Colloidal CoFe2O4-based nanoparticles for Magnetic Fluid Hyperthermia

In the field of biomedicine, important issues to address are the early-stage diagnosis and targeted therapies. Since the last two decades, magnetic nanoparticles have been proposed as potentially powerful due to their unique chemical-physical properties. Magnetic nanoparticles can be applied in a wide variety of biomedical fields from the magnetic separation and Magnetic Resonance Imaging (MRI) to drug delivery and Magnetic Fluid Hyperthermia (MFH).1 In particular, MFH is based on the heat released by magnetic nanoparticles subjected to an alternate external magnetic field. Among the different material features affecting the hyperthermic efficiency, the magnetic properties are clearly the most important. Therefore, the optimisation of the magnetic properties, aimed to increase the heating ability and to reduce the magnetic material dose to be inserted in the human body, is still an active research field. In 2013 alone, 682 works have been published in the literature on the topic of magnetic hyperthermia.2 Despite cobalt toxicity, cobalt-containing materials and especially cobalt ferrite nanoparticles have been proposed as promising heat mediators due to its high anisotropy.3–13 In this thesis, the results obtained on two different systems, designed with the idea of studying the effect on the hyperthermic properties of proper tuning of the magnetic properties, are presented. Both the sets of samples are based on cobalt ferrite nanoparticles. The first strategy consists on the substitution of cobalt ions with zinc ones with the aim of tuning the magnetic properties of the system and, at the same time, decrease the toxicity of the material. The second way is on the contrary represented by the coating of cobalt ferrite cores by means of biocompatible or less toxic isostructural phases (i.e. magnetite/maghemite or manganese ferrite).