Plasmonic nanostructures for the ultrasensitive detection of biomolecules

The central physical phenomenon described in this paper is the optical generation of surface plasmon polaritons within different kinds of nanostructures. It determines the local enhancement of the incident and scattered electromagnetic field by nearby molecules. The paper reviews different plasmonic devices whose design and spatial arrangement offer an optimal detection level of biomolecules when combined with Raman spectroscopy or hot electrons imaging. Recent results, obtained by the authors, demonstrated that it is possible to reach an analytical sensitivity in the attomolar concentration range, with an analytical specificity to solve complex peptide mixtures characterized by single point mutation in cancer detection experiments. In a different context, exploiting the adiabatic compression phenomenon, we have reported the possibility to generate both light and hot electrons sources in a localized area of few nanometers. Their energy control and accurate spatial localization allow the investigation of matter with unprecedented accuracy and richness of information.