Magnetic particle imaging performance of liposomes encapsulating iron oxide nanoparticles

Magnetic Particle Imaging (MPI) is a new imaging modally that quantifies spatial distribution of super-paramagnetic iron oxide nanoparticles in a field of view through their non-linear magnetization response to an applied magnetic field. Liposomes loaded with magnetic nanoparticles (magnetoliposomes) are potential theranostic drug carriers that can combine magnetic properties with drug carrier ability. Prior work suggests that MPI signal can be affected by dipolar interactions between magnetic nanoparticles in close proximity - for instance, in a polymer matrix. Here we evaluate if encapsulating magnetic nanoparticles in liposomes has an impact in their MPI performance. For this purpose, magnetoliposomes were prepared using charge-stabilized iron oxide nanoparticles (IONPs) and their physical, magnetic and MPI properties were characterized. Interestingly, encapsulation of IONPs in magnetoliposomes led to an increase in MPI signal per unit mass.