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Combined toxicity of nano-CuO/nano-TiO2 and CuSO4/nano-TiO2 on Escherichia coli in aquatic environments under dark and light conditions
NanoImpact ( IF 4.7 ) Pub Date : 2020-07-01 , DOI: 10.1016/j.impact.2020.100250
Xiaoya Chen , Carolyn M. Wilke , Jean-François Gaillard , Kimberly A. Gray

Abstract Copper(II) oxide nanoparticles (n-CuO) and copper(II) sulfate (CuSO4), commonly used in industrial and agricultural applications, are released in substantial amounts to the environment where they may then interact in unexpected ways with other materials such as engineered nanomaterials (ENM). In this study, we assessed the combined effects of their interaction with titanium(IV) dioxide nanoparticles (n-TiO2), a widely used ENM, on the ATP levels and cell membrane integrity of Escherichia coli in a natural aqueous medium (Lake Michigan water). Under dark conditions, we observed that n-TiO2 addition had negligible effects on copper toxicity, except in the case of higher doses of CuSO4 where n-TiO2 attenuated bacterial stress effects presumably by the adsorption of copper ions at the n-TiO2 surface. However, an opposite effect was observed under exposure to simulated solar irradiation (SSI) with synergistic stress occurring in mixtures of n-TiO2 with either CuSO4 or n-CuO. Enhanced photoactivity (as measured by methylene blue decay) in both CuSO4/n-TiO2 and n-CuO/n-TiO2 mixtures compared to single-component solutions explains the amplified stress effects of the mixtures under SSI, but we were unable to directly measure an increase in the production of reactive oxygen species (ROS) in the mixtures. Under environmental conditions that include light exposure, then, Cu/n-TiO2 mixtures exert amplified cellular stress exceeding that expected based on individual component effects.

中文翻译:

纳米CuO/纳米TiO2和CuSO4/纳米TiO2在黑暗和光照条件下对水生环境中的大肠杆菌的综合毒性

摘要 工业和农业应用中常用的氧化铜 (II) 纳米粒子 (n-CuO) 和硫酸铜 (II) (CuSO4) 会大量释放到环境中,然后它们可能会以意想不到的方式与其他材料相互作用,例如作为工程纳米材料(ENM)。在这项研究中,我们评估了它们与广泛使用的 ENM 的二氧化钛 (IV) 纳米粒子 (n-TiO2) 相互作用对大肠杆菌在天然水性介质(密歇根湖水)中的 ATP 水平和细胞膜完整性的综合影响。 )。在黑暗条件下,我们观察到添加 n-TiO2 对铜毒性的影响可以忽略不计,除非在更高剂量的 CuSO4 的情况下,其中 n-TiO2 可能通过在 n-TiO2 表面吸附铜离子来减弱细菌胁迫效应。然而,在暴露于模拟太阳辐射 (SSI) 下观察到相反的效果,在 n-TiO2 与 CuSO4 或 n-CuO 的混合物中出现协同应力。与单组分溶液相比,CuSO4/n-TiO2 和 n-CuO/n-TiO2 混合物中增强的光活性(通过亚甲蓝衰减测量)解释了 SSI 下混合物的放大应力效应,但我们无法直接测量混合物中活性氧 (ROS) 的产生增加。在包括光照在内的环境条件下,Cu/n-TiO2 混合物会产生超出基于单个组分效应的预期的放大细胞应力。与单组分溶液相比,CuSO4/n-TiO2 和 n-CuO/n-TiO2 混合物中增强的光活性(通过亚甲蓝衰减测量)解释了 SSI 下混合物的放大应力效应,但我们无法直接测量混合物中活性氧 (ROS) 的产生增加。在包括光照在内的环境条件下,Cu/n-TiO2 混合物会产生超出基于单个组分效应的预期的放大细胞应力。与单组分溶液相比,CuSO4/n-TiO2 和 n-CuO/n-TiO2 混合物中增强的光活性(通过亚甲蓝衰减测量)解释了 SSI 下混合物的放大应力效应,但我们无法直接测量混合物中活性氧 (ROS) 的产生增加。在包括光照在内的环境条件下,Cu/n-TiO2 混合物会产生超出基于单个组分效应的预期的放大细胞应力。
更新日期:2020-07-01
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