Présentation de Emilie Nehlig

Surface Engineering of Iron Oxide Nanoparticles with Redox Ligands: Toward New Functionalities E.

E.Nehlig1, V.Dupuis1, H.Vezin2, S.Neveu1, A-L.Rollet1, L.Fensterbank3, M.Desage-El Murr4, A. Abou-Hassan1
1
Sorbonne Universités, PHENIX, CIN, UMR 8234, 2 Université de Lille, LASIR, UMR 8516, 3 Sorbonne Universités, IPCM, MACO, UMR 8232, 4 Université de Strasbourg, Institut de Chimie de Strasbourg, OMECA, UMR 7177

Magnetite nanoparticles (NPs) in their oxidized form maghemite are largely used in biomedical applications such as theranostics. One of their limitations in magnetic hyperthermia (MHT) is the low heating yield/mg[1]. We propose to overcome this by combining MHT with photothermia (PT) by using the optical properties of magnetite instead of building nanohybrids[2, 3]. Magnetite is a conducting mixed valence iron oxide has an inverse spinel structure with both Fe (II) and Fe (III) in octahedral sites of the crystal[4]. This distribution of mixed oxidation states at the surface was found to produce and intervalence d-d charge transfer that gives rise to absorption in the second near infrared region (1000-1350 nm)[5]. However, aerobic oxidation of Fe (II) ions in Fe (III) at the surface of magnetite, induces disappearance in the charge transfer band, and loss of photothermal applications[5]. The PT properties could be maintained by stabilization of the plasmonic NIR intervalence charge transfer band of magnetite. Bioinspired by nature, redox non-innocent ligand (NILs) are molecular scaffolds bearing extended conjugation and have been shown to delocalize spin density when complex to a metal[6]. Herein we propose to use these redox ligands as a multiplatform for surface engineering of magnetite nanoparticles in order to prevent their surface oxidation, to investigate possible ligand-induced surface effect, as anchors for targeting and theranostics, and to bring new magnetic properties modulated by the ligands.

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