It is proposed to develop methods to analyze protein adsorption data and, utilizing data obtained by the solute depletion technique with model proteins, to develop a model for protein adsorption at solid-liquid interfaces. The model will be based on fundamental considerations of hydrophobit, ionic, and charge-transfer interactions. Surfaces will be selected, prepared, and characterized to permit the rigorous testing of the model. Competitive protein adsorption will also be studied and modeled. Information on protein conformation during the adsorption process is desired. The total internal reflection fluorescence (TIRF) spectroscopy technique will be developed for this purpose, utilizing the intrinsic tryptophan fluorescence of most of the proteins of interest. Information derived from the TIRF conformation studies will be utilized to attempt to expand the model of protein adsorption to account for conformation changes upon adsorption. Total internal reflection Raman spectroscopy, (TIRRS) will also be considered and evaluated to obtain adsorption and conformation data. All solid surfaces will be prepared and characterized by rigorous means, including X-ray photoelectron spectroscopy, zeta potential, and contact angle methods. Protein solutes in solution will be characterized by standard means and by circular dichroism, dichroism, UV fluorescence, and Raman spectroscopy. It is expected that a firm, simi-quantitative understanding of protein adsorption will result which will be of major significance in understanding and predicting blood-materials interactions.