AVS 51st International Symposium
    Biomaterial Interfaces Monday Sessions
       Session BI-MoM

Paper BI-MoM8
Study of Metal Film-Tethered (Bio)Molecules in Aqueous Solution by Enhanced ATR-IR Spectroscopy

Monday, November 15, 2004, 10:40 am, Room 210D

Session: In-Situ Spectroscopy of Biomolecules at Interface
Presenter: D.P. Land, University of California, Davis
Authors: D.P. Land, University of California, Davis
J.S. Toofan, University of California, Davis
C.M. Gerth, University of California, Davis
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Data are presented illustrating the application of overlayer-enhanced attenuated transmission-Fourier transform infrared spectroscopy (E-ATR-FTIR). The presence of a thin metal film at in internal reflection interface accomplishes several important feats. It enhances and concentrates the electric field in the near-surface region. It introduces a wide range of chemical possibilities for surface modifications by which analytes can likewise be concentrated near the interface. And it minimizes interactions with the bulk solvent, facilitating the use of IR spectroscopy in aqueous (and other) solutions. The combination of effects facilitates the study of numerous solution systems, and most importantly, perhaps, aqueous solutions. The experiment has been modeled to reveal details of the dependence upon prism material (ZnSe and Ge), thin film thickness and composition (metals and oxides), as well as angle of incidence and adsorbate properties. Experimentally, several key experiments have been performed. Data will be shown which includes the study of reactions of thiols with the gold films, in aqueous and other solutions. Additionally, spectra for tethered proteins, antibodies, and protein-antibody reactions have already been acquired and will be presented. Detection limits in the tens of femtomoles for proteins and antibodies has been achieved. Experiments currently underway include reactions of enzymes with tethered inhibitors and of tethered enzymes with substrates and co-factors.