Synthesis and characterization of magnetic materials for self-controlled hyperthermia therapy

The major challenges in magnetic hyperthermia treatment (MHT) are the low heat generation of magnetic nanoparticles for cancer therapy and the avoidance of overheating via the temperature self-control characteristic at the ideal therapeutic range. Hence the aims of this PhD thesis are to develop a new magnetic implant material with high heat generation and temperature self-control capability, and to study their potential for safe MHT applications. In order to develop a ceramic magnetic implant, a series of highly crystalline Mg-ferrites nanoparticles were successfully prepared by an improved co-precipitation method. The structure and the magnetic properties of these nanoparticles were characterised and the results showed that the maximum SAR value is obtained for 10 ± 0.5 nm particles. The 10 ± 0.5 nm MgFe2O4 nanoparticles show higher heat generation and faster temperature rise in comparison to the Fe3O4 commercial suspension which demonstrates the potential of these nanoparticles for MHT. However, it was found that the maximum temperature rise and the overheating of MgFe2O4 nanoparticles need to be controlled through adjusting the amplitude of the external magnetic field, thus providing the motivation for preparation of magnetic nanoparticles with self-controlled heating capability. In order to induce the self-controlled heating ability, (Mg,Ti)-ferrite nanoparticles were attained by substituting Ti4+ ions into the Mg-ferrite. The magnetic properties of these nanoparticles were studied and it was found that the low saturation magnetization of these nanoparticles made undesirable their application as implants for effective MHT. In order to achieve an safe an effective hyperthermia therapy hydrided La(Fe,Si)13 were then investigated. It was found that the compound could be used to prevent the overheating effect as well as to provide the giant heat generation at low effective magnetic field strength (H.f) for MHT in comparison to other magnetic suspensions studied in this research. Finally, to achieve hydrided La(Fe,Si)13 nanoparticles, hydrided La(Fe,Si)13 ribbons were milled using the surfactant-assisted ball milling method. This research provides significant new insights into magnetic implant materials with both high heat generation and temperature self-control capability for safe MHT applications. In particular, first order unmilled compounds with self-controlled heating capability and high heat generation ability under magnetic field strength of (H.f) hold great promise for use as highly effective magnetic materials for safe and effective MHT