Time filter

Source Type

Saint-Étienne, France

Kurtz-Chalot A.,Lina Laboratoire Interdisciplinaire Detude Des Nanoparticules Aerosolisees Ea 4624 | Kurtz-Chalot A.,Ecole Nationale Superieure des Mines de Saint - Etienne CMP | Klein J.P.,Lina Laboratoire Interdisciplinaire Detude Des Nanoparticules Aerosolisees Ea 4624 | Klein J.P.,Jean Monnet University | And 12 more authors.
Journal of Nanoparticle Research | Year: 2014

Silica nanoparticles are particularly interesting for medical applications because of the high inertness and chemical stability of silica material. However, at the nanoscale their innocuousness must be carefully verified before clinical use. The aim of this study was to investigate the in vitro biological toxicity of silica nanoparticles depending on their surface chemical functionalization. To that purpose, three kinds of 50 nm fluorescent silica-based nanoparticles were synthesized: (1) sterically stabilized silica nanoparticles coated with neutral polyethylene glycol molecules, (2) positively charged silica nanoparticles coated with amine groups, and (3) negatively charged silica nanoparticles coated with carboxylic acid groups. RAW 264.7 murine macrophages were incubated for 20 h with each kind of nanoparticles. Their cellular uptake and adsorption at the cell membrane were assessed by a fluorimetric assay, and cellular responses were evaluated in terms of cytotoxicity, pro-inflammatory factor production, and oxidative stress. Results showed that the highly positively charged nanoparticle were the most adsorbed at cell surface and triggered more cytotoxicity than other nanoparticle types. To conclude, this study clearly demonstrated that silica nanoparticles surface functionalization represents a key parameter in their cellular uptake and biological toxicity. © 2014, Springer Science+Business Media Dordrecht.

Pourchez J.,Ecole Nationale Superieure des Mines de Saint - Etienne CMP | Forest V.,Ecole Nationale Superieure des Mines de Saint - Etienne CMP | Boumahdi N.,SFR IFRESIS | Boumahdi N.,Ecole Nationale Superieure des Mines de Saint - Etienne CMP | And 11 more authors.
Journal of Nanoparticle Research | Year: 2012

Silicon carbide is an extremely hard, wear resistant, and thermally stable material with particular photoluminescence and interesting biocompatibility properties. For this reason, it is largely employed for industrial applications such as ceramics. More recently, nano-sized SiC particles were expected to enlarge their use in several fields such as composite supports, power electronics, biomaterials, etc. However, their large-scaled development is restricted by the potential toxicity of nanoparticles related to their manipulation and inhalation. This study aimed at synthesizing (by laser pyrolysis or sol-gel methods), characterizing physico-chemical properties of six samples of SiC nanopowders, then determining their in vitro biological impact(s). Using a macrophage cell line, toxicity was assessed in terms of cell membrane damage (LDH release), inflammatory effect (TNF-α production), and oxidative stress (reactive oxygen species generation). None of the six samples showed cytotoxicity while remarkable pro-oxidative reactions and inflammatory response were recorded, whose intensity appears related to the physico-chemical features of nano-sized SiC particles. In vitro data clearly showed an impact of the extent of nanoparticle surface area and the nature of crystalline phases (α-SiC vs. β-SiC) on the TNF-α production, a role of surface iron on free radical release, and of the oxidation state of the surface on cellular H 2O 2 production. © Springer Science+Business Media B.V. 2012.

Boudard D.,Jean Monnet University | Forest V.,SFR IFRESIS | Forest V.,Ecole Nationale Superieure des Mines de Saint - Etienne CMP | Pourchez J.,SFR IFRESIS | And 10 more authors.
Toxicology in Vitro | Year: 2014

Silicon carbide (SiC) an industrial-scale product manufactured through the Acheson process, is largely employed in various applications. Its toxicity has been poorly investigated. Our study aims at characterizing the physico-chemical features and the in vitro impact on biological activity of five manufactured SiC powders: two coarse powders (SiC C1/C2), two fine powders (SiC F1/F2) and a powder rich in iron impurities (SiC I). RAW 264.7 macrophages were exposed to the different SiC particles and the cellular responses were evaluated. Contrary to what happens with silica, no SiC cytotoxicity was observed but pro-oxidative and pro-inflammatory responses of variable intensity were evidenced. Oxidative stress (H2O2 production) appeared related to SiC particle size, while iron level regulated pro-inflammatory response (TNFα production). To investigate the impact of surface reactivity on the biological responses, coarse SiC C1 and fine SiC F1 powders were submitted to different thermal treatments (650-1400°C) in order to alter the oxidation state of the particle surface. At 1400°C a decrease in TNFα production and an increase in HO, COO- radicals production were observed in correlation with the formation of a surface layer of crystalline silica. Finally, a strong correlation was observed between surface oxidation state and in vitro toxicity. © 2014 Elsevier Ltd.

Douard N.,Ecole Nationale Superieure des Mines de Saint - Etienne CMP | Leclerc L.,SFR IFRESIS | Leclerc L.,Ecole Nationale Superieure des Mines de Saint - Etienne CMP | Leclerc L.,Jean Monnet University | And 12 more authors.
Biomedical Microdevices | Year: 2016

To improve the biological properties of calcium phosphate (CaP) bone substitute, new chemical compositions are under development. In vivo such materials are subject to degradation that could lead to particles release and inflammatory reactions detrimental to the bone healing process. This study aimed at investigating the interactions between a murine macrophage cell line (RAW 264.7) and substituted hydroxyapatite particles presenting promising biological properties. Micron size particles of stoichiometric and substituted hydroxyapatites (CO3 substitution for PO4 and OH; SiO4 substitution for PO4; CO3 and SiO4 co-substitution) were obtained by aqueous precipitation followed by spray drying. Cells, incubated with four doses of particles ranging from 15 to 120 μg/mL, revealed no significant LDH release or ROS production, indicating no apparent cytotoxicity and no oxidative stress. TNF-α production was independent of the chemistry of the particles; however the particles elicited a significant dose-dependent pro-inflammatory response. As micron size particles of these hydroxyapatites could be at the origin of inflammation, attention must be paid to the degradation behavior of substituted hydroxyapatite bone substitute in order to limit, in vivo, the generation of particulate debris. © 2016, Springer Science+Business Media New York.

Discover hidden collaborations