Hybridization chain reaction methods for in situ molecular detection
The disclosure provides a method for detecting a target analyte in a biological sample including contacting the sample with one or more probe sets each comprising a primary probe and a linker, contacting the sample with an initiator sequence, contacting the sample with a plurality of fluorescent DNA hairpins, wherein the probe binds the target molecule, the linker connects the probe to the initiator sequence, and wherein the initiator sequence nucleates with the cognate hairpin and triggers self-assembly of tethered fluorescent amplification polymers, and detecting the target molecule by measuring fluorescent signal of the sample.
1. A method for identifying a plurality of target analytes in a sample, comprising:
(a) for each target analyte of said plurality of target analytes, contacting said sample with a probe coupled to a linker to bind said probe to said target analyte, wherein said linker is unique to said target analyte;
(b) subsequently adding a first hybridization chain reaction (HCR) initiator comprising an initiator sequence to said sample and contacting said sample with said first HCR initiator under conditions sufficient to permit said first HCR initiator to bind to said linker, wherein said first HCR initiator is separate from said probe, and wherein upon contacting said sample with said first HCR initiator, said linker couples said probe with said first HCR initiator;
(c) contacting said sample with HCR amplifiers to trigger a hybridization chain reaction, generating a first amplification product coupled to said probe;
(d) detecting said first amplification product;
(e) disrupting or reversing binding between said first HCR initiator and said linker;
(f) contacting said sample with a second HCR initiator comprising a second initiator sequence under conditions sufficient to permit said second HCR initiator to bind to said linker, wherein said second HCR initiator is separate from said probe, and wherein upon contacting said sample with said second HCR initiator, said linker couples said probe with said second HCR initiator;
(g) contacting said sample with additional HCR amplifiers to trigger an additional hybridization chain reaction, thereby generating a second amplification product coupled to said probe;
(h) detecting said second amplification product, and
(i) using at least signals from detecting said first amplification product and signals from detecting said second amplification product to generate a combined time-ordered composite signal unique for the each target analyte.
2. The method of claim 1 , wherein said disrupting or reversing comprises using toehold displacement to remove said first HCR initiator bound to said linker.
3. The method of claim 1 , further comprising generating said first amplification product or said second amplification product in situ.
4. The method of claim 1 , further comprising, detecting a spatial localization of said target analyte.
5. The method of claim 1 , wherein said probe comprises a protein, a peptide, an aptamer, a deoxyribonucleic acid hybridization probe, a ribonucleic acid hybridization probe, or any combination thereof.
6. The method of claim 1 , wherein said probe comprises a nucleotide sequence that is complementary to a sequence of said target analyte.
7. The method of claim 1 , wherein said probe comprises an antibody capable of binding to said target analyte.
8. The method of claim 1 , wherein said disrupting or reversing comprises using heat or a denaturant to remove said first HCR initiator bound to said linker.
9. The method of claim 1 , wherein said disrupting or reversing comprises using chemical, enzymatic, or light treatment that disrupts a linkage between said first HCR initiator and said linker.
10. The method of claim 1 , wherein an HCR amplifier of said HCR amplifiers comprises an HCR monomer that comprises a detectable label.
11. The method of claim 10 , wherein said detectable label comprises a fluorescent label.
12. The method of claim 10 , wherein said detectable label of said HCR monomer comprises a sequencing template for fluorescent sequencing and (d) comprises sequencing said sequencing template by fluorescent sequencing by hybridization, fluorescent sequencing by ligation, or fluorescent sequencing by synthesis.
13. The method of claim 10 , wherein said HCR monomer comprises one or more enzymatic or chemical sensitive groups, or photo-labile groups in a DNA backbone of said HCR monomer.
14. The method of claim 2 , wherein said toehold displacement comprises using a modified HCR monomer comprising one or more additional sequences for toehold strand displacement.
15. The method of claim 1 , wherein said target analyte is associated with a unique plurality of signals comprising signals detected from said first amplification product or said second amplification product.
16. The method of claim 1 , wherein said disrupting or reversing comprises cleaving said first HCR initiator.