Drum Tower Clinical Medical College Nanjing Medical University Nanjing 210008 China;
Department of Biomedical Engineering College of Engineering and Applied Sciences Nanjing University Nanjing 210008 China;
Department of Biomedical Engineering University of Illinois at Urbana-Champaign Illinois 61801 USA;
nanomedicine; drug delivery; maytansinoid; extremely potent drug; pH-sensitive nanocarrier;