Tissue engineering is an exciting new field at the interface of engineering and - ology that uses implanted cells, scaffolds, DNA, proteins, protein fragments, and inductive molecules to repair or replace injured or diseased tissues and organs. Tremendous progress in biological and biomaterial aspects of this field have been accomplished to date, and several engineered tissues are now being used clinically. However, tissue engineers face major challenges in repairing or repl- ing tissues that serve a predominantly biomechanical function. To meet this challenge, the United States National...