Silicon nanowires-based highly-efficient SERS-active platform for ultrasensitive DNA detection

A nanostructured complex, silicon nanowires (SiNWs) coated with in situ grown AgNPs (SiNWs@AgNPs), is developed as a well-defined surface-enhanced Raman Scattering (SERS)-active platform for ultrasensitive DNA detection. Such SiNWs@AgNPs nanostructure possesses an extremely high SERS enhancement factor of similar to 10(10). We design a DNA sensor based on the nanostructure via immobilization of capture probe DNA at the surface of AgNPs, and a sandwich strategy for the detection of target DNA that brings a reporter probe labeled with a dye to the proximity of the surface, leading to high SERS signals. This silicon nanostructure-based biosensor platform can detect a remarkably low DNA concentration at similar to 1 fM, which is comparable to the lowest DNA concentration ever detected via SERS. We expect this highly sensitive and robust SiNWs-based SERS platform may serve as a practical and powerful tool for biomolecular sensing and biomedical analysis. (C) 2011 Elsevier Ltd. All rights reserved.