Cytotoxicity of functionalized CeO2 nanoparticles towards Escherichia coli and adaptive response of membrane properties. (October 2021)

• Record Type: Journal Article
• Authors: Zhuo, Meihui; Ma, Jingyun; Quan, Xiangchun
• Is Part Of: Chemosphere. Volume 281(2021)
• Publication Date: 2021-10
• Subjects: CeO2-NPs -- Cytotoxicity -- Membrane damage -- Functional group -- Oxidative stress; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2021.130865
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: The cytotoxicity and mechanisms of cerium oxide nanoparticles (CeO2 -NPs) on organisms have attracted great concerns recently, while that of CeO2 -NPs with functional groups remains unclear. This study investigated cytotoxic effects and mechanisms of CeO2 -NPs with hydroxyl, carboxyl, or amino functional groups towards a strain Escherichia coli ( E. Coli ). Results showed that CeO2 -NPs produced a stronger cytotoxicity in NaCl medium than in PBS medium at the concentrations of 10–400 mg/L. The toxicity followed the order of CeO2 –COOH > CeO2 –NH2 > CeO2 –OH. Exposing to CeO2 -NPs increased cell membrane permeability and reduced membrane fluidity. The membrane phospholipid fatty acid compositions also varied greatly as a response to the stress of CeO2 -NPs, with the proportion of unsaturated fatty acids increased and saturated fatty acids decreased. Both intracellular reactive oxygen species (ROS) level and malonaldehyde (MDA) level declined, suggesting the oxidative stress from ROS may be not the primary reason for the membrane damage. Other mechanisms such as direct membrane oxidation by Ce 4+ or physical penetration based on a close contact between nanoparticles and microbes might contribute to the membrane damages and cell viability loss. The present study provides a significant insight into the influence of functionalized CeO2 -NPs on a gram-negative bacterium. Graphical abstract: Image 1 Highlights: The cytotoxicity of CeO2 –COOH, CeO2 –NH2, and CeO2 –OH was investigated. CeO2 –COOH showed the highest cytotoxicity towards E. Coli. The functional CeO2 -NPs damaged membrane and decreased cell viability. Oxidative stress from ROS may be not the primary reason for membrane damage.