Cytotoxicity of blank ECT2 nanoparticles and CPT-loaded nanoparticles to the cultured C4-2B cells. Representative live/dead staining of C4-2B cells cultured in the presence of filtered DI H2O (5%, v/v, A) and blank ECT2 nanoparticles (95μg/mL, B) for 24 h. Live (green) and dead (red) cell nuclei were stained with SYTO 13 and propidium iodide, respectively. C: Apoptosis assay of vehicle controls, including filtered DI H2O (5%, v/v), DMSO (0.1%, v/v) and blank ECT2 nanoparticles (95 μg/mL).