Cytotoxicity upon Ag-NP and AgNO
exposure. Cell integrity as estimated by quantification of extracellular LDH release relative to the unexposed and untreated control (red dashed line) was measured 4 h (grey bars) and 24 h (black bars) after exposure. Cells were exposed to 30 ng/cm2 and 270 ng/cm2 Ag-NP (A) and equal concentrations of 0.22 mM and 2.2 mM as well as 22 mM AgNO3 (B). As positive control (Triton) cells were treated with Triton X-100 for 4 h and 24 h. LDH release was also measured for cells treated with TNF-α. Error bars represent the standard error of the mean (SEM) for at least 3 independent experiments. A two-way analysis of variance (ANOVA) with a subsequent Bonferroni post-hoc test was performed. Values were considered significantly different compared to the unexposed and untreated control with p < 0.01 (**).