Protein-resistant surface coatings

PEGylation is also the most widely used bioinert polymeric surface coating currently used [39]. Although it is considered as a gold standard for protein-resistant surfaces, recent observations indicate that PEGylation is far from being the optimal candidate for biomedical applications. Even though PEG is... 

Poly(ethylene glycol) (PEG) has been of great interest in the preparation of protein-resistant surfaces, and PEG coatings have proven to successfully reduce or prevent nonspecific protein adsorption, especially when they are in a brush conformation. PEG—a simple linear poly ether—does, however, have some limitations for instance it is susceptible to thermal and oxidative... 

Wagner et al. [108] developed a PLS model to predict the amount of protein adsorbed in a metallic basis using time-of-flight SIMS (TOF-SIMS) spectra. Study of the multivariate models yielded insight into the surface chemistry and the mechanism for protein resistance of the coatings. The same group reported two other similar studies with satisfactory results [109,110]. 

Fig. 4 Examples (a) PEGylated monolayer (b) Glucose-modified monolayer (c) Surface-attached hyper-branched polyethylene imine and (d) Surface-attached hyperbranched polyglycerols of surface-coatings that resist the nonspecific adsorption of proteins. (Figure reproduced in part with permission from [41])...

The above results suggest intimate association of proteins and proteoglycans in desmosomes and in surface coats of cells. A possible example of this kind of association is provided by studies of films made with various proportions of protein and proteoglycan. Mixtures of 2 parts gelatin and 1 part hyaluronic acid are much more resistant to diflFusion of various substances than other combinations of these ingredients (40). Perhaps intercellular discs represent mechanically dense and viscid complexes of similar nature. The disappearance of desmosomal components into reconstituted intercellular cement suggests that they have similar chemical components but different stoichiometry. 

Polymer surface modifications are omnipresent in applications where the surface properties of materials with favorable bulk properties are insufficient. By altering the surface characteristics using physical or chemical modification the desired surface properties may be achieved. Such treatments are required e.g. to enhance printability of films, the adhesion of paints, metal or other coatings, biocompatibility, protein resistances/reduced biofouling, etc. The diverse approaches met in practice include, among others, wet chemical and gas phase chemistry, plasma or corona, UV/ozone and flame treatments. In most cases surface chemical modification reactions take place that alter the surface energy in a desired way. For example,... 

Mechanisms Amantadine and rimantadine inhibit the first steps in replication of the influenza A and rubella viruses (Figure 49-1). These steps involve viral adsorption to the host cell membrane, penetration into the cell via endocytosis. and viral particle uncapping. The inhibitory action of these drugs may be due to their alkaline reaction, which raises the endo-somal pH. At low concentrations, amantadine also binds to a specific protein in the surface coat of the influenza virus to prevent fusion. Drug-resistant influenza A virus mutants can emerge and infect contacts of patients in treatment. 

After implantation, the surface of the prosthesis is the first component to come into contact with the surrounding biological milieu. Therefore, surface characteristics play an important role in controlling the course of subsequent biological reactions. Antifouling materials are materials that can resist protein adsorption or microbial adhesion [205,206]. Hence, they have potential applications as surface coatings on implantable devices such as heart valves and hip joint prostheses to minimize biofihn formation and subsequent device-associated infections. 

Lee JH, Kopeckova P, Kopecek J, Andrade JD. (1990) Surface properties of copolymers of alkyl methacrylates with methoxy (polyethylene oxide) methacrylates and their application as protein-resistant coatings. Biomaterials, 11 455-464. 

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