Preparation Of And Basic Research On Polymeric Biomedical Materials

Polymeric biomedical material research is the new branch of the biomedical study, which is an edged cross-discipline of Biology, Iatrology, Chemistry, Physics and Material. It is the basis of artificial tissue or organ preparation, medical devices manufacture, new drug development and Bionic study.Polymeric biomedical materials, also called biomaterials for short, are a kind of materials with particularly properties such as biocompatibility. They could be used for tissue and organ repair or substitution and disease diagnose and therapy. With excellent mechanical properties, synthetic polymers were an important part of biomaterials and widely used in cardiovascular disease, bone repair, nerve transfer, skin, apparatus and drug control.Part one: Research on Antithrombogenic BiomaterialsBiocompatibility, especially blood compatibility, is the most important property with regard to biomedical materials.Up to now, only three types of such as PEO chain structure polymers, phospholipid polymers and surface heparinized biomaterials were considered better. It is an important way to develop biomaterials by constructing special molecules onto the proper mechanical material surface for developing bloodcompatible biomedical devices, which ideally do not require anticoagulants when they are used in contact with blood or plasma. Under the guidance of the Hypothesis of Maintaining Normal Conformation, biomaterials with zwitterionic interfacial molecular structure having good blood compatibility was found.In this research work, zwitterionic molecular structures, such as sulfobetaine, phosphorybetaine and carboxybetaine, were constructed onto the surfaces of common used polymers to further testify the antithrombogenicity of zwitterionic compounds. It was proved by experiment that constructing zwitterionic molecular structure, especially sulfobetaine structure, onto any polymer surface could greatly improve its biocompability. There were many methods to construct zwitterionic molecular structure onto the polymer surface. Among those methods, Ozonization method was widely used and has many advantages.Part Two: Research on Biodegradable and Bioabsorble PolymersBiodegradable polymers are useful for various applications in the medical fields, which include temporary barriers, drug carriers and temporary scaffolds or supports. Study on biodegradable polymers is greatly furthered with the development of tissue engineering. Many kinds of biodegradable polymers have been introduced into medical fields, both nature polymers and synthetic polymers, with various characters. Poly(a-hydroxy acids) are now used or are being developed for many medical applications, based on their distinguished mechanic strength, degradation properties and qualified processibility. The major concern of this paper is the synthesis and characterizations of polymers and copolymers of lactic acid and glycolic acid. Relationships among compositions, structures and properties are focused, with the objective of developing their applications. The applied research of poly(a-hydroxy acids) in this paper focused on poly-D,L-lactic acid for internal fixation and reconstruction of mandibular fractures.A series of poly(a-hydroxy acids), such as PLLA, PDLLA, copolymers of L-LA and D,L-LA, PGA, copolymers of GA and LA, are prepared and they arecharacterized by FT-IR and H-NMR. An oligomer, initiated by glycerine, was synthesized via ring opening polymerization and its molecular weight was determined by 'H-NMR and Ubbellohde type viscometer. By cross-linking reaction between the oligomer and MDI, a microparticle was prepared.WAXD was used in characterization of crystallization of the series of poly(a-hydroxy acids). Both the crystallinity and dimensions of unit cell of PLLA, PGA, copolymers of D,L-LA and L-LA were determined.A means to evaluate the in vitro degradation phenomena of poly(a-hydroxy acids) is used in this paper. In the other hand, the mole ratio of GA and LA also effectively influenced the degradation of poly(hydroxy acids). The degradation of PLA micropartic...