1. CAS Key Laboratory for Biomedical Effects of Nanomaterials and NanosafetyCAS Center for Excellence in NanoscienceNational Center for Nanoscience and Technology of China No. 11, First North Road Zhongguancun Beijing 100190 P. R. China
2. University of Chinese Academy of Sciences Beijing 100049 P. R. China
3. Key Laboratory of Medicinal Chemistry and Molecular Diagnosis of the Ministry of EducationHebei University Baoding 071002 P. R. China
4. Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of EducationCollege of Chemistry and Materials ScienceNorthwest University Xi'an 710069 P. R. China
5. Tissue Engineering Research Center of the Academy of Military Medical Sciences No. 27, Taiping Road, Haidian District Beijing 100850 P. R. China