1. Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety (Chinese Academy of Sciences), and Key Laboratory of Standardization and Measurement for Nanotechnology (Chinese Academy of Sciences), National Center for Nanoscience and Technology, Beijing 100190, P. R. China
2. University of Chinese Academy of Sciences, Beijing 100049, P. R. China
3. College of Mathematical Sciences, University of Chinese Academy of Sciences, Beijing 100049, P. R. China
4. Academy of Mathematics and Systems Science, Chinese Academy of Sciences, Beijing 100190, P. R. China
5. California NanoSystems Institute, Department of Chemistry and Biochemistry, and Department of Materials Science and Engineering, University of California, Los Angeles, Los Angeles, California 90095-7227, United States
6. CAS Center for Excellence in Brain Science, Chinese Academy of Sciences, Beijing 100101, P. R. China