Open Access

Dryed Mohammadali Dadfar, Denise Camozzi, Milita Darguzyte, Karolin Roemhild, Paola Varvarà, Josbert Metselaar, Srinivas Banala, Marcel Straub, Nihan Güver, Ulrich M. Engelmann, Ioana Slabu, Miriam Buhl, Jan van Leusen, Paul Kögerler, Benita Hermanns-Sachweh, Volkmar Schulz, Fabian Kiessling, Twan Lammers

• 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.