1. Department of Respiratory and Critical Care Medicine Targeted Tracer Research and Development Laboratory West China Hospital, Sichuan University Chengdu, Sichuan 610041 P. R. China
2. Institute for Nanobiomedical Technology and Membrane Biology Sichuan University Chengdu Sichuan 610041 P. R. China
3. School of Chemical Engineering Sichuan University Chengdu Sichuan 610041 P. R. China