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

Abstract

The nature of occupational risks and hazards in industries that produce or use synthetic amorphous silica (SAS) nanoparticles is still under discussion. Manufactured SAS occur in amorphous form and can be divided into two main types according to the production process, namely, pyrogenic silica (powder) and precipitated silica (powder, gel or colloid). The physical and chemical properties of SAS may vary in terms of particle size, surface area, agglomeration state or purity, and differences in their toxicity potential might therefore be expected. The aim of this study was to compare the cytotoxicity and genotoxicity of representative manufactured SAS samples in Chinese hamster lung fibroblasts (V79 cells). Five samples from industrial SAS producers were evaluated, that is, two pyrogenic SAS powders (with primary particle sizes of 20 nm and 25/70 nm), one precipitated SAS powder (20 nm) and two precipitated SAS colloids (15 and 40/80 nm). V79 cell cultures were treated with different concentrations of SAS pre-dispersed in bovine serum albumin -water medium. Pyr (pyrogenic) 20, Pre (precipitated) 20 and Col (colloid) 15 significantly decreased the cell viability after 24 h of exposure, whilst Pyr 25/70 and Col 40/80 had negligible effects. The cytotoxicity of Pyr 20, Pre 20 and Col 15 was revealed by the induction of apoptosis, and Pyr 20 and Col 15 also produced DNA damage. However, none of the SAS samples generated intracellular reactive oxidative species, micronuclei or genomic mutations in V79 cells after 24 h of exposure. Overall, the results of this study show that pyrogenic, precipitated and colloidal manufactured SAS of around 20 nm primary particle size can produce significant cytotoxic and genotoxic effects in V79 cells. In contrast, the coarser-grained pyrogenic and colloid SAS (approximately 50 nm) yielded negligible toxicity, despite having been manufactured by same processes as their finer-grained equivalents. To explain these differences, the influence of particle agglomeration and oxidative species formation is discussed.

In vitro evaluation of the internalization and toxicological profile of silica nanoparticles and submicroparticles for the design of dermal drug delivery strategies

“…In addition, the size increment from 20 to 70 nm importantly increased the viability levels, being more similar to those achieved by sub‐microparticles (SiPs ≥200 nm). These results are in agreement with previous findings describing that cytotoxicity generated by SiPs strongly depended on particle size and administered dose, with smaller silica particles producing a higher toxic effect (Guichard et al, ). Similar results were observed by McCarthy, Inkielewicz‐Stepniak, Corbalan, and Radomski () using 10, 150 and 500 nm SiPs in Calu‐3 cells.…”

Balanced TH1 and TH2 immunopotentiating effects of silicates partly containing nanoparticles present in calcined serpentine

“…Recent literature has reported on the cytotoxic and allergic effects of theses agents. Guichard et al (2015) reported cytotoxic and genotoxic effects in V79 cells exposed to 20-nm size amorphous silica that had been pre-dispersed in bovine serum albumin-water medium. Induction of allergen-specific T H 2-type allergic immune responses to nano-silica was reported by Yoshida et al (2011).…”

In vitro cell transformation induced by synthetic amorphous silica nanoparticles

“…Data on the genotoxic properties of SAS, mostly assessed by the comet assay for detecting DNA damage or by the micronucleus assay for chromosomal damage, are however less clear. Generally, positive responses in genotoxicity assays are reported more frequently in vitro [5][6][7][8][9] than in vivo [10][11][12]. However, in vitro results remain quite variable and depend on the physical and chemical characteristics of the SAS and the cell type used.…”