Fluorescence Spectroscopy is inherently a very sensitive technique; it already forms the basis of most non-radioactive real time assays like PCR. Our lab previously collaborated with former fellows (now in biotech industry) to develop alternatives to PCR like CataCleave probes for SNPs. We continue to study the photophysics and proper coupling of DNA components to multilayer metal nanoparticles for much faster PCR analysis and the use of FCS (see MPM report) to quantify very tight protein-protein and protein-DNA binding in sub-microliter drops (analytes are present in sub-femtomole amounts). We temporarily suspended (this year) doing MPM-FCS and Time-Resolved Fluorescence together; in previous years, we had numerically combined time-resolved fluorescence detection with translational mobility (FCS) to help identify free and bound signatures for assay. We are presently designing STAQ probes (see nanoscopy project) for DNA/RNA probing, analagous to catacleave, in plans to only superresolve tight binding sites. Recently we have used TCSPC to begin untangling designed aptamer heterogeneity questions (see MPM project and TR project). This year, we also began studying Excitonic probes that self-quench unless unfolded or cleaved, in collaboration with industry.
