Dr. Jeffrey Petty is interested in the interface of physical chemistry, biochemistry, and inorganic chemistry. He trained with Brad Moore in the spectroscopy of atmospherically significant free radicals. He then continued his studies with Dick Keller in the area of ultrasensitive, laser-based biomolecular detection. Dr. Petty continues his studies with his students and colleagues in the area of silver cluster-DNA interactions.
- Ph.D., University of California, Berkeley
- B.S., Furman University
Our studies revolve around the small sizes of silver clusters. These molecular metals have discrete electronic states, localized optical transitions, and strong fluorescence. DNA strands serve two purposes: (1) Their nucleobases coordinate specific species, and specific sequences yield chromophores with spectra that span the visible and near-infrared spectral regions; (2) They direct cluster transformations via changes in their secondary structure. Our studies revolve around pairs of chromophores that interconvert via hybridization. These conjugate cluster-DNA chromophores are innovative because of two features – hybridization switches on fluorescence and two-color laser excitation enhances the overall cluster emission. Mass spectrometry and X-ray absorption spectroscopy establish the basis for the fluorescence switching. Changes in the stoichiometry, charge, and structure of pairs of dim/bright chromophores are investigated. Fluorescence correlation spectroscopy evaluates the basis for the two-color enhanced fluorescence. These two sets of studies will provide the foundation to develop a new class of optical sensors. These sensors will be used to detect low abundance microRNA sequences that are relevant for early cancer intervention.