Fig. 1

Cytotoxicity of the NPs in THP-1, A549 and Calu-3 cells. Cells were incubated or not with increasing concentrations (3–200 µg/mL) of the NPs for 24 h and their viability was assessed with the MTT assay. Results are expressed as percentage of viability when compared to control (unexposed cells). They are means ± SEM of n = 3–6 experiments. Concentration-response curves were obtained after logarithmic transformation of the data and fit with the Hill equation. Whenever possible, IC50 values were graphically determined (dashed lines)