1. State Key Laboratory of Natural Medicines, Key Laboratory on Protein Chemistry & Structural Biology, Department of Pharmaceutics, China Pharmaceutical University, Nanjing 210009, P.R. China
2. State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing 210093, P.R. China
3. Laboratory of Cellular & Molecular Biology, Jiangsu Province Academy of Traditional Chinese Medicine, Nanjing 210028, P.R. China
4. Department of Pharmaceutical Sciences, Center for Drug Delivery & Nanomedicine, University of Nebraska Medical Center, Omaha, NE 68198, USA