1. Department of Chemistry and Medicinal Chemistry Programme; National University of Singapore; Singapore 117543 Singapore
2. State Key Laboratory of Chemo/Biosensing and Chemometrics; College of Chemistry and Chemical Engineering; Hunan University; Changsha 410082 (PR China
3. Department of Pharmacy, National; University of Singapore; Singapore 117543 Singapore
4. Laboratory of Bioimaging Probe Development; Singapore Bioimaging Consortium; Singapore 138667 Singapore