1. Center for Cellular and Molecular Engineering Department of Orthopaedic Surgery University of Pittsburgh School of Medicine Pittsburgh PA 15219 USA
2. Department of Pathology University of Pittsburgh School of Medicine Pittsburgh PA 15261 USA
3. Department of Orthopaedic Surgery Stanford University Stanford CA 94305 USA
4. Department of Bioengineering University of Pittsburgh Swanson School of Engineering Pittsburgh PA 15260 USA
5. Institute of Physics University of Freiburg Freiburg 79104 Germany
6. School of Engineering Monash University Malaysia Selangor 47500 Malaysia
7. Center for Stem Cell Research and Regenerative Medicine Tulane University School of Medicine Orleans LA 70112 USA
8. Fischell Department of Bioengineering University of Maryland College Park MD 20742 USA
9. McGowan Institute for Regenerative Medicine University of Pittsburgh School of Medicine Pittsburgh PA 15219 USA