Molarity Effects of Fe and NaOH on Synthesis and Characterisation of Magnetite (Fe₃O₄) Nanoparticles for Potential Application in Magnetic Hyperthermia Therapy

In this study, the effect of molarity on the structural, magnetic, and heat dissipation properties of magnetite nanoparticles (MNPs) was investigated to optimise the parameters for potential application in magnetic hyperthermia therapy (MHT). MHT works based on the principle of local temperature rise at the tumour site by magnetic iron oxide nanoparticles (MIONPs) with the application of an alternating magnetic field. MHT is a safe method for cancer treatment and has minimal or no side effects. Magnetite (Fe₃O₄) is the best material among MIONPs to be applied in local MHT due to its biocompatibility and high saturation magnetisation value. MNPs were prepared by co-precipitation at varying molarity. Structural characterisation was performed via X-ray powder diffraction (XRD) for crystalline structure analysis and field-emission scanning electron microscopy (FESEM) for morphology and particle size analysis. Measurement of the magnetic properties of the as-synthesised MNPs was carried out using a vibrating sample magnetometer (VSM). Power loss (P) was determined theoretically. The increase in molarity resulted in significant effects on the structural, magnetic, and heat dissipation properties of MNPs. The particle size and saturation magnetisation (M_s) decreased with the gradual addition of base but increased, together with crystallinity, with the gradual addition of iron source. M3 recorded the smallest crystalline size at 3.559 nm. The sample with the highest molarity (M4) displayed the highest heat generation capacity with a p value of up to 0.4056 W/g. High p values at the nano-scale are crucial, especially in local MHT, for effective heat generation, thus proving the importance of molarity as a vital parameter during MNP synthesis.