Dr. Madeleine Djabourov, Professor, Dept. of Food Engineering,University of São Paulo.,Brazil

Title: Scaffolds for tissue engineering

Abstract: In the new field of tissue engineering, polymers were designed to assist regeneration of three-dimensional tissues and organ structures and to comply with biological demands. Engineering of tissues or organs to treat patients appears as a promising therapeutic approach that combines biomaterials, cells and environmental factors, promoting tissue repair and/or functional restoration. Biomaterials called “scaffolds” play an important role as extracellular matrices to enable to create the correct microenvironment and promote in vitro tissue development. Scaffolds are the porous solid materials that provide a three-dimensional framework for selective cell penetration and facilitate the formation of the new tissue. Scaffolds are designed to have optimal pore sizes depending on the cells which are expected to grow inside: for fibroblasts and hepatocytes, it should be around 20 µm, for skin regeneration, between 20 and 150 µm or for bone regeneration in the range of 100–250 µm. In this presentation we report on scaffolds designed for skin regeneration. We illustrate the relation between the chemical composition (choice of different biopolymers in solution) and their relative proportion, and the structure of the scaffolds allowing the growth of fibroblasts and mesenchymal stem cells (MSC). Several thermal and chemical treatments are necessary to create the freeze dried scaffolds starting from initial dilute solutions. These steps are designed to control the microstructure and the mechanical properties of the scaffolds. In addition to these constraints, cell attachment to the scaffolds is another critical factor in tissue regeneration together, with the control of biodegradation during the wound healing. Those properties will be discussed.

Keywords: Tissue engineering, scaffolds, microstructure, processing, chemical composition