Figure 1.

Confocal microscopic image of A549 cells showing SiO₂NP uptake. (A) A549 cells growing on Permanox^® chamber slide were incubated with Rhodamine labelled SiO₂NP (30 nm) for 24 h. After this time, culture media was carefully removed, cells were washed in PBS and cells were fixed in 3% paraformaldehyde. Nuclei were stained with Hoechst (blue). A representative sample population of cells were visualized by confocal microscopy using a 63 X oil immersion lens. (B) Three dimensional image stacks showing cytosolic accumulation of 30 nm SiO₂NP (Z-stack = 27 slices at 0.45 μm per slices, Z-height 12.15 μm), (top image = x-z plane; centre image = x-y plane; right image = y-z plane). (C) Transmission Electron Microscope (TEM) image shows SiO₂NP cytoplasmic accumulation, particle size distribution within an A549 epithelial lung cell (magnification 10 x and 120 KeV accelerating voltage).