X Frank Zhang1,2, Xuanhong Cheng3,4. 1. Department of Bioengineering, Lehigh University, Bethlehem, PA, USA. xiz310@lehigh.edu. 2. Department of Mechanical Engineering and Mechanics, Lehigh University, Bethlehem, PA, USA. xiz310@lehigh.edu. 3. Department of Bioengineering, Lehigh University, Bethlehem, PA, USA. 4. Department of Materials Science and Engineering, Lehigh University, Bethlehem, PA, USA.