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Reims, France

Oudadesse H.,CNRS Chemistry Institute of Rennes | Wers E.,CNRS Chemistry Institute of Rennes | Bui X.V.,CNRS Chemistry Institute of Rennes | Roiland C.,CNRS Chemistry Institute of Rennes | And 9 more authors.
Korean Journal of Chemical Engineering | Year: 2013

Bioactive glass 46S6 and biodegradable therapeutic polymer (Chitosan: CH) have been elaborated to form 46S6-CH composite by freeze-drying process. The kinetics of chemical reactivity and bioactivity at the surface were investigated by using physicochemical techniques, particularly solid-state MAS-NMR. Immortalized cell line used to construct multicellular spheroids was employed as three-dimensional (3D) cell cultures for in vitro studies. Obtained results showed a novel structure of the composite; the chemical treatment (ultrasound, magnetic stirring, freeze drying process and lyophilization) led the bioactive glass particles to be loaded in the chitosan-based materials. 29Si and 31P MAS-NMR results showed the emergence of two new species, QSi 3(OH) and QSi 4, which are characteristic of the vitreous network dissolution in simulated body fluid (SBF). MAS-NMR also confirmed the formation of amorphous calcium phosphate (ACP) at the surface of the initial 46S6-CH. Three-dimensional (3D) cell cultures highlighted the effect of chitosan, where the cell viability reached up to 78% in 46S6-CH composite and up to 67% in 46S6. The association of (CH) and bioactive glass (BG) matrix promotes a highly significant bioactivity, demonstrating surface bone formation and satisfactory behavior in biological environment. © 2013 Korean Institute of Chemical Engineers, Seoul, Korea.

Faure J.,LISM URCA | Drevet R.,LISM URCA | Potiron S.,LISM URCA | Gordin D.M.,INSA Rennes | And 3 more authors.
Key Engineering Materials | Year: 2012

Titanium alloys used in orthopedic surgery are usually coated with hydroxyapatite to improve their biocompatibility and osseointegration. Bioactive glasses (BGs) are an interesting alternative to hydroxyapatite for the production of prosthetic coatings due to their osteoproductive property (Class A bioactivity) and to their resorbability. However the classical techniques used to obtain prosthetic coatings are not suitable in the case of BGs. In this study bioactive glass coatings are obtained by electrophoretic deposition on a Ti12Mo5Ta alloy. These coatings were obtained from ethanol suspensions of two different bioglass powders: a Sol-Gel derived 58S and a Melting- Quenching derived 46S. Scanning electron microscopy observations were used to characterize the coatings (morphology and thickness) and the coating/substrate interfaces. The chemical composition of the coatings was studied by X-ray microanalysis and X-ray maps were performed to characterize the spatial distributions of all elements composing the coatings. © (2012) Trans Tech Publications, Switzerland.

Pi Y.,LISM URCA | Agoda-Tandjawa G.,LISM URCA | Potiron S.,LISM URCA | Demangel C.,CRITT MDTS | And 2 more authors.
Journal of Nanoscience and Nanotechnology | Year: 2012

In this study, microstructural and mechanical properties of Ti-6Al-4V alloy, before and after the SMA treatment (SMAT) as well as the duplex SMAT/Nitriding process at different treatment conditions, were investigated in order to deepen the knowledge of these properties for biomedical devices. For that purpose, tribological (wear resistance, coefficient of friction) and mechanical (Vickers microhardness) tests were performed. To carry out the microstructural and surface topographical characterization of the samples, the scanning electron microscopy (SEM) and the 3D-SEM reconstruction from stereoscopic images have been used. By means of profiles deduced from the 3D images, the surface roughness has been calculated. The obtained results allowed to find an interesting SMAT condition which, followed by nitriding at low temperature, can greatly improve tribological and mechanical properties of Ti-6Al-4V alloy. It was also shown from SEM characterization and the original method of 3D-SEM reconstruction, that SMAT can reduce the machined grooves and consequently the roughness of the samples decreases. Moreover, we demonstrated, for the first time, that instead of usual etching method, the ionic polishing allowed to reveal the grains, the grain boundaries and the twins as well as the surface nanocrystalline layer generated by SMAT. Thus, the thickness of the SMATed layer decreases with the nitriding temperature, whereas the surface grain size increases. Copyright © 2012 American Scientific Publishers All rights reserved.

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