Biomedical materials plasma protein

Biomedical Applications Due to their excellent blood compatibility (low interaction with plasma proteins) and high oxygen and moisture permeabilities, siloxane containing copolymers and networks have been extensively evaluated and used in the construction of blood contacting devices and contact lenses 376). Depending on the actual use, the desired mechanical properties of these materials are usually achieved by careful design and selection of the organic component in the copolymers. 

A wide variety of natural and synthetic materials have been used for biomedical applications. These include polymers, ceramics, metals, carbons, natural tissues, and composite materials (1). Of these materials, polymers remain the most widely used biomaterials. Polymeric materials have several advantages which make them very attractive as biomaterials (2). They include their versatility, physical properties, ability to be fabricated into various shapes and structures, and ease in surface modification. The long-term use of polymeric biomaterials in blood is limited by surface-induced thrombosis and biomaterial-associated infections (3,4). Thrombus formation on biomaterial surface is initiated by plasma protein adsorption followed by adhesion and activation of platelets (5,6). Biomaterial-associated infections occur as a result of the adhesion of bacteria onto the surface (7). The biomaterial surface provides a site for bacterial attachment and proliferation. Adherent bacteria are covered by a biofilm which supports bacterial growth while protecting them from antibodies, phagocytes, and antibiotics (8). Infections of vascular grafts, for instance, are usually associated with Pseudomonas aeruginosa Escherichia coli. Staphylococcus aureus, and Staphyloccocus epidermidis (9). 

For biomedical applications, inhibition of protein adsorption, as well as platelet activation and adhesion on the polymer surface, is critical to the efficiency of the material. For example, use of PHAs as artificial blood contacting devices such as arteries and anticoagulant films was limited by surface-induced thrombosis. The adsorption of plasma proteins and adherence of activated platelets onto the polymer surface resulted in their transformation to pseudopods and subsequent release of platelet biochemical content, which in turn activated other platelets leading to the... 

Tan, J., Brash, J. L. (2009). Nonfouling biomaterials based on polyethylene oxide-containing amphiphilic triblock copolymers as surface modifying additives adsorption of proteins from human plasma to copolymer/polyurethane blends. Journal of Biomedical Materials Research Part A, 90A, 196-204. http //dx.doi.Org/10.1002/jbm.a.32074. 

PEO Is a non-toxic water-soluble polymer which is extensively used for biomedical applications. PEO resists the adsorption of plasma proteins because of their strong hydrophlllcity, chain mobility, and lack of ionic charge [30]. The PEO immobilization on any polymer surface would result in the decrease in the protein adsorption and platelet adhesion. This versatile nature of PEO has led to many studies not only on the preparation of PEO derived surfaces but also on the subsequent uses of these surfaces as biomaterials [31-34]. The PEO layer if adhered on the normal material surface may be washed off because of the absence of any interaction between the two surfaces. Therefore, covalent immobilization of PEO has been carried out either by grafting PEO molecule on a base polymer or by grafting a monomer bearing pendant PEO groups. 

The literature contains a considerable number of experimental observations on trace element interchanges between dilute aqueous solutions and various container materials [51,66-70]. Although these studies give some indications on the adsorption characteristics of existing polymers, the observations cannot be simply transposed to the biomedical field. For example, plasma or serum has a high content of proteins (approximately 7 g/100 mL) which bind numerous elements. There can hardly be any doubt that this must have a profound effect on exchange phenomena. 

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