Figure 2From: Role of surface charge and oxidative stress in cytotoxicity of organic monolayer-coated silicon nanoparticles towards macrophage NR8383 cellsEffect of 24 hours exposure of NR8383 cells to increasing concentrations of Si NP-NH 2 (black triangle), Si NP-N 3 (black square) and Si NP-COOH (black dot) on phagocytosis (measured as the phagocytic index). Error bars show standard error of mean (n = 3). The asterisk (*) sign signifies P < 0.05.Back to article page