Toxic effects of nanoparticles on bioluminescence activity, seed germination, and gene mutation

Abstract

The potential environmental toxicities of several metal oxide nanoparticles (NPs; CuO, TiO2, NiO, Fe2O3, ZnO, and Co3O4) were evaluated in the context of bioluminescence activity, seed germination, and bacterial gene mutation. The bioassays exhibited different sensitivities, i.e., each kind of NP exhibited a different level of toxicity in each of the bioassays. However, with a few exceptions, CuO and ZnO NPs had most toxic for germination of Lactuca seed (EC50 0.46 mg CuO/l) and bioluminescence (EC50 1.05 mg ZnO/l). Three NPs (Co3O4, TiO2, and Fe2O3) among all tested concentrations (max. 1,000 mg/l) showed no inhibitory effects on the tested organisms, except for Co3O4 NPs on bioluminescence activity (EC50 62.04 mg/l). The sensitivity of Lactuca seeds was greater than that of Raphanus seeds (EC50 0.46 mg CuO/l versus 26.84 mg CuO /l ). The ranking of metal toxicity levels on bioluminescence was in the order of ZnO > CuO > Co3O4 > NiO > Fe2O3, TiO2, while CuO > ZnO > NiO > Co3O4, Fe2O3, TiO2 on germination. No revertant mutagenic ratio (greater than 2.0) of Salmonella typhimurium TA 98 was observed under any tested condition. These findings demonstrate that several bioassays, as opposed to any single one, are needed for the accurate assessment of NP toxicity on ecosystems.

Nanotoxicology of Metal Oxide Nanoparticles

“…The hazard ranking on seed germination was CuO > ZnO > Co3O4, Fe2O3, TiO2. Under bioluminescence, the ranking was ZnO > CuO > Co3O4 > Fe2O3 > TiO2 [131].…”

“…The literature suggests that nanotoxicity is related to (i) the possible release of (toxic) ions from metallic nanoparticles and (ii) the oxidative stress caused by the intrinsic characteristic of the nanoparticle (morphology, surface charge, size and chemical surface composition) [131]. Further studies are required to understand these mechanisms.…”

“…The effect of metal oxide nanoparticles on humans and the environment is a topic that has received increasing interest and debate [129][130][131]. The reviewed literature indicates that the potential toxicities of these nanomaterials have not been completely addressed.…”

“…The authors reported strong oxidative stress from the CuO nanoparticles [130]. Ko et al [131] compared the toxic effects of different metal oxide nanoparticles on seed germination, gene mutation and bioluminescence activity of the Lactuca seed. The hazard ranking on seed germination was CuO > ZnO > Co3O4, Fe2O3, TiO2.…”

“…Finally, the toxicity of nanoparticles can differ depending on the experimental method employed [131]. Nanoparticles themselves can interfere with many tests, and it is often necessary to adapt the protocol to obtain reliable results [134,135].…”