Hairpin DNA-assisted silicon/silver-based surface-enhanced Raman scattering sensing platform for ultrahighly sensitive and specific discrimination of deafness mutations in a real system.

Surface-enhanced Raman scattering (SERS) is well-recognized as a powerful analytical tool for ultrahighly sensitive detection of analytes. In this article, we present a kind of silicon-based SERS sensing platform made of a hairpin DNA-modified silver nanoparticles decorated silicon wafer (AgNPs@Si). In particular, the AgNPs@Si with a high enhancement factor (EF) value of ~4.5 × 10(7) is first achieved under optimum reaction conditions (i.e., pH = 12, reaction time = 20 min) based on systematic investigation. Such resultant AgNPs@Si is then employed for construction of a silicon-based SERS sensing platform through surface modification of hairpin DNA, which is superbly suitable for highly reproducible, multiplexed, and ultrasensitive DNA detection. A detection limit of 1 fM is readily achieved in a very reproducible manner along with high specificity. Most significantly, for the first time, we demonstrate that the silicon-based SERS platform is highly efficacious for discriminating deafness-causing mutations in a real system at the femtomolar level (500 fM), which is about 3-4 orders of magnitude lower than that (~5 nM) ever reported by conventional detection methods. Our results raise the exciting potential of practical SERS applications in biology and biomedicine.