1. Department of Chemistry Center for Bioanalytical Chemistry University of Science and Technology of China Hefei 230026 P. R. China
2. Hefei National Research Center for Physical Sciences at Microscale University of Science and Technology of China Hefei 230026 P. R. China
3. College of Pharmaceutical Sciences Anhui Xinhua University Hefei 230001 P. R. China
4. Departments of Diagnostic Radiology Surgery Chemical and Biomolecular Engineering and Biomedical Engineering Yong Loo Lin School of Medicine and College of Design and Engineering National University of Singapore Singapore 119074 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
7. Institute of Molecular and Cell Biology Agency for Science Technology and Research (A*STAR) 61 Biopolis Drive, Proteos Singapore 138673 Singapore