1. National Engineering Laboratory for Modern Silk & Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou 215123, P. R. China
2. Department of Dermatology, Shanghai Ninth People’s Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200011, P. R. China
3. Department of Biomedical Engineering, Tufts University, Medford, Massachusetts 02155, United States