Biomaterials and tissue engineering - A role for microgravity?

Tissue engineering is a relatively new field whose goal is to grow or regenerate tissues in the body that have been damaged and may not be healed by the body itself due to a variety of reasons. This review describes the concept of tissue engineering which uses threedimensional porous biomaterial constructs called scaffolds seeded with cells. Several scaffold fabrication techniques are reviewed. The essential characteristics of such scaffolds are discussed, including the importance of their mechanical properties. These properties influence the stress-strain micro-environment around the cells and hence the mechanical stimuli delivered to the cells. Concepts of mechanotransduction are introduced including results of cells culture studies performed under microgravity during space flights. Finally, based on the above discussions, the potential role of microgravity in tissue engineering is addressed. An argument is made that although microgravity can play an important role in the fabrication of ideal scaffolds and in understanding the role of mechanotransduction, tissue regenerated entirely in space may not be viable.