Fig. 4From: Size and surface modification of silica nanoparticles affect the severity of lung toxicity by modulating endosomal ROS generation in macrophagesSize and surface modification indicate uptake and subsequent inflammatory response of Raw264.7 cells to silica-NPs. A. Cellular uptake of silica particles was studied by immunofluorescence in vitro. Raw264.7 cells, a murine phagocytic cell line, were exposed to different silica-NPs, and cellular uptake was assessed 6 h later by confocal microscopy. In the images, blue indicates cell nucleus, green indicates FITC-labeled silica particles, and red indicates Alexa 594-labeled anti-F4/80 antibody as a cell surface marker of murine macrophages. Scale bars in low magnification (top panels) = 50 μm, and in high magnification (bottom panels) = 10 μm. B-C. Flow cytometric detection of intracellular silica-NP accumulation in Raw264.7 cells after 6 h endocytosis. Representative scatter plots showing endocytosis of FITC-labeled silica-NPs are shown in B. The graph in C shows the proportions of cells that endocytosed FITC-labeled silica particles. D-F. Cytokine expressions in RAW264.7 cells 6 h after exposure to silica-NPs. Gene expressions of inflammatory cytokine genes (MIP1α(D), MIP2(E), and TNF-α(F)) were determined by qRT-PCR. Results are shown as mean ± SEM of five independent experimentsBack to article page