1. Lawrence Berkeley National Laboratory, Materials Sciences Division, Berkeley, California.
2. Institute of Bioengineering and Information Technology Materials, Tongji University, Shanghai, China.
3. Department of Orthopedic Surgery, Shanghai Sixth People's Hospital, Shanghai Jiaotong University, Shanghai, China.
4. Department of Materials Science and Engineering, Center for Bone and Tissue Repair and Regeneration, Missouri University of Science and Technology, Rolla, Missouri.