简介

Research in our group seeks to maximize the impact of single-molecule fluorescence and nanophotonics by applying them to investigations of live cells. The extension of sophisticated nanoscale optoelectronic tools, techniques and materials to biological systems will enable fundamental discoveries, broaden our understanding of key biological processes, and assist in the development of novel therapeutics. Undertaking such an endeavor at the crossroads of chemistry, biology and engineering requires the development of sensitive experimental methods and careful, quantitative analysis procedures. Super-resolution techniques based on single-molecule optical microscopy can reach nanometer-scale accuracy. These non-invasive, non-perturbative methods are ideal for investigating biological specimens, and we focus on improving these methods and applying them to physiologically relevant problems. Because of their small size and lack of subcellular compartments, the cell biology of bacteria is particularly interesting for super-resolution imaging. We have developed novel methods for single-molecule investigations and have been applying them to three prokaryotic systems: membrane-bound transcription activation in Vibrio cholerae, carbohydrate catabolism in Bacteroides thetaiotaomicron, and DNA mismatch repair in Bacillus subtilis. In order to treat these and other problems, we seek to improve current single-molecule imaging techniques. One major thrust is to combine single-molecule fluorescence imaging with plasmon-enhanced fluorescence. In this work, we explore the fundamental optical properties of noble metal nanoparticles, and use the enhanced local field about resonantly excited nanoparticles to increase fluorescence intensity and photostability in bio-imaging applications.