Theory of near-field detection of core-gold nanoshells inside biosystems

Metal nanoshells composed by a dielectric core with a thin gold layer are stimulating growing interests due to the unique optical, electric and magnetic properties exhibited by the local field enhancement near the metal - dielectric core interface due to strong local plasmon resonance and the high tunability of such resonance as a function of shape and core-material. These unique characteristics have found promising applications in a wide range of areas, such as biosensing, optical communication and medicine. In this paper, we developed a theoretical and numerical simulation based on a near-field approach to study the possibility to identify nanoshells inside mouse cells. Taking advantage from the characteristic near-infrared transparency window of many biological systems, i.e. the low light absorption coefficient of biological systems between 750-1100nm, we show the possibility to identify and detect 100-150nm diameter gold nanoshells inside the animal cells.