Fig. 2.

Pro-inflammatory response upon exposure to ZnO-NPs monitored by pIL8 A549 reporter cell lines under submerged and ALI conditions. Data are presented as mean x-fold increase over untreated control (submerged) or NaCl-nebulized control (ALI) (dashed line). Error bars indicate the SEM of at least three independent experiments. A one-way analysis of variance (ANOVA) with a subsequent Tukey’s Multiple Comparison test was performed. Values were considered significantly different compared to the unexposed (submerged) or NaCl-nebulized (ALI) control or as indicated with p < 0.05 (*), p < 0.001 (**) and p < 0.0001 (***); Ns = not significant