Superparamagnetic particles are ideal for use in biomedical fields because of their tiny size, interesting magnetic properties and absence of remnant magnetism at room temperature. Through application of a radio-frequency (RF) magnetic field, they can be heated to produce local hyperthermia and kill cancer cells.
However, for magnetic hyperthermia-based cancer therapy applications, heating efficiency must be improved in order to reduce the RF field exposure time due to physiological limits. For their paper, Ranoo et al. enhanced the heating efficiency of phosphate-coated superparamagnetic Fe3O4 nanoparticles by orienting them in a static magnetic field.
To do this, the researchers coated a monolayer of phosphate ions over Fe3O4 nanoparticles and dispersed the material in water at biological pH conditions to ensure its biocompatibility. They found that with the application of a low, static magnetic field, the nanoparticles form chain-like structures that are oriented along the field direction. This in situ orientation of the particles improves the heating efficiency by 62% and was confirmed by atomic force microscopy.
The group also studied the material’s cytotoxicity to confirm its practical applicability. Though the phosphate coating increases the cytotoxicity at high concentrations, the sample remains significantly biocompatible.
This work suggests a route to enhancing the effectiveness of magnetic field hyperthermia for cancer treatment. The researchers plan further studies on the biocompatibility and long-term stability of the material. “Our approach is an innovative strategy to reduce exposure time and dosage during magnetic hyperthermia-based cancer therapy,” said author John Philip. “Having established the right kind of particle with required heating efficiency, we need to do further clinical trials in collaboration with medical institutions.”
Source: “Enhancement in hyperthermia efficiency under in situ orientation of superparamagnetic iron oxide nanoparticles in dispersions,” by Surojit Ranoo, B. B. Lahiri, T. Muthukumaran, and John Philip, Applied Physics Letters (2019). The article can be accessed at https://doi.org/10.1063/1.5100077.