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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Desenvolvimento de arcabouços a base de polímeros biocompatíveis PLA e PCL com agentes antibacterianos

Silva, Fernanda Waitman de Oliveira January 2015 (has links)
Orientador: Prof. Dr. Jean Jacques Bonvent / Dissertação (mestrado) - Universidade Federal do ABC, Programa de Pós-Graduação em Biotecnociência, 2015. / Arcaboucos polimericos sao de interesse crescente no campo da engenharia de tecidos. Alguns biopolimeros tais como PLLA -poli (acido latico) e PCL . poli(¿Ã- caprolactona) tem sido amplamente utilizados na composicao destes arcaboucos devido a sua biocompatibilidade, biodegradabilidade e baixa toxicidade. Alem disso, estes biomateriais precisam ter uma boa adesao celular e proliferacao para serem eficazes na reparacao de tecidos. A fim de evitar a invasao de microorganismos, durante o processo de cicatrizacao, e importante a incorporacao de um agente antimicrobiano, para servir como uma barreira protetora e prevenir a infeccao no local da lesao. Tres tipos de arcaboucos foram desenvolvidos a base de PLLA e PCL, e da blenda PCL/PLA - 50/50. A porosidade das membranas de biopolimero foi controlada pela incorporacao de particulas de cloreto de sodio com determinada faixa de tamanho, como agente porogenico, na solucao polimerica, a qual foi, em seguida, removido apos a evaporacao do solvente, por imersao da membrana para a agua para dissolver o sal. A tetraciclina tem sido incorporados a membrana como um agente antibiotico. A morfologia da membrana, estrutura molecular e incorporacao da tetraciclina foram analisados por microscopia eletronica de varredura (MEV), FTIR e microscopia de fluorescencia. A cinetica de libertacao do farmaco foi investigadam atraves da monitorizacao da concentracao de tetraciclina difundida em solucao de PBS (pH 7,4), por meio de espectroscopia de UV-VIS. Os dados experimentais mostraram que a uma porosidade de cerca de 69% foi obtida. A incorporacao de tetraciclina mostrou ser bastante eficaz e uniforme nos arcaboucos, contudo observa-se melhores resultados no caso de PCL puro. A cinetica de libertacao do farmaco e de primeira ordem para arcaboucos com PLA e PCL, puros. No entanto, no caso da blenda, o processo de libertacao do farmaco nao segue nenhum modelo cinetico estabelecido. Tais resultados sugerem que estes suportes de biopolimero podem ser eficazmente produzida com caracteristicas porosas e com a incorporacao de antibioticos, a fim de promover uma libertacao controlada da droga para o processo de reparo tecidual. / Polymeric scaffolds are of growing interest in the field of tissue engineering . Some biopolymers such as PLA - poly lactic acid and PCL - polycaprolactone have been widely used in the composition of these scaffolds due to their biocompatibility, biodegradability and low toxicity. In addition, these biomaterials need to have a good cell adhesion and proliferation to be effective in tissue repair. Furthermore, the formation of pores in the scaffolds is directly related to a better adhesion of material to the cells. In order to avoid microorganism invasion that during the healing process it is important to incorporate an antimicrobial such as tetracycline, to serve as a protective barrier and prevents infection at the site of the injury. Three types of scaffolds were develop, based on PCL, and their blend 50/50, by means of casting process. The porosity of the biopolymer membranes was controlled achieved by the incorporation of sodium chloride particles of given size, as a porogene agent, into the polymer solution, which was then removed after the solvent evaporation by immersion of the membrane into water to dissolve the salt. Tetracycline has been incorporated into to the membrane as an antibiotic agent. The membrane morphology, molecular structure e incorporation of the tetracycline were analyzed by Scanning Electron Microscopy (SEM), FTIR and Fluorescence Microscopy. The drug release kinetic was investigated by monitoring the concentration of tetracycline that diffused to a PBS solution (pH 7.4), by means of uv-vis spectroscopy. The experimental data showed that a medium porosity, of about 69%, could be reached. The incorporation of tetracycline was found to be quite effective and uniform into the scaffolds, tending to lead to better results in the case of pure PCL. The drug release kinetic is of first order for the pure PLA and PCL scaffold. Nevertheless, in the case of the blend, any of the usual kinetic model could describe the drug release process.Such results suggested these biopolymer scaffolds could be effectively produced with porous characteristics and with incorporation of antibiotics in order to promote a controlled drug liberation for wound healing process.

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