Superparamagnetic magnetite nanoparticles for cancer cells treatment via magnetic hyperthermia: effect of natural capping agent, particle size and concentration

Superparamagnetic iron oxide nanoparticles (SPMNPs) continue to emerge as one of the most potential candidates in biomedical applications. Their multiple functionalities arise from several advantages, such as their responsiveness to external magnetic stimuli, availability, biocompatibility, lack of toxicity, and easier to synthesize. Such MNPs can generate heat when they subjected to an alternating magnetic field, which can be used in tumor treatment if the released heat is as enough as to increase the tumor area temperature the tumor area from physiological temperature of 37 °C to 42–45 °C. In this regard, the size, distribution, magnetic properties of the magnetic nanoparticles play an important role. Thus, the Fe3O4 NPs were synthesized via a simple and inexpensive coprecipitation route with the assistance of natural extracts of Peppermint (P) and Dracocephalum (D) as capping agents. The structural, morphological, and magnetic properties were characterized through the XRD, HRTEM, and vibrating sample magnetometer, respectively. Cytotoxic effect and IC50 values of the as-synthesized Fe3O4 NPs on K562 were evaluated using MTT assay, being of 106.3 and 146.0 of the IC50 values for NPs synthesized with P and D-capping agents, respectively. The growth inhibition was dependent on treatment time, dose of NPs, and type of the employed capping agent. Furthermore, the synthesized NPs with dracocephalum had a more inhibitory effect than that of the other sample. The heating efficiency of the Fe3O4 NPs was investigated via an induction heater generating alternating magnetic field at frequency of 92 kHz and amplitude of 10 kA/m. The temperature rise (ΔT) of the as-prepared ferrofluids in the AC magnetic field was studied on different concentrations of magnetic nanoparticles. The specific absorption rate (SAR), as an indicative of heating efficiency, was obtained from Box-Lucas equation and linear fitting of ΔT-time curve. The results showed that the ΔT sharply increases with increasing the concentration of NPs from 3 to 9 mg/mL, but it was dependent on the size, distribution, and magnetic properties of the samples synthesized with two different capping agents. The SAR values of 33 W/g at 9 mg/mL obtained, for the P SPIONPs, suggests the use of those MNPs as the potential materials in tumor treatment via magnetic fluid hyperthermia.