1. Tissue and Therapeutic Engineering Lab, Johns Hopkins Singapore, Level 5 Clinical Research Center, NUS, 10 Medical Drive, Singapore 117597
2. Laboratory of Biomedical Polymeric Materials, Department of Chemistry, Wuhan University, Wuhan 430072, China
3. Department of Chemical Engineering, National University of Singapore, Singapore 119260
4. Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Room 726, Ross Building, 720 Rutland Avenue, Baltimore, Maryland 21205