Morphological Evolution and Magnetic Property of Rare‐Earth‐Doped Hematite Nanoparticles: Promising Contrast Agents for T1‐Weighted Magnetic Resonance Imaging

Abstract

A series of uniform rare‐earth‐doped hematite (α‐Fe2O3) nanoparticles are synthesized by a facile hydrothermal strategy. In a typical case of gadolinium (Gd)‐doped α‐Fe2O3, the morphology and chemical composition can be readily tailored by tuning the initial proportion of Gd3+/Fe3+ sources. As a result, the products are observed to be stretched into more elongated shapes with an increasing dopant ratio. As a benefit of such an elongated morphological feature and Gd3+ ions of larger effective magnetic moment than Fe3+, the doped product with the highest ratio of Gd3+ at 5.7% shows abnormal ferromagnetic features with a remnant magnetization of 0.605 emu g−1 and a coercivity value of 430 Oe at 4 K. Density of states calculations also reveal the increase of total magnetic moment induced by Gd3+ dopant in α‐Fe2O3 hosts, as well as possible change of magnetic arrangement. As‐synthesized Gd‐doped α‐Fe2O3 nanoparticles are probed as contrast agents for T1‐weighted magnetic resonance imaging, achieving a remarkable enhancement effect for both in vitro and in vivo tests.

Rare‐Earth Doped Iron Oxide Nanostructures for Cancer Theranostics: Magnetic Hyperthermia and Magnetic Resonance Imaging

“…It is believed that Gd ions have a high spin moment that can accelerate binding with water to shorten the longitudinal spin-lattice relaxation time of protons inside tissues. [35,57,92,206,207] This designed multifunctional RE doped nanoparticles as T 1 -T 2 dual-modal MRI contrast agents can change the signal intensity of the tumor site and improve the accuracy of MRI diagnosis at an early stage of all types of tumors. [208,209] In addition, these multifunctional nanoparticles can provide the difference in the signal intensity under different scanning sequences.…”

“…The white arrows refer to tumors injected with α-Fe 2 O 3 dispersions while the grey arrows stand for blank experiments. [206] Reproduced with permission. [57] Copyright 2016, Royal Society of Chemistry; Reproduced with permission.…”

Magnetic Properties and SAR for Gadolinium-Doped Iron Oxide Nanoparticles Prepared by Hydrothermal Method

“…The bars representing the two magnetic phases, maghemite and hematite, are patterned. The saturation magnetization of bulk maghemite is 60 emu/g [35], whereas hematite is weakly ferromagnetic at room temperature [64]. Taking into account the lowering in magnetization that occurs due to the evolution of a dead magnetic layer on the surface of the particles at the nanoscale [65], it is observed that the magnetization is consistent with the crystal structure of the samples.…”

Structural, Dielectric and Magnetic properties of Yttrium doped Hematite Nanoparticle

“…Mathevula et al [19] have shown the enhancement in optical properties with doping of Holmium (Ho). Wan et al [20] also reported the enhancement in magnetic properties with the incorporation of Gd +3 ions in -Fe2O3.Bhat et al [21] study the synthesis and optical studies of α-Fe2O3 and erbium (Er 3+ ) ion-doped α-Fe2O3 nanoparticles (NPs) and confirms the hexagonal (rhombohedral) crystal structure, with no additional phase formation.…”