1. State Key Laboratory of Oral Diseases and Department of Oral and Maxillofacial Surgery, West China College of Stomatology; Sichuan University; Chengdu 610041 China
2. Department of Surgery, Division of Plastic and Reconstructive Surgery; Stanford School of Medicine, Stanford University; Stanford California 94305
3. Research Center for Nano-Biomaterials, Analytical and Testing Center, Sichuan University; Chengdu 610064 China