COLL 314 |
| Sergio B. Mendes, Anne Runge, and S. Scott Saavedra. Department of Chemistry, University of Arizona, Tucson, AZ 85721 |
| In some types of electrochemical biosensors, direct electron transfer between an immobilized metalloprotein layer and an underlying electrode transducer is required for device operation. In this type of structure, the rate of electron transfer should be influenced by the orientation-distance distribution of the metal centers in the protein layer. To study this relationship, we are investigating molecular orientation and direct electrochemical activity in cytochrome c (cyt c) films immobilized on transparent, planar indium tin oxide (ITO) electrodes. Cyt c films formed on ITO by adsorption from solution and by microcontact printing are compared in terms of total and electrochemical surface coverage, rate of direct electron transfer, and orientation distribution of the prosthetic heme groups. Orientation distributions are determined by measuring absorption linear dichroism in a waveguide ATR geometry and fluorescence anisotropy in a TIRF geometry. The order parameters are fit to a Boltzmann function to recover the distribution of molecular tilt angles relative to the electrode plane. Recent results obtained on both dielectric and electroactive substrates will be presented. |
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Symposium in Memory of Arthur W. Adamson
8:30 AM-11:10 AM, Tuesday, March 30, 2004 Marriott -- Orange County 4, Oral
Division of Colloid and Surface Chemistry |