Department of Earth and Environmental Sciences, University of Milan Bicocca, Italy.
Department of Chemistry, University of Milan, Italy.
Environ Pollut. 2020 Feb;257:113597. doi: 10.1016/j.envpol.2019.113597. Epub 2019 Nov 9.
The ongoing development of nanotechnology has raised concerns regarding the potential risk of nanoparticles (NPs) to the environment, particularly aquatic ecosystems. A relevant aspect that drives NP toxicity is represented by the abiotic and biotic processes occurring in natural matrices that modify NP properties, ultimately affecting their interactions with biological targets. Therefore, the objective of this study was to perform an ecotoxicological evaluation of CeONPs with different surface modifications representative of NP bio-interactions with molecules naturally occurring in the water environment, to identify the role of biomolecule coatings on nanoceria toxicity to aquatic organisms. Ad hoc synthesis of CeONPs with different coating agents, such as Alginate and Chitosan, was performed. The ecotoxicity of the coated CeONPs was assessed on the marine bacteria Aliivibrio fischeri, through the Microtox® assay, and with the freshwater crustacean Daphnia magna. Daphnids at the age of 8 days were exposed for 48 h, and several toxicity endpoints were evaluated, from the molecular level to the entire organism. Specifically, we applied a suite of biomarkers of oxidative stress and neurotoxicity and assessed the effects on behaviour through the evaluation of swimming performance. The different coatings affected the hydrodynamic behaviour and colloidal stability of the CeONPs in exposure media. In tap water, NPs coated with Chitosan derivative were more stable, while the coating with Alginate enhanced the aggregation and sedimentation rate. The coatings also significantly influenced the toxic effects of CeONPs. Specifically, in D. magna the CeONPs coated with Alginate triggered oxidative stress, while behavioural assays showed that CeONPs coated with Chitosan induced hyperactivity. Our findings emphasize the role of environmental modification in determining the NP effects on aquatic organisms.
纳米技术的不断发展引发了人们对纳米粒子（NPs）可能对环境，尤其是水生生态系统造成潜在风险的担忧。驱动 NP 毒性的一个相关方面是在自然基质中发生的非生物和生物过程，这些过程改变了 NP 的性质，最终影响了它们与生物靶标的相互作用。因此，本研究的目的是对具有不同表面修饰的 CeONPs 进行生态毒理学评价，这些表面修饰代表了 NP 与水环境中天然存在的分子的生物相互作用，以确定生物分子涂层对水生生物中纳米氧化铈毒性的作用。使用海藻酸钠和壳聚糖等不同的涂层剂专门合成了 CeONPs。通过 Microtox®测定法评估了涂层 CeONPs 对海洋细菌 Aliivibrio fischeri 的生态毒性，并用淡水甲壳类动物大型溞进行了评估。处于 8 天大的溞类暴露于 CeONPs 48 小时，并评估了从分子水平到整个生物体的多个毒性终点。具体来说，我们应用了一系列氧化应激和神经毒性生物标志物，并通过评估游泳性能来评估行为影响。不同的涂层会影响暴露介质中 CeONPs 的流体动力行为和胶体稳定性。在自来水中，用壳聚糖衍生物涂层的 NPs 更稳定，而用藻酸盐涂层则增强了聚集和沉降速度。涂层还显著影响 CeONPs 的毒性作用。具体来说，在大型溞中，用藻酸盐涂层的 CeONPs 引发了氧化应激，而行为测定表明，用壳聚糖涂层的 CeONPs 诱导了过度活跃。我们的研究结果强调了环境修饰在确定 NP 对水生生物的影响方面的作用。
