1. State Key Laboratory of Medicinal Chemical Biology; Key Laboratory of Functional Polymer Materials, Ministry of Education; and Institute of Polymer Chemistry, College of Chemistry, Nankai University, Tianjin 300071, P.R. China.
2. University of Groningen and University Medical Center Groningen, Department of Biomedical Engineering, Antonius Deusinglaan 1, 9713 AV Groningen, Netherlands.
3. University of Groningen and University Medical Center Groningen, Department of Orthodontics, Hanzeplein 1, 9700 RB Groningen, Netherlands.
4. Tianjin Key Laboratory of Radiation Medicine and Molecular Nuclear Medicine, Institute of Radiation Medicine, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin 300192, P.R. China.