1. Laboratory
of Molecular Imaging and Nanomedicine, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, Maryland 20892, United States
2. Center for Molecular Imaging and Translational
Medicine, School of Public Health, Xiamen University, Xiamen, Fujian 361102, China
3. Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
4. School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
5. Ocean NanoTech LLC, Springdale, Arkansas 72764, United States