The primary objective of this work is to characterize the mobility of proteins adsorbed at solid-liquid interfaces. This research represents a shift in the emphasis of protein adsorption studies towards a molecular understanding of the complex behavior of adsorbed proteins. It is hoped to quantify the mobility of adsorbed proteins, characterize the factors governing mobility, identify the mechanism of adsorbed protein translation, and measure the extent of self-assembly of proteins into surface islands. Using a combination of total internal reflection fluorescence and fluorescence recovery after pattern photobleaching, the research will determine protein surface diffusion coefficients and the fraction of adsorbed proteins that are mobile. Mobility will be quantified as a function of shear rate, surface coverage, and surface residence time in order to identify the governing factors. Understanding the mobility of adsorbed proteins, as well as the related issues of protein structure and organization will aid the development of effective processes to manufacture protein and polypeptide materials. The utility of these materials is increasing, not only as pharmaceuticals, but also as novel means of organic catalysis, and as the active agent in biosensors for chemical analysis. Protein or polypeptide adsorption to solid surfaces is inevitable in all processes to manufacture, modify, or purify these materials. This is particularly important to protein and polypeptide manufacture in that an adsorbed protein layer can influence the biological activity of the cells it contacts, including the genetically engineered microorganisms commonly employed in industry. In addition, the proper function of a protein or polypeptide depends on the preservation of the correct structure. Adsorption to a solid surface can alter that structure.
