Intracellular degradation of functionalized carbon nanotube/iron oxide hybrids is modulated by iron via Nrf2 pathway.

The in vivo fate and biodegradability of carbon nanotubes is still a matter of debate despite tremendous applications. In this paper we describe a molecular pathway by which macrophages degrade functionalized multi-walled carbon nanotubes (CNTs) designed for biomedical applications and containing, or not, iron oxide nanoparticles in their inner cavity. Electron microscopy and Raman spectroscopy show that intracellularly-induced structural damages appear more rapidly for iron-free CNTs in comparison to iron-loaded ones, suggesting a role of iron in the degradation mechanism. By comparing the molecular responses of macrophages derived from THP1 monocytes to both types of CNTs, we highlight a molecular mechanism regulated by Nrf2/Bach1 signaling pathways to induce CNT degradation via NOXjournal article2017 Jan 252017 01 25importe

Les nanomatériaux : une caractérisation difficile ...

The field of nanomaterials is of widespread interest since the beginning of the nineties. We describe several methods of synthesis of nanophased materials and of nanostructured materials. The problems related to the characterization of nanosized particles and to the influence of the synthesis method on their properties are illustrated first from a comparison of nanometric titanoferrites synthesized by two different methods, then by a phase transformation from face-centered cubic to hexagonal which takes place in Ni at a nanometer crystallite size and finally by the Rietveld analysis of phases found in TiO$_2$ powders ground for short times.Depuis le début des années 90, les recherches sur les nanomatériaux ont connu un essor considérable. Nous décrivons ici différentes méthodes de synthèse de nanoparticules et de matériaux nanostructurés. Les problèmes liés à la caractérisation des particules nanométriques et à l'influence de la méthode de synthèse sur les propriétés sont illustrés par la comparaison de ferrites de titane nanométriques élaborés par deux méthodes différentes, par l'étude d'une transition Ni hexagonal - Ni cubique faces centrées liée à la taille et par la quantification par la méthode de Rietveld des phases présentes dans des poudres de TiO$_2$ broyées

Towards nanoprinting with metals on graphene

International audienc

Influence of the crystallite size on the phase transformation of yttria irradiated with swift heavy ions

The irradiation effects induced by swift heavy ions are now widely described in `bulk' materials. It is shown here that the behaviour of matter under irradiation depends on its crystalline state in the sense that a given material is all the more sensitive to swift heavy ion irradiations as the mean crystallite size L is small. The present paper relates the experimental results obtained in yttrium oxide from `in situ' X-ray diffraction measurements. Three kinds of sample have been irradiated: sintered samples ($L = 1 \mu$m), non-ground powders (L = 45 nm) and ground powders (L = 28 nm). A cubic to monoclinic phase transformation appears if the electronic energy loss of the incident particle is higher than a threshold. The comparison between the different kinds of samples reveals that this phase transformation is all the easier as the mean crystallite size of the target is weak

Mécanosynthèse de composés et de composites nanocristallins

La mécanosynthèse d'alliages Fe-Ni et Cr-Sn, du carbure Fe7C3 , de nanocomposites alumine-métal et d'oxydes est décrite. Les hétérogénéités des poudres en cours de broyage, les défauts des nanomatériaux ainsi élaborés, les propriétés magnétiques de solutions solides Cr-Sn, les mécanismes de synthèse des nanocomposites sont caractérisés par spectrométrie Mössbauer. L'influence de la nature des matériaux de broyage est mise en évidence dans le cas des oxydes.Mechanical alloying of alloys like Fe-Ni, Cr-Sn, of Fe7C3 carbide, synthesis of alumina-metal nanocomposites by reactive milling and grinding of oxydes is described. Heterogeneities of powders during grinding, defects of synthesized nanomaterials, magnetic properties of Cr-Sn solid solutions, mechanisms of synthesis of nanocomposites are haracterized by Mössbauer spectroscopy. The influence of the materials constituting the grinding media is displayed in the case of oxides

Functionalization strategies and dendronization of iron oxide nanoparticles

International audienceThe explosive growth of nanotechnology has brought challenging innovations in the synthesis of multifunctional nano-objects able to revolutionize the field of diagnosis and therapy in medicine. Furthermore, one important input of today's nanotechnology in biology is that their design will also allow real progress to achieve temporal and spatial site local therapy and imaging. Such a breakthrough is made possible by the development of multifunctional biocompatible nanosystems resulting from cutting-edge researches based on pluridisciplinary approaches. Among the challenges are the design of the organic coating and its grafting at the surface of NPs while preserving the properties of both NPs and molecules. The molecules should ensure the colloidal stability of NPs in physiological media, their biocompatibility and biodistribution, and may bear functions to couple bioactive groups. This paper aims at providing challenges in functionalization of iron oxide nanoparticles for biomedical applications. © 2015 by De Gruyter 2015