Paramagnetic MgF₂ Nanocrystals for ¹⁹F Magnetic Resonance Imaging

Abstract

MgF 2 -based formulations have unique physicochemical properties, making them attractive for diverse applications. Here, we show the ability to control the morphology of Sm 3+ -doped, paramagnetic MgF 2 nanocrystals (Sm:MgF 2 NCs) for use as nanosized imaging agents for 19 F-magnetic resonance imaging ( 19 F-MRI). By reducing the temperature of the reaction mixture from 160 to 110 °C and shortening the reaction time from 16 to 3 h, the morphology of the fabricated oleate-coated Sm:MgF 2 NCs was transitioned from rod-shaped to spherical-shaped nanofluorides, both with a characteristic high-resolution liquidstate 19 F-NMR resonance at −198 ppm. Further coating the surface of the spheric Sm:MgF 2 NCs with a phospholipid layer resulted in a water-soluble formulation that was used to show its detectability with 19 F-MRI.