title: Relation between the redox state of iron-based nanoparticles and their cytotoxicity toward Escherichia coli.
abstract: Iron-based nanoparticles have been proposed for an increasing number of biomedical or environmental applications although in vitro toxicity has been observed. The aim of this study was to understand the relationship between the redox state of iron-based nanoparticles and their cytotoxicity toward a Gram-negative bacterium, Escherichia coli. While chemically stable nanoparticles (gammaFe2O3) have no apparent cytotoxicity, nanoparticles containing ferrous and, particularly, zerovalent iron are cytotoxic. The cytotoxic effects appear to be associated principally with an oxidative stress as demonstrated using a mutant strain of E. coli completely devoid of superoxide dismutase activity. This stress can result from the generation of reactive oxygen species with the interplay of oxygen with reduced iron species (Fe(II) and/or Fe(0)) or from the disturbance of the electronic and/or ionic transport chains due to the strong affinity of the nanoparticles for the cell membrane.
authors.affiliation: CEREGE UMR 6635 CNRS/Aix-Marseille Université, Europôle de l'Arbois, 13545 Aix-en-Provence, France. auffan@cerege.fr
authors.forename: Mélanie
authors.initials: M
authors.lastname: Auffan
authors.forename: Wafa
authors.initials: W
authors.lastname: Achouak
authors.forename: Jérôme
authors.initials: J
authors.lastname: Rose
authors.forename: Marie-Anne
authors.initials: MA
authors.lastname: Roncato
authors.forename: Corinne
authors.initials: C
authors.lastname: Chanéac
authors.forename: David T
authors.initials: DT
authors.lastname: Waite
authors.forename: Armand
authors.initials: A
authors.lastname: Masion
authors.forename: Joseph C
authors.initials: JC
authors.lastname: Woicik
authors.forename: Mark R
authors.initials: MR
authors.lastname: Wiesner
authors.forename: Jean-Yves
authors.initials: JY
authors.lastname: Bottero
mesh_terms: D004926:Escherichia coli / Q000187:drug effects*; D007501:Iron / Q000737:chemistry*; D053768:Metal Nanoparticles; D046529:Microscopy, Electron, Transmission; D010084:Oxidation-Reduction; D013057:Spectrum Analysis / Q000379:methods; D014961:X-Ray Diffraction
chemical_list: D007501:Iron