Increasing use of nanomaterials necessitates an improved understanding of their potential impact on environment health. This study evaluated the cytotoxicity of nanosized HfO2, SiO2, Al2O3 and CeO2 towards the eukaryotic model organism Saccharomyces cerevisiae, and characterized their state of dispersion in bioassay medium. Nanotoxicity was assessed by monitoring oxygen consumption in batch cultures and by analysis of cell membrane integrity.CeO2, Al2O3, and HfO2 nanoparticles were highly unstable in yeast medium and formed micron-sized, settleable agglomerates. A non-toxic polyacrylate dispersant (Dispex A40) was used to improve nanoparticle stability and determine the impact of enhanced dispersion on toxicity. None of the NPs tested without dispersant inhibited O2 uptake by yeast at concentrations as high as 1000mg/L. Dispersant supplementation only enhanced the toxicity of CeO2 (47% at 1000mg/L). Dispersed SiO2 and Al2O3 (1000mg/L) caused cell membrane damage, whereas dispersed HfO2 and CeO2 did not cause significant disruption of membrane integrity at the same concentration. These results suggest that the O2 uptake inhibition observed with dispersed CeO2 NPs was not due to reduced cell viability. This is the first study evaluating toxicity of nanoscale HfO2, SiO2, Al2O3 and CeO2 to S. cerevisiae. Overall the results obtained demonstrate that these nanomaterials display low or no toxicity to yeast.
ASJC Scopus subject areas
- Environmental Engineering
- Environmental Chemistry
- Waste Management and Disposal
- Health, Toxicology and Mutagenesis