1. State Key Laboratory of Tribology, Department of Mechanical Engineering, Tsinghua University, Beijing 100084, P.R. China
2. Shanghai Key Laboratory for Prevention and Treatment of Bone and Joint Diseases, Shanghai Institute of Traumatology and Orthopaedics, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, P.R. China
3. Key Laboratory of Advanced Technologies of Materials, Ministry of Education, School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031, P.R. China
4. Institute for NanoBioTechnology, Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, Maryland 21218, United States
5. Department of Biomedical Engineering, Translational Tissue Engineering Center, Johns Hopkins School of Medicine, Baltimore, Maryland 21287, United States