Synthesis of iron oxide nanoparticles for hyperthermia application: effect of ultrasonic irradiation assisted co-precipitation route

Z Erfani Gahrouei, M Imani, M Soltani and A Shafyei

Abstract

In this research, maghemite (γ-Fe₂O₃) and magnetite (Fe₃O₄) nanoparticles (NPs) were synthesised by co-precipitation route with the aid of ultrasonic irradiation. The morphology, crystallite size, particle size, and structural analysis of magnetic NPs were investigated by transmission electron microscope (TEM) and X-ray diffraction (XRD). Thermal properties of magnetic NPs were also investigated by specific loss power (SLP) measurements. The X-ray diffraction patterns determined the formation of maghemite and magnetite phases. The results obtained from the TEM analysis indicated that the mean particle size of maghemite and magnetite NPs was 20 ± 0.2 nm and 22 ± 0.3 nm, respectively. Moreover, the crystallite size was calculated by modified Scherrer method. Vibration sample magnetometer (VSM) was used to evaluate magnetic behaviour of the synthesised NPs. The magnetic saturation for both γ-Fe₂O₃ and Fe₃O₄ was 44 emu g⁻¹ and 55 emu g⁻¹, and coercivity field was 2 Oe and 70 Oe, respectively. The SLP values for synthesised NPs were significant, and the temperature of these magnetic NPs reached 44 °C–47 °C within 10 min in the existence of an external magnetic field with an intensity of about 6 kA/m. This temperature range seems to be appropriate for hyperthermia application and destruction of cancerous cells. In addition, the size of these magnetic NPs was less than 50 nm, which facilitates better penetration of these NPs into the cancerous tumours.