Fluorine-mediated synthesis of anisotropic iron oxide nanostructures for efficient T2-weighted magnetic resonance imaging

Abstract

Herein, we developed a novel strategy for the shape-controlled synthesis of iron oxide nanostructures with superior r₂ values through the introduction of fluoride ions as a morphology controlling agent and dopant. The selective adsorption of fluoride ions onto the specified crystal planes of iron oxide nanocrystals leads to the formation of octapod nanoparticles (ONPs) and cubic nanocrystal clusters (CNCs). Both ONPs and CNCs present high r₂ values (526.5 and 462.2 mM⁻¹ s⁻¹, respectively) due to the synergistic effect of a larger effective radius, clustering and fluorine doping. The in vivo MRI results show significant enhancement in T₂-weighted images of the liver after the intravenous injection of ONPs and CNCs, suggesting their great potential as efficient T₂-weighted MRI contrast agents. This new approach of achieving anisotropic fluorine-doped iron oxide nanostructures with high r₂ relaxivity provides an alternative strategy for the development of highly sensitive T₂ contrast agents for MRI.