The adsorption of blood plasma proteins at the solid/liquid interface is vital to understanding blood/material interactions of polymeric prosthetic devices. We propose to use the evanescent field intensity at optical slab waveguide surfaces to excite fluorescence and Raman scattered light in proteins adsorbed at the waveguide/liquid interface. Protein fluorescence is a proven method for studyng the kinetics of protein adsorption. Raman spectroscopy is the preferred technique for conformational studies of aqueous protein solutions. The wageguide evanescent field is a virtual """"""""evanescent streak"""""""" resulting from the 500-2000 total internal reflections per cm of the optical field as it propagates down the waveguide. Waveguide evanescent streak excitation (WESE) offers a larger and more defined excitation volume than conventional total internal reflection methods. We contend that WESE will: 1) provide a stronger protein fluorescence signal at lower laser power than that obtained by conventional total internal reflection methods, and 2) make Raman spectroscopy of surface adsorbed protein layers a feasible experiment. 1-3 Mum films of sputtered glass or spuncast polymer films supported by a Pyrex substrate will serve as waveguides. The proteins will be delivered to the waveguide/liquid interface via a flow cell device. Extrinsic FITC labeled and intrinsic tryptophan fluorescence of adsorbed IgG will be investigated in the WESE-fluorescence study. The WESE-Raman study will concentrate on the resonance spectrum of adsorbed met-Hb. Nonresonance Raman of adsorbed proteins will be pursued depending upon the results of the met-Hb study.
