Nanomaterials for magnetic hyperthermia

Background Cancer remains as one of the major causes of mortality worldwide. Recent advances in nanoparticles based therapy mark a new era on cancer treatment. Many groups have investigated biological/physical effects of nanoparticles on tumour cells and how these vary with physical parameters such as particle size, shape, concentration and distribution. Magnetic hyperthermia (MHT) can be an alternative or an add-value therapy with demonstrated effectiveness. MHT uses magnetic nanoparticles, which can be directly applied to the tumour, where, by applying an external ac magnetic field, will promote a localized temperature increment that can be controlled. Methods LiFe5O8 nanocrystallites were synthesized by a novel and eco-friendly sol-gel process, using powder coconut water (PCW) has a mediated reaction medium. The dried powders were heat-treated between 400 and 1000 °C, being analysed their structure, morphology and magnetic properties; cytotoxicity and magnetic hyperthermia assays were performed. Results The heat-treated LiFe5O8 powder led to crystallite sizes from 50 nm to 200 nm. Increasing the temperature of the heat treatment, secondary phases tend to disappear. The cytotoxicity results revealed a non-cytotoxicity property, for concentrations below 5 mg/mL. The sample HT at 1000 °C, revealed hysteresis and magnetic saturation of 73 emu.g−1 at 300 K and a specific absorption rate(SAR) of about 80 W/g. Conclusions It was possible to synthesize LiFe5O8 by a novel, eco-friendly and sustainable route. The nanoparticles have a high heat efficiency, especially the sample heat-treated at 1000 °C, with SAR values similar to Fe3O4, showing potential to be used in the treatment of cancer, by MHT.