Fig. 5

Evaluation of intracellular localization of silica-nanoparticles and endo-lysosomal membrane damage. A-B. Images of confocal microscopy showing intracellular distribution of FITC-labeled silica particles. RAW264.7 cells were incubated with indicated silica-NPs for 24 h in the presence of A. Texas Red-labeled dextran (TR-dextran; red) or B. LysoTracker (red in B) in RAW cells. Cellular nuclei were visualized with Hoechst33342. C. Evaluation of lysosomal membrane permeabilization (LMP) in Raw264.7 cells that endocytosed silica-NPs with/without surface modification. Raw264.7 cells transfected with pmCherry-Gal3 (LMP-reporter) were incubated with silica-NPs (50 nm-plain or 50 nm-NH₂) or LLoMe (LMP inducer) for 6 h. Images were obtained by confocal microscopy. Arrows indicate cells with diffuse cytosolic signal of mCherry-tagged Gal3. Arrowheads indicate cells with punctate signals of accumulated Gal3, suggesting lysosomal membrane rupture. Scale bars in low magnification (top panels) = 50 μm, in high magnification (bottom panels) = 10 μm