1. CAS Key Laboratory of Standardization and Measurement for Nanotechnology; CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety; CAS Center for Excellence in Nanoscience; National Center for Nanoscience and Technology of China; Beijing 100190 China
2. Department of Chemistry; Stanford University; Stanford CA 94305 USA
3. Department of Materials Science and Engineering; South University of Science and Technology of China; Shenzhen 518055 China
4. Institute of Chemistry; Chinese Academy of Sciences; Beijing 100190 China
5. Sino-Danish College; University of Chinese Academy of Sciences; Beijing 100049 China
6. Center for Neuroscience Research; School of Basic Medical Sciences; Fujian Medical University; Fuzhou 350108 China