Genotoxicity of nano-silica in mammalian cell lines

Abstract

Nanomaterials are defined by the U.S. National Nanotechnology Initiative as materials that have at least one dimension in the 1-to 100-nm range. Due to their unique physical and chemical characteristics, nanotechnology has become one of the leading technologies over the past 10 years. This study represents data on genotoxic effects of nanoparticles and their application for assessing human health risks. Silica (SiO 2 ) is a multi-functional ceramic material that is being used in various industries to improve surfaces and mechanical properties of diverse materials, such as paints and coatings, plastics, synthetic rubber, adhesives, sealants, or insulation materials. However, recent studies have shown that nano-sized silica (nano-silica) (10 nm in diameter) can generate adverse effects, like liver injury and inflammation. The cytotoxicity and genotoxicity of nano-silica were investigated using the dye exclusion assay, comet assay, and mouse lymphoma thymidine kinase (tk +/-) mouse lymphoma assay (MLA). IC 20 of nano-silica in L5178Y cells was determined to be of 2,441.41 μg/mL and 2,363.28 μg/mL without and with S-9, respectively. Also IC 20 of nano-silica in BEAS-2B cells was determined to be of 2,324.23 μg/mL and 537.11 μg/mL without and with S-9, respectively. In the comet assay, treating L5178Y cells and BEAS-2B cells with nanosilica treatment induced approximately 2-fold increases in tail moment (P⁄0.05) without and with S-9. Also, the mutant frequencies in the nano-silica treated L5178Y cells were not significantly increased compared to the solvent controls. The results of this study indicate that nano-silica can cause primary DNA damage and cytotoxicity but not mutagenicity in cultured mammalian cells.

Biocompatibility assessment of Si-based nano- and micro-particles

“…[199] Additionally, hypomethylation of DNA was found after the treatment of human keratinocytes (HaCaT) with SiO NPs. [200] Jin et al observed that luminescent SiO NPs induced an increase in hOgg1 enzyme (related to DNA repair) expression, but no change in enzyme activity in A549 cells.…”

Undetactable levels of genotoxicity of SiO2 nanoparticles in in vitro and in vivo tests

“…Even though the majority of the studies have reported negative results for the genotoxicity of SiO 2 , 11,17,47 a few investigations have indicated otherwise. 49 Downs et al investigated the genotoxic effects of exposure to three consecutive intravenous injections of SiO 2 nanoparticles by in vivo comet assay in rat liver and lung tissues, and observed the induction of DNA damage by SiO 2 . 50 Hence, the different administration route can lead to different results for genotoxicity evaluation.…”

Cyto and Genotoxicity of Positive and Negative Coated Silica Nanoparticles on Celomocytes of Earthworms Eisenia fetida (Oligochaeta, Annelida)

“…The cyto and genotoxicity of functionalized Si-NPs with different charge on Eisenia fetida coelomocytes is not reported. Choi, et al [10] studied the cyto and genotoxicity of Si-NPs in mammalian cell lines, using the dye exclusion, comet, and mouse lymphoma assays. Authors reported an inhibition concentration for 20% of the assayed L5178Y and BEAS-2B cell populations (IC20) of Si-NPs, ranged between 2.441-2.363 mg/mL, 2.324-0.537 mg/mL, respectively.…”