Preparation and biodistribution of 59Fe-radiolabelled iron oxide nanoparticles

We report on the 59 Fe radiolabelling of iron oxide nanoparticle cores through post-synthetic isotope exchange ( 59 Fe-IONP ex ) and precursor labelling ( 59 Fe-IONP pre ). Scanning electron microscopy and dynamic light scattering measurements showed no impact of radiolabelling on nanoparticle size or morphology. While incorporation efficiencies of these methods are comparable—83 and 90% for precursor labelling and post-synthetic isotope exchange, respectively— 59 Fe-IONP pre exhibited much higher radiochemical stability in citrated human plasma. Quantitative ex vivo biodistribution study of 59 Fe-IONP pre coated with triethylene glycol was performed in Wistar rats. Following the intravenous administration, high 59 Fe concentration was observed in the lung and the organs of the reticuloendothelial system such as the liver, the spleen and the femur.