Evaluation of biochemical effects of copper oxide and platinum nanoparticles on the cladoceran Daphnia magna

Abstract

The use and production of copper oxide nanoparticles (CuO NPs) and platinum nanoparticles (NPs Pt) has increased significantly over the past years, being applied in several areas such as industry, nanomedicine and agriculture. Due to the wide application of these NPs, it is possible that their release occurs in aquatic environments, representing a risk for aquatic organisms. Some studies have already reported the toxicity of these NPs to a few organisms, however, the investigation of their effects on the antioxidant system and oxidative damage in cladocerans is limited. The use of biochemical biomarkers may help to explain the NPs toxicity mechanisms and they have the potential to be used as early warning signs for ecologically relevant effects. Therefore, the aim of this study will be to evaluate the toxicity and biochemical responses of oxidative stress on cladoceran Daphnia magna exposed to copper oxide and platinum NPs. Assays to determine NPs toxicity on the test organism will be performed. Afterward, the cladocerans will be exposed to NPs sublethal concentrations to evaluate the effects of oxidative stress using biochemical biomarkers. Oxidative stress will be analyzed by determining of the reactive oxygen species levels, the antioxidant enzymes activity (superoxide dismutase, catalase and glutathione peroxidase) and the occurrence of lipid peroxidation on cladoceran. Overall, this research may elucidate the main effects and toxicity mechanisms of CuO NPs and Pt NPs on cladocerans, besides providing information that will subsidize regulatory actions to improve the protection of aquatic biota.