Plasmonics and Surface-Enhanced Raman Scattering (SERS) Nanoprobes for Biomedical Diagnostics

Raman spectroscopy has recently enjoyed a resurgence of interest among researchers because of the practical development of nanostructured materials that can produce enormous Raman enhancement for molecules adsorbed on metal surfaces. This increase in Raman signal is the result of a surface enhancement process often referred to as the surface-enhanced Raman scattering (SERS) effect. The observed Raman scattering signals for the adsorbed molecules are found to be more than a million times larger than those expected from gas-phase molecules or from non-adsorbed compounds, thus providing unprecedented sensitivity for a Raman technique. The development of biochemical probes based on SERS for diagnosis is described. The detection method uses nanostructured metallic substrates as SERS active platforms. The surface enhanced Raman gene (SERGen) probes and “Molecular Sentinels” (MS) probes can be used to detect DNA targets via hybridization to DNA sequences complementary to these probes. Results on the detection of DNA sequences for breast cancer gene and other diseases, and various pathogens are presented and discussed. The usefulness of the SERGen and MS approach and their applications in biomedical diagnostics is discussed.