Detection of single, fluorescently labeled biomolecules is providing a powerful approach to measuring molecular transport, biomolecular interactions, and localization in biological systems. Because the biological... More »
I am currently on the faculty of the Department of Chemistry at the University of Utah, and I also hold an appointment in the Department of Bioengineering. I received a B.S. degree from Duke University and my Ph.D. from Purdue University. I am a Fellow of the American Association for the Advancement of Science and the Society for Applied Spectroscopy and a recipient of an Alfred P. Sloan Fellowship, the Coblentz Award in Molecular Spectroscopy, the ACS Division of Analytical Chemistry Award in Chemical Instrumentation, the Pittsburgh Conference Analytical Chemistry Award, and the ACS Award in Analytical Chemistry.
My research group focuses on analytical chemistry and spectroscopy of trace-level species in colloidal particles and at liquid/solid interfaces. My students have developed new measurement concepts in the analysis of multi¬dimensional fluorescence and Raman spectroscopic data, confocal Raman microscopy, and quantitative single-molecule detection. We have applied these concepts to investigating liquid/solid interfaces, and the interfacial molecular transport, adsorption, and binding kinetics that govern chemical separations and analysis.
Our program addresses both the measurement challenges and new opportunities for chemical analysis using colloidal materials: 1) Time-resolved luminescence spectroscopy is used to probe molecular transport and surface reactions at the single-molecule level. 2) Vibrational spectroscopy methods, both Raman scattering and infrared absorption, are being adapted to observing interfacial reactions in colloidal dispersions and in porous solids. 3) Single-molecule detection methods are used to report distributions of particle sizes, aggregation, and chemical composition. Optical-trapping provides long residence times to observe Raman scattering from individual colloidal particles to monitor chemistry in these nanoscale structures.
We are using these tools to investigate metal-ion complexation at silica-immobilized ligands, the mechanisms and rates of binding siloxane ligands to silica surfaces, and the specific molecular interaction responsible for adsorption, solid-phase extraction, and molecular recognition at chemically-modified silica surfaces. Surface-enhanced Raman spectroscopy at the surface is being adapted to fast relaxation kinetic measurements through the use of electric-field perturbations.