1. School of Materials Science and Engineering National Engineering Research Center for Tissue Restoration and Reconstruction South China University of Technology Guangzhou 510006 P. R. China
2. School of Chemical Engineering and Light Industry Guangdong University of Technology Guangzhou 510006 P. R. China
3. Guangzhou Key Laboratory of Spine Disease Prevention and Treatment Department of Spine Surgery the Third Affiliated Hospital Guangzhou Medical University Guangzhou 510150 P. R. China