The present disclosure relates to biosensors and methods of use thereof.
The most common methods for testing patients suspected to be infected by a pathogen include real-time reverse-transcriptase polymerase chain reaction (RT-PCR) assays, lateral flow antigen detection and serological tests for antibodies. While the RT-PCR assay is accurate, the assay is time consuming and labor intensive, whereas antigen detection is limited in its sensitivity. In addition, serological tests fail to provide an accurate diagnosis in patients during an early phase of the infection or in cases involving immunodeficient individual. What is needed are systems and methods for accurate and fast detection of an infection or a disorder. The biosensors and methods disclosed herein address these and other needs.
In some aspects, disclosed herein is a biosensor comprising:
In some embodiments, each of the one or more overhang staple strands comprises one or more fastening sequences. In some embodiments, the DNA origami hinge is in a closed configuration when the latch strand is hybridized to the one or more fastening sequences. In some embodiments, the latch strand comprises at least 3 nucleotides complementary to each of the one or more fastening sequences. In some embodiments, the toehold domain does not hybridize to the fastening sequences.
In some embodiments, the latch strand has a higher binding affinity to the target nucleic acid than to the one or more fastening sequences.
In some embodiments, the toehold domain comprises a sequence complementary to the target nucleic acid. In some embodiments, the target nucleic acid displaces the one or more fastening sequences when hybridizing to the latch strand.
In some embodiments, the DNA origami hinge is in an open configuration when the latch strand is not hybridized to the fastening sequences.
In some embodiments, the latch strand comprises a sequence at least 80% identical to SEQ ID NO: 62, 64, 66, 303, 304, 305, 306, 307, or 308.
In some embodiments, the toehold domain comprises a sequence at least 80% identical to SEQ ID NO: 63, 65, 67, or 318.
In some embodiments, the one or more overhang staple strands comprises one or more sequences at least 80% identical to SEQ ID NOs: 2-61 or 310-317.
In some embodiments, the target nucleic acid is a single stranded nucleic acid.
In some embodiments, the target nucleic acid is a viral RNA. In some embodiments, the viral RNA is a SARS-COV-2 RNA. In some embodiments, the RNA virus comprises an influenza virus, HIV, hepatitis C virus, Ebola virus, rabies virus, or Dengue virus. In some embodiments, the influenza virus is influenza A virus or influenza B virus.
In some embodiments, the DNA origami hinge comprises two arms, wherein each of the two arms comprises a multi-layer structure.
In some embodiments, the DNA origami hinge further comprises a moiety bound to one or more staple strands. In some embodiments, the moiety comprises BHQ, FAM, BHQ2, BHQ3, AlexaFluor 488, AlexaFluor 555, AlexaFluor 647, Cy3, Cy5, quantum dots in the equivalent fluorophore wavelengths, Iowa Black RQ, Iowa Black FQ, gold nanoparticles, biotinylated oligonucleotide/Horse Radish Peroxidase (HRP)-streptavidin, or glucose oxidase-GOx. In some embodiments, the moiety comprises BHQ and/or FAM.
In some embodiments, a first arm of the DNA origami hinge comprises one or more quenchers, and wherein a second arm of the DNA origami hinge comprises one or more fluorophores. In some embodiments, the first arm of the DNA origami hinge comprises at least 30 quenchers and the second arm of the DNA origami hinge comprises at least 30 fluorophores. In some embodiments, the quencher is BHQ. In some embodiments, the fluorophore is BHQ.
In some embodiments, the one or more fluorophores and the one or more quenchers are positioned on an inner surface of the DNA origami hinge when the DNA origami hinge is in a closed configuration.
In some aspects, disclosed herein is a method of detecting a virus in a subject, comprising
In some embodiments, the method further comprises a step of purifying a nucleic acid from the biological sample.
In some embodiments, the virus is an RNA virus. In some embodiments, the RNA virus is a coronavirus. In some embodiments, the coronavirus comprises SARS-COV-2.
In some embodiments, the RNA virus comprises influenza, HIV, hepatitis C virus, Ebola virus, rabies virus, or Dengue virus.
In some aspects, disclosed herein is a biosensor comprising:
The accompanying figures, which are incorporated in and constitute a part of this specification, illustrate several aspects described below.
Reference will now be made in detail to the embodiments of the invention, examples of which are illustrated in the drawings and the examples. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this disclosure belongs.
Terms used throughout this application are to be construed with ordinary and typical meaning to those of ordinary skill in the art. However, Applicant desires that the following terms be given the particular definition as defined below.
As used herein, the article “a,” “an,” and “the” means “at least one,” unless the context in which the article is used clearly indicates otherwise.
The terms “about” and “approximately” are defined as being “‘close to” as understood by one of ordinary skill in the art. In one non-limiting embodiment, the terms are defined to be within 10%. In another non-limiting embodiment, the terms are defined to be within 5%. In still another non-limiting embodiment, the terms are defined to be within 1 %.
“Activate”, “activating”, and “activation” mean to increase an activity, response, condition, or other biological parameter. This may also include, for example, a 10% increase in the activity, response, or condition, as compared to the native or control level. Thus, the increase can be a 10, 20, 30, 40, 50, 60, 70, 80, 90, 100%, or any amount of reduction in between as compared to native or control levels.
“Administration” to a subject includes any route of introducing or delivering to a subject an agent. Administration can be carried out by any suitable route, including oral, topical, intravenous, subcutaneous, transcutaneous, transdermal, intramuscular, intra-joint, parenteral, intra-arteriole, intradermal, intraventricular, intracranial, intraperitoneal, intralesional, intranasal, rectal, vaginal, by inhalation, via an implanted reservoir, or via a transdermal patch, and the like. Administration includes self-administration and the administration by another.
The term “biocompatible” generally refers to a material and any metabolites or degradation products thereof that are generally non-toxic to the recipient and do not cause significant adverse effects to the subject.
The term “biological sample” as used herein means a sample of biological tissue or fluid. Such samples include, but are not limited to, tissue isolated from animals. Biological samples can also include sections of tissues such as biopsy and autopsy samples, frozen sections taken for histologic purposes, saliva, nasal swab, blood, plasma, serum, sputum, stool, tears, mucus, hair, and skin. Biological samples also include explants and primary and/or transformed cell cultures derived from patient tissues. A biological sample can be provided by removing a sample of cells from an animal, but can also be accomplished by using previously isolated cells (e.g., isolated by another person, at another time, and/or for another purpose), or by performing the methods as disclosed herein in vivo. Archival tissues, such as those having treatment or outcome history can also be used.
The term “biosensor” is defined as an analytical tool comprised of biological components that are used to detect the presence of target(s) and to generate a signal.
As used herein, the term “comprising” is intended to mean that the compositions and methods include the recited elements, but not excluding others. “Consisting essentially of” when used to define compositions and methods, shall mean excluding other elements of any essential significance to the combination. Thus, a composition consisting essentially of the elements as defined herein would not exclude trace contaminants from the isolation and purification method and pharmaceutically acceptable carriers, such as phosphate buffered saline, preservatives, and the like. “Consisting of” shall mean excluding more than trace elements of other ingredients and substantial method steps for administering the compositions of this invention. Embodiments defined by each of these transition terms are within the scope of this invention.
A “composition” is intended to include a combination of active agent and another compound or composition, inert (for example, a detectable agent or label) or active, such as an adjuvant.
“Complementary” or “substantially complementary” refers to the hybridization or base pairing or the formation of a duplex between nucleotides or nucleic acids, such as, for instance, between the two strands of a double stranded DNA molecule or between an oligonucleotide primer and a primer binding site on a single stranded nucleic acid. Complementary nucleotides are, generally, A and T/U, or C and G. Two single-stranded RNA or DNA molecules are said to be substantially complementary when the nucleotides of one strand, optimally aligned and compared and with appropriate nucleotide insertions or deletions, pair with at least about 80% of the nucleotides of the other strand, usually at least about 90% to 95%, and more preferably from about 98 to 100%. Alternatively, substantial complementarity exists when an RNA or DNA strand will hybridize under selective hybridization conditions to its complement. Typically, selective hybridization will occur when there is at least about 65% complementary over a stretch of at least 14 to 25 nucleotides, at least about 75%, or at least about 90% complementary. See Kanehisa (1984) Nucl. Acids Res. 12:203
A “control” is an alternative subject or sample used in an experiment for comparison purposes. A control can be “positive” or “negative.”
“Decrease” can refer to any change that results in a lower level of gene expression, protein expression, amount of a symptom, disease, composition, condition, or activity. A substance is also understood to decrease the level of the gene, the protein, the composition, or the amount of the condition when the level of the gene, the protein, the composition, or the amount of the condition is less/lower relative to the output of the level of the gene, the protein, the composition, or the amount of the condition without the substance. A decrease can be any individual, median, or average decrease in a condition, symptom, activity, composition in a statistically significant amount. Thus, the decrease can be a 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, or 100% decrease so long as the decrease is statistically significant.
“Increase” can refer to any change that results in a higher level of gene expression, protein expression, amount of a symptom, disease, composition, condition, or activity. A substance is also understood to increase the level of the gene, the protein, the composition, or the amount of the condition when the level of the gene, the protein, the composition, or the amount of the condition is more/higher relative to the output of the level of the gene, the protein, the composition, or the amount of the condition without the substance. Also, for example, an increase can be a change in the symptoms of a disorder such that the symptoms are less than previously observed. An increase can be any individual, median, or average increase in a condition, symptom, activity, composition in a statistically significant amount. Thus, the increase can be a 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, or 100% increase so long as the increase is statistically significant.
“Encoding” refers to the inherent property of specific sequences of nucleotides in a polynucleotide, such as a gene, a cDNA, or an mRNA, to serve as templates for synthesis of other polymers and macromolecules in biological processes having either a defined sequence of nucleotides (i.e., rRNA, tRNA and mRNA) or a defined sequence of amino acids and the biological properties resulting therefrom, Thus, a gene encodes a protein if transcription and translation of mRNA.
The term “nucleic acid” as used herein means a polymer composed of nucleotides, e.g. deoxyribonucleotides or ribonucleotides.
The terms “ribonucleic acid” and “RNA” as used herein mean a polymer composed of ribonucleotides.
The terms “deoxyribonucleic acid” and “DNA” as used herein mean a polymer composed of deoxyribonucleotides.
The term “oligonucleotide” denotes single- or double-stranded nucleotide multimers. Suitable oligonucleotides may be prepared by the phosphoramidite method described by Beaucage and Carruthers, Tetrahedron Lett., 22: 1859-1862 (1981), or by the triester method according to Matteucci, et al., J. Am. Chem. Soc., 103:3185 (1981), both incorporated herein by reference, or by other chemical methods using either a commercial automated oligonucleotide synthesizer or VLSIPSTM technology. When oligonucleotides are referred to as “double-stranded,” it is understood by those of skill in the art that a pair of oligonucleotides exist in a hydrogen-bonded, helical array typically associated with, for example, DNA. In addition to the 100% complementary form of double-stranded oligonucleotides, the term “double-stranded,” as used herein is also meant to refer to those forms which include such structural features as bulges and loops, described more fully in such biochemistry texts as Stryer, Biochemistry, Third Ed., (1988), incorporated herein by reference for all purposes.
The term “polynucleotide” refers to a single or double stranded polymer composed of nucleotide monomers.
The term “promoter” or “regulatory element” refers to a region or sequence determinants located upstream or downstream from the start of transcription and which are involved in recognition and binding of RNA polymerase and other proteins to initiate transcription. Promoters need not be of bacterial origin, for example, promoters derived from viruses or from other organisms can be used in the compositions, systems, or methods described herein.
The term “recombinant” refers to a human manipulated nucleic acid (e.g. polynucleotide) or a copy or complement of a human manipulated nucleic acid (e.g. polynucleotide), or if in reference to a protein (i.e, a “recombinant protein”), a protein encoded by a recombinant nucleic acid (e.g. polynucleotide). In some embodiments, a recombinant expression cassette comprising a promoter operably linked to a second nucleic acid (e.g. polynucleotide) may include a promoter that is heterologous to the second nucleic acid (e.g. polynucleotide) as the result of human manipulation (e.g., by methods described in Sambrook et al., Molecular Cloning-A Laboratory Manual, Cold Spring Harbor Laboratory, Cold Spring Harbor, N.Y., (1989) or Current Protocols in Molecular Biology Volumes 1-3, John Wiley & Sons, Inc. (1994-1998)). In another example, a recombinant expression cassette may comprise nucleic acids (e.g. polynucleotides) combined in such a way that the nucleic acids (e.g. polynucleotides) are extremely unlikely to be found in nature. For instance, human manipulated restriction sites or plasmid vector sequences may flank or separate the promoter from the second nucleic acid (e.g. polynucleotide). One of skill will recognize that nucleic acids (e.g. polynucleotides) can be manipulated in many ways and are not limited to the examples above.
The term “expression cassette” or “vector” refers to a nucleic acid construct, which when introduced into a host cell, results in transcription and/or translation of a RNA or polypeptide, respectively. In some embodiments, an expression cassette comprising a promoter operably linked to a second nucleic acid (e.g. polynucleotide) may include a promoter that is heterologous to the second nucleic acid (e.g. polynucleotide) as the result of human manipulation (e.g., by methods described in Sambrook et al., Molecular Cloning-A Laboratory Manual, Cold Spring Harbor Laboratory, Cold Spring Harbor, N.Y., (1989) or Current Protocols in Molecular Biology Volumes 1-3, John Wiley & Sons, Inc. (1994-1998)).
The terms “identical” or percent “identity,” in the context of two or more nucleic acids or polypeptide sequences, refer to two or more sequences or subsequences that are the same or have a specified percentage of amino acid residues or nucleotides that are the same (i.e., about 60% identity, preferably 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%,94%, 95%, 96%, 97%, 98%, 99% or higher identity over a specified region when compared and aligned for maximum correspondence over a comparison window or designated region) as measured using a BLAST or BLAST 2.0 sequence comparison algorithms with default parameters described below, or by manual alignment and visual inspection (see, e.g., NCBI web site or the like). Such sequences are then said to be “substantially identical.” This definition also refers to, or may be applied to, the compliment of a test sequence. The definition also includes sequences that have deletions and/or additions, as well as those that have substitutions. As described below, the preferred algorithms can account for gaps and the like. Preferably, identity exists over a region that is at least about 10 amino acids or 20 nucleotides in length, or more preferably over a region that is 10-50 amino acids or 20-50 nucleotides in length. As used herein, percent (%) nucleotide sequence identity is defined as the percentage of amino acids in a candidate sequence that are identical to the nucleotides in a reference sequence, after aligning the sequences and introducing gaps, if necessary, to achieve the maximum percent sequence identity. Alignment for purposes of determining percent sequence identity can be achieved in various ways that are within the skill in the art, for instance, using publicly available computer software such as BLAST, BLAST-2, ALIGN, ALIGN-2 or Megalign (DNASTAR) software. Appropriate parameters for measuring alignment, including any algorithms needed to achieve maximal alignment over the full-length of the sequences being compared can be determined by known methods.
For sequence comparisons, typically one sequence acts as a reference sequence, to which test sequences are compared. When using a sequence comparison algorithm, test and reference sequences are entered into a computer, subsequence coordinates are designated, if necessary, and sequence algorithm program parameters are designated. Preferably, default program parameters can be used, or alternative parameters can be designated. The sequence comparison algorithm then calculates the percent sequence identities for the test sequences relative to the reference sequence, based on the program parameters.
One example of an algorithm that is suitable for determining percent sequence identity and sequence similarity are the BLAST and BLAST 2.0 algorithms, which are described in Altschul et al. (1977) Nuc. Acids Res. 25:3389-3402, and Altschul et al. (1990) J. Mol. Biol. 215:403-410, respectively. Software for performing BLAST analyses is publicly available through the National Center for Biotechnology Information (http://www.ncbi.nlm.nih.gov/). This algorithm involves first identifying high scoring sequence pairs (HSPs) by identifying short words of length W in the query sequence, which either match or satisfy some positive-valued threshold score T when aligned with a word of the same length in a database sequence. T is referred to as the neighborhood word score threshold (Altschul et al. (1990) J. Mol. Biol. 215:403-410). These initial neighborhood word hits act as seeds for initiating searches to find longer HSPs containing them. The word hits are extended in both directions along each sequence for as far as the cumulative alignment score can be increased. Cumulative scores are calculated using, for nucleotide sequences, the parameters M (reward score for a pair of matching residues; always >0) and N (penalty score for mismatching residues; always <0). For amino acid sequences, a scoring matrix is used to calculate the cumulative score. Extension of the word hits in each direction are halted when: the cumulative alignment score falls off by the quantity X from its maximum achieved value; the cumulative score goes to zero or below, due to the accumulation of one or more negative-scoring residue alignments; or the end of either sequence is reached. The BLAST algorithm parameters W, T, and X determine the sensitivity and speed of the alignment. The BLASTN program (for nucleotide sequences) uses as defaults a wordlength (W) of 11, an expectation (E) or 10, M=5, N=-4 and a comparison of both strands. For amino acid sequences, the BLASTP program uses as defaults a wordlength of 3, and expectation (E) of 10, and the BLOSUM62 scoring matrix (see Henikoff and Henikoff (1989) Proc. Natl. Acad. Sci. USA 89:10915) alignments (B) of 50, expectation (E) of 10, M=5, N=-4, and a comparison of both strands.
The BLAST algorithm also performs a statistical analysis of the similarity between two sequences (see, e.g., Karlin and Altschul (1993) Proc. Natl. Acad. Sci. USA 90:5873-5787). One measure of similarity provided by the BLAST algorithm is the smallest sum probability (P(N)), which provides an indication of the probability by which a match between two nucleotide or amino acid sequences would occur by chance. For example, a nucleic acid is considered similar to a reference sequence if the smallest sum probability in a comparison of the test nucleic acid to the reference nucleic acid is less than about 0.2, more preferably less than about 0.01.
Nucleic acid is “operably linked” when it is placed into a functional relationship with another nucleic acid sequence. For example, DNA for a presequence or secretory leader is operably linked to DNA for a polypeptide if it is expressed as a preprotein that participates in the secretion of the polypeptide; a promoter or enhancer is operably linked to a coding sequence if it affects the transcription of the sequence; or a ribosome binding site is operably linked to a coding sequence if it is positioned so as to facilitate translation. Generally, “operably linked” means that the DNA sequences being linked are near each other, and, in the case of a secretory leader, contiguous and in reading phase. However, operably linked nucleic acids (e.g. enhancers and coding sequences) do not have to be contiguous. Linking is accomplished by ligation at convenient restriction sites. If such sites do not exist, the synthetic oligonucleotide adaptors or linkers are used in accordance with conventional practice. In some embodiments, a promoter is operably linked with a coding sequence when it is capable of affecting (e.g. modulating relative to the absence of the promoter) the expression of a protein from that coding sequence (i.e., the coding sequence is under the transcriptional control of the promoter).
The term “subject” refers to, for example, a human in need of treatment for any purpose, and more preferably a human in need of treatment to treat a disease or disorder. The term “subject” can also refer to non-human animals, such as dogs, cats, horses, cows, pigs, sheep and non-human primates, among others.
The term “purification” as used herein refers to purification from a biological sample, i.e., blood, plasma, tissues, exosomes, or cells. As used herein the term “isolated” or “purified” when used in the context of, e.g., a nucleic acid, refers to a nucleic acid of interest that is at least 60% free, at least 75% free, at least 90% free, at least 95% free, at least 98% free, and even at least 99% free from other components with which the nucleic acid is associated with prior to purification.
The current methods used for detecting a virus are mainly RT-PCR-based assays. Such methods are time-consuming and labor intensive. The methods require an RNA isolation step that can take 45-60 minutes. Further, the purification of the RNA can affect the accuracy of the RT-PCR testing results. Therefore, a new system and method for accurate and fast detection of an infection or a disorder is needed. The biosensors disclosed herein allow for rapid and inexpensive detection of target nucleic acid sequences. Importantly, the biosensors generate a greater signal per copy upon detection of a target. Further, in some embodiments, no RNA purification step is required.
In some aspects, disclosed herein is a DNA-based biosensor constructed via the DNA origami molecular self-assembly process. In some embodiments, the biosensor is based on a hinge-like design consisting of two or more arms that are initially held in a closed configuration by a latching interaction. In some embodiments, the hinge-like design is shown, for example, in
Accordingly, in some aspects, disclosed herein is a biosensor comprising:
DNA origami structures incorporate DNA as a building material to make nanoscale shapes. In general, the DNA origami process involves the folding of one or more long “scaffold” strands into a particular shape using a plurality of rationally designed “staple” strands. The sequences of the staple strands are designed such that they hybridize to particular portions of the scaffold strands and, in doing so, force the scaffold strands into a particular shape. Methods useful in the making of DNA origami structures can be found, for example, in Rothemund, P. W., Nature 440:297-302 (2006); Douglas et al., Nature 459:414-418 (2009); Dietz et al., Science 325:725-730 (2009); and U.S. Pat. App. Pub. Nos. 2007/0117109, 2008/0287668, 2010/0069621 and 2010/0216978, each of which are incorporated by reference in their entireties.
In some embodiments, the one or more scaffold strands comprise a polynucleotide sequence at least 60% (for example, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99%) identical to SEQ ID NO: 1.
In some embodiments, the one or more staple strands comprise a polynucleotide sequence at least 60% (for example, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99%) identical to SEQ ID NOs: 68-299. In some embodiments, the one or more staple strands comprise a polynucleotide sequence at least 60% (for example, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99%) identical to SEQ ID NOs: 68-124. In some embodiments, the one or more staple strands comprise a polynucleotide sequence at least 60% (for example, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99%) identical to SEQ ID NOs: 134-184.
In some embodiments, the one or more overhang staple strands comprise a polynucleotide sequence at least 60% (for example, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99%) identical to SEQ ID NOs: 187-201, 203-218, or 221-229.
In some embodiments, the DNA origami hinge disclosed herein comprises a first arm and a second arm. In some embodiments, the first arm comprises one or more staple strands selected from the group consisting of SEQ ID NOs: 134-184. In some embodiments, the second arm comprises one or more staple strands selected from the group consisting of SEQ ID NOs: 68-124.
It should be understood and herein contemplated that the DNA origami hinge disclosed herein confers a greater stability in comparison to prior DNA origami designs, such as DNA nanorobot (or DNA robot). A DNA nanorobot has a single layer structure, causing the nanorobot to have a poor stability in low magnesium environments and in low amounts of serum, which both can occur with in vitro and in vivo applications. Unlike the prior designs, in some embodiments, the DNA origami hinge disclosed herein comprises one or more bundles that are multi-layers of helices (for example,
In some embodiments, the first and the second arms are connected by the scaffold strands at the vertex of the hinge. In some embodiments, the first and the second arms are further connected by one or more hinge connectors. “Hinge connector” used herein refers to staple strands that hybridize with the scaffold DNA loops at the vertex of the hinge. The length and composition of the hinge connector sequences help the “angle control” of the hinge (e.g., control an angle of an open hinge) and may or may not be used depending on the hinge version and desired angle distribution (e.g., an angle of at least about 5 degrees, at least about 10 degrees, at least about 20 degrees, at least about 30 degrees, at least about 40 degrees, at least about 50 degrees, at least about 60 degrees, at least about 70 degrees, at least about 80 degrees, at least about 90 degrees, at least about 100 degrees, at least about 120 degrees, at least about 140 degrees, at least about 160 degrees, or at least about 180 degrees). In some embodiments, the hinge-like design is shown, for example, in
In some embodiments, the hinge connector comprises a polynucleotide sequence at least 60% (for example, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99%) identical to SEQ ID NOs: 125-130.
In general, an inner surface is any surface area of the DNA origami hinge that is precluded from interacting a particle (e.g., a particle bigger than about 1 nm, 2 nm, 3 nm, 4 nm, 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, 15 nm, 20 nm, 15 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, 55 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 150 nm, 200 nm, 250 nm, 300 nm, 350 nm, 400 nm, 450 nm, 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, 1000 nm, 5 µm, or 10 µm) outside the DNA origami hinge, while an outer surface is any surface area of the DNA origami hinge that is not precluded from interacting with a particle (e.g., a particle bigger than about 1 nm, 2 nm, 3 nm, 4 nm, 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, 15 nm, 20 nm, 15 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, 55 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 150 nm, 200 nm, 250 nm, 300 nm, 350 nm, 400 nm, 450 nm, 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, 1000 nm, 5 µm, or 10 µm) outside the DNA origami hinge.
The latch strand (also referred to as the “zipper” or “zipper strand”) used herein refers to a single stranded nucleic acid sequence that serves to close the first arm and the second arm of the DNA origami hinge, sense a target sequence (e.g., a nucleic acid sequence), and respond to the target sequence via a complementary base pair binding to cause the DNA origami hinge to change from a closed to an open configuration. It should be understood herein that the latch strand is not a part of the DNA origami hinge. Therefore, in some examples, the design disclosed herein overcomes the challenges of reusing the DNA origami hinges by, for example, reloading the latch strands onto the DNA origami hinges.
In some examples, the overhang staple strand described herein comprises one or more fastening sequences located near the 5′-end and/or 3′-end of the overhang staple strand. It is also contemplated herein that the latch strand keeps the DNA origami hinge in a closed configuration by base pairing with one or more fastening sequences of one or more overhang staple strands, wherein the one or more fastening sequences protrude from DNA helices from a first arm and DNA helices from a second arm of the DNA origami hinge. The 5′-end portion and/or 3′-end portion of the latch strand includes free unbound sequences known as the “toehold domains”. The toehold domains facilitate a toehold-mediated strand displacement by the target sequence to release the latch strand from the first and second arms of the DNA origami hinge. This results in the DNA origami hinge to change from a closed to open configuration.
In some examples, the fastening sequences of the first hinge arm hybridize to the fastening sequences of the second hinge arm to facilitate hinge closing.
In some embodiments, the latch strand comprises at least about 20 nucleotides, 22, nucleotides, 24 nucleotides, 26 nucleotides, 28 nucleotides, 30 nucleotides, 32 nucleotides, 34 nucleotides, 36 nucleotides, 38 nucleotides, 40 nucleotides, 42 nucleotides, 44 nucleotides, 46 nucleotides, 48 nucleotides, 50 nucleotides, 52 nucleotides, 54 nucleotides, 56 nucleotides, 58 nucleotides, 60 nucleotides, 62 nucleotides, 64 nucleotides, 66 nucleotides, 68 nucleotides, 70 nucleotides, 72 nucleotides, 74 nucleotides, 76 nucleotides, 78 nucleotides, 80 nucleotides, 82 nucleotides, 84 nucleotides, 86 nucleotides, 88 nucleotides, 90 nucleotides, 92 nucleotides, 94 nucleotides, 96 nucleotides, 98 nucleotides, 100 nucleotides, 110 nucleotides, 120 nucleotides, 130 nucleotides, 140 nucleotides, 150 nucleotides, 160 nucleotides, 170 nucleotides, 180 nucleotides, 190 nucleotides, 200 nucleotides, 250 nucleotides, 300 nucleotides, 350 nucleotides, 400 nucleotides, 450 nucleotides, or 500 nucleotides. In some embodiments, the latch strand is an RNA or a DNA. In some embodiments, the latch strand comprises about 100 nucleotides. In some embodiments, the latch strand comprises a polynucleotide sequence at least 60% (for example, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99%) identical to SEQ ID NO: 62, 64, 66, 303, 304, 305, 306, 307, or 308.
In some embodiments, the latch strand comprises at least 1 nucleotide, 2 nucleotides, 3 nucleotides, 4 nucleotides, 5 nucleotides, 6 nucleotides, 7 nucleotides, 8 nucleotides, 9 nucleotides, or 10 nucleotides complementary to each of the one or more overhang staple strands. In some embodiments, the toehold domain does not hybridize the fastening sequence. In some embodiments, the latch strand has a higher binding affinity to the target nucleic acid than to the one or more fastening sequences. In some embodiments, the latch strand has at least 85% (at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99%) reverse complementarity to the target sequence or a fragment thereof. In some embodiments, the latch strand has 100% reverse complementarity to the target sequence or a fragment thereof.
In some embodiments, the latch strand comprises one or more toehold domains. In some embodiments, the toehold domain comprises at least about 2 nucleotides, 3 nucleotides, 4 nucleotides, 5 nucleotides, 6 nucleotides, 7 nucleotides, 8 nucleotides, 9 nucleotides, 10 nucleotides, 11 nucleotides, 12 nucleotides, 13 nucleotides, 14 nucleotides, 15 nucleotides, 16 nucleotides, 17 nucleotides, 18 nucleotides, 19 nucleotides, 20 nucleotides, 25 nucleotides, 30 nucleotides, 35 nucleotides, 40 nucleotides, 45 nucleotides, 50 nucleotides, 55 nucleotides, 60 nucleotides, 65 nucleotides, 70 nucleotides, 75 nucleotides, 80 nucleotides, 85 nucleotides, 90 nucleotides, 95 nucleotides, or 100 nucleotides. In general, the toehold domain used herein can be a polynucleotide sequence of any length and is complementary to a target sequence (e.g., a viral nucleic acid or a tumor-derived/tumor-specific nucleic acid). In some embodiments, the toehold domain comprises a polynucleotide sequence at least 60% (for example, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99%) identical to SEQ ID NO: 63, 65, 67, 193, or 318.
In some embodiments, the toehold domain has at least 85% (at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99%) reverse complementarity to the target sequence or a fragment thereof. In some embodiments, the toehold domain has 100% reverse complementarity to the target sequence or a fragment thereof.
Overhang staple strands comprise fastening sequences (herein also termed “overhang sequences” or “OH”) that protrude from the front edge of each of the first and/or the second hinge arms that hybridize to the latch/zipper strand to facilitate hinge closing. In some examples, the fastening sequences locate at the 5′-end and the 3′-end of the overhang staple strand. In some embodiments, the overhang staple strand comprises a polynucleotide sequence at least 60% (for example, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99%) identical to SEQ ID NOs: 205-211. In some embodiments, the overhang staple strand comprises a polynucleotide sequence at least 60% (for example, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99%) identical to SEQ ID NOs: 187-201, 203-218, or 221-229.
In some embodiments, the fastening sequence comprises a polynucleotide sequence at least 60% (for example, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99%) identical to SEQ ID NOs: 2-13. In some embodiments, the fastening sequence comprises a polynucleotide sequence at least 60% (for example, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99%) identical to SEQ ID NOs: 14-21. In some embodiments, the fastening sequence comprises a polynucleotide sequence at least 60% (for example, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99%) identical to SEQ ID NOs: 22-33. In some embodiments, the fastening sequence comprises a polynucleotide sequence at least 60% (for example, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99%) identical to SEQ ID NOs: 34-41. In some embodiments, the fastening sequence comprises a polynucleotide sequence at least 60% (for example, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99%) identical to SEQ ID NOs: 42-53. In some embodiments, the fastening sequence comprises a polynucleotide sequence at least 60% (for example, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99%) identical to SEQ ID NOs: 54-61. In some embodiments, the fastening sequence comprises a polynucleotide sequence at least 60% (for example, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99%) identical to SEQ ID NOs: 310-317.
In some embodiments, the fastening sequence comprises one or more thymine bases (including, for example, at least one thymine base, at least two thymine bases, at least three thymine bases, at least four thymine bases, at least five thymine bases, at least six thymine bases, at least seven thymine bases, at least eight thymine bases, at least nine thymine bases, or at least ten thymine bases) at the 5′-end and/or 3′-end of the fastening sequence. In some embodiments, the fastening sequence comprises five thymine bases at its 5′-end and/or 3′-end. In some embodiments, the fastening sequence comprises seven thymine bases at its 5′-end and/or 3′-end. In some embodiments, the design of the thymine bases is shown, for example, in
In some embodiments, the target nucleic acid displaces the one or more fastening sequences when hybridizing to the latch strand. In some embodiments, the DNA origami hinge is in an open configuration when the latch strand is not hybridized to the fastening sequences.
In some embodiments, the target nucleic acid is a single stranded nucleic acid. In some embodiments, the target nucleic acid is a tumor-specific nucleic acid. In some embodiments, the target nucleic acid is a nucleic acid derived from a pathogen (for example, a virus, a bacterium, a fungus, or a parasite). In some embodiments, the target nucleic acid is a viral RNA or a viral DNA. In some embodiments, target nucleic acid is an RNA or a DNA of a coronavirus.
Coronaviruses constitute the subfamily Orthocoronavirinae, in the family Coronaviridae, order Nidovirales, and realm Riboviria. They are enveloped viruses with a positive-sense single-stranded RNA genome and a nucleocapsid of helical symmetry. The genome size of coronaviruses ranges from approximately 27 to 34 kilobases. The structure of coronavirus generally consists of the following: spike protein (S), hemagglutinin-esterase dimer (HE), a membrane glycoprotein (M), an envelope protein (E) a nucleocapsid protein (N) and RNA. The coronavirus family comprises genera including, for example, alphacoronavius (e.g., Human coronavirus 229E, Human coronavirus NL63, Miniopterus bat coronavirus 1, Miniopterus bat coronavirus HKU8, Porcine epidemic diarrhea virus, Rhinolophus bat coronavirus HKU2, Scotophilus bat coronavirus 512), betacoronavirus (e.g., SARS-CoV-2, Betacoronavirus 1, Human coronavirus HKU1, Murine coronavirus, Pipistrellus bat coronavirus HKU5, Rousettus bat coronavirus HKU9, Severe acute respiratory syndrome-related coronavirus, Tylonycteris bat coronavirus HKU4, Middle East respiratory syndrome-related coronavirus (MERS), Human coronavirus OC43, Hedgehog coronavirus 1 (EriCoV)), gammacoronavirus (e.g., Beluga whale coronavirus SW1, Infectious bronchitis virus), and deltacoronavirus (e.g., Bulbul coronavirus HKU11, Porcine coronavirus HKU15). In some embodiments, the target nucleic acid is a SARS-COV-2 RNA or a SARS-COV-2 DNA (e.g., an RNA/ DNA encoding a spike protein (S), hemagglutinin-esterase dimer (HE), a membrane glycoprotein (M), an envelope protein (E), or a nucleocapsid protein (N) of a SARS-COV-2) or a fragment thereof. The target nucleic acid can be a viral RNA or viral DNA of any SARS-CoV-2 variant, including, for example, an Alpha variant (B.1.1.7, Q.1-Q.8), a Beta variant (B.1.351, B.1.351.2, B.1.351.3), a Delta variant (B.1.617.2 and AY.1 sublineages), a Gamma variant (P.1, P.1.1, P.1.2), an Epsilon variant (B.1.427 and B.1.429), an Eta variant (B.1.525), an Iota variant (B.1.526), a Kappa variant (B.1.617.1), B.1.617.3, a Mu variant (B.1.621, B.1.621.1), or a Zeta variant (P.2).
In some embodiments, the target nucleic acid is a nucleic acid of a virus, wherein the virus comprises Herpes Simplex virus- 1, Herpes Simplex virus-2, Varicella-Zoster virus, Epstein-Barr virus, Cytomegalovirus, Human Herpes virus-6, Variola virus, Vesicular stomatitis virus, Hepatitis A virus, Hepatitis B virus, Hepatitis C virus, Hepatitis D virus, Hepatitis E virus, Rhinovirus, Influenza virus A, Influenza virus B, Measles virus, Polyomavirus, Human Papillomavirus, Respiratory syncytial virus, Adenovirus, Coxsackie virus, Dengue virus, Mumps virus, Poliovirus, Rabies virus, Rous sarcoma virus, Reovirus, Yellow fever virus, Zika virus, Ebola virus, Marburg virus, Lassa fever virus, Eastern Equine Encephalitis virus, Japanese Encephalitis virus, St. Louis Encephalitis virus, Murray Valley fever virus, West Nile virus, Rift Valley fever virus, Rotavirus A, Rotavirus B, Rotavirus C, Sindbis virus, Simian Immunodeficiency virus, Human T-cell Leukemia virus type-1, Hantavirus, Rubella virus, Simian Immunodeficiency virus, Human Immunodeficiency virus type-1, or Human Immunodeficiency virus type-2. In some embodiments, the target nucleic acid is an RNA or a DNA or an influenza virus (including, for example, influenza A virus or influenza B virus).
In some embodiments, the target nucleic acid comprises a SARS-COV-2 S gene or a fragment thereof, wherein the target nucleic acid comprises a polynucleotide sequence at least 60% (for example, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99%) identical to SEQ ID NO: 300.
In some embodiments, the target nucleic acid comprises a SARS-COV-2 N gene or a fragment thereof, wherein the target nucleic acid comprises a polynucleotide sequence at least 60% (for example, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99%) identical to SEQ ID NO: 301.
In some embodiments, the target sequences are the sequences near the USA N1 and USA N3 primer-targeting regions in the SARS-CoV-2 genome. These regions are recommended by the FDA and CDC for detection of SARS-CoV-2. In some embodiments, the target sequences are human RNAse P gene or influenza A matrix protein encoding gene. Thus, the “USA N1 primer SARS-CoV-2 Zipper-closing sequence” and “USA N3 primer SARS-CoV-2 Zipper-closing sequence” refer to the sequences of Zipper strands that target the corresponding the US N1 and US N3 primer-targeting sites in the SARS-CoV-2 genome. These regions are more resistant to mutations than SARS-CoV-2 S gene. In some embodiments, the target nucleic acid comprises a polynucleotide sequence at least 60% (for example, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99%) identical to SEQ ID NO: 309. Accordingly, in some embodiments, the latch strand comprises a polynucleotide sequence at least 60% (for example, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99%) identical to SEQ ID NO: 62, 64, 66, 303, 304, 305, 306, 307, or 308.
In some embodiments, the DNA origami hinge further comprises a moiety bound to one or more staple strands. In some examples, the moiety is located on the inner surface when the DNA origami hinge is in a close configuration. The moiety can be bound to the one or more staple strands using any method known in the art. For example, the moiety can be covalently bonded to the one or more staple strands or by hybridizing to the free unbound sequence of the one or more staple strands. The moiety can also be indirectly attached to the one or more staple strands through, for example, another nucleic acid sequence or a linker.
Any type of moiety can be bound to the staple strands of the DNA origami hinge. In some examples, the moiety used herein can produce colorimetric, fluorescence, or radiation readouts. In some embodiments, the moiety comprises a fluorophore and/or a quencher. In some embodiments, the moiety comprises BHQ, FAM, BHQ2, BHQ3, AlexaFluor 488, AlexaFluor 555, AlexaFluor 647, Cy3, Cy5, quantum dots in the equivalent fluorophore wavelengths, Iowa Black RQ, Iowa Black FQ, gold nanoparticles, biotinylated oligonucleotide/Horse Radish Peroxidase (HRP)-streptavidin and/or glucose oxidase-GOx. The fluorophore and the quencher used herein can be any of those known in the art, including, for example, FAM fluorescent molecules and Black Hole quenchers (BHQ).
Other detection methods can include electrochemical and surface plasmon resonance-based detection schemes (see for example, “An electrochemical biosensor exploiting binding-induced changes in electron transfer of electrode-attached DNA origami to detect hundred nanometer-scale targets.” Nanoscale, 2020, 12, 13907; see also “Binding to Nanopatterned Antigens is Dominated by the Spatial Tolerance of Antibodies.” Nat Nanotechnol. 2019 February; 14(2): 184-190.). The sensor can be immobilized on a surface, usually gold-coated (or some conductive coating). The presence of the sensor, made from charged DNA material, and/or binding of the target influences the surface electrical and/or optical properties, which provides a measurable readout. Alternatively, the DNA origami can be modified with a reporter molecule that interacts with the surface to change a readout signal. Because the biosensor herein is based on a large conformational change, these readout methods can provide a strong signal change.
Lining up the fluorophores with their respective quencher thereof is challenging. The DNA origami hinge design disclosed herein overcomes these challenges. Accordingly, in some examples, a first arm of the DNA origami hinge comprises one or more quenchers, and wherein a second arm of the DNA origami hinge comprises one or more fluorophores. In some embodiments, the staple strands bounded to the quenchers comprises a polynucleotide sequence at least 60% (for example, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99%) identical to SEQ ID NOs: 230-264. In some embodiments, the staple strands bounded to the fluorophores comprises a polynucleotide sequence at least 60% (for example, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99%) identical to SEQ ID NOs: 265-299.
In some embodiments, the staple strand bounded to the quencher/fluorophore comprises a short nucleotide sequence (also herein referred as “reacher” sequence) at the end of staple strand and directly/non-directly linked to the quencher/fluorophore, wherein the reacher sequence linked to the quencher is complementary to the reacher sequence linked the paired fluorophore. In some embodiments, the reacher sequence is TATA. In some embodiments, the reacher sequence is ATAT. In some embodiments, the design of the reacher sequence is shown, for example, in
The quenching efficiency can be improved by changing the direction of the overhangs (left side) to the zipper. In some embodiments, the latch strand/zipper helices are directionally parallel to the structure’s helices (for example, as shown in
In some embodiments, the first arm of the DNA origami hinge comprises at least 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, or 60 quenchers. In some embodiments, the second arm of the DNA origami hinge comprises at least 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, or 60 fluorophores. In some embodiments, the first arm of the DNA origami hinge comprises at least 2 quenchers and the second arm of the DNA origami hinge comprises at least 2 fluorophores. In some embodiments, the first arm of the DNA origami hinge comprises at least 4 quenchers and the second arm of the DNA origami hinge comprises at least 4 fluorophores. In some embodiments, the first arm of the DNA origami hinge comprises at least 30 quenchers and the second arm of the DNA origami hinge comprises at least 30 fluorophores. In some embodiments, the first arm of the DNA origami hinge comprises at least 45 quenchers and the second arm of the DNA origami hinge comprises at least 45 fluorophores.
The limit of detection of the DNA origami hinge described herein can be less than 1×10- 8 molar concentration (M), less than 1 × 10-9 M, less than 1 × 10-10 M, less than 1 × 10-10 M, less than 1 × 10-11 M, less than 1 × 10-12 M, less than 1 × 10-13 M, less than 1 × 10-14 M, less than 1 × 10-15 M, less than 1 × 10-16 M, less than 1 × 10-17 M, or less than 1 × 10-18 M. The limit of detection can decrease as the number of fluorophores/quenchers increases. In some embodiments, the limit of detection of an DNA origami hinge having 4 pairs of fluorophores and quenchers is about 5 × 10- 11 M. In some embodiments, the limit of detection of an DNA origami hinge having 45 pairs of fluorophores and quenchers is from about 5 × 10-14 M to about 2× 10-13 M.
In some embodiments, an increase in fluorescence emission is detected when the DNA origami hinge is in the open configuration as compared to the fluorescence emission detected when the DNA origami hinge is in the closed configuration.
In some aspects, disclosed herein is a biosensor comprising:
In some aspects, disclosed herein is a method of detecting a nucleic acid in a subject, comprising
As discussed above, the biosensors disclosed herein are for accurate and fast detection of an infection or a disorder. The biosensors are highly stable in low magnesium environments or in biological samples. The biosensors also show an improvement in nuclease resistance. Accordingly, in some embodiments, the method disclosed herein does not require a step of purification of nucleic acid. In some embodiments, the method disclosed herein further comprises a step of purifying a nucleic acid from the biological sample.
In some embodiments, the biological sample is a saliva sample or a nasal swab sample. In some embodiments, the biological sample is a nasopharyngeal fluid sample.
In some embodiments, the nucleic acid is a nucleic acid of a pathogen (for example, a virus, a bacterium, a fungus, or a parasite) or a disease-specific nucleic acid (e.g., a tumor-specific nucleic acid).
In some embodiments, the nucleic acid is a nucleic acid of a virus, wherein the virus comprises Herpes Simplex virus- 1, Herpes Simplex virus-2, Varicella-Zoster virus, Epstein-Barr virus, Cytomegalovirus, Human Herpes virus-6, Variola virus, Vesicular stomatitis virus, Hepatitis A virus, Hepatitis B virus, Hepatitis C virus, Hepatitis D virus, Hepatitis E virus, Rhinovirus, Coronavirus, Influenza virus A, Influenza virus B, Measles virus, Polyomavirus, Human Papillomavirus, Respiratory syncytial virus, Adenovirus, Coxsackie virus, Dengue virus, Mumps virus, Poliovirus, Rabies virus, Rous sarcoma virus, Reovirus, Yellow fever virus, Zika virus, Ebola virus, Marburg virus, Lassa fever virus, Eastern Equine Encephalitis virus, Japanese Encephalitis virus, St. Louis Encephalitis virus, Murray Valley fever virus, West Nile virus, Rift Valley fever virus, Rotavirus A, Rotavirus B, Rotavirus C, Sindbis virus, Simian Immunodeficiency virus, Human T-cell Leukemia virus type-1, Hantavirus, Rubella virus, Simian Immunodeficiency virus, Human Immunodeficiency virus type-1, or Human Immunodeficiency virus type-2.
In some embodiments, the virus is an RNA virus. In some embodiments, the RNA virus is a coronavirus. In some embodiments, the coronavirus comprises SARS, SARS-COV-2, or MERS.
In some embodiments, the nucleic acid is a SARS-COV-2 RNA or a SARS-COV-2 DNA (e.g., an RNA/ DNA encoding a spike protein (S), hemagglutinin-esterase dimer (HE), a membrane glycoprotein (M), an envelope protein (E), or a nucleocapsid protein (N) of a SARS-COV-2) or a fragment thereof.
Accordingly, in some aspects, disclosed herein is a method of detecting SARS-COV-2 in a subject, comprising
In some embodiments, the RNA virus comprises an influenza virus (e.g., influenza A virus or influenza B virus), HIV, hepatitis C virus, Ebola virus, rabies virus, or Dengue virus. According, in some embodiments, disclosed herein is a method of detecting a viral nucleic acid of influenza, HIV, hepatitis C virus, Ebola virus, rabies virus, or Dengue virus.
In some embodiments, the nucleic acid is a nucleic acid of an influenza virus (e.g., an RNA encoding a PB1 protein, a PB2 protein, a PA protein, a neuraminidase protein (NA), a hemagglutinin protein (HA), a nucleocapsid protein (NP), nonstructural protein (NS), matrix protein M1 and M2 of an influenza virus) or a fragment thereof.
Accordingly, in some aspects, disclosed herein is a method of detecting an influenza virus in a subject, comprising
In some embodiment, the influenza virus is influenza A virus or influenza B virus.
In some embodiments, the nucleic acid is a nucleic acid of bacteria, wherein the bacteria comprises Mycobaterium tuberculosis, Mycobaterium bovis, Mycobaterium bovis strain BCG, BCG substrains, Mycobaterium avium, Mycobaterium intracellular, Mycobaterium africanum, Mycobaterium kaususii, Mycobaterium marinum, Mycobaterium ulcerans, Mycobaterium avium subspecies paratuberculosis, Nocardia asteroides, other Nocardia species, Legionella pneumophila, other Legionella species, Acetinobacter baumanii, Salmonella typhi, Salmonella enterica, other Salmonella species, Shigella boydii, Shigella dysenteriae, Shigella sonnei, Shigella flexneri, other Shigella species, Yersinia pestis, Pasteurella haemolytica, Pasteurella multocida, other Pasteurella species, Actinobacillus pleuropneumoniae, Listeria monocytogenes, Listeria ivanovii, Brucella abortus, other Brucella species, Cowdria ruminantium, Borrelia burgdorferi, Bordetella avium, Bordetella pertussis, Bordetella bronchiseptica, Bordetella trematum, Bordetella hinzii, Bordetella pteri, Bordetella parapertussis, Bordetella ansorpii, other Bordetella species, Burkholderia mallei, Burkholderia psuedomallei, Burkholderia cepacian, Chlamydia pneumoniae, Chlamydia trachomatis, Chlamydia psittaci, Coxiella burnetii, Rickettsial species, Ehrlichia species, Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pneumoniae, Streptococcus pyogenes, Streptococcus agalactiae, Escherichia coli, Vibrio cholerae, Campylobacter species, Neiserria meningitidis, Neiserria gonorrhea, Pseudomonas aeruginosa, other Pseudomonas species, Haemophilus influenzae, Haemophilus ducreyi, other Hemophilus species, Clostridium tetani, Clostridium difficile, other Clostridium species, Yersinia enterolitica, and other Yersinia species, or Mycoplasma species.
In some embodiments, the method herein is for detection of a tumor-specific nucleic acid, including, for example, tumor-specific nucleic acids or oncogenes (derived from point mutations, amplification, or fusion) that encode tumor antigens, such as a glioma-associated antigen, carcinoembryonic antigen (CEA), EGFRvIII, EGFR, FAP, B7H3, Kit, CA LX, CS-1, BCMA, β-human chorionic gonadotropin, alphafetoprotein (AFP), cyclin Bl, lectin-reactive AFP, Fos-related antigen 1, ADRB3, thyroglobulin, AKAP-4, OY-TESI, CLL-1, fucosyl GM1, GloboH, MN-CA IX, EVT6-AML, TGS5, human telomerase reverse transcriptase, plysialic acid, intestinal carboxyl esterase, lewisY, sLe, LY6K, mut hsp70-2, M-CSF, RhoC, TRP-2, CYPIBI, BORIS, prostate-specific antigen (PSA), LAGE-la, NCAM, Ras mutant, gp100, prostein, OR51E2, PANX3, PSCA, HMWMAA, HAVCR1, VEGFR2, telomerase, legumain, sperm protein 17, SSEA-4, tyrosinase, TARP, prostate-carcinoma tumor antigen- 1 (PCTA-1), ML-IAP, MAD-CT-1, MAD-CT-2, MelanA/MART 1, XAGE1, ELF2M, NA17, neutrophil elastase, sarcoma translocation breakpoints, NY-BR-1, ephnnB2, androgen receptor, insulin growth factor (IGF)-I, IGF1, IGF-I receptor, GD2, o-acetyl-GD2, GD3, GM3, GPRC5D, GPR20, CXORF61, folate receptor (FRa), folate receptor beta, TAG72, TN Ag, Tie 2, TEM1, TEM7R, CLDN6, UPK2, mesothelin, BAGE proteins, CA9, CALR, CCR5, CD19, CD20 (MS4A1), CD22, CD24, CD27, CD30, CD33, CD38, CD40, CD44, CD52, CD56, CD79, Cd123, CD97, CD171, CD179a, CDK4, CEACAM3, CEACAM5, CLEC12A, DEPDC1, ERBB2 (HER2/neu), ERBB3, ERBB4, EPCAM, EPHA2, EPHA3, FCRL5, FOLR1, GAGE proteins, GPNMB, GPR112, IL3RA, LGR5, EBV-derived LMP2, LICAM, MAGE proteins, MAGE-A1, MLANA, MSLN, MUC1, MUC2, MUC3, MUC4, MUC5, MUC16, MUM1, ANKRD30A, NY-ESO1 (CTAGlB), OX40, PAP, PLAC1, PRLR, PMEL, PRAME, PSMA (FOLH1), RAGE proteins, RGS5, ROR1, ROS1, RU1, RU2, SART1, SART3, SLAMF7, SLC39A6 (LIV1), STEAP1, STEAP2, TMPRSS2, Thompson-nouvelle antigen, TNFRSF17, TYR, UPK3A, VTCN1, gp72, the ras oncogene product, HPV E6, HPV E7, beta-catenin, telomerase, melanoma gangliosides, ABL1, ABL2, AF15Q14, AFlQ, AF3p21, AF5q31, AKT, AKT2, ALK, ALO17, AML1, API, APC, ARHGEF, ARHH, ARNT, ASPSCR1, ATIC, ATM, AXL, BCL10, BCL11A, BCL11B, BCL2, BCL3, BCL5, BCL6, BCL7A, BCL9, BCR, BCR-ABL, BHD, BIRC3, BIRC5, BIRC7, BLM, BMPR1A, BRCA1, BRCA2, BRD4, BTG1, CBFA2T1, CBFA2T3, CBFB, CBL, CCND1, c-fos, CDH1, c-jun, CDK4, c-kit, CDKN2A- p14ARF, CDKN2A - p16 INK4A, CDX2, CEBPA, CEP1, CHEK2, CHIC2, CHN1, CLTC, c-met, c-myc, COL1A1, COPEB, COX6C, CREBBP, c-ret, CTNNB1, CYLD, D10S170, DDB2, DDIT3, DDX10, DEK, EGFR, EIF4A2, ELKS, ELL, EP300, EPS15,, ERCC2, ERCC3, ERCC4, ERCC5, ERG, ETV1, ETV4, ETV6, EVI1, EWSR1, EXT1, EXT2, FACL6, FANCA, FANCC, FANCD2, FANCE, FANCF, FANCG, FEV, FGFR1, FGFR10P, FGFR2, FGFR3, FH, FIPlL1, FLI1, FLT3, FLT4, FMS, FNBP1, FOXO1A, FOXO3A, FPS, FSTL3, FUS, GAS7, GATA1, GIP, GMPS, GNAS, GOLGA5, GPC3, GPHN, GRAF, HEI10, HER3, HIP1, HIST1H4I, HLF, HMGA2, HOXA 11, HOXA13, HOXA9, HOXC13, HOXD11, HOXD13, HRAS, HRPT2, HSPCA, HSPCB, hTERT, IGHα, IGKα, IGLα, IL-11Ra, IL-13Ra, IL21R, IRF4, IRTA1, JAK2, KIT, KRAS, KRAS2, LAF4, LASP1, LCK, LCP1, LCX, LHFP, LMO1, LMO2, LPP, LYL1, MADH4, MALT1, MAML2, MAP2K4, MDM2, MECT1, MEN1, MET, MHC2TA, MLF1, MLHI1, MLL, MLLT1, MLLT10, MLLT2, MLLT3, MLLT4, MLLT6, MLLT7, MLM, MN1, MSF, MSH2, MSH6, MSN, MTSI1, MUTYH, MYC, MYCL1, MYCN, MYH11, MYH9, MYST4, NACA, NBS1, NCOA2, NCOA4, NFl, NF2, NOTCH1, NPM1, NR4A3, NRAS, NSDI, NTRK1, NTRK3, NUMA1, NUP214, NUP98, NUT, OLIG2, p53, mutant p53, p27, p57, p16, p21, p73, PAX3, PAX5, PAX7, PAX8, PBX1, PCM1, PDGFB, PDGFRA, PDGFRB, PICALM, PIM1, PML, PMS1, PMS2, PMX1, PNUTL1, POU2AF1, PPARG, PRAD-1, PRCC, PRKAR1A, PRO1073, PSIP2, PTCH, PTEN, PTPN11, RAB5EP, RAD51L1, RAF, RAP1GDS1, RARA, RAS, Rb, RB1, RECQL4, REL, RET, RPL22, RUNX1, RUNXBP2, SBDS, SDHB, SDHC, SDHD, SEPT6, SET, SFPQ, SH3GL1, SIS, SMAD2, SMAD3, SMAD4, SMARCB1, SMO, SRC, SS18, SS18L1, SSH3BP1, SSX1, SSX2, SSX4, Stathmin, STK11, STL, SUFU, TAF15, TAL1, TAL2, TCF1, TCF12, TCF3, TCL1A, TEC, TCF12, TFE3, TFEB, TFG, TFPT, TFRC, TIF1, TLX1, TLX3, TNFRSF6, TOP1, TP53, TPM3, TPM4, TPR, TRAα, TRBα, TRDα, TRIM33, TRIP11, TRK, TSC1, TSC2, TSHR, VHL, WAS, WHSC1L1 8, WRN, WT1, XPA, XPC, ZNF145, ZNF198, ZNF278, ZNF384, or ZNFN1A1.
It should be understood and herein contemplated that the methods described can detect more than one targets simultaneously, comprising adding multiple types of the biosensors described herein into a biological sample, wherein each type of the biosensors targets a nucleic acid that is different from the targeting nucleic acids of the other types of the biosensors. The methods can be used for detecting more than one type of pathogen and/or for diagnosing an infectious disease.
Accordingly, in some aspects, disclosed herein is a method of simultaneously detecting more than one type of pathogen in a subject, comprising
The following examples are set forth below to illustrate the compositions, methods, and results according to the disclosed subject matter. These examples are not intended to be inclusive of all aspects of the subject matter disclosed herein, but rather to illustrate representative methods and results. These examples are not intended to exclude equivalents and variations of the present invention which are apparent to one skilled in the art.
As of mid-April 2020, the CDC’s preferred method of testing patients suspected to be infected by the COVID-19 virus is the real time reverse transcriptase polymerase chain reaction (RT-PCR) assay, designed to qualitatively detect the presence of the COVID-19 single-stranded RNA (ssRNA) genome from upper respiratory samples. This method, while accurate and indicative of current infection, is time consuming, labor intensive and requires significant materials. The current workflow for RT-PCR requires steps of sample collection, RNA extraction, RNA isolation, cDNA synthesis, qPCR, and readout. All these steps together can take hours to days. A more rapid method is the serological test for antibodies (15 to 20 minutes). However, the serological test fails to provide an accurate COVID-19 diagnosis from patients presenting an early to middle phase of infection or in cases involving immunodeficient individuals. Thus, developing an accurate COVID-19 positive assay confirming infection in a timely manner can be lifesaving.
DNA origami is a nanotechnology that allows for detailed design and construction of 2D and 3D nanoscale objects and can combine different molecular functional items on a single nanostructure with unprecedented precision. A nanoscale hinge was constructed (
A rapid COVID-19 diagnostic assay employs the DNA origami “Hinge” nanostructure (
The methods herein show positive correlation with RT-PCR testing procedures. In addition, the methods confirm the existence of low concentrations of COVID-19 RNA, which allows the full test to occur in less than 30 minutes. The sensitivity is improved by further increasing the number of FAM/BHQ pairs or Hinge device concentrations to increase the fluorescent readout. Alternatively, geometric shape design parameters can also be changed in a rapid manner.
DNA origami is a versatile tool that is emerging for use in biomedical applications, such as drug delivery, bio-sensing, and imaging. Similar to the Hinge device disclosed herein, many PCR systems use a combination of FAM fluorophores and Black Hole quenchers for an experimental readout, although they are generally limited to a single FAM fluorophore per (complementary) cDNA strand, which is copied from cDNA of the original RNA target (COVID-19). Alternatively, many fluorophores (up to 30 or more) can be attached on a single nanostructure enabling a bright signal without amplification of the COVID-19 cDNA, which saves time without altering the original readout. Recently, it was shown that fluorophores spaced within 2-5 nm display increased photons (over 6x) compared to a singular fluorophore, resulting in greater sensitivity. The DNA origami diagnostic test can be performed in about an hour with 40 minutes of that time using the same Viral RNA extraction kit that is used for current RT-PCR-based COVID-19 testing. The Hinge actuation occurs very rapidly, in seconds to minutes. Furthermore, the origami nanostructures disclosed herein have shown resistance to nuclease degradation, and the detection can be performed in cell lysate, which reduces the experimental procedural time to under 30 minutes. Additionally, the process requires only a simple addition of the DNA nanostructures to the RNA solution, allowing for the process to be performed with limited expertise and equipment.
The DNA origami hinge is roughly the same size as a virus (~100 nm). It can produce bright, glowing signal for each virus copy detected. The key design parts include the triggers for conformation changes and how the those occur.
DNA origami bio-sensing applications are not limited to the current COVID-19 pandemic, as changing the target sequence requires just a few oligonucleotide (out of 150+ in the total design) alterations to the DNA origami. This allows for adapting the technology to detect and diagnose many other DNA/RNA based viruses with only minor changes, and additionally can supplement some PCR functionalities. Furthermore, it was shown that DNA origami can be easily and quickly fabricated in large amounts (mg to g’s), with scaled-up manufacturing being cheap and attainable (estimates have origami produced for as low as ~$0.18 per mg). Thus, benefits of the technology include: 1) Faster than RT-PCR, can be performed in under 30 minutes; 2) Combines many fluorophores per nanostructure for an increased signal; 3) Uses similar readouts as existing technology and adaptable to other DNA/RNA based viruses; and 4) Fast, scalable fabrication.
Disclosed herein is a DNA-based nanoscale Biosensor constructed via the DNA origami molecular self-assembly process. The Biosensor is based on a hinge-like design consisting of two or more arms that are initially held in a closed configuration by a latching interaction. The latching interaction consists of nucleic acid base pairing between strands on distinct components, which are disrupted in the presence of a target nucleic acid sequence to convert the sensor into an open configuration. The latching interaction contains a section of the sequence that remains single stranded (ss) even in the closed configuration, referred to as a “toehold.” The target nucleic sequence causes the sensor to open by initially binding to the ssDNA or ssRNA toehold sequence and then competitively unbinds the latching sequence. This opening of the sensor reconfigures and/or exposes the functional molecules used for fluorescence, colorimetric, precipitation, or color changing readouts. Employing DNA origami Hinge-like devices as a platform for specific nucleic acid detection allows for a myriad of functionalities for this readout as a positive test for multiple disease states, such as RNA or DNA viral infections including SARS-CoV-2 (COVID-19). The device design includes the addition of fluorescent and quencher molecules on opposing arms of the ‘closed’ Hinge Biosensor. In the closed configuration, the quenchers are located near the fluorescent molecules, and when the sensor opens, the molecules separate leading to a strong increase in fluorescence. The DNA origami Hinge Biosensor can have many pairs of fluorophore/quenchers arranged in parallel so they “turn on” in unison to elicit an amplified signal (device contains about 45 pairs). This allows for the elimination of the time-consuming PCR or quantitative real time RT-PCR reactions that are common in the detection of viruses (including COVID-19) and other target nucleic acids. Additionally, Förster resonance energy transfer (FRET) can be used as a different signal output option.
A second version of the DNA origami Hinge Biosensor is designed with an internal cavity that contains catalytic molecules, which are occluded, or inaccessible, in the closed configuration (
A third version of the DNA origami Hinge Biosensor allows for the exposure of internal DNA sequences for two purposes. First, this is used as an amplification mechanism where strands that are exposed upon opening can trigger other devices so that one detection event can lead to a cascade of many devices fluorescing. This allows for detection of lower levels of target, even a single copy. Second, devices are designed where exposure of DNA sequences allows for higher order assembly of filaments or networks of the nanostructures. These networks can be detected by multiple possible methods. First, if they are large enough, they can precipitate and cause a cloudy solution. Second, staining with a DNA intercalator, or polymerizing with colored streptavidin/biotin, renders a visible change in color in the presence of large assemblies. Third, the assembly of networks can change the viscosity of the solution. Specific nucleic acid targets that the DNA origami Hinge Biosensor can detect include SARS-Cov-2 (also known as COVID-19), MERS, SARS and other viruses such as influenza. Furthermore, adding design features to any of the hinges, like cross-linking proximal thymidines by irradiating the nanostructures increases stability at high temperature, renders an increase in melting temperature and detection of double-stranded nucleotide targets. This increases the number of targets, including improved sensitivity in liquid biopsy detecting free circulating DNA, PCR-based experiments, or even loop-mediated isothermal amplification (LAMP).
The DNA origami designs provided herein comprises significant improvements over the prior designs. The challenges during processes of these improvements include, for example, increasing the number of overhang staple strand locations, lining up the fluorophore with the quenchers, hinge angle of the DNA origami “default” to be open configuration but still able to close hinge, latching mechanism that is strong enough to keep the DNA origami in a closed configuration but is still able to release and convert the DNA origami to an open configuration, the reuse mechanism, requirement of specific equipment for fluorescence readout, and optimal salt conditions.
The challenges are overcome by the improvements in design, including, for example, flattening the hinge, while still keeping stiff enough; changing the back section of design to change free body diagram; using “zipper” strand latch, which is about 100 bases complement to target nucleic acid; designing the zipper strand as not a part of DNA origami hinge structure such that DNA origami hinges can be “reloaded” with zipper strand; using trap design to protect from solution color changing molecules; and low enough to reduce secondary binding of Target/Zipper (internally), but still bind to structure. Patient samples come in various versions of transport media and contain a variety of protein, such as DNases and difference in cation concentration, that can have adverse effects on structure morphology and zipper binding, designing a structure with the optimal resilience in its stability is key. Using a square lattice and limiting the cross-overs in the design, in a similar fashion to previous designs, allows for a higher order of continuously bound segment sections before a holiday junction occurs. This improves the overall stability of the origami structure. In order to have the optimal quenching of the fluorophores, the attachment sites on each hinge arm must line up with their corresponding attachment site on the adjacent arm. Careful and deliberate structure design is necessary to ensure that the arms with line up and the fluorophores will be close enough to quench. Alternatively, to eliminate the need for equipment to read out, the Hinge Trap is designed to contain a protected molecule, that only changes color when in the open state, keeping the color-changing reaction apart when in the closed configuration. This technology is a rapid RNA-diagnostic based solution for quick and cheap testing (under 30 minutes) (estimates have DNA origami cost to be about $0.18 per mg in large scale production).
Definition of “Latch ”. The “latch” (also referred to as the “zipper” or “zipper strand”) is defined as the single stranded nucleic acid sequence that serves to: 1) close the “top arm” and “bottom arm” of the Hinge DNA origami nucleic acid biosensor 2) “sense” the intended nucleic acid target sequence of the DNA/RNA viral nucleic acid, or tumor specific DNA/RNA nucleic acid material and 3) respond to the intended nucleic acid target sequence via complementary base pair binding to cause the Hinge DNA origami nucleic acid biosensor to change from a “closed” to “open” configuration to allow for emission of a fluorescent, colorimetric, or precipitation signal readout.
Composition and Mechanism of “Latch”. The “latch” consists of a single stranded ~100 base DNA or RNA oligonucleotide sequence designed with a potion with reverse complementarity (can be 100% identity) to the pre-defined target DNA/RNA viral or tumor nucleic acid sequence. The ‘latch’ oligonucleotide ‘closes’ the DNA origami Hinge Biosensor by base pairing with distinct regions of ‘overhang’ staple sequences that protrude from DNA helices from the ‘top arm’ and DNA helices from the ‘bottom arm’ of the Hinge DNA origami biosensor (se
Provided herein is a fluorescence-based DNA Origami COVID-19 diagnostic biosensor used in a clinical setting. Product iterations are designed to allow for a simple color change upon sensing SARS-CoV-2 target nucleic acid to facilitate rapid diagnostic testing at field point-of-care centers. Key steps toward product validation and de-risking include: 1) Effective DNA origami (DO) COVID-19 biosensor detection of viral nucleic acid in clinical samples; 2) Determining DO COVID-19 biosensor sensitivity in clinical samples (defining a lower limit of detection of viral nucleic acid material); 3) Evaluating long-term storage conditions and demonstrating capability to scale product production.
Demonstrate effective SARS-CoV-2 detection by DNA origami (DO) COVID-19 diagnostic biosensor in Clinical Samples: The DO COVID-19 biosensor design is optimized and evaluated/validated using i) long RNA target primers, ii) Research Use Only (RUO) SARS-CoV-2 viral material, and iii) COVID-19 clinical samples vs. healthy control samples. Outcomes include: 1) detection of 100 fM concentration of long SARS-CoV-2 RNA primer; 2) test negative against all non-target viral RNA and positive against SARS-CoV-2 RNA; 3) test negative for 100 out of 100 healthy patient samples, and test positive for 95 out of 100 COVID-19 patient samples.
Determine DO COVID-19 Diagnostic Biosensor Sensitivity in Clinical Samples: This study focuses on determining the biosensor limits of detection and detection variability in COVID-19 clinical samples. Outcomes include: 1) detection of 100 fM concentration of SARS-CoV-2 viral material; 2) low experimental variability between both replicate measurements and independently prepared batches of DO COVID-19 biosensors.
Quantify long-term storage stability and increased production of DO COVID-19 diagnostic biosensor: Stability of the DO COVID-19 diagnostic biosensor is tested under various storage conditions at various time points up to 6 months. Outcomes include: 1) optimal storage conditions are identified to preserve DO COVID-19 biosensor structural integrity, stability, and SARS-CoV-2 detection capabilities 2) scaling production process is established.
The equipment necessary to produce and interpret diagnostic results, prior to testing detection, is provided by the clinical laboratory. This equipment includes:
Once testing laboratory receives samples, testing device is mixed with samples, heated to 37° C. for various time points, and read on a fluorometer instrument, real time PCR instrument, or a fluorescence based plate reader in the testing laboratory. All handling of de-identified patient samples are conducted in a BSL-2 bio-safety cabinet and in accordance with IBC protocol 202R00000058.
No deviations from these procedures are allowed without approval of the study sponsor (and the IRB/Ethics Committee if appropriate). Standard Precautions should be followed when working with clinical specimens and live microorganisms, including working in a biosafety cabinet. The tasks listed in this procedure must be performed by individuals who do not have knowledge of the test results.
1. Use the following selection criteria to determine if a specimen is appropriate for enrollment: Inclusion Criteria:
2. If a specimen qualifies for the study, record the name of the subject from whom the specimen was collected (or other appropriate subject identifier) on Appendix A: De-Identification Key. Also record the date and time the specimen was collected (as listed on the primary specimen container).
3. Assign the subject a number
4. Record the date of testing and results.
NOTE: Do not enroll specimens unless they appear to meet the inclusion criteria sufficient specimen volume is left over following diagnostic analysis as prescribed by the physician.
NOTE: The De-Identification Key should be the only link between the subject’s identification and the SCN assigned to the subject’s specimen. It should be maintained in accordance with IRB/EC-approved procedures and handled in compliance with local regulations.
Only leftover clinical samples that arrive to the clinical microbiology laboratory for COVID testing are being considered for this study. The samples are collected by qualified nurses and doctors following standard procedures. Only leftover samples are used for the study. Importantly, all leftover samples are heat inactivated on a heat block (65° C. for 30 minutes), and stored at -20° C. until sample transfer to testing laboratory.
Initial specimen information is entered. Enter other information including specimen type, collection date and testing, and results. Record the diagnostic call (Negative/Positive) as well as genotyping data if available.
Assay Overview. This experimental assay includes a ‘Hinge’ DNA origami nanostructure biosensor designed to detect low concentrations of SARS-CoV-2 RNA in solution. This biosensor can have 2-30 fluorescent molecules incorporated (paired with fluorescent quenching molecules), which only fluoresce when the target sequence RNA (SARS-CoV-2) is present.
The ‘Hinge’ DNA origami nanostructure is latched ‘closed’ by a ~100 base oligonucleotide that is the reverse complementary sequence to specific regions of the SARS-CoV-2 RNA genome. When the ‘Hinge’ DNA origami biosensor is mixed with a sample that contains SARS-CoV-2 RNA target sequences, the ‘Hinge’ DNA origami biosensor changes from a ‘closed’ to an ‘open’ configuration thus exposing fluorophore molecules that were quenched. Fluorescence can then be read on a real-time PCR instrument, a fluorometer, or a plate reader capable of fluorescence detection.
1.) Heat inactivated (65° C. for 30 minutes) deidentified clinical samples are obtained from the clinical laboratory by the testing laboratory (NBL) and kept frozen at -20° C. until use.
2.) Clinical samples are thawed in a BSL-2 biosafety cabinet and mixed with closed, open, or closed ‘off-target’ ‘Hinge’ DNA origami COVID-19 biosensors.
3.) Samples are heated at 37° C. for various time points (15-60 minutes).
4.) Sample fluorescence are measured in 3 different instruments including: 1) fluorometer 2) real time PCR instrument and 3) fluorescence-based plate reader.
Custom Matlab Code Example. Written to design overhang sequences (for standard Hinge DNA origami biosensor 10-10 design). Example of input and output is shown in
Unless defined otherwise, all technical and scientific terms used herein have the same meanings as commonly understood by one of skill in the art to which the disclosed invention belongs. Publications cited herein and the materials for which they are cited are specifically incorporated by reference.
Those skilled in the art will appreciate that numerous changes and modifications can be made to the preferred embodiments of the invention and that such changes and modifications can be made without departing from the spirit of the invention. It is, therefore, intended that the appended claims cover all such equivalent variations as fall within the true spirit and scope of the invention.
SEQ ID NO: 1 (sequence of scaffold strand, M13mp18 bacteriophage genome (7249 bases in length plus an 815 base insert sequence, total length = 8064 bases)
This application claims the benefit of U.S. Provisional Application No. 63/086,644, filed Oct. 2, 2020, which is expressly incorporated herein by reference in its entirety.
Filing Document | Filing Date | Country | Kind |
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PCT/US2021/053204 | 10/1/2021 | WO |
Number | Date | Country | |
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63086644 | Oct 2020 | US |