Novel platform for the multidimensional analysis of magnetic nanoparticles

The success of Magnetic Particle Imaging (MPI) as a clinical imaging modality is inextricably linked to the availability of purpose-build magnetic nanoparticles (MNP). Attempts to develop MNP with tailored properties and predictable MPI-performance are underway and still of great debate. However, it is well-known that the MPI performance is hampered by the size distribution present in MNP systems. The hyphenation of asymmetric flow field-flow fractionation (AF4) with on-line detectors has proven to provide reliable multidimensional information of MNP size distributions in a quasi-closed system without additional preparation steps. We recently introduced a novel combination of AF4 with a magnetic detector. This detector is based on the same physical principle as MPI, called Magnetic Particle Spectroscopy (MPS), which has already proven a straightforward technique for MNP specific quantification and characterization. In this study we demonstrate that the AF4 multidetector approach, including our MPS detector, is feasible to assist the targeted development of MNP with optimized imaging capabilities in MPI by directly measuring the MNP size as well as the indispensable magnetic functionality. Furthermore, the new platform provides important insights into the physics of MNP and can be used for quality control of MNP in biomedical applications.