Publication

Abstract : Magnetic hyperthermia (MHT) utilizing magnetic nanoparticles has emerged as an effective treatment for heat-induced cancer cell destruction. The current work employs a two-step synthesis strategy to develop oleic acid-modified Fe3O4 (OA-Fe3O4) nanocubes, followed by a ligand exchange mechanism to enhance the physicochemical, magneto-thermal and biological properties, with a specific focus on potential MHT applications. Tetramethylammonium 11-aminoundecanoate (TMAAD) polymer is chosen as a suitable surface ligand for transferring hydrophobic OA-Fe3O4 nanocubes to the aqueous phase. Well-defined cube shaped particles with a magnetite phase of iron oxide are obtained. Hydrophobic-to-hydrophilic transition is confirmed using static contact-angle measurements and the responsible surface functional groups are identified using Fourier transform infrared (FTIR) spectroscopy. Magnetization is observed to decrease from 69 emu/g for OA-Fe3O4 to 42 emu/g for TMAAD-OA-Fe3O4 due to the presence of an additional magnetically inactive surface layer of TMAAD polymer. Heating efficiency, in terms of specific absorption rate (SAR) is systematically investigated as a function of particle concentration, magnetic field amplitude and nature of the dispersion medium. Remarkably, the nanocubes exhibit concentration-independent heating efficiency, attributed to the presence of magnetic dipolar interactions. TMAAD-OA-Fe3O4 nanocubes evidence the highest SAR of 595 W/g with an intrinsic loss power (ILP) of 0.82 nHm2/kg at a maximum magnetic field strength of 600 Oe. Additionally, the nanocubes demonstrate improved cytotoxicity against MDA-MB-231 human breast cancer cells and show antioxidant activity by neutralizing free radicals and reactive oxygen species (ROS), making them promising as efficient MHT heat mediators for cancer therapy.