Avaliação de biocompósitos à base de colágeno I, agregado trióxido de mineral e nanotubos de carbono de paredes múltiplas na regeneração óssea

• Ano de defesa: 2015
• Autor(a) principal: Thalita Marcolan Valverde
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Minas Gerais; Brasil; ICB - INSTITUTO DE CIÊNCIAS BIOLOGICAS; Programa de Pós-Graduação em Biologia Celular; UFMG
• Palavras-chave em Português: Biologia Celular; Biologia celular; Regeneração Óssea; Colágeno Tipo I; Osteoblastos
• Link de acesso: http://hdl.handle.net/1843/32232

One of the main challenges of regenerative medicine is the development of biomaterials for bone tissue regeneration. In this thesis, we characterize 3D biocomposite scaffolds composed of type I collagen plus mineral trioxide aggregate (MTA) and/or multiwall carbon nanotubes (MWCNT) for use in bone tissue regeneration. Collagen provides a physiologically relevant scaffold, which allows osteoblast adhesion and migration to occur. MTA has a chemical composition similar to the mineral components of bone and is used as a material in endodontical applications, where it displays osteoinductive activities, suggesting that in a dispersed form it may provide bone nucleation sites throughout the scaffold. MWCNT were included since they have been shown to increase the mechanical stability of collagen gels. The objectives of this thesis were to determine the optimal concentrations of collagen, MTA and MWCNT necessary for osteoblast viability, migration, and differentiation in vitro and then test the biocomposites for osteoinductive potential in vivo. Preosteoblasts (MC3T3-E1) were cultured on or in biocomposite scaffolds containing different concentrations of collagen, MTA and MWCNT and then the cellular responses were determined at various time points. Viability was > 95% for all variations of the biocomposite tested in vitro. Migration into scaffolds also occurred efficiently, except in the presence of high concentrations of MWCNT. Specific concentrations of either MTA or MWCNT, or combinations of MTA + MWCNT, caused an increase in mineralization of scaffolds. For in vivo studies, a 1.6 mm diameter defect was made in the tibial bone of rats and filled with biocomposite. After seven days, samples were collected and analyzed using computerized micro-tomography and histological-morphometric analysis. The results obtained thus far indicate a significant increase in mineralization and advanced maturation of newly-formed trabecular bone in the presence of collagen scaffold alone, but only slight increases when MTA and/or MWCNT are present as compared to controls. Thus, these novel type I collagen / MTA / MWCNT biocomposites show potential as physiologically relevant scaffolds for use in bone tissue regeneration.