Optical properties of gold nanostructures: Application to the surface enhanced Raman scattering and to the development of a nanobiosensor

The application of Surface Enhanced Raman Spectroscopy (SERS) for detection of biomolecules is a subject of intense current research worldwide. In this article the observation of the dependence of the Raman enhancement versus the nanoparticle size is clearly demonstrated on nanocylinders and nanowires. Remarkably the enhancement is observed to be maximum for a specific diameter or length. We finally show that the SERS signal depends on the molecule used and that the SERS active substrates should be actually optimized for each targeted protein.