1. Research Center for Nano-Biomaterials, Analytical and Testing Center, Sichuan University, Chengdu 610064, China
2. State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610065, China
3. Department of Biomaterials, Radboud University Medical Center, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands