Size-isolation of superparamagnetic iron oxide nanoparticles improves MRI, MPI and hyperthermia performance

Abstract

Superparamagnetic iron oxide nanoparticles (SPION) are extensively used for magnetic resonance imaging (MRI) and magnetic particle imaging (MPI), as well as for magnetic fluid hyperthermia (MFH). We here describe a sequential centrifugation protocol to obtain SPION with well-defined sizes from a polydisperse SPION starting formulation, synthesized using the routinely employed co-precipitation technique. Transmission electron microscopy, dynamic light scattering and nanoparticle tracking analyses show that the SPION fractions obtained upon size-isolation are well-defined and almost monodisperse. MRI, MPI and MFH analyses demonstrate improved imaging and hyperthermia performance for size-isolated SPION as compared to the polydisperse starting mixture, as well as to commercial and clinically used iron oxide nanoparticle formulations, such as Resovist ® and Sinerem ®. The size-isolation protocol presented here may help to identify SPION with optimal properties for diagnostic, therapeutic and theranostic applications.

Micromagnetic Simulations of Submicron Vortex Structures for the Detection of Superparamagnetic Labels

“…Due to their biocompatibility and chemical stability, iron-oxide nanoparticles made of magnetite (Fe 3 O 4 ) are suitable for labels in biomedical applications [ 21 , 22 , 23 , 24 , 25 , 26 , 27 ]. Their synthesis is investigated in a wealth of literature, indicating that the superparamagnetic limit highly depends on the synthesis procedure [ 28 , 29 , 30 ].…”

Combining magnetic particle imaging and magnetic fluid hyperthermia for localized and image-guided treatment

“…To address this important technical challenge, several research groups have demonstrated experimentally that the MPI gradient field can localize MFH heating [21,22,[61][62][63][64]. Despite using a 300 kHz magnetic field, we and others have demonstrated localized heating to millimeter-scale resolution.…”

Magnetisation Processes in Geometrically Frustrated Spin Networks with Self-Assembled Cliques

“…Note that these theoretical predictions are based on zero-temperature dynamics and interacting nanoparticle assemblies on a profoundly complex structure. In contrast, many laboratory experiments consider simpler structures or super-paramagnetic assemblies designed for specific applications; see, for example, [51][52][53]. Apart from the finite temperature and a continuous spin symmetry, this topological equivalence can be lifted, leading to a smooth hysteresis loop in the presence of long-range dipolar interactions; the impact of the substrate on which the assembly is realised; and the distributed size of nanoparticles.…”