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Leclerc L.,Laboratoire Interdisciplinaire dEtude des Nanoparticules Aerosolisees | Leclerc L.,Ecole Nationale Superieure des Mines de Saint - Etienne CMP | Rima W.,INSA Lyon | Boudard D.,Laboratoire Interdisciplinaire dEtude des Nanoparticules Aerosolisees | And 17 more authors.
Inhalation Toxicology | Year: 2012

Background: Micrometric and nanometric particles are increasingly used in different fields and may exhibit variable toxicity levels depending on their physicochemical characteristics. The aim of this study was to determine the impact of the size parameter on cellular uptake and biological activity, working with well-characterized fluorescent particles. We focused our attention on macrophages, the main target cells of the respiratory system responsible for the phagocytosis of the particles. Methods: FITC fluorescent silica particles of variable submicronic sizes (850, 500, 250 and 150nm) but with similar surface coating (COOH) were tailored and physico-chemically characterized. These particles were then incubated with the RAW 264.7 macrophage cell line. After microscopic observations (SEM, TEM, confocal), a quantitative evaluation of the uptake was carried out. Fluorescence detected after a quenching with trypan blue allows us to distinguish and quantify entirely engulfed fluorescent particles from those just adhering to the cell membrane. Finally, these data were compared to the in vitro toxicity assessed in terms of cell damage, inflammation and oxidative stress (evaluated by LDH release, TNF-α and ROS production respectively). Results and conclusion: Particles were well characterized (fluorescence, size distribution, zeta potential, agglomeration and surface groups) and easily visualized after cellular uptake using confocal and electron microscopy. The number of internalized particles was precisely evaluated. Size was found to be an important parameter regarding particles uptake and in vitro toxicity but this latter strongly depends on the particles doses employed. © 2012 Informa Healthcare USA, Inc.

Forest V.,Laboratoire Interdisciplinaire dEtude des Nanoparticules Aerosolisees | Forest V.,Ecole Nationale Superieure des Mines de Saint - Etienne CMP | Pailleux M.,Laboratoire Interdisciplinaire dEtude des Nanoparticules Aerosolisees | Pailleux M.,Ecole Nationale Superieure des Mines de Saint - Etienne CMP | And 11 more authors.
Inhalation Toxicology | Year: 2014

Boehmite (γ-AlOOH) nanoparticles (NPs) are used in a wide range of industrial applications. However, little is known about their potential toxicity. This study aimed at a better understanding of the relationship between the physico-chemical properties of these NPs and their in vitro biological activity. After an extensive physico-chemical characterization, the cytotoxicity, pro-inflammatory response and oxidative stress induced by a bulk industrial powder and its ultrafine fraction were assessed using RAW264.7 macrophages. Although the bulk powder did not trigger a significant biological activity, pro-inflammatory response was highly enhanced with the ultrafine fraction. This observation was confirmed with boehmite NPs synthesized at the laboratory scale, with well-defined and tightly controlled physico-chemical features: toxicity was increased when NPs were dispersed. In conclusion, the agglomerates size of boehmite NPs has a major impact on their toxicity, highlighting the need to study not only raw industrial powders containing NPs but also the ultrafine fractions representative of respirable particles. © 2014 Informa Healthcare USA, Inc. All rights reserved: reproduction in whole or part not permitted.

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