Biomedical polymers biocompatibility

Anderson, J.M., Spilizevs ski, K.I.. and Hiltner, A. (1985) Poly-a amino acids as biomedical polymers. Biocompatibility of Tissue Analogs. Boca Raton, CRC Press Inc. (V7-88. 

Polymer surfaces play an important role in many polymer applications especially biomaterials. The design and synthesis of desired surface properties of biomedical polymers are among our approaches to biomedical polymers. Biocompatibility was defined in 1987 as the ability of a material to perform with an appropriate host response in a specific application . Bulk and surface properties of biomaterials used for implant devices directly influence the tissue interface dynamics from initial implantation until explantation. The most important influence on how proteins, cells, and the organism respond to a material is the surface structure, in both chemical and morphological terms. 

Fatty acids have been used previously in the development of polymers for biomedical applications as they are considered to be inert, inexpensive and biocompatible. The main fatty acids which are used as a base for synthesis of biomedical polymers (polyanhydrides) are stearic acid (/), erucic acid (C22 unsaturated fatty acid) dimer (2), bile acid dimer (i), ricinoleic acid 4) and other fatty acids (5), middle long carbon chain (C12 - 15) dibasic acids, such as dodecanedioic, brassylic acid, tetradecandioic acid and pentadecandioic acid (/). 

Hydrophobicity of biomedical polymers influences the biocompatibility depending on the particular application such as tissue engineering, blood contacting devices, and dental implants [35]. Polymers are dynamic structures and can switch their surface functional groups depending on the environment. For example, polymeric biomaterials need to have a hydrophilic smface for most of the applications, so that the cell-adhesive proteins present in the serum will be adsorb and promote cell adhesion and proliferation. This is achieved by snrface treatment procedures such as... 

Hirano, S., Seino, H., Akiyama, Y, and Nonaka, I. 1990. Chitosan A biocompatible material for oral and intravenous administrations. In Progress in Biomedical Polymers, Gebelein C. G. and Dunn R. L. (eds.). New York Plennm, pp. 283-290. 

J. M. Anderson, K. L. Spilizewski, A. Hiltner, Poly-alpha-amino acids as biomedical polymers, in Biocompatibility of Tissue Analogs (CRC Press, Boca Raton, 1985) pp 67-88. 

PPy is the first and most extensively studied and used CP for biomedical and tissue engineering applications [241-245]. It was one of the first known polymers biocompatible to cells both in vitro and in vivo and promoting their adhesion and growth in vitro. PPy implants have also shown to be compatible with minimum or no response from tissues. The electrical stimulation of PPy has also been found to... 

Williams, D.E (1994) Molecular biointeractions of biomedical polymers with extracellular exudate and inflammatory cells and their effect on biocompatibility, in-vivo. Biomaterials. 15, 779-785. 

Dankert, J., Hogt, A. H. Feijen, J. (1986). Biomedical Polymers Bacterial Adhesion, Colonization, and Infection. Critical Reviews in Biocompatibility, Vol. 2, No. 3, Qune 1986), pp. (219-301), ISSN 0748-5204... 

Biopolymers are often used throughout the human body they are also called biomedical polymers. A biomedical material can be of natural origin (biopolymer) or a synthetic polymer and can be used for any period of time, as a whole or as part of a system that treats, augments, or replaces any organ or function of the body, as well as for medical technical applications outside the body. When a prosthetic device is placed into the body, two aspects must be taken into account functional performance and biocompatibility. The former requires special functions of the biomedical polymers, in particular including load transmission and stress distribution. Biocompatibility between a polymer and a biological system (e.g., soft tissue,... 

Biomedical applications biocompatible shape memory polymers... 

Recently, for the example ofpoly(3-hydroxybutyrate) (PHB) and a number of its composites [14-16] we have studied physical-chemical, dynamic and transport characteristics of macroscopic biodegradable matrices and microparticles of PHB which were designed for controlled dmg release [16, 17]. High biocompatibility, controlled biodegradation and appropriate mechanical properties allow one to consider this biopolymer as one of the most promising biomedical polymers. Besides therapeutical aims, PHB is widely used as bone implants, nervous conduits, matrices in cell engineering, filters and membranes, in cardiology and in the other areas [14,18,19]. 

It is worth mentioning here that PEG is a biomedical polymer with excellent biocompatibility and resistance to platelet and protein adsorption due to its mobility in aqueous environments [30]. Indeed, PEG allows biomaterials to retain their excellent water swelling properties, whereas PDMS modifies its surface to inhibit protein adsorption [17]. Hence, PDMS-PEG copolymers are considered to be ideal candidates as biomaterials... 

Applications. Polymers with small alkyl substituents, particularly (13), are ideal candidates for elastomer formulation because of quite low temperature flexibiUty, hydrolytic and chemical stabiUty, and high temperature stabiUty. The abiUty to readily incorporate other substituents (ia addition to methyl), particularly vinyl groups, should provide for conventional cure sites. In light of the biocompatibiUty of polysdoxanes and P—O- and P—N-substituted polyphosphazenes, poly(alkyl/arylphosphazenes) are also likely to be biocompatible polymers. Therefore, biomedical appHcations can also be envisaged for (3). A third potential appHcation is ia the area of soHd-state batteries. The first steps toward ionic conductivity have been observed with polymers (13) and (15) using lithium and silver salts (78). 

The realization of sensitive bioanalytical methods for measuring dmg and metaboUte concentrations in plasma and other biological fluids (see Automatic INSTRUMENTATION BlosENSORs) and the development of biocompatible polymers that can be tailor made with a wide range of predictable physical properties (see Prosthetic and biomedical devices) have revolutionized the development of pharmaceuticals (qv). Such bioanalytical techniques permit the characterization of pharmacokinetics, ie, the fate of a dmg in the plasma and body as a function of time. The pharmacokinetics of a dmg encompass absorption from the physiological site, distribution to the various compartments of the body, metaboHsm (if any), and excretion from the body (ADME). Clearance is the rate of removal of a dmg from the body and is the sum of all rates of clearance including metaboHsm, elimination, and excretion. 

Nicholson, J. W., Braybrook, J. H. Wasson, E. A. (1991). The biocompatibility of glass-poly(alkenoate) (glass-ionomer) a review. Journal of Biomedical Science, Polymer Edition, 2, 277-85. 

Biocompatibility. The analysis of polymer implants has been employed using FTIR spectroscopy to elucidate the long-term biocompatibility and quality control of biomedical materials. This method of surface analysis allows the determination of the specific molecular composition and structures most appropriate for long-term compatibility in humans. 

Apart from modifications in the bulk, also surface modification of PHAs has been reported. Poly(3HB-co-3HV) film surfaces have been subjected to plasma treatments, using various (mixtures of) gases, water or allyl alcohol [112-114]. Compared to the non-treated polymer samples, the wettability of the surface modified poly(3HB-co-3HV) was increased significantly [112-114]. This yielded a material with improved biocompatibility, which is imperative in the development of biomedical devices. 

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