1. Department of Biomedical Engineering, Tufts University, 4 Colby Street, Medford, Massachusetts 02155, United States
2. National Engineering Laboratory for Modern Silk, College of Textile and Clothing Engineering, Soochow University, Suzhou 215123, China
3. Department of Histology & Embryology, College of Basic Medical Sciences, Dalian Medical University, Dalian 116044, China