Fig. 4

ROS and caspase-3 production induced by NPs. a, b NPs induced ROS generation in HepG2 cells, which could be inhibited by pretreatment with the ROC inhibitor NAC. The production of intracellular ROS was detected by DCFH-DA staining and observed by inverted-type laser scanning confocal microscopy, and measurements of the average radiant efficiencies. c, d Caspase-3 activity and cell viability were detected with or without NAC or with the caspase-3 inhibitor Z-VAD-FAM