title: Cytotoxicity of CeO2 nanoparticles for Escherichia coli. Physico-chemical insight of the cytotoxicity mechanism.
abstract: The production of nanoparticles (NPs) is increasing rapidly for applications in electronics, chemistry, and biology. This interest is due to the very small size of NPs which provides them with many interesting properties such as rapid diffusion, high specific surface areas, reactivity in liquid or gas phase, and a size close to biomacromolecules. In turn, these extreme abilities might be a problem when considering a potentially uncontrolled exposure to the environment. For instance, nanoparticles might be highly mobile and rapidly transported in the environment or inside the body through a water or air pathway. Accordingly, the very fast development of these new synthetic nanomaterials raises questions about their impact on the environment and human health. We have studied the impact of a model water dispersion of nanoparticles (7 nm CeO2 oxide) on a Gram-negative bacteria (Escherichia coli). The nanoparticles are positively charged at neutral pH and thus display a strong electrostatic attraction toward bacterial outer membranes. The counting of colony forming units (CFU) after direct contact with CeO2 NPs allows for the defining of the conditions for which the contact is lethal to Escherichia coli. Furthermore, a set of experiments including sorption isotherms, TEM microscopy, and X-ray absorption spectroscopy (XAS) at cerium L3 edge is linked to propose a scenario for the observed toxic contact.
authors.affiliation: CEA Saclay, Direction des Sciences de la Matiere, Departement de Recherche sur l'Etat Condense les Atomes et les Molecules, Laboratoire Interdisciplinaire sur l'Organisation Nanometrique et Supramoleculaire, Gif-sur-Yvette, France. antoine.thill@cea.fr
authors.forename: Antoine
authors.initials: A
authors.lastname: Thill
authors.forename: Ophélie
authors.initials: O
authors.lastname: Zeyons
authors.forename: Olivier
authors.initials: O
authors.lastname: Spalla
authors.forename: Franck
authors.initials: F
authors.lastname: Chauvat
authors.forename: Jerôme
authors.initials: J
authors.lastname: Rose
authors.forename: Mélanie
authors.initials: M
authors.lastname: Auffan
authors.forename: Anne Marie
authors.initials: AM
authors.lastname: Flank
mesh_terms: D000327:Adsorption; D002563:Cerium / Q000633:toxicity*; D015169:Colony Count, Microbial; D004926:Escherichia coli / Q000737:chemistry / Q000187:drug effects*; D053758:Nanoparticles / Q000633:toxicity*
chemical_list: D002563:Cerium; C030583:ceric oxide