1. Department of Orthopedic; Academy of Orthopedics, Guangdong Province, The Third Affiliated Hospital, Southern Medical University; Guangzhou 510280 China
2. Department of Cell Biology; School of Basic Medical Science, Southern Medical University; Guangzhou 510515 China
3. Department of Biomedical Engineering; Materials Research Institute, The Huck Institutes of The Life Sciences, The Pennsylvania State University, University Park; Pennsylvania 16802