Protein adsorption on biomaterials

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... 

Despite of hybridization with biological ligands, the general strategy for optimizing protein adsorption on biomaterial surfaces relies on chemical or physicochemical modulation of surface hydrophilicity [38,39]. The common approach is surface immobilization of hydrophilic polymers like polyethylene glycol [PEG] or polysaccharides. Four categories of surface-modification pathways have been developed ... 

This volume contains manuscripts based on 28 of the 32 contributions presented at the Chicago AIChE Biomaterials Symposium. These manuscripts are organized into three major sections Blood-Materials Interactions, Protein Adsorption on Biomaterials, and New Biomaterials Systems and Applications. Introductory chapters are placed at the beginning of each section of the book to provide nonspecialists with background material and a perspective into these evolving research areas. 

L. Brash, in Modern Aspects of Protein Adsorption on Biomaterials, Ed. by Y. F. Missirlis and W. Lemm, Kluwer Academic, Dordrecht, 1991, pp. 39-47. 

The studies of protein adsorption to biomaterials undertaken so far have shown that the process is understandable in terms of the principles of surface activity, mass action, surface chemistry, and transitions in the structure of proteins. Furthermore, cells with receptors for certain of the adsorbed proteins are likely to respond to surfaces in proportion to the amount of this protein on the surface, although other processes involving... 

Proteins play a critical role in regulating cell interactions with both biological and synthetic surfaces. The type and density of proteins presented on a surface are major determinants in cell function. Because proteins are present in all bodily fluids and most cell culture media, it is important to understand the dynamics of protein adsorption to biomaterials. Additionally, protein adsorption to materials impacts the overall performance of biomaterials in several manners, including regulation or inhibition of cell adhesion. 

Sun, Y., Hoffman. A. S., and Gombotz, W. R.. Non-fouling biomaterial surfaces II. Protein adsorption on radiation grafted polyethylene glycol methacrylate copolymers, Polym. Prep., 25(1) 292 (1987). 

The electronically conducting polymers are particularly interesting because one can control the oxidation state of these polymers in a reversible and predictable manner by the application of a small potential or current. The implication is that one may be able to control the charge density on the surface of the polymer. The nature and density of surface charges play a very important role in defining the extent and nature of protein adsorption on a biomaterial surface, which in turn is key in determining cellular-biomaterial interactions. 

When a medical device is in contact with body fluid such as blood, the first thing that occurs on the surface is protein adsorption [96-98]. Proteins in solution trying to minimize the total surface energy is the thermodynamic driving force of protein adsorption on solid surfaces. In blood contact protein adsorption is believed to be the initial event in thrombus formation [99-101], calcification [102-104], and biofilm attachment [105-107], which leads to the failure of implanted devices. Therefore, protein-reducing surface modifications of polyurethane biomaterials have been applied to improve the service life of implants. Previous studies of protein adsorption have focused on adsorption of albumin, IgG, and Fg, which are the predominant three proteins in blood plasma. Surface protein adsorption can be quantitated by several methods such as quartz crystal microbalance (QCM) [108-112], surface plasmon resonance (SPR) [113-118], and iodonization radiolabeling [78,119-125]. 

Tan J, McClung WG, Brash JL. Nonfouhng biomaterials based on polyethylene oxide-containing amphiphilic triblock copolymers as surface modifying additives protein adsorption on PEO-copolymer/pol5turethane blends. J Biomed Mater Res A 2008 85(4) 873-80. 

Considering the peptides and proteins adsorption on solid surfaces we must remark that this is a quite complex route influenced by several factors as for instance the state of hydratation of both biomolecule and surface, the molecular structure, the intermolecular interaction and the ambient conditions [54]. In several biomaterials using a key attempt is taking place to organize protein adsorption, by structuring and/or chemical patterning the surface at a sub-micrometer scale [55-57]. 

Similarly, protein adsorption to biomaterials involves two stages. The first is a reversible binding in which the native protein retains its shape. The second involves protein unfolding or spreading on the surface (3). This stage is irreversible, although severe conditions can cause these proteins to desorb (4). 

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