Fig. 5

Response of THP-1 macrophages to the second set of MWCNTs. A WST-1 assay in THP-1 cells after 24 h of exposure to increasing applied doses of MWCNTs (mean ± SD; n = 4 experimental replicates). Samples with the same letter do not have a statistically different activity [two-ways ANOVA followed by Tukey’s multiple comparison test (mean effect)]. B IL-1β secretion by THP-1 cells after 24 h of exposure to increasing applied doses of MWCNTs (mean ± SD; n = 4 experimental replicates). Samples with the same letter do not have a statistically different activity [two-ways ANOVA followed by Tukey’s multiple comparison test (mean effect)]. C Turbidity kinetics of the different MWCNT samples suspended in RPMI at 50 μg/ml (n = 2–6 experimental replicates). Symbols with the same letter are not statistically different (mixed effect model followed by Tukey’s test). D Femtosecond pulsed laser signal of deposited MWCNTs after 24 h in the absence (w/o) of cells (a.u., arbitrary unit; mean ± SD; n = 3 experimental replicates). E Femtosecond pulsed laser signal of deposited MWCNTs after 24 h in presence of THP-1 cells (a.u., arbitrary unit; mean ± SD; n = 3 experimental replicates). Columns with the same letter are not statistically different (one-way ANOVA followed by Tukey’s multiple comparison test)