Biocompatible polymers, synthetic

Nowadays, a strategic area of research is the development of polymers based on carbohydrates due to the worldwide focus on sustainable materials. Since the necessary multi-step synthesis of carbohydrate-based polymers is not economical for the production of commodity plastics, functionalization of synthetic polymers by carbohydrates has become a current subject of research. This aims to prepare new bioactive and biocompatible polymers capable of exerting a temporary therapeutic function. The large variety of methods of anchoring carbohydrates onto polymers as well as the current and potential applications of the functionalized polymers has been discussed recently in a critical review [171]. Of importance is that such modification renders not only functionality but also biodegradability to the synthetic polymers. 

Polyvinyl alcohol (PVA), which is a water soluble polyhidroxy polymer, is one of the widely used synthetic polymers for a variety of medical applications [197] because of easy preparation, excellent chemical resistance, and physical properties. [198] But it has poor stability in water because of its highly hydrophilic character. Therefore, to overcome this problem PVA should be insolubilized by copolymerization [43], grafting [199], crosslinking [200], and blending [201], These processes may lead a decrease in the hydrophilic character of PVA. Because of this reason these processes should be carried out in the presence of hydrophilic polymers. Polyfyinyl pyrrolidone), PVP, is one of the hydrophilic, biocompatible polymer and it is used in many biomedical applications [202] and separation processes to increase the hydrophilic character of the blended polymeric materials [203,204], An important factor in the development of new materials based on polymeric blends is the miscibility between the polymers in the mixture, because the degree of miscibility is directly related to the final properties of polymeric blends [205],... 

Protein drugs have been formulated with excipients intended to stabilize the protein in the milieu of the pharmaceutical product. It has long been known that a variety of low molecular weight compounds have the effect of preserving the activity of proteins and enzymes in solution. These include simple salts, buffer salts and polyhydroxylated compounds such as glycerol, mannitol, sucrose and polyethylene glycols. Certain biocompatible polymers have also been applied for this purpose such as polysaccharides and synthetic polymers such as polyvinyl pyrrolidone and even nonionic surfactants. 

Interestingly, protein adsorption is also a field of biological interfacial chemistry which parallels that of synthetic materials at the solid - liquid interface. A number of spectroscopic advances have been made which allow FT-IR to be used in kinetic monitoring of protein adsorption on metals and "biocompatible" polymers. In addition to providing in - situ measurements of total adsorbed protein, FT-IR can also yield information about perturbation of protein secondary structure in adsorbed layers. 

T Tydrogels are a class of synthetic polymers of diverse chemical nature distinguished from other polymers by the capacity to imbibe relatively large amounts of water in their structure. The water content of these materials varies from about 30 to 90 wt % depending on both the chemical nature and physical structure of the polymer. Many natural or biocompatible polymers are also highly hydrated, e.g. 30-50 wt % water is bound by globular proteins (I). Partly for this reason, hydrogels... 

Peptide-poly(ethylene glycol) (PEG) block copolymers are ofparticiflar interest, both from a structural and a functional point of view. Poly(ethylene glycol) is also often referred to as poly(ethylene oxide) (PEG). Throughout this article, however, this polyether will be referred to as PEG. In contrast to the hybrid block copolymers discussed in the previous paragraphs, which were based on amorphous synthetic polymers, PEG is a semi-crystalline polymer. In addition to microphase separation and the tendency of the peptide blocks towards aggregation, crystallization of PEG introduces an additional factor that can influence the structure formation of these hybrid block copolymers, furthermore, PEG is an FDA approved biocompatible polymer, which makes peptide-PEG hybrid block copolymers potentially interesting materials for biomedical applications. 

In general, the properties of a biosystem and a synthetic polymer as well as the nature of the biological medium dictate the degree and type of interaction between a biostructure and a polymer. The biocompatibility of synthetic polymers depends on their chemical nature, physical state, and macroscopic form, which can be modified by functionalization of the polymer skeleton. Many biopolymers, such as proteins and nucleic acids, are natural poly electrolytes. Similarly, the outer cell membrane of living cells has charged groups. The biological medium is an electrolyte with an aqueous phase. Therefore, electrostatic... 

Oshiro,T. 1983. Thrombosis, antithrombogenic characteristics of immobilized urokinase on synthetic polymers. In Biocompatible Polymers, Metals, and Composites, M. Szycher, Ed. pp. 275-299. Technomic, Lancaster, PA. 

Besides natural polymers, polyesters have also been associated with different synthetic polymers to produce scaffolds with combined properties. In their study, in order to improve the scaffold hydrophilicity, Shaffie and colleagues produced hybrid scaffolds using PCL and poly(vinyl alcohol) (PVA) via co-electrospinning. PVA is a hydrophilic and also biodegradable and biocompatible polymer. The PCL/PVA scaffolds had a higher hydrophilicity and also supported a greater initial adhesion and proliferation rate of MSC than PCL scaffolds. When they... 

Injectable poly-L-lactic acid is a biocompatible, biodegradable, synthetic polymer that is approved for correction of HIV-related facial Upoatrophy, as well as for cosmetic processes. After injection, it elicits a gradual increase in facial volume by hypothesized endogenous production of fibroblasts and collagen, enabling global facial rejuvenation to be tailored, as required, over time. Substantial increases in dermal thickness after injection have been observed to last for up... 

Sem micrographs of SCN and SCS synthetic activated carbons are compared with conventional activated carbons " obtained from peat coal or wood in Figure 5.12. The figure clearly shows that the synthetic carbons have a smooth external surface, ensuring favorable conditions for hemocytes membranes that are very sensitive to heterogeneity of the contact surface and that their surface does not need any additional covering by biocompatible polymer films. The bottommost micrographs show that the internal structure of synthetic activated carbon spheres has well-developed channels and pores with sizes considerably smaller than the size of the platelets. The surface characteristics of some hemosorbents are compared in Table 5.11. 

The synthetic biocompatible polymer, Jeffamine D2000, which was shown earlier to have interfacial properties [24], was added to the monomer phase to ensure cationic stabilization of the weak spots during the polymerization process. In this case, high solid contents were obtained when adding only small amounts of Jeffamine (0.5 to 2.5 wt.% with respect to the monomer phase), and very small and monodisperse latexes in the size range ca. 100 to 200 nm without any coagulate could easily be synthesized. It is interesting to note that when the Jeffamine con-... 

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