Optimizing the magnetic field strength and concentration of silica coated cobalt ferrite nanoparticles for magnetic hyperthermia

Abstract

A therapeutic breakthrough in cancer treatment has recently been made by using magnetic nanoparticles (MNPs) for heating in hyperthermia therapy. Unapproachable tumors are being effectively destroyed by focused heat produced by MNPs. The major challenges regarding practical application of this therapy include the control and improvement of induction heating ability of MNPs and hyperthermia temperature range between 42–47 °C, for secure treatment at targeted area. Here, in this study, we have reported the synthesis and characterization of core–shell structured silica-coated cobalt ferrite nanoparticles (SiO2 coated CoFe2O4 MNPs), which are potential candidates for use as heat source in magnetic hyperthermia therapy. The SiO2 coated CoFe2O4 MNPs were synthesized using the reverse micelle method, with the SiO2 coating performed simultaneously during MNP synthesis. Various analytical tools were utilized for the characterization. The structural measurements were probed by X-ray diffraction (XRD). Monodisperse MNPs with nearly spherical core–shell structure was revealed by Transmission electron microscopy (TEM) results. The average diameter of MNPs obtained from TEM analysis was 15 nm. The surface coating of cobalt ferrite MNPs with silica was verified by Fourier transform infrared spectrometry (FTIR). The saturation magnetization values obtained using vibrating sample magnetometer (VSM) measurements were 45.74 emu/g, revealing the superparamagnetic nature of the nanoparticles. The heating efficiency of different concentrations of synthesized nanoparticles was evaluated in an aqueous solution under an alternating magnetic field of strength 5.5 kA/m at a frequency of 260 kHz. A saturation temperature of 42 °C was attained at an optimum concentration of 1.7 mg/mL, while a magnetic field strength of 3.9 kA/m achieved 42 °C at a fixed concentration of 3.5 mg/ml. The obtained specific absorption rate (SAR) values for all the samples were between 56.23 to 100.1 W/g. The correlation between SAR values, MNP concentration, and applied magnetic field strength was also examined. The high saturation magnetization, efficient heating rates, and high SAR values make our synthesized silica-coated cobalt ferrite nanoparticles promising candidates for magnetic hyperthermia treatments, potentially improving therapeutic outcomes for cancer patients.