1. Department of Materials Science and Engineering, Lehigh University, Bethlehem, Pennsylvania 18015, USA
2. Department of Electrical and Computer Engineering, Lehigh University, Bethlehem, Pennsylvania 18015, USA
3. Bioengineering Program, Lehigh University, Bethlehem, Pennsylvania 18015, USA
4. Department of Mechanical Engineering and Mechanics, Lehigh University, Bethlehem, Pennsylvania 18015, USA