Stimulus responsive smart supports and scaffold/cell constructs for bone tissue engineering =Suportes inteligentes com capacidade de responder a estímulos e novas combinações suportes/células para engenharia de tecidos ósseo

Tissue engineering (TE) has emerged as a new interdisciplinary science for the repair of various tissues, restoring their functions by means of using biomaterials, cells, and/or bioactive factors. Three main general strategies have been adopted for the creation of new bone tissue: i) direct in vivo implantation of isolated cells; ii) direct in vivo implantation of scaffolds; and iii) cells placed on or within scaffolds. In the bone tissue engineering approach, a temporary scaffold is required to serve as an adhesive substrate for the implanted cells and a physical support to guide the formation of the new tissue. In the second and third approaches, a porous material acts as a scaffold, serving in the later case as transplant vehicle for cultured cells and template to guide tissue regeneration, playing an important role in transforming the cell seeded scaffolds in to a new tissue. The present thesis is divided in two main groups of studies: in the first one we describe the TE strategy of using scaffold and seeded cells with osteogenic media supplemented with several enzymes (Chapter III and IV). The second part describes the development of acellular scaffolds with in situ pore forming ability in vitro, improvement of their properties (namely degradation and osteoconductivity) and finally the validation of in situ pore forming concept in vivo (Chapters V, VI, VII and VIII). (Abstract shortened by ProQuest.).