Protein Interactions with Biomaterial Surfaces

Specific domains of proteins (for example, those mentioned in the section Organic Phase ) adsorbed to biomaterial surfaces interact with select cell membrane receptors (Fig. 8) accessibility of adhesive domains (such as specific amino acid sequences) of select adsorbed proteins may either enhance or inhibit subsequent cell (such as osteoblast) attachment (Schakenraad, 1996). Several studies have provided evidence that properties (such as chemistry, charge, and topography) of biomaterial surfaces dictate select interactions (such as type, concentration, and conformation or bioactivity) of plasma proteins (Sinha and Tuan, 1996 Horbett, 1993 Horbett, 1996 Brunette, 1988 Davies, 1988 Luck et al., 1998 Curtis and Wilkinson, 1997). Albumin has been the protein of choice in protein-adsorption investigations because of availability, low cost (compared to other proteins contained in serum), and, most importantly, well-documented conformation or bioactive structure (Horbett, 1993) recently, however, a number of research groups have started to examine protein (such as fibronectin and vitronectin) interactions with material surfaces that are more pertinent to subsequent cell adhesion (Luck et al., 1998 Degasne et al., 1999 Dalton et al., 1995 Lopes et al., 1999). 

SURFACE PROPERTIES AFFECTING PROTEIN ADSORPTION HYDROPHILICITY/HYDROPHOBICITY TOPOGRAPHY ENERGY CHARGE ETC. 

Recent studies have attempted to further elucidate mechanisms of protein adsorption on biomaterial surfaces. For example, Ellingsen (1991) reported that adsorption of calcium on titanium surfaces subsequently enhanced binding of select proteins. In contrast, adsorption of other ions (such as 

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Red cell-surface interactions may play a role in the dynamics of protein adsorption. We have been investigating the turnover of protein between solution and surface for several years (27-29), and have established that turnover occurs on a variety of surfaces. The rate and extent of turnover depend strongly on the surface character, with hydrophilic materials, for example, showing much more rapid turnover than hydrophobic materials. If red cells have the ability to strip protein off a biomaterial surface, then clearly this effect could influence the characteristics of the turnover process, particularly from a rate point of view. This process, in turn, could affect the development of the protein layer over a period of time. 

RAS of Complex Molecules RAS has significant potential for the study of interactions between important biological molecules and surfaces, as illustrated by a study of the adsorption of amino acids. The interactions of proteins with biomaterial surfaces... 

Figure 2.38 Influence of substrate surface energy on cell spreading with preadsorbed serum proteins (solid line) and without (dashed line). Reprinted, by permission, from J. M. Schakemaad Cells Their Surfaces and Interactions with Materials, in Biomaterials Science An Introduction to Materials in Medicine, B. D. Ratner, A. S. Hoffman, F. J. Schoen, and J. E. Lemons, p. 144. Copyright 1996 by Academic Press.

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