Role of dextran decomposition process on the magnetite nanoparticles crystallization and magnetic hyperthermia effect

Magnetite nanoparticles (MNPs) are constantly studied in various biomedical applications, including magnetically-induced hyperthermia. This study tested the role of the dextran decomposition process on the MNPs crystallization and magnetic hyperthermia effect. It was confirmed that the modification of the synthesis method (medium and the procedure of the dextran introduction) results in the synthesis of magnetite nanoparticles with an average crystallite size from 3.88 ± 1.38 to 45.97 ± 0.76 nm and different magnetic properties. It was possible to synthesize nanoparticles with superparamagnetic properties (magnetization of 54.26 emu g⁻¹ and coercivity of 0.36 Oe) as well as a sample with a higher coercivity equal to 19.26 Oe and magnetization equal to 51.35 emu g⁻¹. The changes in the structure, morphology, and magnetic properties reflect the applicability potential of the magnetite nanoparticles in magnetic hyperthermia. The highest effect was observed for the sample synthesized in benzyl ether in the presence of dextran 40 000. For a concentration of 0.25 mg ml⁻¹, the specific absorption rate (SAR) was even higher than 200 W g⁻¹. However, as shown, the SAR parameter is insufficient to analyze the applicability potential, and the temperature increase must be consequently analyzed. For a concentration of 0.25 mg ml⁻¹, the temperature change was equal to 8.83 ± 1.03℃, while for 2 mg ml⁻¹ to 21.20 ± 0.83 ℃.