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Séminaire 13.11.2012 à 14h00

par Benjamin Rotenberg - 10 octobre 2012

S. Bégin-Colin, de l’Institut de Physique et Chimie des Matériaux (Strasbourg), présentera un séminaire le 13 novembre 2012 à 14h00 dans la salle F 629 (6e étage, bâtiment F) intitulé :

Synthesis and functionalisation of iron oxide nanoparticles for spintronic and biomedical applications


The synthesis and functionalisation of nanoparticles (NPs) is a way to develop hybrid nanomaterials with new properties. Functionalized iron oxides nanoparticles are intensively studied for biomedical applications and are also considered as the building blocks of the future nanotechnological devices. Superparamagnetic iron oxide NPs with appropriate surface coating are widely used for numerous in vivo applications and in particular for MRI contrast enhancement. Most studies are performed for improving the materials biocompatibility and ensuring multifunctionalization (targeting, imaging…), but only a few investigations have been carried out improving the quality of the magnetic NPs, their size distribution and studying the effect of their functionalization on their structural and magnetic properties. Indeed particle size, surface chemical structures and the nature of interactions of the organic coating with the NPs surface appear as critical parameters determining the opsonization, biokinetics and biodistribution of magnetic NPs. Therefore, the design of the coating and the nature of the interaction of the coating with the NPs surface are more and more key points to address. In this context, we develop a novel strategy based on the grafting, at the surface of NPs, of small-sized dendritic molecules (favoring the suspensions stability by steric hindrance and constituting a platform for the grafting of functional molecules) via a phosphonate coupling agent (allowing a direct grafting and a stronger binding) in order to develop small nano-objects for multimodal imaging.

In the field of spintronic and for magnetic applications, the development of strategies for processing NPs into thin films or into 3D architectures has become a strategic challenge. Multidimensional assembly of magnetic NPs may be used to elaborate many original and significant magnetic and electronic devices. Monodisperse spherically- and cubic-shaped Fe3-xO4 NPs in the range 8-20 nm have been synthesized by thermal decomposition of an iron complex by adjusting synthesis parameters and reactants. Among the different assembling techniques, the Langmuir-Blodgett and the Layer by Layer techniques and the deposition on well-addressed substrates have been investigated. The parameters leading to uniform arrays with a high density and degree of order have been determined for all methods. Then the dipolar interactions in such 2D and 3D arrays have been studied by comparing DC and AC SQUID measurements on powdered NPs, 2D and 3D organized NPs and on diluted NPs. The magneto-transport properties of these NPs have been studied on LB multilayer deposited between two electrodes.

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