1. N.1 Institute for Health, National University of Singapore, 28 Medical Drive, #05-COR, 117456 Singapore
2. Department of Mechanical Engineering and Engineering Science, Center for Biomedical Engineering and Science, University of North Carolina at Charlotte, Charlotte, North Carolina 28223, United States
3. Center of Nanofibers & Nanotechnology, Department of Mechanical Engineering, National University of Singapore, 117575 Singapore