Highly magnetic iron carbide nanoparticles as effective T2 contrast agents

Abstract

This paper reports that iron carbide nanoparticles with high air-stability and strong saturation magnetization can serve as effective T₂ contrast agents for magnetic resonance imaging. Fe₅C₂ nanoparticles (∼20 nm in diameter) exhibit strong contrast enhancement with an r₂ value of 283.2 mM⁻¹ S⁻¹, which is about twice as high as that of spherical Fe₃O₄ nanoparticles (∼140.9 mM⁻¹ S⁻¹). In vivo experiments demonstrate that Fe₅C₂ nanoparticles are able to produce much more significant MRI contrast enhancement than conventional Fe₃O₄ nanoparticles in living subjects, which holds great promise in biomedical applications.