Subcellular Distribution and Genotoxicity of Silica Nanoparticles 
in Human Bronchial Epithelial Cells

Background and objective Silicon nanoparticles are widely used in daily life. Therefore, they attract increased attention because of their potential biotoxicity to the lungs when inhaled. The aims of this study are to explore the organism distribution and genotoxicity of silica nanoparticles in human bronchial epithelial cells (BEAS-2B). Methods The biodistribution of silica with different particle sizes in human bronchial epithelial cells was observed by transmission electron microscopy (TEM). DNA damage was detected by single-cell gel electrophoresis (comet assay). Results TEM revealed that SiO2 nanoparticles with different sizes can be uptaken by cells and be localized in the cytoplasm and the nucleus. Compared with micro-silica, nano-silica in BEAS-2B cells can inflict more severe DNA damage (P<0.05). Conclusion The particle size of silica nanoparticles can be used to determine their distribution in biological cells. Compared with micro-silica, nano-silica has higher genotoxicity