Modeling the optical response of nanoparticle-based surface plasmon resonance sensors

We model the optical response of surface plasmon resonance (SPR) sensors based on colloidal metal nanoparticles using extended Mie theory. The theoretical description includes the particle adsorption layer, the surrounding medium as well as particle-particle and particle-substrate electromagnetic coupling effects. We obtain quantitative agreement with recently reported experimental results on gold nanoparticle SPR sensors, indicating the possibility to perform accurate a priori estimates of detector sensitivity for different particle sizes and compositions in a variety of electromagnetic environments. The possibility to increase sensitivity by using non-spherical silver particles as SPR sensors is discussed. (C) 2002 Elsevier Science B.V. All rights reserved.