People | Faculty | Sandy Asher
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Sandy Asher Department of Chemistry |
Professor Asher's research program is interdisciplinary and brings together scientists in analytical chemistry, biophysical chemistry, materials science and physical chemistry to solve important scientific and technological problems. The research has both
fundamental and applied aspects. The most fundamental research involves calculations of the interactions between light and matter, and the examination of excited states of molecules. Applied work includes the spectroscopic investigation of protein structure and function, and development of a chemical understanding of the gas phase and solid phase reactions occurring during synthesis of diamond in CVD diamond reactors. Another example is the fabrication of new "smart" materials for use in novel optical devices, sensors, and for use in optical computers. Examples of research projects underway include:
Amide Excited States and Proteins Folding. The Asher group has pioneered the development of UV Raman spectroscopy to study molecular structure. UV excitation with novel laser sources, allows us to study interactions between the molecular electron cloud and nuclear vibrations. This gives us incisive glimpses into molecular structure.
We have developed a new methodology for structure characterization of proteins using UV resonance Raman spectroscopy. For the first time, we have applied nanosecond time-resolved UVRR spectroscopy for kinetic studies of protein folding. Rapid laser-induced temperature jumps are used to initiate the folding process; transient vibrational spectra are recorded using time-delayed probe pulses to characterize of the intermediate states involved (Fig. 1).
Diamond Growth Chemistry: We have constructed a UV Raman instrument on a CVD diamond reactor at Westinghouse Corp. and are developing an in situ spectroscopic method to monitor the diamond growth and the gas phase chemistry, in order to optimize the growth conditions. This project represents a unique partnership between academia and industry.
Materials Science and Non Linear Optics: We have developed novel materials based on crystalline colloidal (CCA) self assembly. CCA are ordered arrays of colloidal particles formed in a liquid. The colloidal particles repel each other and form a cubic array which Bragg diffracts light from the UV through the visible and the IR spectral region. These arrays serve as diffracting optical devices. We have developed methods to polymerize these arrays in solid films that change dimension in response to chemical, electrical, and thermal environmental changes (Fig. 2). We have utilized these materials to develop a new chemical sensing motif which creates a new generation of optical switches for use in optical computing, for chemical separations and for thin film display devices.
Awards
Distinguished Professor of Chemistry, University of Pittsburgh, 2005 Sigi Ziering Award for Outstanding Contribution of a Publication in the Journal, Clinical Chemistry (2005), 2004 University of Missouri-St. Louis Distinguished Alumnus Award, 2002 ACS Pittsburgh Award, 2002 Ellis R. Lippincott Award, 2000 Pittsburgh Technology Council EnterPrize Award, 1999 Bomen-Michelson Award, 1998 Lester W. Strock Award, 1996 University of Pittsburgh Chancellor's Distinguished Research Award, 1994 ACS Analytical Division Spectrochemical Analysis Award, American Heart Association Established Investigatorship Award, 1988 Distinguished Alumni Award of the University of Missouri.
Selected Publications
"Progress in Developing Polymerized Crystalline Colloidal Array Sensors for Point-of-Care Detection of Myocardial Ischemia ", J.T. Baca, D.N. Finegold and S.A. Asher, The Analyst, 133, 385-390 (2008).
"Computational and Experimental Determination of the Alpha-Helix Unfolding Reaction Coordinate", E. Asciutto, J. Madura, A. Mikhonin and S.A. Asher, Biochemistry, 47, 2046-2050 (2008).
"Polymerized PolyHEMA Photonic Crystals pH and Ethanol Sensor Materials", X. Xu, A.V. Goponenko and S.A. Asher, J. Am. Chem. Soc., 130, 3113-3119 (2008).
"Poly(vinyl alcohol) Rehydratable Photonic Crystal Sensor Materials", M.M. Ward Muscatello and S.A. Asher, Adv. Funct. Mat., 18, 1-8 (2008).
"Dependence of Glycine CH2 Stretching Frequencies on Conformation, Ionization State, and Hydrogen Bonding", S. Bykov, N. Myshakina and S.A. Asher, J. Phys. Chem. B., 112, 5803-5812 (2008).
“Mass Spectral Determination of Fasting Tear Glucose Concentrations in Nondiabetic Volunteers”, J.T. Baca, C.R. Taormina, E. Feingold, D.N. Finegold, J.J. Grabowski and S.A. Asher, Clinical Chemistry, 53 (7), 1370-1383 (2007).
“Photonic Crystal Sensor for Organophosphate Nerve Agents Utilizing the Organophosphorus Hydrolase Enzyme”, J.P. Walker, K.W. Kimble and S.A. Asher, Analytical and Bioanalytical Chemistry, 389 (7-8), 2115-2124 (2007).
“Tear Glucose Analysis for the Noninvasive Detection and Monitoring of Diabetes Mellitus”, J.T. Baca, D.N. Finegold and S.A. Asher, The Ocular Surface, 5 (4), 280-293 (2007).
“UV Raman Spatially Resolved Melting Dynamics of Isotopically Labeled Polyalanyl Peptide: Slow a-Helix Melting Follows 310-Helices and π-Bulges Premelting”, A.V. Mikhonin, S.A. Asher, S.V. Bykov and A. Murza, Journal of Physical Chemistry B, 111, 3280-3292
(2007).
“UV Resonance Raman Measurements of Poly-l-Lysine’s Conformational Energy Landscapes: Dependence on Perchlorate Concentration and Temperature”, L. Ma, Z. Ahmed, A.V. Mikhonin and S.A. Asher, J. Phys. Chem. B., 111, 7675-7680 (2007).
“Direct UV Raman Monitoring of 310-Helix and π-Bulge Premelting during a-Helix Unfolding”, A.V. Mikhonin and S.A. Asher, Journal of the American Chemical Society, 128, 13789-13795 (2006).
“UV Resonance Raman Investigation of a 310-Helical Peptide Reveals a Rough Energy Landscape”, Z. Ahmed and S.A. Asher, Biochemistry, 45, 9068-9073 (2006).