Fabrication of High Magnetic Susceptibility Nano-FeS₂ via Electronic Reconstruction Induced by Alternating Magnetic Field.

Abstract

Magnetic materials, such as Ferumoxytol and Gd-DTPA, have played an important role in biomedical areas. The relentless pursuit of novel magnetic materials that are clinically applicable is an eternal theme in biomedical engineering. Pyrite (FeS₂) is a mineral drug in China that has been used for a long history. Besides the inherent biocompatibility proved in the human body as well as the donor of H₂S, pyrite also belongs to the family of transition metal dichalcogenides, which endows it with flexible functional tunability of magnetism to be a promising candidate for novel magnetic nanodrug. However, the nano-FeS₂ synthesized by common coprecipitation often shows poor magnetic susceptibility, so its application has greatly been limited. Herein, we reported an innovative strategy to prepare nano-FeS₂ with high magnetic susceptibility (HS-nano-FeS₂) via alternating magnetic field-assisted coprecipitation. AMF treatment effectively regulated electronic reconstruction of Fe²⁺ in nano-FeS₂ without foreign-element doping, and super-exchange interaction is proposed as the dominant factor for the optimized magnetic susceptibility toward a favorable spin-polarized configuration. The HS-nano-FeS₂ is suitable for long-term MR angiography imaging with excellent biosafety. We believe HS-nano-FeS₂ provides a novel magnetic candidate for clinical translation and demonstrates an innovative strategy at the electronic level.