Facile synthesis of zinc ferrite nanoparticles as non-lanthanide T1 MRI contrast agents

Abstract

Monodisperse ZnFe₂O₄ nanoparticles were synthesized using a simple and low-cost polyol process based on thermal decomposition of the precursors of Fe(acac)₃ and Zn(acac)₂ in triethylene glycol without any surfactant. The as-prepared ZnFe₂O₄ nanoparticles are highly crystalline, uniform in size, superparamagnetic and can be easily dispersed in aqueous media due to being coated by a layer of hydrophilic polyol ligands in situ. Magnetic study shown that the ZnFe₂O₄ nanoparticles had a low magnetic anisotropy and low magnetic moment compared to the conventional Fe₃O₄ nanoparticles. As a result, the as-prepared ZnFe₂O₄ nanoparticles provide an optimized r₂/r₁ ratio for T₁-weighted magnetic resonance imaging (MRI) in the clinical field strength. A preliminary in vitro cytotoxicity test suggests that the zinc ferrite nanoparticles possess a good safety profile. Therefore, the as-prepared ZnFe₂O₄ nanoparticles have great potential to serve as a novel non-lanthanide T₁ MRI contrast agent.