Optical detection of core-gold nanoshells inside biosystems

Metal nanoshells having a dielectric core with a thin gold layer are generating new interest due to the unique optical, electric and magnetic properties exhibited by the local field enhancement near the metal - dielectric core interface. These nanoshells possess strong, highly tunable local plasmon resonances with frequencies dependent upon the nanoshell shape and core material. These unique characteristics have applications in biosensing, optical communication and medicine. In this paper, we developed a theoretical, numerical and experimental approach based on a scanning near optical microscope to identify nanoshells inside mouse cells. Taking advantage of the characteristic near-infrared transparency window of many biological systems, i.e. the low light absorption coefficient of biological systems between 750â^'1100 nm, we were able to identify a 100â^'150 nm diameter barium titanate-gold nanoshell inside the h9c2 mouse cells.