title: Toxicity of metal oxide nanoparticles in Escherichia coli correlates with conduction band and hydration energies.
abstract: Metal oxide nanoparticles (MOx NPs) are used for a host of applications, such as electronics, cosmetics, construction, and medicine, and as a result, the safety of these materials to humans and the environment is of considerable interest. A prior study of 24 MOx NPs in mammalian cells revealed that some of these materials show hazard potential. Here, we report the growth inhibitory effects of the same series of MOx NPs in the bacterium Escherichia coli and show that toxicity trends observed in E. coli parallel those seen previously in mammalian cells. Of the 24 materials studied, only ZnO, CuO, CoO, Mn2O3, Co3O4, Ni2O3, and Cr2O3 were found to exert significant growth inhibitory effects; these effects were found to relate to membrane damage and oxidative stress responses in minimal trophic media. A correlation of the toxicological data with physicochemical parameters of MOx NPs revealed that the probability of a MOx NP being toxic increases as the hydration enthalpy becomes less negative and as the conduction band energy approaches those of biological molecules. These observations are consistent with prior results observed in mammalian cells, revealing that mechanisms of toxicity of MOx NPs are consistent across two very different taxa. These results suggest that studying nanotoxicity in E. coli may help to predict toxicity patterns in higher organisms.
authors.forename: Chitrada
authors.initials: C
authors.lastname: Kaweeteerawat
authors.forename: Angela
authors.initials: A
authors.lastname: Ivask
authors.forename: Rong
authors.initials: R
authors.lastname: Liu
authors.forename: Haiyuan
authors.initials: H
authors.lastname: Zhang
authors.forename: Chong Hyun
authors.initials: CH
authors.lastname: Chang
authors.forename: Cecile
authors.initials: C
authors.lastname: Low-Kam
authors.forename: Heidi
authors.initials: H
authors.lastname: Fischer
authors.forename: Zhaoxia
authors.initials: Z
authors.lastname: Ji
authors.forename: Suman
authors.initials: S
authors.lastname: Pokhrel
authors.forename: Yoram
authors.initials: Y
authors.lastname: Cohen
authors.forename: Donatello
authors.initials: D
authors.lastname: Telesca
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Zink
authors.forename: Lutz
authors.initials: L
authors.lastname: Mädler
authors.forename: Patricia A
authors.initials: PA
authors.lastname: Holden
authors.forename: Andre
authors.initials: A
authors.lastname: Nel
authors.forename: Hilary
authors.initials: H
authors.lastname: Godwin
mesh_terms: D000890:Anti-Infective Agents / Q000737:chemistry; D002462:Cell Membrane / Q000187:drug effects; D004926:Escherichia coli / Q000187:drug effects*; D020128:Inhibitory Concentration 50; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000633:toxicity*; D008826:Microbial Sensitivity Tests; D018384:Oxidative Stress / Q000187:drug effects; D010087:Oxides / Q000494:pharmacology; D016016:Proportional Hazards Models; D017382:Reactive Oxygen Species / Q000737:chemistry
chemical_list: D000890:Anti-Infective Agents; D010087:Oxides; D017382:Reactive Oxygen Species