High yttrium retention in magnetite nanoparticles functionalized with hybrid silica-dextran shells

Oncologic thermoradiotherapy combines hyperthermia and radiotherapy treatments, and their simultaneous use has been shown to be more efficient than their alternate use. Targeted and simultaneous thermoradiotherapy can be achieved with radioactive magnetic nanoparticles, however radioactive isotope leakage is a concern for clinical application. Here, we propose a novel wet-chemical functionalization procedure to coat magnetite nanoparticles with silica-dextran hybrid shells labelled with natural trivalent Y cations. While the surface functionalization procedure performed in the absence of Y(III) yielded homogenously thick silica-dextran shells, for the Y(III) containing counterparts, thinner silica-dextran shells have been obtained. The latter effectively traps the Y cations, with a retention above 99 %. Systematic studies showed that surface functionalization did not affect the magnetic properties of the as prepared hybrid materials. This work paves the way for further developments towards the development of safe and efficient hybrid nanoparticles for thermoradiotherapy and theragnosis.