1. Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA.
2. Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, PA 19104, USA.
3. Department of Mechanical Engineering, Inha University, Incheon, Korea.
4. Department of Biological Engineering, Inha University, Incheon, Korea.
5. NSF Science and Technology Center for Engineering Mechanobiology, University of Pennsylvania, Philadelphia, PA 19104, USA.
6. Institute for Regenerative Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.