Oxygen vacancy-regulated superparamagnetic iron oxide nanoparticles for magnetic particle imaging

Magnetic particle imaging (MPI) is an emerging medical imaging technique with the advantages of high sensitivity, linear quantitation, and no ionizing radiation. In MPI, superparamagnetic iron oxide nanoparticles (SPIOs) serve as the sole signal source, making their properties critical for imaging performance. This study investigates the influence of oxygen vacancies in SPIOs on MPI performance. We synthesized SPIOs with varying degrees of oxygen vacancies and systematically evaluated their MPI performance. The results demonstrate a non-monotonic relationship: MPI signal initially increases and then decreases with increasing oxygen vacancy number. SPIOs with two oxygen vacancies exhibited optimal MPI imaging performance, providing effective evidence for designing high-performance MPI tracers.