Shape-optimized soft-hard tandem tracers for enhanced magnetic particle imaging

Abstract

Magnetic Particle Imaging (MPI) is a leading molecular imaging technique with unmatched potential for disease diagnosis, offering high contrast and sensitivity without radiation. However, current MPI tracers, such as Vivo Trax and Resovist, have a detection threshold of 100 ?M, far from the theoretical 20 nM limit. To address this, we propose a Soft-Strength Tandem (SST) magnetic control strategy using octahedral-IONPs (O-IONPs) to enhance MPI performance. Our O-IONPs reduce surface spin disorder, increasing saturation magnetization (M_s), and their shape influences coercivity (H_c), addressing the balance between these properties. The octahedral shape promotes crystallization behavior that impacts atomic magnetic moments and surface magnetic anisotropy (K_s), essential for H_c. Our tracers achieve comparable imaging to Vivo Trax at significantly lower doses, setting a new paradigm for shape-mediated MPI tracers and unlocking MPI's full diagnostic potential.