Fig. 2

MTT assay. Growth inhibition effects of ZnO NPs on HepG2 in different times (24, 48, and 72 h) and concentration (87, 175, 350, 700, 1400, and 2800 μg/ml). The longer incubation time and increasing concentrations of nanoparticles lead to more percent inhibition of cell growth in comparison with control group (***P value < 0.001). All in vitro experiments were performed in triplicate and expressed ad the mean ± standard deviation