Fluorescence Spectroscopy is inherently a very sensitive technique; it already forms the basis of most non-radioactive real time assays like PCR. Our lab has collaborated with former fellows (now in biotech industry) to develop alternatives to PCR like CataCleave probes for SNPs, leading to previous publication. 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 had examined the structural transitions of similar amounts of DNA between G-quadruplexed and linear forms, using both MPM-FCS and Time-Resolved Fluorescence tools, with the goal of developing very sensitive 'G-quad' and aptamer detection assays. We have begun to translate aptamer experience into BCC/melanoma detection collaboration, although whole-animal aptamer distribution has been difficult to date. We have numerically combined time-resolved fluorescence detection with translational mobility (FCS) to help identify free and bound signatures for assay. We are also 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 aptamer heterogeneity questions as well.
