Effects Of Copper Oxide Nanoparticles With Different Particle Sizes And Morphologies On The Toxicity Of Danio Rerio

The important role of copper oxide nanoparticles(Cu O-NPs)in many fields makes it widely used,and it is inevitable to enter the water environment.Exploring the biotoxic effect of Cu O-NPs is one of the current research hotspots,but the toxic effects of Cu O-NPs with different particle sizes and different morphologies on biology have not been reported yet.In this study,the model organism Danio rerio was used as the test organism,and the effects of Cu O-NPs with different particle sizes and shapes on the acute toxicity and sub-chronic toxicity of Danio rerio were studied,and the following conclusions were obtained:1.In the acute toxicity test,the 96h LC₅₀was 641.4254 mg·L^-1for 150-250 nm spherical Cu O-NPs;530.5617 mg·L^-1for 40 nm spherical Cu O-NPs;224.2424 mg·L^-1for flake Cu O-NPs.The flaky Cu O-NPs was the most acutely toxic to Danio rerio,followed by 40 nm spherical Cu O-NPs,and 150-250 nm spherical Cu O-NPs was relatively less toxic.2.In the growth and development toxicity experiments,the three kinds of Cu O-NPs can reduce the body weight,body length and respiratory frequency of Danio rerio,and with the increase of exposure concentration,the inhibitory effect on Danio rerio is gradually strengthened.The growth and development toxicity of flaky Cu O-NPs is the strongest,followed by 40 nm spherical Cu O-NPs,and 150-250 nm spherical Cu O-NPs is the lowest.3.Histopathological results it can be seen that the degree of lesions in the tissues and organs of Danio rerio will become more and more serious with the increase of concentration and time of exposure to Cu O-NPs.The flaky Cu O-NPs was the most toxic to Danio rerio,followed by 40 nm spherical Cu O-NPs,and 150-250 nm spherical Cu O-NPs was the least toxic.4.The results of oxidative stress-related enzymes and MDA content indicate that Cu O-NPs can activate the antioxidant defense system of Danio rerio,cause oxidative stress in Danio rerio,and affect the body of Danio rerio.Among the three Cu O-NPss,the flaky Cu O-NPs caused the greatest degree of oxidative stress,followed by 40 nm spherical Cu O-NPs,and 150-250 nm spherical Cu O-NPs was the least.5.The results of genotoxicity experiments showed that among the different Cu O-NPs groups,the 40 nm spherical Cu O-NPs group had the highest micronucleus rate,then the 150-250 nm spherical Cu O-NPs group,and the flake Cu O-NPs group had the lowest micronucleus rate.6.The results of intestinal microorganisms showed that three kinds of Cu O-NPs treatments reduced microbial diversity,changed the changes of dominant bacteria at the'gate'level and'genus'level,and also revealed that the effect of Cu O-NPs on Danio rerio had two sides.The results of this study can enrich the toxicological data of nanomaterials on vertebrates,and are of great help to comprehensively understand the toxic effects of Cu O-NPs and its toxicity mechanism.It also provides a theoretical reference for the design of new nanomaterials.Environmental safety assessment of nanomaterials under conditions provides data support.