Fig. 2

Concentration-dependent THP-1-derived macrophage association of MNPs. MNP cell association after 24 h of exposure to 7.8, 15.6, 31.3, 62.5 or 125 µg/ml of serum-coated or digested+serum-coated MNPs. The graphs show the cell association of serum-coated (white bars) or digested+serum-coated (black bars) A PS50, B PS100, C PS100 (+), D PS100 (−), E PS200, F PS500 and G PS1000 MNPs. The y-axis shows the fold change increase in fluorescence compared to untreated cells that has been corrected to reflect the difference in fluorescence per µg of MNPs as determined by fluorimetry (Additional file 1: Fig. S5). A two-way ANOVA with Bonferroni post hoc correction was performed to assess significant differences from the medium control. Mean ± SD of n = 3, * indicates P < 0.05