Evaluation Of A Class Of New Copper-based Nanomaterials By Caenorhabditis Elegans

Nanomaterials(NPs)are natural or man-made materials that are widely used for their unique physicochemical properties such as small size and large specific surface area compared to other particles of the same chemical composition.Currently copper-based nanomaterials are widely used for research in feed additives,gas sensors,wound dressings and other applications.However,as copper is a heavy metal,the potential toxicity and ecosystem effects of copper nanomaterials are of increasing concern as their use increases the exposure of humans and other organisms to them,and it is particularly important to evaluate the in vivo safety of copper-based nanomaterials.In this thesis,five new copper-based nanomaterials were designed and prepared:copper imidazole,copper methyl imidazole,copper ethyl imidazole,copper propyl imidazole and copper butyl imidazole,and the toxic effects of the five copper-based nanomaterials were comprehensively evaluated by testing various physiological parameters of the Caenorhabditis elegans(C.elegans).The results showed that the five copper-based nanomaterials had similar effects on C.elegans in terms of basic indicators,and the effects on the life span of the C.elegans were not significant in the concentration range of 0-200μg/m L,thus screening the safe concentration range for subsequent experiments.All five copper-based nanomaterials reduced the motility of C.elegans,restricted the diet of C.elegans and inhibited the growth of C.elegans body length,indicating that all five materials caused some degree of damage to the nematodes.However,the results also showed that copper exposure reduced fat accumulation in the C.elegans and significantly reduced ROS levels in the C.elegans,reducing the damage caused by oxidative stress in the C.elegans.In addition,the effect of five copper-based nanomaterials on the expression of stress resistance genes was investigated using three mutant nematodes,TJ375,CL2166 and CF1553,which showed that copper exposure enhanced the expression of the heat shock gene(hsp-16.2)but did not affect the expression of gst-4 and sod-3 genes.Transcriptome sequencing analysis showed that the pathways of action of the five copper-based nanomaterials on the nematodes tested were not entirely similar,but were related to the length of the alkane chains of the nanomaterials,with the pathways of action mainly related to cytochrome and oxidative stress when the alkane chains were short,and to lipid and glucose metabolism when the alkane chains were long.Given that the five copper-based nanomaterials have an impact on the basic indicators of living organisms,caution should be taken in their application from a biosafety point of view,but they are predicted to have some prospective applications in the reduction of ROS in living organisms and nanoenzyme catalysis.