1. State Key Laboratory of Polymer Physics and Chemistry; Changchun Institute of Applied Chemistry; Chinese Academy of Sciences; Changchun 130022 P. R. China
2. Department of Gastroenterology, the Second Affiliated Hospital; Medical School of Xi'an Jiaotong University; Xi'an 710004 P. R. China
3. The First Hospital of Jinlin University; Changchun 130021 P. R. China
4. State Key Laboratory of Polymer Physics and Chemistry; Beijing National Laboratory for Molecular Sciences; Institute of Chemistry; Chinese Academy of Sciences; Beijing 100190 P. R. China
5. Key Laboratory of Polymer Ecomaterials; Changchun Institute of Applied Chemistry; Chinese Academy of Sciences; Changchun 130022 P. R. China