Nanomaterials safety investigation: analysis of genotoxic effects in a human br...

• Author(s): Louro, Henriqueta ; Tavares, Ana ; Silva, Maria João
• Date: 2013
• Persistent ID: http://hdl.handle.net/10400.18/1974
• Origin: Repositório Científico do Instituto Nacional de Saúde
• Subject(s): Genotoxicidade Ambiental; Genotoxicity; Nanomaterials; Lung Cells; Micronucleus Assay; Comet Assay
• Document Type: Conference Object
• Language: English

Description

The human and environment exposure to manufactured nanomaterials (NMs) has been increasing worldwide. The specific properties of MNMs (as size and high surface area/mass) render them attractive for many applications, but may also be associated to higher toxicity in biological systems and adverse effects in humans. The objective of the present work was to evaluate the potential genotoxic effects of several well characterized NMs- titanium dioxide (TiO2), a multiwalled carbon-nanotube (MWCNT) and silicon dioxide (SiO2)- in human bronchial epithelial (BEAS-2B) cells. Dispersions of each NM were prepared according to a standardized protocol and BEAS-2B cultures were exposed to several concentrations of each NM. Genotoxicity was characterized by the combination of the comet and the cytokinesis-block micronucleus assays. Concurrent positive chemical controls (EMS and MMC) and a nanoparticle control (ZnO) were included. The results showed that the exposure of the cells to TiO2 (32-128 µg/cm2, 24h) caused a 3-fold increase in the level of DNA damage (comet assay) over control (P<0.058) but no dose-response could be ascribed using regression analysis. Moreover, this NM was not able to induce micronucleus formation in the same cell line (48h exposure). The MWCNT and SiO2 NM yielded negative results in both genotoxicity assays. Finally, the highest dose of ZnO (3.75 µg/cm2) was able to induce a significant increase in DNA damage but it was clearly cytotoxic in the micronucleus assay. Overall, no clear genotoxic effects were disclosed in BEAS-2B cells for the analysed nanomaterials. Further data from other cell lines and from other endpoints will be gathered in order to clarify nanomaterials safety concerning its genotoxic effects in vitro.