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

J Nanobiotechnology. 2020 Jan 28;18(1):22. doi: 10.1186/s12951-020-0580-1.


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.

Keywords: Hyperthermia; Iron oxide nanoparticles; MPI; MRI; SPION.

MeSH terms

  • Contrast Media / chemistry*
  • Dextrans / chemistry
  • Humans
  • Hyperthermia, Induced
  • Image Enhancement
  • Magnetic Resonance Imaging / methods*
  • Magnetite Nanoparticles / chemistry*
  • Particle Size
  • Structure-Activity Relationship
  • Theranostic Nanomedicine


  • Contrast Media
  • Dextrans
  • Magnetite Nanoparticles
  • ferumoxtran-10
  • ferumoxides