Non-superparamagnetic iron-oxide architectures with controlled T2 contrast ability in magnetic resonance imaging

In this work, numerous antiferromagnetic (AFM) and weak ferromagnetic (WFM) iron oxides were fabricated and used as contrast agents in magnetic resonance imaging application. These non-superparamagnetic iron oxides exhibit r2/r1 ratios in a range of 20–110, and hence making them potential for T2 contrast enhancers. Most strikingly, a Langevin-function relationship was found between r2/r1 ratios and the specific surface area (S) values, r2/r1 ∼ L−2(S−1), which is quite unique for AFM and WFM iron oxides. This finding enables us to precisely tailor their r2/r1 ratios simply by manipulating their specific surface area via controlling morphology and structure in preparation.