1. Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania.
2. McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania.
3. Department of Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania.
4. C. R. Bard, Inc. (Davol), Providence, Rhode Island.
5. Division of Plastic Surgery, Miller School of Medicine, University of Miami, Miami, Florida.
6. Department of Molecular Pharmacology, Physiology and Biotechnology, Brown University, Providence, Rhode Island.