1. Department of Bioengineering, Center for Bioactive Materials and Tissue Engineering, University of Pennsylvania, Philadelphia, Pennsylvania.
2. Departments of Bioengineering and Orthopaedic Surgery, Center for Bioactive Materials and Tissue Engineering, University of Pennsylvania, Philadelphia, Pennsylvania.
3. Department of Biochemistry, School of Dental Medicine, Center for Bioactive Materials and Tissue Engineering, University of Pennsylvania, Philadelphia, Pennsylvania.