Medical applications biomaterials

Ikada Y. Surface modification of polymers for medical application. Biomaterials, 1994, 15, 725-736. James SJ, Pogribna M, Miller BJ, Bolon B, and Muskhelishvili L. Characterization of cellular response to silicone implants in rats Implications for foreign-body carcinogenesis. Biomaterials, 1997, 18, 667-675. 

Ikada, Y. 1994. Surface modification of polymers for medical applications. Biomaterials, 15 725-36. 

The first definition described a biomaterial as a nonviable material used in a medical device, intended to interact with biological systems [4]. Nowadays, this definition has evolved and takes in consideration many new topics, such as biodegradability and biocompatibility. In medical applications, biomaterials are rarely used as isolated materials, but are more commonly integrated into devices or implants. 

After almost half a century of use in the health field, PU remains one of the most popular biomaterials for medical applications. Their segmented block copolymeric character endows them with a wide range of versatility in tailoring their physical properties, biodegradation character, and blood compatibility. The physical properties of urethanes can be varied from soft thermoplastic elastomers to hard, brittle, and highly cross-linked thermoset material. 

As a preeminent biomaterial, silicones have been the most thoroughly studied polymer over the last half century. From lubrication for syringes to replacements for soft tissue, silicones have set the standard for excellent blood compatibility, low toxicity durability, and bioinertness. Many medical applications would not have been possible without this unique polymer. 

Engelberg I and Kohn J. Physio-mechanical properties of degradable pol3miers used in medical applications A comparative study. Biomaterials, 1991, 12, 292-304. 

Martin DP and Williams SF. Medical applications of poly 4-hydroxybutyrate A strong flexible absorbable biomaterial. Biochem Eng J, 2003, 16, 97-105. 

From the foregoing, it seems likely that apart from a small number of specialist medical applications, the efficacy of surface coated devices may be compromised by antibiotic-resistant bacteria, together with the barrier effect provided by conditioning films that will rapidly coat biomaterials in situ.43... 

In dentistry, silicones are primarily used as dental-impression materials where chemical- and bioinertness are critical, and, thus, thoroughly evaluated.546 The development of a method for the detection of antibodies to silicones has been reviewed,547 as the search for novel silicone biomaterials continues. Thus, aromatic polyamide-silicone resins have been reviewed as a new class of biomaterials.548 In a short review, the comparison of silicones with their major competitor in biomaterials, polyurethanes, has been conducted.549 But silicones are also used in the modification of polyurethanes and other polymers via co-polymerization, formation of IPNs, blending, or functionalization by grafting, affecting both bulk and surface characteristics of the materials, as discussed in the recent reviews.550-552 A number of papers deal specifically with surface modification of silicones for medical applications, as described in a recent reference.555 The role of silicones in biodegradable polyurethane co-polymers,554 and in other hydrolytically degradable co-polymers,555 was recently studied. 

TIRF has been used to study equilibrium adsorption of proteins to artificial surfaces both to learn about the surface properties of various biomaterials that have medical applications and also to test the TIRF technique itself. 

Sousa, R. A., Mano, J. F., Reis, R. L., Cunha, A. M., Bevis, M. J. (2002). Mechanical performance of starch based bioactive composite biomaterials molded with preferred orientation for potential medical applications. Polym. Eng. Sci.,42(5), 1032-1045. 

Significant developments have occurred in recent years in the fields of biopolymers and biomaterials. New synthetic materials have been synthesized and tested for a variety of biomedical and related applications from linings for artifical hearts to artifical pancreas devices and from intraocular lenses to drug delivery systems. Of particular interest in the future is the development of intelligent polymers or materials with special functional groups that can be used either for specialty medical applications or as templates or scaffolds for tissue regeneration. 

In addition to dense monolithic ceramics, porous silicon nitrides are gaining more importance in technological applications [24], Some porous silicon nitrides with high specific surface area have already been applied as catalysis supports, hot gas filters and biomaterials [25], There is an emerging tendency to facilitate silicon nitride as biomaterial, because of specific mechanical properties that are important for medical applications [25], Moreover, in a recent study it was shown that silicon nitride is a non-toxic, biocompatible ceramic which has the ability to propagate human bone cells in vitro [25], Bioglass and silicon nitride composites have already been realized to combine... 

In contrast, in experimental and clinical medicine only a few groups have been active in the research and development of shaped BC as implant biomaterial [65-76]. Therefore - from our viewpoint - it is necessary to specify BC design and handling for medical applications in detail. 

Recently, considerable attention has been directed on biomaterials that are used in contact with living tissue and biological fluids for medical applications. One of the... 

Engelberg, I., and Kohn, J. "Physicomechanical properties of degradable polymers used in medical applications - a comparative-study". Biomaterials 12(3), 292-304 (1991). 

Kroschwitz, J. I. (1989), Polymers Biomaterials and Medical Applications, Wiley, New York. 

Nonstandard amino acids can be either incorporated globally at multiple sites within a protein or inserted at specific locations (1, 15). Global misincorporation of nonstandard amino acids can produce protein polymers with altered physical properties that confer, for example, varied tensile strengths and elasticities (16). These unique biomaterials can be used in many medical applications, such as altering properties associated with cell adhesion. In other applications, routine replacement of methionine by selenomethionine aids in X-ray crystal structure determination. 

Powell, D.G. Medical applications of polycarbonate. Medical Plastics and Biomaterials 1998. http //www.devicelink.com/mpb/archive/ 98/09/003.html (accessed November 2004). 

The term biomaterials encompasses all materials used for medical applications that are interfaced with living systems. Although this definition addresses specifically materials used in contact with living systems (intra-corporeal uses), other systems developed for extracorporeal uses 1-4) are also commonly classified as biomaterials. 

Among the many classes of polymeric materials now available for use as biomaterials, non-degradable, hydrophobic polymers are the most widely used. Silicone, polyethylene, polyurethanes, PMMA, and EVAc account for the majority of polymeric materials currently used in clinical applications. Consider, for example, the medical applications listed in Table A.l most of these applications require a polymer that does not change substantially during the period of use. This chapter describes some of the most commonly used non-degradable polymers that are used as biomaterials, with an emphasis on their use in drug delivery systems. 

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