1. Center for Programmable Materials; School of Materials Science and Engineering; Nanyang Technological University; 50 Nanyang Avenue Singapore 639798 Singapore
2. School of Biosystems Engineering and Food Science; Zhejiang University; 866 Yuhangtang Road Hangzhou 310058 P. R. China
3. College of Materials Science and Engineering; Zhejiang University of Technology; Hangzhou 310014 P. R. China
4. Singapore Institute of Manufacturing Technology; Agency for Science, Technology and Research (A*STAR); 71 Nanyang Drive Singapore 638075 Singapore