Synthesis and Characterization of Iron Oxide Nanotubes for Targeted Hyperthermia and Drug Delivery

Iron oxide nanoparticles have been studied for magnetic hyperthermia and targeted drug delivery applications due to their tunable magnetic properties and biocompatibility. However, the low heating efficiency (evaluated as Specific Absorption Rate - SAR) of these magnetic particles hinders their practicality. It has recently been shown that increasing the anisotropy of the nanoparticles by synthesizing one-dimensional (1D) nanorods with high saturation magnetization (SM), their SAR value increases significantly. We propose 1D magnetic nanotubes due to an enhanced surface area compared to nanorods. Crystalline, tunable aspect ratio Fe₃O₄ nanotubes have been synthesized using a hydrothermal method. Magnetic measurements show a clear Verwey transition and a high SM at 300 K, confirming a high quality of the nanotubes. Calorimetric experiments on the nanotubes dispersed in water (1mg/mL) show a large SAR value of 400 W/g in an AC magnetic field of 800 Oe. Our study shows the potential of using Fe₃O₄ nanotubes as a multifunctional tool for targeted hyperthermia and drug delivery.