1. University of Pennsylvania 1 Department of Bioengineering , , Philadelphia, PA 19104 , USA
2. McKay Orthopaedic Research Laboratory 2 , Department of Orthopaedic Surgery, Perelman School of Medicine , , Philadelphia, PA 19104 , USA
3. University of Pennsylvania 2 , Department of Orthopaedic Surgery, Perelman School of Medicine , , Philadelphia, PA 19104 , USA
4. Translational Musculoskeletal Research Center, Corporal Michael J. Crescenz VA Medical Center 3 , Philadelphia, PA 19104 , USA
5. BioFrontiers Institute, University of Colorado Boulder 4 , Boulder, CO 80303 , USA
6. University of Colorado Boulder 5 Department of Chemical and Biological Engineering , , Boulder, CO 80303 , USA