1. Division of Chemistry and Biological Chemistry; School of Physical and Mathematical Sciences; Nanyang Technological University; Singapore 637371 Singapore
2. School of Materials Science and Engineering and Centre for Biomimetic Sensor Science; Nanyang Technological University; 50 Nanyang Drive Singapore 637553 Singapore
3. School of Chemical and Biomedical Engineering; Nanyang Technological University; 62 Nanyang Drive Singapore 637459 Singapore