Combined toxicity of nano-CuO/nano-TiO2 and CuSO4/nano-TiO2 on Escherichia coli in aquatic environments under dark and light conditions

Xiaoya Chen; Carolyn M. Wilke; Jean François Gaillard; Kimberly A. Gray

doi:10.1016/j.impact.2020.100250

Combined toxicity of nano-CuO/nano-TiO₂ and CuSO₄/nano-TiO₂ on Escherichia coli in aquatic environments under dark and light conditions

Xiaoya Chen, Carolyn M. Wilke, Jean François Gaillard^*, Kimberly A. Gray

^*Corresponding author for this work

Civil and Environmental Engineering

Research output: Contribution to journal › Article › peer-review

10 Scopus citations

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.

Original language	English (US)
Article number	100250
Journal	NanoImpact
Volume	19
DOIs	https://doi.org/10.1016/j.impact.2020.100250
State	Published - Jul 2020

Funding

We thank Shushan Wu and Bingqing Liu for their assistance during the preparation of this manuscript, Jinglin Hu for her technical support with bacterial preparation, Natalia Orbutz for performing DLS and NTA measurements, and Elise Goldfine for powder XRD. This work was supported by the Northwestern University Keck Biophysics Facility and a Cancer Center Support Grant ( NCI CA060553 ), the Analytical bioNanoTechnology (ANTEC) Core Facility of the Simpson Querrey Institute at Northwestern University supported by the U.S. Army Research Office , the U.S. Army Medical Research and Materiel Command , and Northwestern University with ongoing support received from the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource ( NSF ECCS-1542205 ), and the Jerome B.Cohen X-Ray Diffraction Facility supported by the MRSEC program of the National Science Foundation ( DMR-1720139 ) at the Materials Research Center of Northwestern University and SHyNE.

Keywords

Copper
Cu/n-TiO mixtures
Nano-TiO
Phototoxicity

ASJC Scopus subject areas

Materials Science (miscellaneous)
Safety, Risk, Reliability and Quality
Safety Research
Public Health, Environmental and Occupational Health

Access to Document

10.1016/j.impact.2020.100250

Cite this

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title = "Combined toxicity of nano-CuO/nano-TiO2 and CuSO4/nano-TiO2 on Escherichia coli in aquatic environments under dark and light conditions",

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.",

keywords = "Copper, Cu/n-TiO mixtures, Nano-TiO, Phototoxicity",

author = "Xiaoya Chen and Wilke, {Carolyn M.} and Gaillard, {Jean Fran{\c c}ois} and Gray, {Kimberly A.}",

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T1 - Combined toxicity of nano-CuO/nano-TiO2 and CuSO4/nano-TiO2 on Escherichia coli in aquatic environments under dark and light conditions

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AU - Wilke, Carolyn M.

AU - Gaillard, Jean François

AU - Gray, Kimberly A.

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N2 - 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.

AB - 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.

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