We proposes to develop a new optical biological assay system which takes advantage of the enormous enhancement of Raman light scattering from molecules brought in close proximity to the surface of plasmon resonant collodial metal nano-particles. In particular, these investigators will focus on the use of fluorescent or dye molecules, as the sensing entities. When such resonant molecules are adsorbed onto the surfaces of certain metal colloidal particles, light scattered from the complex exhibits a resonance Raman spectrum specific to the chromophore of the adsorbed molecular species. Recent work has shown that the Raman spectrum from even a single dye can be acquired and resolved. In this Phase I study, the investigators wish to show that the nano-detection system they proposed to develop is capable of forming the basis for a homogeneous assay with the potential of single molecule sensitivity. PROPOSED COMMERCIAL APPLICATION: We believe that the sales of an instrument that is capable of detecting small quanities of analytes will have board commercial appeal to the pharmaceutical industry, for environmental protection, and for biochemical detection and defense. Moreover, the development and sales of novel biosensors with single molecule detection sensitivity based on the output of Raman Scattered light will be readily appreciated by the marketplace.