Concentration- and time-dependent particle uptake by NR8383 cells. Results of FACS analysis demonstrate increased particle uptake by AM based on SSC of laser light indicating cellular granularity. AM were treated with (A) ufTiO2 , (B) fTiO2 and (C) DQ12 particles in concentrations of 10, 20 or 40 μg/cm2 for 1 or 3 h. (D) Particle internalization by NR8383 cells are demonstrated in MGG-stained cytospin preparations. Light microscopic images show AM either untreated or treated with 10 μg/cm2 of particles for 4 h (upper panel) or 24 h (lower panel). Original magnification 1000-fold (Olympus BX60). Figure A - C represent median ± SEM of three independent experiments, with * p < 0.05, ** p < 0.01 and *** p < 0.001 vs. control (ANOVA with Dunnett post-hoc comparison).