1. Department of Orthopaedic Surgery, Center for Cellular and Molecular Engineering, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
2. Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
3. Department of Orthopaedic Surgery, Stanford University, California, USA.
4. Department of Neurobiology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
5. Department of Medicine and Epidemiology and Public Health, University of Maryland, Baltimore, Maryland, USA.
6. Department of Microbiology, Immunology, and Genetics, University of North Texas Health Science Center, Fort Worth, Texas, USA.
7. Institute for Tissue Engineering and Regenerative Medicine, The Chinese University of Hong Kong, Hong Kong SAR, China.
8. Department of Bioengineering, Stanford University, California, USA.
9. McGowan Institute for Regenerative Medicine, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.