Cytotoxic and genotoxic evaluation of different synthetic amorphous silica nanomaterials in the V79 cell line

Synthetic silica nanoparticles (SNPs) are the most produced nanomaterials and have many industrial applications, but their hazard is still discussed. Manufactured SNPs occur in amorphous form and can be distinguished in three different types, depending on their industrial process: pyrogenic silica, precipitated silica (powder, gel or colloid) and silica fume. The physical and chemical properties of SNPs may differ, for example in term of particle size, surface, aggregation, agglomeration or purity, and one could expect differences in their toxicity potential. The aim of the present study was to compare the in vitro genotoxicity of representative manufactured SNP samples. Genotoxic effects were assessed in Chinese hamster lung fibroblast (V79 cells) using the micronucleus assay for chromosome damage and the FPG-modified comet assay for DNA damage. Results showed no significant increase in micronuclei formation after 24 h of exposure for all silica samples tested. However after the same exposure time, SNPs induced cytotoxicity and oxidative DNA damages at different levels. Those effects were more related to the primary size and the surface area of SNPs than on their types.