1. Division of Chemistry & Biological Chemistry School of Physical and Mathematical Sciences Nanyang Technological University Singapore 637371 Singapore
2. Key Laboratory of Optic-electric Sensing and Analytical Chemistry for Life Science, MOE Shandong Key Laboratory of Biochemical Analysis Key Laboratory of Analytical Chemistry for Life Science in Universities of Shandong College of Chemistry and Molecular Engineering Qingdao University of Science and Technology Qingdao 266042 P. R. China
3. NTU-Northwestern Institute for Nanomedicine (NNIN) Interdisciplinary Graduate School (IGS) Nanyang Technological University Singapore 637553 Singapore
4. School of Materials Science and Engineering Nanyang Technological University Singapore 639798 Singapore