1. a Research Center for Nano-Biomaterials, Analytical and Testing Center, Sichuan University, Chengdu 610064, P. R. China
2. b Research Center for Nano-Biomaterials, Analytical and Testing Center, Sichuan University, Chengdu 610064, P. R. China
3. c West China College of Stomatology, Sichuan University, Chengdu 610041, P. R. China
4. d West China College of Stomatology, Sichuan University, Chengdu 610041, P. R. China
5. e West China College of Stomatology, Sichuan University, Chengdu 610041, P. R. China
6. f West China College of Stomatology, Sichuan University, Chengdu 610041, P. R. China
7. g Department of Periodontology and Biomaterials, Radboud University Nijmegen Medical Center, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands
8. h Research Center for Nano-Biomaterials, Analytical and Testing Center, Sichuan University, Chengdu 610064, P. R. China