Hybridization chain reaction-based aptameric system for the highly selective and sensitive detection of protein

We introduce here a novel assay for the detection of platelet-derived growth factor BB (PDGF-BB) via hybridization chain reaction (HCR) based on an aptameric system, where stable DNA monomers assemble only upon exposure to a target PDGF-BB aptamer. In this process, two complementary stable species of biotinylated DNA hairpins coexist in solution until the introduction of initiator aptamer strands triggers a cascade of hybridization events that yields nicked double helices analogous to alternating copolymers. In detail, the aptamer firstly opens the hairpins in the solution, creating long concatemers, and then reacts with the antibody captured PDGF-BB on the well surface. Moreover, several experimental conditions including different PDGF-BB aptamers, the spacer length of the selected aptamer and hairpin, etc. are investigated and optimized. Our results show that the coupling of HCR to aptamer triggers for the amplification detection of PDGF-BB achieves a better performance in the fluorescence detection of PDGF-BB as compared to the traditional antibody-antigen-aptamer assays. Upon modification, the approach presented herein could be extended to detect other types of targets. We believe such advancements will represent a significant step towards improved diagnostics and more personalized medical treatment and environmental monitoring.