1. Department of Mechanical Engineering, National University of Singapore, 9 Engineering Drive 1, Singapore 117 576, Singapore
2. Singapore Institute of Manufacturing Technology, 71 Nanyang Drive, Singapore 638 075, Singapore
3. School of Materials Science and Engineering, Nanyang Technology University, 50 Nanyang Avenue, Singapore 639 798, Singapore
4. Department of Microbiology, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore 119 757, Singapore