Magnetic Particle Fractionation and In-line Characterization for Enhancing Magnetic Particle Imaging Tracers

Refining the size distribution of magnetic nanoparticles (MNPs) holds great potential for enhanced performance in magnetic particle imaging (MPI). This work demonstrates the coupling of a preparative-scale magnetic fieldcontrolled
size fractionation technique with in-line magnetic particle spectroscopy (MPS) for the real-time assessment
of magnetic nanoparticle downstream processing performance. In-line magnetic particle spectroscopy
monitoring allowed for the concurrent evaluation of the amplitude spectrum and derived parameters including the
harmonic ratio A5/A3, enabling real-time selection of fractions with desired characteristics during the fractionation
process. Furthermore, magnetic particle spectroscopy offered increased sensitivity and more comprehensive
characterization capabilities than conventional in-line analysis techniques such as light absorption spectroscopy.
A theoretical model delineating the dependency of magnetic particle spectroscopy signal on core/shell size ratio
was developed. These results potentially have significant implications for prospective applications in the realm of
in-line magnetic particle spectroscopy analysis for real-time process control and quality assurance.