Optimization of Zn-Mn ferrite nanoparticles for low frequency hyperthermia: Exploiting the potential of superquadratic field dependence of magnetothermal response

Abstract

Magnetothermal applications of nanoparticles in biomedicine are currently limited by low thermal responses to oscillating magnetic fields on one side and by detrimental physiological effects of electromagnetic radiation on the other side. In this paper, using Zn-Mn ferrite nanoparticles, we demonstrate that an appropriate choice of size and chemical composition of magnetic nanoparticles results in the superquadratic (upto 5th power) dependence of the Specific Absorption Rate (SAR) on a magnetic field (SAR proportional to H5). This gives an opportunity to obtain SAR values above 10 W/g in an oscillating magnetic field, while maintaining the field-frequency product at a level close to the physiological Brezovich's limit ∼109A/(m s).