Desenvolvimento de metodologia para produção de estruturas tridimensionais porosas de vidro bioativo para aplicação em Engenharia de tecidos

• Ano de defesa: 2003
• Autor(a) principal: Marlene de Barros Coelho
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Minas Gerais; UFMG
• Palavras-chave em Português: Engenharia Metalúrgica e de Minas; Engenharia metalúrgica
• Link de acesso: http://hdl.handle.net/1843/KASA-5RQQ3T

In order to reach these specific structural features, it was developed during the present work a processing method to obtain the macroporous structure by foaming different compositions of sol-gel derived bioactive glasses solution, system CaO-P2O5-SiO2, with the addition of surfactants. It was evaluated structures with different chemical composition and temperatures of heat treatment. In vitro bioactivity and dissolution tests were conducted. The characterization results of the structures after the stabilization heat treatment were discussed. The network of the scaffolds was divided in two levels, macroporous and mesoporous. Physical characterization of the samples consisted of microstructural observation, pore size and textural analysis. For this the mercury porosimetry, scanning electron microscopy, image analysis by software Quantikov and nitrogen adsorption were performed. The porosity were calculated from Archimedes´ technique and compared with porosity analyzed by mercury porosimetry. Complementary analysis of the materials was got from Fourier transform infrared spectroscopy (FTIR), X-ray diffraction and Inductive Coupled Plasma Spectroscopy (ICP), for dissolution evaluating. In addition, it was shown some results of the cell culture. After thermal treatment at the 700ºC for 4h, the material remained amorphous and some crystallization could be observed for samples treated at 800ºC and 900ºC, in such case some peaks of the crystalline phases Wollastonite, Bredigite and Nagelschimidtite were identified. The mesoporous presented pore size distribution ranging from 10 to 30nm and a specific surface area of 60-170m2/g at 700ºC, varying with glass compositions. For higher temperatures of stabilization this value was huge smaller, 3-7m2/g with small pore volumes, this can be an indication of the high densification of the structures. Pore diameters were in the range of 70-500m for the macroporous network. It was observed from the in vitro tests and FTIR analysis that the structures developed in this work were bioactivies.