1. Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration, Ministry of Education, Tongji Hospital, The Institute for Biomedical Engineering & Nano Science, School of Medicine, Tongji University, 200092 Shanghai, P. R. China
2. Shanghai Skin Disease Hospital, The Institute for Biomedical Engineering & Nano Science, School of Medicine, Tongji University, 200092 Shanghai, P. R. China