RETRACTED: Optimal DNA structure of reverse-hairpin beacons for label-free and positive surface enhanced Raman scattering assays

Abstract

We developed a label-free and positive-readout surface enhanced Raman scattering (SERS) assay using reverse-hairpin molecular beacons (RHBs) for the detection of RNA genetic markers associated with a high pathogenicity influenza (HPAI) virus. The structure of RHBs flexibly changed from a linear configuration (open state) to hairpin (closed state) upon targeting, such that the Raman label was closed on the SERS substrate and induced an increase of SERS intensity (OFF-to-ON). By improving sequence-specific RNA/DNA hybridization efficiency, we adjusted the stem-loop ratio of RHB, which was efficient at values of less than 1. The optimized RHBs exhibited dramatic changes in signal based on a fluorescence system in which the target was present. We demonstrated that the OFF-to-ON SERS system using RHB immobilized on silver-coated gold nanobowls permitted rapid hybridization. This proof-of-concept could provide a potential diagnostic tool for point-of-care influenza virus detection.