1. Key Laboratory of Advanced Technologies of MaterialsMinistry of EducationSchool of Materials Science and EngineeringSouthwest Jiaotong University Chengdu 610031 P. R. China
2. Department of OrthopaedicsChengdu First People's Hospital Chengdu 610041 P. R. China
3. Department of Biochemistry and Molecular BiologyCollege of Basic and Forensic MedicineSichuan University Chengdu 610041 P. R. China
4. National Engineering Research Center for BiomaterialsEngineering Research Center in BiomaterialsSichuan University Chengdu 610064 P. R. China