Biomaterials for Stem Cell Tissue Engineering

Stem cells have become a promising cell source in the tissue engineering field. Intense studies have been focused at the cell and molecular biology levels on understanding the relationship between stem cell growth and terminal differentiation in an effort to control these processes. Recent discoveries have shown that the microenvironment can influence stem cell self-renewal and differentiation, which has had a tremendous impact on identifying potential strategies for using these cells effectively in the body. This presentation will describe studies examining the influence of biomaterials on stem cell behavior with an emphasis on identifying biomaterials designs and chemistries that impart appropriate cues to stem cells to affect their behavior both in vitro and in vivo. Specifically, surface wettability can influence stem cell osteogenesis, which is relevant for bone repair applications.

Hydrophobic polymers and their use with bioactive ceramics to create bioactive composites have been identified to greatly enhance the expression of bone cell markers. Biomaterial design such as fiber and pore size dimension can also greatly influence differentiation. Studies using polymers having fiber dimensions varying from the nano to micron-scale influenced chondrogenic differentiation of stem cells. The resulting changes in pore size also had a significant effect, but variations in mechanical properties played a minor role. The effect of electromechanical properties of polymeric materials, specifically piezoelectric polymers, on stem cell differentiation along bone, cartilage and neural lineages will also be discussed. Current results with their use in vivo will be presented.