Fig. 1

Interaction of steady-state DCs with nanomaterials. Flt3L-generated immature DCs were incubated for 1 h at 37 °C with the indicated concentrations of SAS (13-nm primary diameter), 11-nm FePO₄ or 33-nm TiO₂ particles, and analyzed by flow cytometry. In culture medium, the SAS particles form aggregates with a mean diameter of 127 nm. The forward scatter (FSC) depends on cell size whereas the side scatter (SSC) reflects intracellular contents like granules [34, 35]. a Flow cytometry distributions demonstrating a SAS dose-dependent increase of DCs with elevated SSC values (numbers denote percentages of events in each gate). b Mean percentage of cells in the selected gate (shown in a) with high SSC values. Upon one-way ANOVA, SAS treatments increased the proportion of high-SSC cells in a significant manner (p < 0.05, n = 4 experiments with independent bone marrow isolates). Error bars, standard errors of the mean (s.e.m.). c Ratios of median SSC. Upon one-way ANOVA, SSC values after incubation with SAS particles were significantly higher than controls (p < 0.05, n = 4). d Comparison with SSC increments resulting from incubation of DCs with FePO₄ and TiO₂ nanoparticles (quantifications are shown in Additional file 1: Figure S3)