1. Key Laboratory of Biomedical Materials and Implant Devices, Research Institute of Tsinghua University in Shenzhen, Shenzhen 518057, P. R. China
2. Department of Orthopedics, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, P. R. China
3. School of Materials Science and Engineering, Xiamen University of Technology, Xiamen 361024, P. R. China
4. State Key Laboratory of Tribology, Department of Mechanical Engineering, Tsinghua University, Beijing 100084, P. R. China