This Small Business Innovation Research Phase I project will exploit the unique fluorescence and signal amplification qualities of poly(phenylene ethynylene)s in a nanoparticle format. This combines the intense solid-state fluorescence and sensing capabilities of poly(phenylene ethynylene)s (PPEs) with the many unique attributes of nanoparticles, including their tremendous surface area and their surface adsorptivity. In this project, a series of charged PPEs whose emissions span the color spectrum will be synthesized and systematically evaluated for the formation of stable, aqueous nanoparticle dispersions. They will be functionalized and conjugated to biologic recognition molecules (i.e. antibodies and nucleic acids). The Phase I effort will yield a series of functional, highly fluorescent nanoparticles which may be used directly for the labeling of biological molecules.<br/> The commercial applications of this project will be in standoff explosives detection for wide area mapping. Standoff, wide area mapping is of intense interest for military and humanitarian uses as well as for environmental remediation of explosives contamination.