1. Research Center of Biomedical Engineering, College of Materials, Technology Research Center of Biomedical Engineering of Xiamen City, The Key Laboratory of Biomedical Engineering of Fujian Province, Xiamen University, Xiamen 361005 (P. R. China), and Institute of Biomedical Engineering, Chinese Academy of Medical Science, Peking Union Medical College, The Key Laboratory of Biomedical Material of Tianjin, Tianjin 300192, P. R. China