1. Department of Biomedical
Engineering, University of North Texas, Denton, Texas 76207, United States
2. Department of Material Science and Engineering, University of North Texas, Denton, Texas 76207, United States
3. Department
of Materials Science and Engineering, College of Engineering, Peking University, Beijing 100871, China
4. Department of Bioengineering, University of Texas at Arlington, Arlington, Texas 76010, United States