Cells were exposed to low, medium and high doses of ZnO NP in DMEM in digests for four hours prior to the cell viability assessment. For panels A & B, data was analyzed with a one-way ANOVA with Tukey’s multiple comparison test and data was considered significant at p<0.05. Mean±SEM is shown, n = 32. In panel C a two-way ANOVA compares the means of each column to each other, Tukey groups are shown and data was considered significant at p<0.05. Mean±SEM is shown, n = 32. Bars that do not share any letters are significantly different statistical analysis. Low, medium and high refer to the dose of ZnO nanoparticles, where low = 9.7 × 10−6 mg/mL, medium = 9.7 × 10−4 mg/mL, and high = 9.7 × 10−2 mg/mL.