HoF3 and DyF3 Nanoparticles as Contrast Agents for High‐Field Magnetic Resonance Imaging. (26th July 2017) - González‐Mancebo, Daniel
Abstract: Clinical contrast agents (CAs) currently used in magnetic resonance imaging (MRI) at low fields are less effective at high magnetic fields. The development of new CAs is mandatory to improve diagnostic capabilities of the new generation of high field MRI scanners. The purpose of this study is to synthesize uniform, water dispersible LnF3 (Ln = Ho, Dy) nanoparticles (NPs) and to evaluate their relaxivity at high magnetic field (9.4 T) as a function of size and composition. Two different types of HoF3 NPs are obtained by homogeneous precipitation in ethylene glycol at 120 °C. The use of holmium acetate as holmium precursor leads to rhombus‐like nanoparticles, while smaller, ellipsoid‐like nanoparticles are obtained when nitrate is used as the holmium salt. To explain this behavior, the mechanism of formation of both kinds of particles is analyzed in detail. Likewise, rhombus‐like DyF3 nanoparticles are prepared following the same method as for the rhombus‐like HoF3 nanoparticles. We have found, to the best of knowledge, the highest transverse relaxivity values at 9.4 T described in the literature for this kind of CAs. Finally, the LnF3 NPs have shown negligible cytotoxicity for C6 rat glioma cells for concentrations up to 0.1 mg mL −1 . Abstract : Rhombus‐ and ellipsoid‐like LnF3 nanoparticles (Ln = Ho, Dy) are obtained by homogeneous precipitation in ethylene glycol at 120 °C from Ln(OAc)3 and Ln(NO3 )3, respectively. Their transversal magnetic relaxivity values 9.4 T are, to the best of knowledge, the highest values described in the literature for magnetic resonance imaging contrast agents.