Ultra-sensitive and simple assay for Hepatitis C virus using reduced graphene oxide-assisted hybridization chain reaction
Hepatitis C virus (HCV) is a major cause of chronic liver disease, which affected the 2-3 % world population. Until now, early detection of HCV is a great challenge especially for those developing countries. In this study, we developed a novel and ultrasensitive assay for HCV RNA based on the reduced graphene oxide nanosheets (rGONS) and hybridization chain reaction (HCR) amplification technique. This detecting system contain a pair of single fluorophore-labeled hairpin probes, which can freely exist in the solution without target RNA. While the introduction of target RNA can robustly trigger HCR with the two probes and produce long nanowires containing double-stranded structure. The weak adsorption to rGONS makes the long nanowires to emit strong fluorescence. Using this enzyme-free amplification strategy, we develop a new method for HCV RNA assay with the detection limit of 10 fM, which is far more sensitive than the common GO-based fluorescence method. Meanwhile, the new method exhibits high selectivity for the discrimination of perfectly complementary and mismatch sequences. Finally, the new method was successfully used for HCV RNA assay in bio-samples with strong anti-interference capability under complicated environments. In summary, these eminent characteristics of the new method highlight the potential usability for clinic sample primary screening.