Reproducible Comet Assay of Amorphous Silica Nanoparticles Detects No Genotoxicity

Abstract

Genotoxicity of commercial colloidal and laboratory-synthesized silica nanoparticles was tested using the single cell gel electrophoresis or Comet assay. By using a carefully developed protocol and careful characterization of the nanoparticle dispersions, Comet assays were performed on 3T3-L1 fibroblasts with 3, 6, and 24 h incubations and 4 or 40 microg/ml of silica nanoparticles. No significant genotoxicity was observed for the nanoparticles tested under the conditions described, and results were independently validated in two separate laboratories, showing that in vitro toxicity testing can be quantitatively reproducible.

Ecotoxicological assessment of silica and polystyrene nanoparticles assessed by a multitrophic test battery

“…These generally low responses have been shown to be in accordance with other ecotoxicity studies using engineered amorphous silica NPs, where little or no toxicity was observed in the tests employed (Barnes et al 2008;Shapero et al 2011;Van Hoecke et al 2008). Thus, the lack of toxicity observed to date with amorphous silica NPs, suggests that, in the different standard toxicity methods, this could generally be used as a good negative NP control, except in the case of the cytotoxicity assays which themselves are shown not to be suitable to NP testing.…”

“…Amorphous silica particles, in comparison, are considered to be relatively harmless and are therefore being produced in large quantities for a large number of applications, especially in biomedical applications and the food sector 5 (Wang et al 2006). Thus, particular concern arises about their possible toxicity and a number of studies have already shown both non toxic (Barnes et al 2008) and toxic effects with amorphous silica NPs (Van Hoecke et al 2008), and specifically in the form of pulmonary inflammation upon inhalation (Rosenbruch 1992).…”

“…Such a response may be expected as amorphous silica NPs are known for their low toxicity (Barnes et al 2008;Rabolli et al 2010), indicating their suitability as a good negative control for NP exposure. In the case of the cytotoxicity testing, both assays indicate a low dose and exposure time dependent response as shown in Figure 3, a slightly larger effect being observed for the 50 nm than the 100 nm silica NPs in both assays.…”

“…Amorphous silica particles, in comparison, are considered to be relatively harmless and are therefore being produced in large quantities for a large number of applications, especially in biomedical applications and the food sector 5 (Wang et al 2006). Thus, particular concern arises about their possible toxicity and a number of studies have already shown both non toxic (Barnes et al 2008) and toxic effects with amorphous silica NPs (Van Hoecke et al 2008), and specifically in the form of pulmonary inflammation upon inhalation (Rosenbruch 1992).Synthesized from organic polymers, with the possibility to produce them in different sizes, surface charge, composition and morphology, polymeric NPs can be obtained with very different functional properties that makes them a perfect product for a wide range of applications (Nowack and Bucheli 2007). Depending on the polymer type, they can potentially be used in a range of applications, the main one being in the medical sector for drug delivery (Chan et al 2010).…”

Nanotechnology towards prevention of anaemia and osteoporosis: from concept to market

“…Due to the small size of nanoparticles, they can easily pass through the biological barriers and membranes and can cause toxicity at various sites in the body, i.e. genotoxicity, carcinogenic potential and oxidative stress in organelles, mitochondrial stress and cell-wall disruption [105][106][107]. Therefore, the safety and the possible impact of these nanomaterials should not only be considered for the affected population, but should also cover the entire manufacturing and disposal processes [102].…”