Electrochemical detection of nucleic acid hybridization
First Claim
1. A method of detecting a target nucleic acid, comprising:
- providing a hybridization complex comprising (a) a capture probe that is attached to an electrode surface directly or via an attachment linker;
(b) a target nucleic acid that is hybridized to the capture probe; and
(c) at least one nanoparticle attached to the target nucleic acid;
removing unhybridized nucleic acid;
contacting the electrode with a redox solution comprising a redox mediator and an electrolyte, such that the complex is in contact with the redox solution; and
detecting a non-photogenerated electrical signal in the electrode, whereby detection of an increased non-photogenerated electrical signal relative to a signal that would be detected in the absence of said target nucleic acid or said nanoparticle indicates the presence or amount of target nucleic acid hybridized to the electrode.
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Abstract
A nucleic acid hybridization detection assay is carried out at an electrode. A solid electrode, such as an indium tin oxide electrode, is modified by capture probes comprising single-stranded oligonucleotides immobilized to the surface of the electrode. In some embodiments using sandwich assay methodology, the capture probes hybridize complementary target nucleic acid sequences, which in turn are bound to detection probes comprising nanoparticle-oligonucleotide conjugates comprising target-complementary oligonucleotides. In some embodiments, detection probes comprise nanoparticles attached to molecules comprising one partner of a ligand-binding pair (e.g., streptavidin), while target sequences comprise the other partner of the ligand-binding pair (e.g., biotin). When the assay is carried out in the presence of a redox mediator, redox reactions catalyzed, and/or facilitated and/or enhanced by the presence of nanoparticles generate electrons that are transferred to the electrode, resulting in a detectable electrical signal.
113 Citations
40 Claims
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1. A method of detecting a target nucleic acid, comprising:
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providing a hybridization complex comprising (a) a capture probe that is attached to an electrode surface directly or via an attachment linker;
(b) a target nucleic acid that is hybridized to the capture probe; and
(c) at least one nanoparticle attached to the target nucleic acid;removing unhybridized nucleic acid; contacting the electrode with a redox solution comprising a redox mediator and an electrolyte, such that the complex is in contact with the redox solution; and detecting a non-photogenerated electrical signal in the electrode, whereby detection of an increased non-photogenerated electrical signal relative to a signal that would be detected in the absence of said target nucleic acid or said nanoparticle indicates the presence or amount of target nucleic acid hybridized to the electrode. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 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)
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14. (canceled)
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40. A method of detecting a target nucleic acid, comprising:
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providing a hybridization complex comprising (a) a capture probe that is attached to an electrode surface directly or via an attachment linker;
(b) a target nucleic acid that is hybridized to the capture probe; and
(c) at least one nanoparticle attached to the target nucleic acid;removing unhybridized nucleic acid; contacting the electrode with a redox solution comprising a redox mediator and an electrolyte, such that the complex is in contact with the redox solution; and detecting an electrical signal in the electrode, whereby detection of an increased electrical signal relative to a signal that would be detected in the absence of said target nucleic acid or said nanoparticle indicates the presence or amount of target nucleic acid hybridized to the electrode, wherein the method is free of exposing a photoelectrochemically active moiety to a laser.
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Specification