1. Beijing Engineering Research Center for BioNanotechnology and CAS Key Laboratory for Biomedical Effects of Nanomaterials and NanosafetyCAS Center for Excellence in NanoscienceNational Center for NanoScience and Technology Beijing 100190 P. R. China
2. School of Life Science and TechnologyHarbin Institute of Technology 2 Yikuang Road, Nangang District Harbin 150001 P. R. China
3. University of Chinese Academy of Sciences Beijing 100049 P. R. China