Shape-Dependent Genotoxicity of Mesoporous Silica Nanoparticles and Cellular Mechanisms.

Although mesoporous silica nanoparticles (MSNs) are widely used in food products, cosmetics and nanomedicines as vector for drug delivery, data on their potential genotoxocity are limited. The aim of this study was to investigate the cytotoxic and genotoxic potentials of MSNs of different shapes, and to establish a high-throughput screening method for nanoparticles. We used functional macrophage receptor with collagenous structure (MARCO)-expressing DNA repair deficient chicken DT40 cells, which are designed to internalize nanoparticles and to be deficient in several specific DNA repair pathways. In addition, we verified the validity of this assay by analyzing and characterizing the genotoxicity of sphere- or rod-shaped MSNs. We demonstrated that both sphere- and rod-shaped MSNs were cytotoxic, and that this effect was greater in FEN1(-/-) and REV3(-/-) cells compared with wild-type cells. Effects of rod-shaped MSNs were more severe compared with sphere-shaped MSNs. Furthermore, MSNs induced oxidative damage and a larger number of mitotic chromosomal aberrations in repair-deficient cells compared with repair-proficient cells. Taken together, this assay system using the chimeric receptor-expressing DNA repair-deficient DT40 cells provides a sensitive method to screen for genotoxicity of MSNs.