296, 2401, 4096, 6561, or 10,000 barcode sequences.
32. A hybridization probe comprising: an oligonucleotide sequence comprising a sequence of any one of SEQ ID NOs: 41 to 80; and a fluorescent label.
33. A reagent comprising a plurality of hybridization probes, wherein each hybridization probe of said plurality is a hybridization probe according to embodiment 32, and wherein each hybridization probe of said plurality (i) comprises an oligonucleotide sequence which is different from the oligonucleotide sequence of every other hybridization probe of the plurality and (ii) comprises a fluorescent label which is spectrally distinguishable from the fluorescent label of every other hybridization probe of the plurality.
34. The reagent of embodiment 33, wherein the plurality of hybridization probes consists of two to four hybridization probes.
35. The reagent of embodiment 33 or 34, wherein: a first hybridization probe of the plurality comprises a sequence selected from a first subset of SEQ ID NOs: 41-80, and a first fluorescent label; a second hybridization probe of the plurality comprises a sequence selected from a second subset of SEQ ID NOs: 41-80, and a second fluorescent label which is spectrally distinguishable from said first fluorescent label, wherein the first and second subsets of SEQ ID NOs: 41-80 are non-overlapping subsets.
36. The reagent of embodiment 35, wherein: a third hybridization probe of the plurality comprises a sequence selected from a third subset of SEQ ID NOs: 41-80, and a third fluorescent label which is spectrally distinguishable from each of said first and second fluorescent labels, wherein the first, second, and third subsets of SEQ ID NOs: 41-80 are non-overlapping subsets.
37. The reagent of embodiment 36, wherein: a fourth hybridization probe of the plurality comprises a sequence selected from a fourth subset of SEQ ID NOs: 41-80, and a fourth fluorescent label which is spectrally distinguishable from each of said first, second, and third fluorescent labels, wherein the first, second, third, and fourth subsets of SEQ ID NOs: 41-80 are non-overlapping subsets.
38. The reagent of any one of embodiments 35 to 37, wherein each subset of SEQ ID NOs: 41-80 comprises at least 10 sequences.
39. The reagent of any one of embodiments 35 to 37, wherein said first subset contains SEQ ID NOs: 41-50, wherein said second subset contains SEQ ID NOs: 51-60, wherein said third subset contains SEQ ID NOs: 61-70, and wherein said fourth subset contains SEQ ID NOs: 71-80.
40. A kit comprising a plurality of reagents according to any one of embodiments 33 to 39, wherein the plurality of hybridization probes of each reagent forms a set that is non-overlapping with the set of hybridization probes of every other reagent in the plurality.
41. The kit of embodiment 40, wherein the kit comprises 3, 4, 5, 6, 7, 8, 9, or 10 said reagents.
42. A method of in-situ identification of one or more capture objects within a microfluidic device, the method comprising: disposing a single capture object of said one or more capture objects into each of one or more sequestration pens located within an enclosure of said microfluidic device, wherein each capture object comprises a plurality of capture oligonucleotides, and wherein each capture oligonucleotide of said plurality comprises a priming sequence, a capture sequence, and a barcode sequence, wherein said barcode sequence comprises three or more cassetable oligonucleotide sequences, each cassetable oligonucleotide sequence being non-identical to the other cassetable oligonucleotide sequences of said barcode sequence; flowing a first reagent solution comprising a first set of hybridization probes into a flow region within said enclosure of said microfluidic device, wherein said flow region is fluidically connected to each of said one or more sequestration pens, and wherein each hybridization probe of said first set comprises an oligonucleotide sequence complementary to a cassetable oligonucleotide sequence comprised by any of said barcode sequences of any of said capture oligonucleotides of any of said one or more capture objects, wherein said complementary oligonucleotide sequence of each hybridization probe in the first set is non-identical to every other complementary oligonucleotide sequence of said hybridization probes in said first set, and a fluorescent label selected from a set of spectrally distinguishable fluorescent labels, wherein the fluorescent label of each hybridization probe in said first set is different from the fluorescent label of every other hybridization probe in said first set of hybridization probes; hybridizing said hybridization probes of said first set to corresponding cassetable oligo-nucleotide sequences in any of said barcode sequences of any of said capture oligonucleotides of any of said one or more capture objects; detecting, for each hybridization probe of said first set of hybridization probes, a corresponding fluorescent signal associated with any of said one or more capture objects; and generating a record, for each capture object disposed within one of said one or more sequestration pens, comprising (i) a location of the sequestration pen within said enclosure of said microfluidic device, and (ii) an association or non-association of said corresponding fluorescent signal of each hybridization probe of said first set of hybridization probes with said capture object, wherein said record of associations and non-associations constitute a barcode which links said capture object with said sequestration pen.
43. The method of embodiment 42 further comprising: flowing an nth reagent solution comprising an nth set of hybridization probes into said flow region of said microfluidic device, wherein each hybridization probe of said nth set comprises an oligonucleotide sequence complementary to a cassetable oligonucleotide sequence comprised by any of said barcode sequences of any of said capture oligonucleotides of any of said one or more capture objects, wherein said complementary oligonucleotide sequence of each hybridization probe in the nth set is non-identical to every other complementary oligonucleotide sequence of said hybridization probes in said nth set and any other set of hybridization probes flowed into said flow region of said microfluidic device, and a fluorescent label selected from a set of spectrally distinguishable fluorescent labels, wherein the fluorescent label of each hybridization probe in said nth set is different from the fluorescent label of every other hybridization probe in said nth set of hybridization probes; hybridizing said hybridization probes of said nth set to corresponding cassetable oligo-nucleotide sequences in any of said barcode sequences of any of said capture oligonucleotides of any of said one or more capture objects; detecting, for each hybridization probe of said nth set of hybridization probes, a corresponding fluorescent signal associated with any of said one or more capture objects; and supplementing said record, for each capture object disposed within one of said one or more sequestration pens, with an association or non-association of said corresponding fluorescent signal of each hybridization probe of said nth set of hybridization probes with said capture object, wherein n is a set of positive integers having values of {2, . . . , m}, wherein m is a positive integer having a value of 2 or greater, and wherein the foregoing steps of flowing said nth reagent, hybridizing said nth set of hybridization probes, detecting said corresponding fluorescent signals, and supplements said records are repeated for each value of n in said set of positive integers.
44. The method of embodiment 43, wherein m has a value greater than or equal to 3 and less than or equal to 20 (e.g., greater than or equal to 5 and less than or equal to 15).
45. The method of embodiment 43, wherein m has a value greater than or equal to 8 and less than or equal to 12 (e.g., 10).
46. The method of any one of embodiments 43 to 45, wherein flowing said first reagent solution and/or said nth reagent solution into said flow region further comprises permitting said first reagent solution and/or said nth reagent solution to equilibrate by diffusion into said one or more sequestration pens.
47. The method of any one of embodiments 43 to 45, wherein detecting said corresponding fluorescent signal associated with any of said one or more capture objects further comprises: flowing a rinsing solution having no hybridization probes through said flow region of said microfluidic device; and equilibrating by diffusion said rinsing solution into said one or more sequestration pens, thereby allowing unhybridized hybridization probes of said first set or any of said nth sets to diffuse out of said one or more sequestration pens; and further wherein said flowing said rinsing solution is performed before detecting said fluorescent signal.
48. The method of any one of embodiments 43 to 47, wherein each barcode sequence of each capture oligonucleotide of each capture object comprises three cassetable oligonucleotide sequences.
49. The method of embodiment 48, wherein said first set of hybridization probes and each of said nth sets of hybridization probes comprise three hybridization probes.
50. The method of any one of embodiments 43 to 47, wherein each barcode sequence of each capture oligonucleotide of each capture object comprises four cassetable oligonucleotide sequences.
51. The method of embodiment 50, wherein said first set of hybridization probes and each of said nth sets of hybridization probes comprise four hybridization probes.
52. The method of any one of embodiments 42 to 51, wherein disposing each of said one or more capture objects comprises disposing each of said one or more capture objects within an isolation region of said one or more sequestration pens within said microfluidic device.
53. The method of any one of embodiments 42 to 52, further comprising disposing one or more biological cells within said one or more sequestration pens of said microfluidic device.
54. The method of embodiment 53, wherein each one of said one or more biological cells are disposed in a different one of said one or more sequestration pens.
55. The method of embodiment 53 or 54, wherein said one or more biological cells are disposed within said isolation regions of said one or more sequestration pens of said microfluidic device.
56. The method of any one of embodiments 53 to 55, wherein at least one of the one or more biological cells is disposed within a sequestration pen having one of said one or more capture objects disposed therein.
57. The method of any one of embodiments 53 to 56, wherein the one or more biological cells is a plurality of biological cells from a clonal population.
58. The method of any one of embodiments 53 to 57, wherein disposing said one or more biological cells is performed before disposing said one or more capture objects.
59. The method of any one of embodiments 42 to 58, wherein said enclosure of said microfluidic device further comprises a dielectrophoretic (DEP) configuration, and wherein disposing said one or more capture objects into one or more sequestration pens is performed using dielectrophoretic (DEP) force.
60. The method of any one of embodiments 53 to 59, wherein said enclosure of said microfluidic device further comprises a dielectrophoretic (DEP) configuration, and said disposing said one or more biological cells within said one or more sequestration pens is performed using dielectrophoretic (DEP) forces.
61. The method of any one of embodiments 42 to 60, wherein said one or more capture objects are capture objects according to any one of embodiments 1 to 25.
62. The method of any one of embodiments 42 to 61, wherein at least one of said plurality of capture oligonucleotides of each capture object further comprises a target nucleic acid captured thereto by said capture sequence.
63. A method of correlating genomic data with a biological cell in a microfluidic device, comprising: disposing a capture object into a sequestration pen of a microfluidic device, wherein said capture object comprises a plurality of capture oligonucleotides, wherein each capture oligonucleotide of said plurality comprises a priming sequence, a capture sequence, and a barcode sequence, wherein said barcode sequence comprises three or more cassetable oligonucleotide sequences, each cassetable oligonucleotide sequence being non-identical to the other cassetable oligonucleotide sequences of said barcode sequence, and wherein each capture oligonucleotide of said plurality comprises the same barcode sequence; identifying said barcode sequence of said plurality of capture oligonucleotides in-situ and recording an association between said identified barcode sequence and said sequestration pen; disposing said biological cell into said sequestration pen; lysing said biological cell and allowing nucleic acids released from said lysed biological cell to be captured by said plurality of capture oligonucleotides comprised by said capture object; transcribing said captured nucleic acids, thereby producing a plurality of transcribed nucleic acids, each transcribed nucleic acid comprising a complementary captured nucleic acid sequence covalently linked to one of said capture oligonucleotides; sequencing said transcribed nucleic acids and said barcode sequence, thereby obtaining read sequences of said plurality of transcribed nucleic acids associated with read sequences of said barcode sequence; identifying said barcode sequence based upon said read sequences; and using said read sequence-identified barcode sequence and said in situ-identified barcode sequence to link said read sequences of said plurality of transcribed nucleic acids with said sequestration pen and thereby correlate said read sequences of said plurality of transcribed nucleic acids with said biological cell placed into said sequestration pen.
64. The method of embodiment 63, further comprising: observing a phenotype of said biological cell; and correlating said read sequences of said plurality of transcribed nucleic acids with said phenotype of said biological cell.
65. The method of embodiment 63, further comprising: observing a phenotype of said biological cell, wherein said biological cell is a representative of a clonal population; and correlating said read sequences of said plurality of transcribed nucleic acids with said phenotype of said biological cell and said clonal population.
66. The method of embodiment 64 or 65, wherein observing said phenotype of said biological cell comprises observing at least one physical characteristic of said at least one biological cell.
67. The method of embodiment 64 or 65, wherein observing said phenotype of said biological cell comprises performing an assay on said biological cell and observing a detectable signal generated during said assay.
68. The method of embodiment 67, wherein said assay is a protein expression assay.
69. The method of any one of embodiments 63 to 68, wherein identifying said barcode sequence of said plurality of capture oligonucleotides in-situ and recording an association between said identified barcode sequence and said sequestration pen is performed before disposing said biological cell into said sequestration pen.
70. The method of any one of embodiments 63 to 68, wherein identifying said barcode sequence of said plurality of capture oligonucleotides in-situ and recording an association between said identified barcode sequence and said sequestration pen is performed after introducing said biological cell into said sequestration pen.
71. The method of any one of embodiments 64 to 68, wherein disposing said capture object and, identifying said barcode sequence of said plurality of capture oligonucleotides in-situ and recording an association between said identified barcode sequence and said sequestration pen are performed after observing a phenotype of said biological cell.
72. The method of any one of embodiments 63 to 68, wherein identifying said barcode sequence of said plurality of capture oligonucleotides in-situ and recording an association between said identified barcode sequence and said sequestration pen is performed after lysing said biological cell and allowing said nucleic acids released from said lysed biological cell to be captured by said plurality of capture oligonucleotides comprised by said capture object.
73. The method of any one of embodiments 63 to 72, wherein identifying said barcode sequence of said plurality of capture oligonucleotide in-situ comprises performing the method of any one of embodiments 42 to 60.
74. The method of any one of embodiments 63 to 73, wherein said capture object is a capture object of any one of embodiments 1-23.
75. The method of any one of embodiments 63 to 74, wherein said enclosure of said microfluidic device comprises a dielectrophoretic (DEP) configuration, and wherein disposing said capture object into said sequestration pen comprises using dielectrophoretic (DEP) forces to move said capture object.
76. The method of any one of embodiments 63 to 75, wherein said enclosure of said microfluidic device further comprises a dielectrophoretic (DEP) configuration, and wherein disposing said biological cell within said sequestration pen comprises using dielectrophoretic (DEP) forces to move said biological cell.
77. The method of any one of embodiments 63 to 76 further comprising: disposing a plurality of capture objects into a corresponding plurality of sequestration pens of said microfluidic device; disposing a plurality of biological cells into said corresponding plurality of sequestration pens; and processing each of said plurality of capture objects and plurality of biological cells according to said additional steps of said method.
78. A kit for producing a nucleic acid library, comprising: a microfluidic device comprising an enclosure, wherein said enclosure comprises a flow region and a plurality of sequestration pens opening off of said flow region; and a plurality of capture objects, wherein each capture object of said plurality comprises a plurality of capture oligonucleotides, each capture oligonucleotide of said plurality comprising a capture sequence, and a barcode sequence comprising at least three cassetable oligonucleotide sequences, wherein each cassetable oligonucleotide sequence of said barcode sequence is non-identical to the other cassetable oligonucleotide sequences of said barcode sequence, and wherein each capture oligonucleotide of said plurality comprises the same barcode sequence.
79. The kit of embodiment 78, wherein said enclosure of said microfluidic device further comprises a dielectrophoretic (DEP) configuration.
80. The kit of embodiment 78 or 79, wherein said plurality of capture objects is a plurality of capture objects according to any one of embodiments 23 to 25.
81. The kit of any one of embodiments 78 to 80, wherein each of said plurality of capture objects is disposed singly into corresponding sequestration pens of plurality.
82. The kit of embodiment 81, further comprising an identification table, wherein said identification table correlates said barcode sequence of said plurality of capture oligonucleotides of each of said plurality of capture objects with said corresponding sequestration pens of said plurality.
83. The kit of any one of embodiments 78 to 82 further comprising: a plurality of hybridization probes, each hybridization probe comprising an oligonucleotide sequence complementary to any one of said cassetable oligonucleotide sequences of said plurality of capture oligonucleotides of any one of said plurality of capture objects, and a label, wherein said complementary sequence of each hybridization probe of said plurality is complementary to a different cassetable oligonucleotide sequence, and wherein said label of each hybridization probe of said plurality is selected from a set of spectrally distinguishable labels.
84. The kit of embodiment 83, wherein each complementary sequence of a hybridization probe of said plurality comprises an oligonucleotide sequence comprising a sequence of any one of SEQ ID NOs: 41 to 80.
85. The kit of embodiment 83 or 84, said label is a fluorescent label.
86. A method of providing a barcoded cDNA library from a biological cell, comprising: disposing said biological cell within a sequestration pen located within an enclosure of a microfluidic device; disposing a capture object within said sequestration pen, wherein said capture object comprises a plurality of capture oligonucleotides, each capture oligonucleotide of said plurality comprising a priming sequence that binds a primer, a capture sequence, and a barcode sequence, wherein said barcode sequence comprises three or more cassetable oligonucleotide sequences, each cassetable oligonucleotide sequence being non-identical to every other cassetable oligonucleotide sequences of said barcode sequence; lysing said biological cell and allowing nucleic acids released from said lysed biological cell to be captured by said plurality of capture oligonucleotides comprised by said capture object; and transcribing said captured nucleic acids, thereby producing a plurality of barcoded cDNAs decorating said capture object, each barcoded cDNA comprising (i) an oligonucleotide sequence complementary to a corresponding one of said captured nucleic acids, covalently linked to (ii) one of said plurality of capture oligonucleotides.
87. The method of embodiment 86, wherein said biological cell is an immune cell.
88. The method of embodiment 86, wherein said biological cell is a cancer cell.
89. The method of embodiment 86, wherein said biological cell is a stem cell or progenitor cell.
90. The method of embodiment 86, wherein said biological cell is an embryo.
91. The method of any one of embodiments 86 to 90, wherein said biological cell is a single biological cell.
92. The method of any one of embodiments 86 to 91, wherein said disposing said biological cell further comprises marking said biological cell.
93. The method of any one of embodiments 86 to 92, wherein said capture object is a capture object according to any one of embodiments 1 to 22.
94. The method of any one of embodiments 86 to 93, wherein said capture sequence of one or more of said plurality of capture oligonucleotides comprises an oligo-dT primer sequence.
95. The method of any one of embodiments 86 to 93, wherein said capture sequence of one or more of said plurality of capture oligonucleotides comprises a gene-specific primer sequence.
96. The method of embodiment 95, wherein said gene-specific primer sequence targets an mRNA sequence encoding a T cell receptor (TCR).
97. The method of embodiment 95, wherein said gene-specific primer sequence targets an mRNA sequence encoding a B-cell receptor (BCR).
98. The method of any one of embodiments 86 to 97, wherein said capture sequence of one or more of said plurality of capture oligonucleotides binds to one of said released nucleic acids and primes said released nucleic acid, thereby allowing a polymerase to transcribe said captured nucleic acids.
99. The method of any one of embodiments 86 to 98, wherein said capture object comprises a magnetic component.
100. The method of any one of embodiments 86 to 99, wherein disposing said biological cell within said sequestration pen is performed before disposing said capture object within said sequestration pen.
101. The method of any one of embodiments 86 to 99, wherein disposing said capture object within said sequestration pen is performed before disposing said biological cell within said sequestration pen.
102. The method of any one of embodiments 86 to 101 further comprising: identifying said barcode sequence of said plurality of capture oligonucleotides of said capture object in situ, while said capture object is located within said sequestration pen.
103. The method of embodiment 102, wherein said identifying said barcode is performed using a method of any one of embodiments 42 to 62.
104. The method of embodiment 102 or 103, wherein identifying said barcode sequence is performed before lysing said biological cell.
105. The method of any one of embodiments 86 to 104, wherein said enclosure of said microfluidic device comprises at least one coated surface.
106. The method of embodiment 105, wherein said at least one coated surface comprises a covalently linked surface.
107. The method of embodiment 105 or 106, wherein said at least one coated surface comprises a hydrophilic or a negatively charged coated surface.
108. The method of any one of embodiments 86 to 107, wherein said enclosure of said microfluidic device further comprises a dielectrophoretic (DEP) configuration, and wherein disposing said biological cell and/or disposing said capture object is performed by applying a dielectrophoretic (DEP) force on or proximal to said biological cell and/or said capture object.
109. The method of any one of embodiments 86 to 108, wherein said microfluidic device further comprises a plurality of sequestration pens.
110. The method of embodiment 109 further comprising: disposing a plurality of said biological cells within said plurality of sequestration pens.
111. The method of embodiment 110, wherein said plurality of said biological cells is a clonal population.
112. The method of embodiment 110 or 111, wherein disposing said plurality of said biological cells within said plurality of sequestration pens comprises disposing substantially only one biological cell of said plurality in corresponding sequestration pens of said plurality.
113. The method of any one of embodiments 109 to 112 further comprising: disposing a plurality of said capture objects within said plurality of sequestration pens.
114. The method of embodiment 113, wherein disposing said plurality of said capture objects within said plurality of sequestration pens comprises disposing substantially only one capture object within corresponding ones of sequestration pens of said plurality.
115. The method of embodiment 113 or 114, wherein disposing said plurality of capture objects within said plurality of sequestration pens is performed before said lysing said biological cell or said plurality of said biological cells.
116. The method of any one of embodiments 113 to 115, wherein said plurality of said capture objects is a plurality of capture objects according to embodiment 23.
117. The method of any one of embodiments 86 to 116 further comprising: exporting said capture object or said plurality of said capture objects from said microfluidic device.
118. The method of embodiment 117, wherein exporting said plurality of said capture objects comprises exporting each of said plurality of said capture objects individually.
119. The method of embodiment 118 further comprising: delivering each said capture object of said plurality to a separate destination container outside of said microfluidic device.
120. The method of any one of embodiments 86 to 119, wherein one or more of said disposing said biological cell or plurality of said biological cells; said disposing said capture object or said plurality of said capture objects; said lysing said biological cell or said plurality of said biological cells and said allowing nucleic acids released from said lysed biological cell or said plurality of said biological cells to be captured; said transcribing; and said identifying said barcode sequence of said capture object or each said capture object of said plurality in-situ is performed in an automated manner.
121. A method of providing a barcoded sequencing library, comprising: amplifying a cDNA library of a capture object or a cDNA library of each of a plurality of said capture objects obtained by a method of any one of embodiments 86 to 120; and tagmenting said amplified DNA library or said plurality of cDNA libraries, thereby producing one or a plurality of barcoded sequencing libraries.
122. The method of embodiment 121, wherein amplifying said cDNA library or said plurality of cDNA libraries comprising introducing a pool index sequence, wherein said pool index sequence comprises 4 to 10 nucleotides.
123. The method of embodiment 122, further comprising combining a plurality of said barcoded sequencing libraries, wherein each barcoded sequencing library of said plurality comprises a different barcode sequence and/or a different pool index sequence.
124. A method of providing a barcoded genomic DNA library from a biological micro-object, comprising: disposing a biological micro-object comprising genomic DNA within a sequestration pen located within an enclosure of a microfluidic device; contacting said biological micro-object with a lysing reagent capable of disrupting a nuclear envelope of said biological micro-object, thereby releasing genomic DNA of said biological micro-object; tagmenting said released genomic DNA, thereby producing a plurality of tagmented genomic DNA fragments having a first end defined by a first tagmentation insert sequence and a second end defined by a second tagmentation insert sequence; disposing a capture object within said sequestration pen, wherein said capture object comprises a plurality of capture oligonucleotides, each capture oligonucleotide of said plurality comprising a first priming sequence, a first tagmentation insert capture sequence, and a barcode sequence, wherein said barcode sequence comprises three or more cassetable oligonucleotide sequences, each cassetable oligonucleotide sequence being non-identical to every other cassetable oligonucleotide sequence of said barcode sequence; contacting ones of said plurality of tagmented genomic DNA fragments with (i) said first tagmentation insert capture sequence of ones of said plurality of capture oligonucleotides of said capture object, (ii) an amplification oligonucleotide comprising a second priming sequence linked to a second tagmentation insert capture sequence, a randomized primer sequence, or a gene-specific primer sequence, and (iii) an enzymatic mixture comprising a strand displacement enzyme and a polymerase; incubating said contacted plurality of tagmented genomic DNA fragments for a period of time, thereby simultaneously amplifying said ones of said plurality of tagmented genomic DNA fragments and adding said capture oligonucleotide and said amplification oligonucleotide to the ends of said ones of said plurality of tagmented genomic DNA fragments to produce said barcoded genomic DNA library; and exporting said barcoded genomic DNA library from said microfluidic device.
125. The method of embodiment 124, wherein disposing said biological micro-object within said sequestration pen is performed before disposing said capture object within said sequestration pen.
126. The method of embodiment 124 or 125, wherein said biological micro-object is a biological cell.
127. The method of embodiment 124 or 125, wherein said biological micro-object is a nucleus of a biological cell (e.g., a eukaryotic cell).
128. The method of embodiment 126 or 127, wherein said biological cell is an immune cell.
129. The method of embodiment 126 or 127, wherein said biological cell is a cancer cell.
130. The method of any one of embodiments 124 to 129, wherein said lysing reagent comprises at least one ribonuclease inhibitor.
131. The method of any one of embodiments 124 to 130, wherein said tagmenting comprises contacting said released genomic DNA with a transposase loaded with (i) a first double-stranded DNA fragment comprising said first tagmentation insert sequence, and (ii) a second double-stranded DNA fragment comprising said second tagmentation insert sequence.
132. The method of embodiments 131, wherein said first double-stranded DNA fragment comprises a first mosaic end sequence linked to a third priming sequence, and wherein said second double-stranded DNA fragment comprises a second mosaic end sequence linked to a fourth priming sequence.
133. The method of embodiment 131 or 132, wherein said first tagmentation insert capture sequence of each capture oligonucleotide of said capture object comprises a sequence which is at least partially complementary to said first tagmentation insert sequence.
134. The method of any one of embodiments 131 to 133, wherein said second tagmentation insert capture sequence of said amplification oligonucleotide comprises a sequence which is at least partially complementary to said second tagmentation insert sequence.
135. The method of any one of embodiments 124 to 134, wherein said capture object is a capture object according to any one of embodiments 1 to 20.
136. The method of any one of embodiments 124 to 135, wherein said capture object comprises a magnetic component.
137. The method of any one of embodiments 124 to 136 further comprising: identifying said barcode sequence of said plurality of capture oligonucleotides of said capture object in situ, while said capture object is located within said sequestration pen.
138. The method of embodiment 137, wherein said identifying said barcode sequence is performed using a method of any one of embodiments 42 to 62.
139. The method of embodiment 137 or 138, wherein identifying said barcode sequence is performed before lysing said biological cell.
140. The method of any one of embodiments 124 to 139, wherein said enclosure of said microfluidic device comprises at least one coated surface.
141. The method of any one of embodiments 124 to 140, wherein said enclosure of said microfluidic device comprises at least one conditioned surface.
142. The method of embodiment 141, wherein said at least one conditioned surface comprises a covalently bound hydrophilic moiety or a negatively charged moiety.
143. The method of any one of embodiments 124 to 142, wherein said enclosure of said microfluidic device further comprises a dielectrophoretic (DEP) configuration, and wherein disposing said biological micro-object and/or disposing said capture object is performed by applying a dielectrophoretic (DEP) force on or proximal to said biological cell and/or said capture object.
144. The method of any one of embodiments 124 to 143, wherein said microfluidic device further comprises a plurality of sequestration pens.
145. The method of embodiment 144 further comprising: disposing a plurality of said biological micro-objects within said plurality of sequestration pens.
146. The method of embodiment 145, wherein said plurality of said biological micro-objects is a clonal population of biological cells.
147. The method of embodiment 145 or 146, wherein disposing said plurality of said biological micro-objects within said plurality of sequestration pens comprises disposing substantially only one biological micro-object of said plurality in corresponding sequestration pens of said plurality.
148. The method of any one of embodiments 144 to 147 further comprising: disposing a plurality of said capture objects within said plurality of sequestration pens.
149. The method of embodiment 148, wherein disposing said plurality of said capture objects within said plurality of sequestration pens comprises disposing substantially only one capture object within corresponding ones of sequestration pens of said plurality.
150. The method of embodiment 148 or 149, wherein disposing said plurality of capture objects within said plurality of sequestration pens is performed before said lysing said biological micro-object or said plurality of said biological micro-objects.
151. The method of any one of embodiments 148 to 150, wherein said plurality of said capture objects is a plurality of capture objects according to embodiment 23.
152. The method of any one of embodiments 124 to 151 further comprising: exporting said capture object or said plurality of said capture objects from said microfluidic device.
153. The method of embodiment 152, wherein exporting said plurality of said capture objects comprises exporting each of said plurality of said capture objects individually.
154. The method of embodiment 153 further comprising: delivering each said capture object of said plurality to a separate destination container outside of said microfluidic device.
155. The method of any one of embodiments 145 to 154, wherein said steps of tagmenting, contacting, and incubating are performed at substantially the same time for each of said sequestration pens containing one of said plurality of biological micro-objects.
156. The method of any one of embodiments 124 to 155, wherein one or more of said disposing said biological micro-object or said plurality of said biological micro-objects; said disposing said capture object or said plurality of said capture objects; said lysing said biological micro-object or said plurality of said biological micro-objects and said allowing nucleic acids released from said lysed biological cell or said plurality of said biological cells to be captured; said tagmenting said released genomic DNA; said contacting ones of said plurality of tagmented genomic DNA fragments; said incubating said contacted plurality of tagmented genomic DNA fragments; said exporting said barcoded genomic DNA library or said plurality of DNA libraries; and said identifying said barcode sequence of said capture object or each said capture object of said plurality in-situ is performed in an automated manner.
157. A method of providing a barcoded cDNA library and a barcoded genomic DNA library from a single biological cell, comprising: disposing said biological cell within a sequestration pen located within an enclosure of a microfluidic device; disposing a first capture object within said sequestration pen, wherein said first capture object comprises a plurality of capture oligonucleotides, each capture oligonucleotide of the plurality comprising a first priming sequence, a first capture sequence, and a first barcode sequence, wherein said first barcode sequence comprises three or more cassetable oligonucleotide sequences, each cassetable oligonucleotide sequence being non-identical to every other cassetable oligonucleotide sequence of said first barcode sequence; obtaining said barcoded cDNA library by performing a method of any one of embodiments 86 to 123, wherein lysing said biological cell is performed such that a plasma membrane of said biological cell is degraded, releasing cytoplasmic RNA from said biological cell, while leaving a nuclear envelope of said biological cell intact, thereby providing said first capture object decorated with said barcoded cDNA library from said RNA of said biological cell; exporting said cDNA library-decorated first capture object from said microfluidic device; disposing a second capture object within said sequestration pen, wherein said second capture object comprises a plurality of capture oligonucleotides, each comprising a second priming sequence; a first tagmentation insert capture sequence, and a second barcode sequence, wherein said second barcode sequence comprises three or more cassetable oligonucleotide sequences, each cassetable oligonucleotide sequence being non-identical to every other cassetable oligonucleotide sequence of said second barcode sequence; obtaining said barcoded genomic DNA library by performing a method of any one of embodiments 124 to 156, wherein a plurality of tagmented genomic DNA fragments from said biological cell are contacted with said first tagmentation insert capture sequence of ones of said plurality of capture oligonucleotides of said second capture object, thereby providing said barcoded genomic DNA library from said genomic DNA of said biological cell; and exporting said barcoded genomic DNA library from said microfluidic device.
158. The method of embodiment 157 further comprising: identifying said barcode sequence of said plurality of capture oligonucleotides of said first capture object.
159. The method of embodiment 158, wherein identifying said barcode sequence of said plurality of capture oligonucleotides of said first capture object is performed before disposing said biological cell in said sequestration pen; before obtaining said barcoded cDNA library from said RNA of said biological cell; or before exporting said barcoded cDNA library-decorated first capture object from the microfluidic device.
160. The method of any one of embodiments 157 to 159 further comprising: identifying said barcode sequence of said plurality of oligonucleotides of said second capture object.
161. The method of embodiment 160, wherein identifying said barcode sequence of said plurality of capture oligonucleotides of said second capture is performed before obtaining said barcoded genomic DNA library or after exporting said barcoded genomic DNA library from said microfluidic device.
162. The method of any one of embodiments 157 to 161, wherein identifying said barcode sequence of said plurality of capture oligonucleotides of said first or said second capture object is performed using a method of any one of embodiments 42 to 60.
163. The method of any one of embodiments 157 to 162, wherein said first capture object and said second capture object are each a capture object of any one of embodiments 1 to 22.
164. The method of any one of embodiments 157 to 163, wherein said first priming sequence of said plurality of capture oligonucleotides of said first capture object is different from said second priming sequence of said plurality of capture oligonucleotides of said second capture object.
165. The method of any one of embodiments 157 to 164, wherein said first capture sequence of said plurality of capture oligonucleotides of said first capture object is different from said first tagmentation insert capture sequence of said plurality of capture oligonucleotides of said second capture object.
166. The method of any one of embodiments 157 to 165, wherein said barcode sequence of said plurality of capture oligonucleotides of said first capture object is the same as said barcode sequence of said plurality of capture oligonucleotides of said second capture object.
167. A method of providing a barcoded B cell receptor (BCR) sequencing library, comprising: generating a barcoded cDNA library from a B lymphocyte, wherein said generating is performed according to a method of any one of embodiments 86 to 109, wherein said barcoded cDNA library decorates a capture object comprising a plurality of capture oligonucleotides, each capture oligonucleotide of said plurality comprising a Not1 restriction site sequence; amplifying said barcoded cDNA library; selecting for barcoded BCR sequences from said barcoded cDNA library, thereby producing a library enriched for barcoded BCR sequences; circularizing sequences from said library enriched for barcoded BCR sequences, thereby producing a library of circularized barcoded BCR sequences; relinearizing said library of circularized barcoded BCR sequences to provide a library of rearranged barcoded BCR sequences, each presenting a constant (C) region of said BCR sequence 3′ to a respective variable (V) sub-region and/or a respective diversity (D) sub-region; and, adding a sequencing adaptor and sub-selecting for said V sub-region and/or said D sub-region, thereby producing a barcoded BCR sequencing library.
168. The method of embodiment 167, further comprising amplifying said BCR sequencing library to provide an amplified library of barcoded BCR sub-region sequences.
169. The method of embodiment 167 or 168, wherein amplifying said barcoded cDNA library is performed using a universal primer.
170. The method of any one of embodiments 167 to 169, wherein said selecting for a BCR sequence region comprises performing a polymerase chain reaction (PCR) selective for BCR sequences, thereby producing said library of barcoded BCR region selective amplified DNA.
171. The method of any one of embodiments 167 to 170, wherein said selecting for barcoded BCR sequences further comprises adding at least one sequencing primer sequence and/or at least one index sequence.
172. The method of any one of embodiments 167 to 171, wherein circularizing sequences from said library enriched for barcoded BCR sequences comprises ligating a 5′ end of each barcoded BCR sequence to its respective 3′ end.
173. The method of any one of embodiments 167 to 172, wherein relinearizing said library of circularized barcoded BCR sequences comprises digesting each of said library of circularized barcoded BCR sequences at said Not1 restriction site.
174. The method of any one of embodiments 167 to 173, wherein adding said sequencing adaptor and sub-selecting for V and/or D sub-regions comprises performing PCR, thereby adding a sequencing adaptor and sub-selecting for said V and/or D sub-regions.
175. The method of any one of embodiments 167 to 174, wherein said capture object is a capture object according to any one of embodiments 1 to 22.
176. The method of any one of embodiments 167 to 175 further comprising: identifying a barcode sequence of said plurality of capture oligonucleotides of said capture object using a method of any one of embodiments 42 to 60.
177. The method of embodiment 176, wherein said identifying is performed before amplifying said barcoded cDNA library.
178. The method of embodiment 177, wherein said identifying is performed while generating said barcoded cDNA library.
179. The method of any one of embodiments 167 to 178, wherein any of said amplifying said barcoded cDNA library; performing said polymerase chain reaction (PCR) selective for barcoded BCR sequences; circularizing sequences; relinearizing said library of circularized barcoded BCR sequences at said Not1 restriction site; and adding said sequencing adaptor and sub-selecting for V and/or D sub-regions is performed within a sequestration pen located within an enclosure of a microfluidic device.
201. A method of assaying a biological cell, comprising:
contacting a biological cell with a test agent for a period of time, wherein the biological cell is disposed within a sequestration pen located within an enclosure of a microfluidic device;
lysing said biological cell and allowing RNA molecules released from said lysed biological cell to be captured by a plurality of capture oligonucleotides, wherein:
wherein the capture oligonucleotides are configured to become covalently associated with a plurality of cDNAs upon transcription of the captured RNA molecules.
202. The method of embodiment 201, comprising disposing said biological cell within said sequestration pen.
203. The method of embodiment 202, wherein disposing said biological cell within said sequestration pen comprises disposing a plurality of biological cells within said sequestration pen.
204. The method of embodiment 203, wherein 2 or more, 2 to 10, 3 to 8, or 4 to 6 biological cells are disposed within said sequestration pen.
205. The method of embodiment 201 or 202, wherein a single biological cell is disposed within said sequestration pen.
206. The method of any one of embodiments 201 to 205, comprising disposing said capture object within said sequestration pen.
207. The method of any one of embodiments 201 to 206, wherein a single capture object is disposed within said sequestration pen.
208. The method of any one of embodiments 201 to 207, comprising transcribing said captured RNA molecules, thereby producing a plurality of cDNAs decorating said capture object, each cDNA comprising an oligonucleotide sequence complementary to a corresponding one of said captured RNA molecules, wherein said complementary oligonucleotide sequence is covalently linked to one of said plurality of capture oligonucleotides.
209. The method of embodiment 208, comprising generating sequence from said plurality of cDNAs decorating said capture object.
210. The method of embodiment 209, comprising analyzing said generated sequence to detect a change in transcription of one or more genes of said biological cell associated with contacting said biological cell with said test substance for said period of time.
211. A method of assaying a biological cell, comprising:
disposing said biological cell within a sequestration pen located within an enclosure of a microfluidic device;
contacting said biological cell with a test agent for a period of time;
disposing a capture object within said sequestration pen, wherein said capture object comprises a plurality of capture oligonucleotides, each capture oligonucleotide of said plurality comprising
lysing said biological cell and allowing RNA molecules released from said lysed biological cell to be captured by said plurality of capture oligonucleotides comprised by said capture object; and
transcribing said captured RNA molecules, thereby producing a plurality of cDNAs decorating said capture object, each cDNA comprising an oligonucleotide sequence complementary to a corresponding one of said captured RNA molecules, wherein the complementary oligonucleotide sequence is covalently linked to one of said plurality of capture oligonucleotides;
generating sequence from said plurality of cDNAs decorating said capture object;
analyzing said generated sequence to detect a change in transcription of one or more genes of said biological cell associated with contacting said biological cell with said test agent for said period of time.
212. The method of embodiment 210 or 211, wherein said one or more genes comprise one or more oncogenes and/or one or more tumor suppressor genes.
213. The method of any one of embodiments 210 to 212, wherein said one or more genes comprise one or more genes involved in cell cycle progression and/or circadian rhythms.
214. The method of any one of embodiments 210 to 213, wherein said one or more genes comprise one or more genes involved in programmed cell death.
215. The method of any one of embodiments 210 to 214, wherein said one or more genes comprise one or more genes involved in maintaining developmental plasticity.
216. The method of any one of embodiments 210 to 215, wherein said one or more genes comprise one or more genes involved in cellular differentiation.
217. The method of embodiment 216, wherein the cellular differentiation is neural differentiation, endothelial differentiation, cardiac differentiation, muscle differentiation, liver differentiation, fat differentiation, bone differentiation, bone marrow differentiation, immunological differentiation, skin differentiation, or gut differentiation.
218. The method of any one of embodiments 210 to 217, wherein analyzing said generated sequence to detect a change in transcription comprises comparing said generated sequence to sequence obtained from one or more control biological cells.
219. The method of embodiment 218, wherein said one or more control biological cells have the same origin as said biological cell.
220. The method of embodiment 218, wherein said one or more control biological cells are from the same cell line, preparation of primary cells, or clonal colony as said biological cell.
221. The method of any one of embodiments 218 to 220, wherein said one or more control biological cells are processed, prior to sequencing, in the same manner as said biological cell, with the exception that said one or more control biological cells are not contacted with said test agent.
222. The method of any one of embodiments 218 to 220, wherein said one or more control biological cells are contacted with a control agent different from the test agent.
223. The method of any one of embodiments 218 to 220, wherein said one or more control biological cells are processed, prior to sequencing, in the same manner as said biological cell, with the exception that said one or more control biological cells are contacted with said test agent for a different period of time and/or at a different concentration of the test agent.
224. The method of any one of embodiments 201 to 223, wherein said biological cell is from a cell line.
225. The method of any one of embodiments 201 to 223, wherein said biological cell is a primary cell.
226. The method of embodiment 224 or 225, wherein said biological cell is an immune cell.
227. The method of embodiment 224 or 225, wherein said biological cell is a cancer cell.
228. The method of embodiment 224 or 225, wherein said biological cell is a stem cell or a progenitor cell.
229. The method of embodiment 224 or 225, wherein said biological cell is an embryonic cell.
230. The method of any one of embodiments 201 to 229, wherein said biological cell (and, optionally, said one or more control biological cells) is contacted with a labeled antibody prior to said lysing.
231. The method of embodiment 230, wherein said labeled antibody specifically binds to a cell surface antigen.
232. The method of embodiment 231, wherein said cell surface antigen is a broadly expressed cell surface antigen or a cell type-specific cell surface antigen.
233. The method of any one of embodiments 230 to 232, wherein said labeled antibody is conjugated to a nucleic acid.
234. The method of embodiment 233, wherein said nucleic acid is an RNA oligonucleotide.
235. The method of embodiment 233, wherein said nucleic acid is a DNA oligonucleotide.
236. The method of any one of embodiments 233 to 235, wherein said nucleic acid is conjugated to said labeled antibody by a chemical linkage which is labile and susceptible to breaking during said lysing step.
237. The method of embodiment 236, wherein said chemical linkage is a covalent bond.
238. The method of any one of embodiments 201 to 237, wherein said capture sequence of one or more of said plurality of capture oligonucleotides comprises an oligo-dT primer sequence.
239. The method of any one of embodiments 201 to 238, wherein said capture sequence of one or more of said plurality of capture oligonucleotides comprises a gene-specific primer sequence.
240. The method of embodiment 239, wherein said gene-specific primer sequence targets an mRNA sequence encoding a T cell receptor (TCR).
241. The method of embodiment 239, wherein said gene-specific primer sequence targets an mRNA sequence encoding a B-cell receptor (BCR).
242. The method of any one of embodiments 201 to 241, wherein each capture oligonucleotide of said plurality further comprises a barcode sequence, wherein said barcode sequence comprises three or more cassetable oligonucleotide sequences, each cassetable oligonucleotide sequence being non-identical to every other cassetable oligonucleotide sequences of said barcode sequence.
243. The method of any one of embodiments 201 to 242, wherein said capture object is a capture object according to any one of embodiments 1 to 22.
244. The method of embodiment 242 or 243 further comprising: identifying said barcode sequence of said plurality of capture oligonucleotides of said capture object in situ, while said capture object is located within said sequestration pen.
245. The method of embodiment 244, wherein said identifying said barcode is performed using a method of any one of embodiments 42 to 60.
246. The method of embodiment 244 or 245, wherein identifying said barcode sequence comprises measuring fluorescence intensities of the capture object in a plurality of fluorescence channels under a plurality of flow conditions.
247. The method of embodiment 246, wherein the fluorescence intensities are determined by subtracting median background brightness from brightness of the capture object.
248. The method of embodiment 246 or 247, wherein each of the plurality of flow conditions comprises contacting the capture object with one or more labeled hybridization probe(s).
249. The method of embodiment 248, wherein each hybridization probe comprises sequence configured to bind specifically to a different cassetable oligonucleotide sequence.
250. The method of any one of embodiments 246 to 249, wherein the plurality of fluorescence channels comprises three fluorescence channels.
251. The method of any one of embodiments 246 to 249, wherein the plurality of fluorescence channels comprises four fluorescence channels.
252. The method of any one of embodiments 246 to 250, wherein the plurality of flow conditions comprises three flow conditions.
253. The method of any one of embodiments 246 to 251, wherein the plurality of flow conditions comprises four flow conditions.
254. The method of any one of embodiments 246 to 253, wherein, for each combination of fluorescence channel and flow condition, a signal value is determined, and determining the signal value comprises subtracting a reference intensity from the fluorescence intensity for the combination, optionally wherein the reference intensity is a fluorescence intensity measured before the first flow condition.
255. The method of embodiment 254, wherein determining the signal value further comprises a noise suppression step; optionally wherein the noise suppression step comprises assigning a pre-determined floor value if the signal value would otherwise be below a pre-determined threshold, further optionally wherein the pre-determined floor value is greater than or equal to the pre-determined threshold.
256. The method of embodiment 254 or 255, wherein a hybridization probe is determined to bind specifically to a capture object if its flow condition is the flow condition that produces the largest relative increase in signal value.
257. The method of any one of embodiments 244 to 256, wherein identifying said barcode sequence further comprises generating one or more data strings indicating in which flow condition the hybridization probe specifically bound the capture object for each fluorescence channel.
258. The method of embodiment 257, wherein the one or more data strings comprise a plurality of binary strings and/or a text string.
259. The method of any one of embodiments 201 to 258, wherein disposing said biological cell within said sequestration pen is performed before disposing said capture object within said sequestration pen.
260. The method of any one of embodiments 201 to 258, wherein disposing said capture object within said sequestration pen is performed before disposing said biological cell within said sequestration pen.
261. The method of any one of embodiments 201 to 260 further comprising: exporting said capture object from said microfluidic device prior to generating said sequence from said plurality of cDNAs decorating said capture object.
262. The method of any one of embodiments 201 to 261, wherein generating said sequence from said plurality of cDNAs is performed according to the method of any one of embodiments 86 to 123.
263. The method of any one of embodiments 201 to 261, wherein generating said sequence from said plurality of cDNAs is performed according to the method of any one of embodiments 157 to 166.
264. The method of any one of embodiments 201 to 261, wherein generating said sequence from said plurality of cDNAs is performed according to the method of any one of embodiments 167 to 179.
265. The method of any one of embodiments 201 to 264, wherein said enclosure of said microfluidic device comprises at least one coated surface.
266. The method of embodiment 265, wherein said at least one coated surface comprises a covalently linked surface.
267. The method of embodiment 265 or 266, wherein said at least one coated surface comprises a hydrophilic or a negatively charged coated surface.
268. The method of any one of embodiments 201 to 267, wherein said enclosure of said microfluidic device further comprises a dielectrophoretic (DEP) configuration, and wherein disposing said biological cell and/or disposing said capture object is performed by applying a dielectrophoretic (DEP) force on or proximal to said biological cell and/or said capture object.
269. The method of any one of embodiments 201 to 268, wherein said microfluidic device further comprises a plurality of sequestration pens.
270. The method of embodiment 269 further comprising: disposing a plurality of biological cells within said plurality of sequestration pens.
271. The method of embodiment 270, wherein said plurality of said biological cells is a clonal population.
272. The method of embodiment 270 or 271, wherein disposing said plurality of said biological cells within said plurality of sequestration pens comprises disposing substantially only one biological cell of said plurality in corresponding sequestration pens of said plurality.
273. The method of any one of embodiments 270 to 272 further comprising: disposing a plurality of said capture objects within said plurality of sequestration pens.
274. The method of embodiment 273, wherein disposing said plurality of said capture objects within said plurality of sequestration pens comprises disposing substantially only one capture object within corresponding ones of sequestration pens of said plurality.
275. The method of embodiment 273 or 274, wherein disposing said plurality of capture objects within said plurality of sequestration pens is performed before said lysing said plurality of said biological cells.
276. The method of any one of embodiments 273 to 275, wherein said plurality of said capture objects is a plurality of capture objects according to embodiment 23.
277. The method of any one of embodiments 201 to 276 further comprising: exporting said capture object or said plurality of said capture objects from said microfluidic device.
278. The method of embodiment 277, wherein exporting said plurality of said capture objects comprises exporting each of said plurality of said capture objects individually.
279. The method of embodiment 277 or 278 further comprising: delivering each said capture object of said plurality to a separate destination container outside of said microfluidic device.
280. The method of any one of embodiments 201 to 279, wherein one or more of said disposing said biological cell or plurality of said biological cells; said disposing said capture object or said plurality of said capture objects; said lysing said biological cell or said plurality of said biological cells and said allowing nucleic acids released from said lysed biological cell or said plurality of said biological cells to be captured; said transcribing; and said identifying said barcode sequence of said capture object or each said capture object of said plurality in-situ is performed in an automated manner.
281. A combination of a first capture object and a second capture object, wherein:
said first capture object comprises a first plurality of cDNAs decorating said capture object, each cDNA of said first plurality comprising an oligonucleotide sequence complementary to a captured RNA molecule from a first cell;
said second capture object comprises a second plurality of cDNAs decorating said capture object, each cDNA of said second plurality comprising an oligonucleotide sequence complementary to a captured RNA molecule from a second cell;
said first cell was contacted with a test agent under a first condition before preparing cDNA therefrom;
said second cell was, before preparing cDNA therefrom: (i) not contacted with said test agent or (ii) contacted with said test agent under a second condition different from said first condition; and
a level of at least one cDNA differs in said first plurality of cDNAs and said second plurality of cDNAs.
282. The combination of embodiment 281, wherein said second cell was not contacted with the test agent.
283. The combination of embodiment 281, wherein said second cell was contacted with said test agent at a lower concentration and/or for a shorter time than said contacting of said first cell.
284. The combination of any one of embodiments 281 to 283, wherein said first and second cells have a same origin.
285. The combination of any one of embodiments 281 to 284, wherein said at least one cDNA with said different level comprises an oncogene cDNA and/or a tumor suppressor cDNA.
286. The combination of any one of embodiments 281 to 285, wherein said at least one cDNA with said different level comprises a cell cycle progression cDNA and/or a circadian rhythm cDNA.
287. The combination of any one of embodiments 281 to 286, wherein said at least one cDNA with said different level comprises a programmed cell death cDNA.
288. The combination of any one of embodiments 281 to 287, wherein said at least one cDNA with said different level comprises a cDNA involved in maintaining developmental plasticity.
289. The combination of any one of embodiments 281 to 288, wherein said at least one cDNA with said different level comprises a cDNA involved in cellular differentiation.
290. The combination of any one of embodiments 281 to 289, wherein said first and second biological cells are immune cells.
291. The combination of any one of embodiments 281 to 290, wherein said first and second biological cells are cancer cells.
292. The combination of any one of embodiments 281 to 289 or 291, wherein said first and second biological cells are stem cells or progenitor cells.
293. The combination of any one of embodiments 281 to 289 or 292, wherein said first and second biological cells are embryonic cells.
294. The combination of any one of embodiments 281 to 293, wherein said first capture object comprises a plurality of first capture oligonucleotides, each cDNA of said first plurality covalently linked to one of said plurality of first capture oligonucleotides, and each first capture oligonucleotide of said plurality comprising:
a first priming sequence that binds a first primer, and
a first capture sequence.
295. The combination of embodiment 294, wherein said first capture sequence of one or more of said plurality of first capture oligonucleotides comprises an oligo-dT primer sequence.
296. The combination of embodiment 294 or 295, wherein said first capture sequence of one or more of said plurality of first capture oligonucleotides comprises a gene-specific primer sequence.
297. The combination of any one of embodiments 294 to 296, wherein each first capture oligonucleotide of said plurality further comprises a first barcode sequence, wherein said first barcode sequence comprises three or more cassetable oligonucleotide sequences, each cassetable oligonucleotide sequence being non-identical to every other cassetable oligonucleotide sequences of said first barcode sequence.
298. The combination of any one of embodiments 281 to 297, wherein said second capture object comprises a plurality of second capture oligonucleotides, each cDNA of said second plurality covalently linked to one of said plurality of second capture oligonucleotides, and each second capture oligonucleotide of said plurality comprising:
a second priming sequence that binds a second primer, and
a second capture sequence.
299. The combination of embodiment 298, wherein said second capture sequence of one or more of said plurality of second capture oligonucleotides comprises an oligo-dT primer sequence.
300. The combination of embodiment 298 or 299, wherein said second capture sequence of one or more of said plurality of second capture oligonucleotides comprises a gene-specific primer sequence.
301. The combination of any one of embodiments 298 to 300, wherein each second capture oligonucleotide of said plurality further comprises a second barcode sequence, wherein said second barcode sequence comprises three or more cassetable oligonucleotide sequences, each cassetable oligonucleotide sequence being non-identical to every other cassetable oligonucleotide sequences of said second barcode sequence.
302. The combination of any one of embodiments 281 to 301, wherein said first and second capture objects are capture objects according to any one of embodiments 1 to 22.
303. The combination of any one of embodiments 281 to 302, wherein said first and second capture objects are disposed within separate sequestration pens of a microfluidic device.
304. A method of detecting a change in transcription, comprising generating sequence from first and second pluralities of cDNA of a combination of capture objects according to any one of embodiments 281 to 303, and analyzing said generated sequence to detect a change in transcription of one or more genes between said first cell and said second cell.
305. The method or combination of any one of embodiments 201 to 280 or 303, wherein the microfluidic device further comprises a flow region for containing a flow of a first fluidic medium; and the sequestration pen comprises an isolation region for containing a second fluidic medium, the isolation region having a single opening, wherein the isolation region of the sequestration pen is an unswept region of the microfluidic device; and a connection region fluidically connecting the isolation region to the flow region; optionally wherein the microfluidic device comprises a microfluidic channel comprising at least a portion of the flow region.
306. The combination or method of embodiment 305, wherein the microfluidic device comprises a microfluidic channel comprising at least a portion of the flow region, and the connection region comprises a proximal opening into the microfluidic channel having a width Wcon ranging from about 20 microns to about 100 microns and a distal opening into the isolation region, and wherein a length Lcon of the connection region from the proximal opening to the distal opening is as least 1.0 times a width Wcon of the proximal opening of the connection region.
307. The combination or method of embodiment 306, wherein the length Lon of the connection region from the proximal opening to the distal opening is at least 1.5 times the width Wcon of the proximal opening of the connection region.
308. The combination or method of embodiment 306, wherein the length Lon of the connection region from the proximal opening to the distal opening is at least 2.0 times the width Wcon of the proximal opening of the connection region.
309. The combination or method of any one of embodiments 306 to 308, wherein the width Wcon of the proximal opening of the connection region ranges from about 20 microns to about 60 microns.
310. The combination or method of any one of embodiments 306 to 309, wherein the length Lon of the connection region from the proximal opening to the distal opening is between about 20 microns and about 500 microns.
311. The combination or method of any one of embodiments 306 to 310, wherein a width of the microfluidic channel at the proximal opening of the connection region is between about 50 microns and about 500 microns.
312. The combination or method of any one of embodiments 306 to 311, wherein a height of the microfluidic channel at the proximal opening of the connection region is between 20 microns and 100 microns.
313. The combination or method of any one of embodiments 305 to 312, wherein the volume of the isolation region ranges from about 2×104 to about 2×106 cubic microns.
This application is a continuation of International Application No. PCT/US2018/067957, filed Dec. 28, 2018, which claims the benefit of priority to U.S. Provisional Application No. 62/612,619, filed Dec. 31, 2017, the contents of each of which are hereby incorporated by reference herein in their entirety.
| Number | Date | Country | |
|---|---|---|---|
| 62612619 | Dec 2017 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/US2018/067957 | Dec 2018 | US |
| Child | 16910682 | US |
