Multicomponent magnetic spinels: From complexity of crystal chemistry to coupled magnetic resonance imaging (MRI)

Spinels have a rich history that spans complexities of their structures to multitude of useful properties and intriguing phenomena. Herein, we demonstrate the versatility and elegance of ferrite-spinel based magnetic nanostructures (MNSs) as a contrast agent in magnetic resonance imaging (MRI). We show that the magnetic properties of the inverse spinel Fe3O4 MNS can be enhanced by tuning their crystal chemistry. After doping with Mn2+ and Zn2+ into Fe3O4 MNS at a right stoichiometry, high saturation magnetization and magnetic anisotropy were observed due to rearrangement and specific positions of Mn2+, Zn2+, Fe2+, and Fe3+ cations in the inverse spinel AB2O4 crystal lattice. The improved magnetic properties were leveraged to develop T-1-weighted MRI contrast agent that are more biocompatible and efficient than currently used Gd-based complexes. This work underscores the rich opportunities in magnetic spinels for not only unusual applications as in MRI contrast enhancement but also the complexity and versatility of its crystal chemistry that forms the basis for its diverse properties. (c) 2023 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).

Automated summary

This study demonstrates the versatility and elegance of ferrite-spinel based magnetic nanostructures (MNSs) as a contrast agent in MRI. By tuning their crystal chemistry, the magnetic properties of Fe3O4 MNS can be enhanced. Doping with Mn2+ and Zn2+ at the right stoichiometry resulted in high saturation magnetization and magnetic anisotropy, which were leveraged to develop more biocompatible and efficient T-1-weighted MRI contrast agents compared to Gd-based complexes.