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Auffan M.,Aix - Marseille University | Rose J.,Aix - Marseille University | Proux O.,GDRi ICEINT | Proux O.,French National Center for Scientific Research | And 9 more authors.
Environmental Science and Technology | Year: 2012

This study investigates the issue of nanoparticles/pollutants cocontamination. By combining viability assays, physicochemical and structural analysis (to probe the As speciation and valence), we assessed how γFe2O3 nanoparticles can affect the cytotoxicity, the intra- and extracellular speciation of As(III). Human dermal fibroblasts were contaminated with γFe2O3 nanoparticles and As(III) considering two scenarios: (i) a simultaneous coinjection of the nanoparticles and As, and (ii) an injection of the nanoparticles after 24 h of As adsorption in water. In both scenarios, we did not notice significant changes on the nanoparticles surface charge (zeta potential ∼ -10 mV) nor hydrodynamic diameters (∼950 nm) after 24 h. We demonstrated that the coinjection of γFe2O3 nanoparticles and As in the cellular media strongly affects the complexation of the intracellular As with thiol groups. This significantly increases at low doses the cytotoxicity of the As nonadsorbed at the surface of the nanoparticles. However, once As is adsorbed at the surface the desorption is very weak in the culture medium. This fraction of As strongly adsorbed at the surface is significantly less cytotoxic than As itself. On the basis of our data and the thermodynamics, we demonstrated that any disturbance of the biotransformation mechanisms by the nanoparticles (i.e., surface complexation of thiol groups with the iron atoms) is likely to be responsible for the increase of the As adverse effects at low doses. © 2012 American Chemical Society.

Bottero J.-Y.,Aix - Marseille University | Auffan M.,Aix - Marseille University | Rose J.,Aix - Marseille University | Mouneyrac C.,GDRI ICEINT | And 8 more authors.
Comptes Rendus - Geoscience | Year: 2011

The inorganic manufactured nanoparticles as TiO2, Ag°, the iron oxides and CeO2 are more and more present in various manufactured products and in the aqueous media (TiO2). Their dispersion in the ecosystems during their life cycle will be associated with interactions with biota (plants, bacteria, fishes). The present work shows strong relations between particular physical chemical properties of very small nanoparticles (size<30nm) and biological activity perturbations. It is shown that Ag° and CeO2 act at very low concentrations. TiO2 act via the ROS production due to their photo-reactivity.

Santaella C.,French Atomic Energy Commission | Santaella C.,French National Center for Scientific Research | Santaella C.,Aix - Marseille University | Allainmat B.,French Atomic Energy Commission | And 14 more authors.
Environmental Science and Technology | Year: 2014

TiO2-based nanocomposite (NC) are widely used as invisible UV protectant in cosmetics. These nanomaterials (NMs) end in the environment as altered materials. We have investigated the properties of T-Lite SF, a TiO 2-NC used as sunscreen, after weathering in water and under light. We have examined the formation of ROS and their consequences on cell physiology of Escherichia coli. Our results show that aged-T-Lite SF produced singlet oxygen under low intensity long wave UV and formed hydroxyl radicals at high intensity. Despite the production of these ROS, T-Lite SF had neither effect on the viability of E. coli nor on mutant impaired in oxidative stress, did not induce mutagenesis and did not impair the integrity of membrane lipids, thus seemed safe to bacteria. However, when pre-exposed to T-Lite SF under low intensity UV, cells turned out to be more sensitive to cadmium, a priority pollutant widely disseminated in soil and surface waters. This effect was not a Trojan horse: sensitization of cells was dependent on the formation of singlet oxygen. These results provide a basis for caution, especially on NMs that have no straight environmental toxicity. It is crucial to anticipate indirect and combined effects of environmental pollutants and NMs. © 2014 American Chemical Society.

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