1. Department of Bone and Joint Surgery, The First Hospital of Jilin University, 71 Xinmin Street, Changchun 130041, P.R. China
2. Key Laboratory of Polymer Ecomaterials, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 5625 Renmin Street, Changchun 130022, P.R. China
3. Jilin Biomedical Polymers Engineering Laboratory, 5625 Renmin Street, Changchun 130022, P.R. China