Toxicity of polyelectrolyte-functionalized titania nanoparticles in zebrafish (Danio rerio) embryos

Abstract

We investigated the effects of short-term exposure of bare TiO 2 NPs and polyelectrolyte-coated TiO 2 NPs in the 5-25 nm size range, at relatively high concentrations (of 500 and 1000 mg/L) under light or dark conditions, in D. rerio embryos. The biological endpoints investigated included embryo viability and mRNA transcript levels of antioxidant and membrane transport genes relative to control embryos. The presence of nanoparticles on the surface of embryos was assessed using TEM. The results confirm an accumulation of TiO 2 NPs on the outer surface (chorion) of the embryo, but not within the embryo. No significant difference in embryo viability was detected following each exposure regime. The expression of antioxidant biomarker, SOD2, was significantly impacted by the type of TiO 2 NP, with TiO 2 NPs/PSS/PAH coating exposure showing down regulation; the concentration of the nanoparticles, with down regulation at 500 mg/L; and dark/light condition with down regulation in the light. The expression levels of the hypoxia and membrane markers, HIF1 and Pxmp2, were not significantly impacted by any factor. The study indicates that SOD2 mRNA expression levels may be useful in the detection of apparent oxidative stress induced by the titania nanoparticle build up on the embryo chorion surface.

Effects of Metal Oxide Nanoparticles in Zebrafish

“…Only one work evaluated the effects of a coating of the TiO 2 NPs on zebrafish during development [65]. Eggs were exposed to bare TiO 2 NPs or TiO 2 NPs with polyelectrolyte on the surface under illumination or darkness.…”