Magnetic fractionation and characterization of magnetic nanoparticles for magnetic particle imaging

We performed magnetic fractionation and characterization of Resovist ® magnetic nanoparticles (MNPs) for use in magnetic particle imaging (MPI). We showed that the core size of the fractionated MNPs can be controlled by adjusting the separation field. We also showed that particles with core size of approximately 27 nm are optimal for MPI applications. To obtain MNPs of an appropriate core size and a narrow size distribution, we performed combined positive and negative fractionation. In the obtained fractionated MNPs, the third harmonic magnetization, which is used as the MPI signal, was 2.75 times as large as that of the original sample.