1. Department of Biomedical Engineering, Research Center for Nano-biomaterials & Regenerative Medicine, College of Biomedical Engineering, Taiyuan University of Technology, Taiyuan 030024, P. R. China
2. Shanxi Key Laboratory of Material Strength & Structural Impact, Institute of Biomedical Engineering, Taiyuan University of Technology, Taiyuan 030024, P. R. China