1. Department of Chemical and Biomolecular Engineering; National University of Singapore; 4 Engineering Drive 4 Singapore 117585 Singapore
2. Singapore Institute for Neurotechnology (SINAPSE); National University of Singapore; 28 Medical Drive, #05-COR Singapore 117456 Singapore
3. Department of Biomedical Engineering; National University of Singapore; 9 Engineering Drive 1, Block EA #03-12 Singapore 117575 Singapore
4. Institute of Materials Research and Engineering (IMRE) A*STAR (Agency for Science, Technology and Research); 2 Fusionopolis Way, Innovis Singapore 138634 Singapore
5. State Key Laboratory of Bioactive Substance and Function of Natural Medicines; Institute of Materia Medica; Chinese Academy of Medical Sciences & Peking Union Medical College; 1 Xian Nong Tan Street Beijing 100050 China