Irregularly Shaped {\gamma}'-Fe4N Nanoparticles for Hyperthermia Treatment and T2 Contrast-Enhanced Magnetic Resonance Imaging with Minimum Dose

TL;DR

This paper presents irregularly shaped {b3}'-Fe4N nanoparticles with high magnetic moments, demonstrating their potential as effective hyperthermia agents and T2 MRI contrast agents at minimal doses, with enhanced magnetic properties over {b3}-Fe2O3.

Contribution

The study introduces {b3}'-Fe4N nanoparticles with superior magnetic properties and surface modifications for improved hyperthermia and MRI contrast applications, which is a novel approach.

Findings

{b3}'-Fe4N nanoparticles have 3 times higher saturation magnetization than {b3}-Fe2O3.

Surface modification enables their use as minimal-dose hyperthermia and MRI contrast agents.

Irregular shape and chemical tuning enhance magnetic response and biocompatibility.

Abstract

Magnetic nanoparticles (MNPs) have been extensively used in drug/gene delivery, hyperthermia therapy, magnetic particle imaging (MPI), magnetic resonance imaging (MRI), magnetic bioassays, etc. With proper surface chemical modifications, physicochemically stable and non-toxic MNPs are emerging contrast agents and tracers for in vivo MRI and MPI applications. Herein, we report the high magnetic moment, irregularly shaped {\gamma}'-Fe4N nanoparticles for enhanced hyperthermia therapy and T2 contrast agent for MRI application. The static and dynamic magnetic properties of {\gamma}'-Fe4N nanoparticles are characterized by vibrating sample magnetometer (VSM) and magnetic particle spectroscopy (MPS) systems, respectively. Compared to the {\gamma}-Fe2O3 nanoparticles, {\gamma}'-Fe4N show at least 3 times higher saturation magnetization (in emu/g), which, as a result, gives rise to the stronger dynamic magnetic responses as proved in the MPS measurement results. In addition, {\gamma}'-Fe4N nanoparticles are functionalized with oleic acid layer by a wet mechanical milling process, the morphologies of as-milled nanoparticles are characterized by transmission electron microscopy (TEM), dynamic light scattering (DLS) and nanoparticle tracking analyzer (NTA). We report that with proper surface chemical modification and tuning on morphologies, {\gamma}'-Fe4N nanoparticles could be used as tiny heating sources for hyperthermia and contrast agents for MRI applications with minimum dose.