PMAO-assisted thermal decomposition synthesis of high-stability ferrofluid based on magnetite nanoparticles for hyperthermia and MRI applications

Abstract

The combination of magnetic fluid hyperthermia and magnetic resonance imaging is recently considered to be one of the most promising non-invasive cancer treatment. In this work, a highly stable ferrofluid based on magnetite nanoparticles with high magnetization and high specific absorption rate will be developed. The ferrofluid was synthesized by thermal decomposition using poly (maleic anhydride-alt-1-octadecene, noted as PMAO) as a phase transferring ligand. The results have demonstrated that the magnetic particles were fully covered at high coverage by long non-magnetic polymeric chains. The particle size was increased by 25–30% while the saturation magnetization was decreased approximately 7–9% after phase transfer process. Remarkably, the prepared ferrofluid revealed excellent colloidal stability over six months of storage with zeta potentials less than −40 mV. As consequently, a relatively high specific absorption rate of 66 W.g-1 was obtained at ferrofluid concentration of only 5 mg.mL-1. Additionally, high-resolution magnetic resonance images with improved transverse relaxation T2 were observed when using magnetite-based ferrofluid for both in-vitro and in-vivo tests. This study demonstrates a novel approach for tailoring magnetic nanoparticles applicable in magnetic fluid hyperthermia and imaging of tumor cells.