1. State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics Center for Molecular Imaging and Translational Medicine School of Public Health Xiamen University Xiamen 361102 P. R. China
2. Key Lab of Organic Optoelectronics & Molecular Engineering Department of Chemistry Tsinghua University Beijing 100084 P. R. China
3. Department of Chemistry University of Miami Miami FL 33146 USA
4. Departments of Diagnostic Radiology Chemical and Biomolecular Engineering, and Biomedical Engineering Yong Loo Lin School of Medicine and Faculty of Engineering National University of Singapore Singapore 117597 Singapore
5. Clinical Imaging Research Centre Centre for Translational Medicine Yong Loo Lin School of Medicine National University of Singapore Singapore 117599 Singapore
6. Nanomedicine Translational Research Program NUS Center for Nanomedicine Yong Loo Lin School of Medicine National University of Singapore Singapore 117597 Singapore