This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. We have been investigating a new series of fluorescent, conjugated polymer materials that contain polyreceptor assemblies. The multiple receptor sites are electronically connected by the conjugated polymer (molecular wire) and exhibit larg sensitivity gains over more conventional molecule-based fluorescent chemosensors. These polymers have been found to respond quantitatively to transition metal ions at concentrations as low as 4*10-9 M. We have also developed a new method to create inorganic/organic hybrid polymers that respond through a "turn-on" fluorescence mechanism. This hybrid system is showing promising results for the selective detection of biological iron. In order to more completely characterize the dynamics of the fluorescent quenching process, time-resolved emission and transient absorption measurements are necessary. This is particularly important in light of the non-linear Stern-Volmer behavior of these polymers that can be attributed to a combination of energy transfer dynamics on the polymer backbone and more traditional static quenching. A specific photophysical goal will be to identify whether charge transfer products are formed during the quenching process.