Cube-Shaped Cetyltrimethyl Ammonium Bromide-Coated Nickel Ferrite Nanoparticles for Hyperthermia Applications

Cetyltrimethyl ammonium bromide (CTAB)-coated nickel ferrite (NiFe2O4) nanoparticles were synthesized using the high-temperature thermal decomposition method. The hydrophobic particles became water-soluble after the coating with CTAB, a positively charged ligand. The morphology and the phases of the nanoparticles were characterized using X-ray diffraction and transmission electron microscopy (TEM). TEM images demonstrated that the particles were cube-shaped; the average length of their side was 32.6 nm. Inductively coupled plasma spectroscopy measurements were performed to confirm the chemical composition of the particles. The particles exhibited superparamagnetic behavior with negligible coercive force. Magnetic heating of the aqueous suspensions of nanoparticles was performed in the presence of a radio-frequency magnetic field of 4.4 kA/m at a frequency of 216 kHz. The 1.5-mg/mL sample reached the hyperthermia target temperature of 42 ◦ C and exhibited a high specific absorption rate (SAR) value of 152 W/g. These findings show that the investigated nanoparticles are suitable for magnetic hyperthermia applications and have the advantage of low dosage owing to their high SAR values.