Magnetic microspheres for MPI and magnetic actuation

Magnetic particle imaging (MPI) systems do not only allow for the visualization of the distribution of magnetic nanoparticles, but the magnetic fields of an MPI scanner can be also used to apply a magnetic force or a torque. This enables the actuation of magnetic particles. Here, we demonstrate that magnetic microspheres (MMS) are well suitable candidates for the actuation and visualization with MPI. By means of magnetic particle spectrometer (MPS) measurements, a promising imaging performance of the MMS for MPI was confirmed. We show that MMS can be actuated by rotating focus fields of a preclinical MPI scanner. Since the used MMS can carry therapeutics, which can be released by means of hyperthermia, this approach paves the way towards an MPI monitored targeted drug delivery.