Graft polymerization, biomaterials

Uyama, Y., Tadokoro, H., Dcada, Y. Low-frictional catheter materials by photo-indnced graft polymerization. Biomaterials 12, 71-75 (1991). doi 10.1016/0142-9612(91)90135-W... 

Uyama Y, Tadokoro H, Ikada Y. Low-frictional catheter materials by photoinduced graft-polymerization. Biomaterials 1991 23. 

V.N. Vasilets, G. Hermel, U. Konig, C. Werner, M. Muller, F. Simon, K. Grundke, Y. Ikada, H.J. Jacobasch, Microw/ave CO2 plasma-initiated vapour phase graft polymerization of acrylic acid onto polytetrafluoroethylene for immobilization of human thrombomodulin. Biomaterials 18 (1997) 1139-1145. 

In this section, we will highlight the use of the grafting technique for designing polymeric biomaterial surfaces that exhibit non-fouling property, selective protein adsorption, enhanced tissue adhesion, and minimum frictional damage to mucosa membranes. 

The increased stability of the graft copolymerized biomaterial has been monitored on the basis of an increase in the number of regeneration cycles. Structurally modified biomaterial (polymerized) could be used up to six times as compared to only four times of unmodified biomaterial, thereby exhibiting the increased environmental stability of the polymerized biosorbent (Table 3.3). 

Hatakeyama H, Kikuchi A, Yamato M et al (2007) Patterned biofunctional designs of thermo-responsive surfaces for spatiotemporally controlled cell adhesion, growth, and thermally induced detachment. Biomaterials 28 3632-3643 Hem DL, Hubbell JA (1998) Incorporation of adhesion peptides into nonadhesive hydrogels useful for tissue resurfacing. J Biomed Mater Res 39 266-276 Huang J, Wang XL, Chen XZ et al (2003) Temperature-sensitive membranes prepared by the plasma-induced graft polymerization of N-isopropylacrylamide into porous polyethylene membranes. J Appl Polym Sci 89 3180-3187... 

K. Fujimoto, H. Tadokoro, Y. Ueda, Y. Ikada, Polyurethane surface modification by graft polymerization of acrylamide for reduced protein adsorption and platelet adhesion. Biomaterials 14 (6) (1993) 442-448. 

Surface modification with hydrophilic polymers, such as poly(ethylene oxide) (PEO), has been beneficial in improving the blo( compatibility of polymeric biomaterials. Surface-bound PEO is expected to prevent plasma protein adsoiption, platelet adhesion, and bacterial adhesion by the steric repulsion mechanism. PEO-rich surfaces have been prepared either by physical adsorption, or by covalent grafting to the surface. Physically adsorbed PEO homopolymers and copolymers are not very effective since they can be easily displaced from the surface by plasma proteins and cells. Covalent grafting, on the other hand, provides a permanent layer of PEO on the surface. Various methods of PEO grafting to the surface and their effect on plasma protein adsorption, platelet adhesion, and bacterial adhesion is discussed. 

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). 

Ji Y, li XT, Chen GQ (2008) Interactions between a poly(3-hydroxybutyrate-co-3-hydroxyvalerate-co-3-hydroxyhexanoate) terpolyester and human keratinocytes. Biomaterials 29 3807—3814 Jiang T, Hu P (2001) Radiation-induced graft polymerization of isoprene onto polyhydroxybu-tyrate. Polym J 33 647-653... 

There are three basic processes which are utilized for preparing new or modilled polymeric biomaterials. They are (1) surface modification via radiation graft copolymerization or plasma gas discharge (2) radiation polymerization of pure monomeifs) in solution, or an emulsion, or in the solid state (e.g., below Tq) and (3) radiation crosslinking, in a solution or swollen state, or in the solid state. 

Gupta B, Plummer C, Bisson I, Frey P, Hilbom J. Plasma-induced graft polymerization of acrylic acid onto poly(ethylene terephthalate) films characterization and human smooth muscle cell growth on grafted films. Biomaterials 2002 23 863-71. 

Archambault JG, Brash JL. Protein repellent polyurethane-urea surfaces by chemical grafting of hydroxyl-terminated poly(ethylene oxide) effects of protein size and charge. Colloids SutfB Biointerfaces 2004 33 111-20. http //dx.doi.Org/10.1016/j.colsurfb.2003.09.004. Desai NP, Hubbell JA. Solution technique to incorporate polyethylene oxide and other water-soluble polymers into surfaces of polymeric biomaterials. Biomaterials 1991 12 144-53. 

LEE 96] Lee S.-D., Hsiue G.-H., Chang P.C.-T. et al, Plasma-induced grafted polymerization of acrylic acid and subsequent grafting of collagen onto polymer film as biomaterials , Bio/wateria/s, vol. 17, pp. 1599-1608, 1996. 

SHI 05] Shi Z., Neoh K.G., Kang E.T., Anti bacterial activity of polymeric substrate with surface graft edviologemnoieties , Biomaterials, vol. 26, pp. 501-508, 2005. 

Keywords Polymer, Biomaterial, Radiation, Plasma, Graft Polymerization, Modification... 

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