Plasmonic technology: Novel approach to ultrasensitive immunoassays

At the Center for Fluorescence Spectroscopy, we have taken advantage of the favorable properties of surface plasmon-coupled emission (SPCE) to improve fluorescence-based immunoassays. SPCE occurs when excited fluorophores near conducting metallic structures efficiently couple to surface plasmons. These surface plasmons, appearing as free electron oscillations in the metallic layer, produce electromagnetic radiation that preserves the spectral properties of fluorophores but is highly polarized and directional. SPCE immunoassays provide several advantages over other fluorescence-based methods. This review explains new approaches to fluorescence immunoassays, including our own use of SPCE for simultaneous detection of more than one fluorescent marker and performance of immunoassays in the presence of an optically dense medium, such as whole blood.