Practical methods for generating alternating magnetic fields for biomedical research

Abstract

Alternating magnetic fields (AMFs) cause magnetic nanoparticles (MNPs) to dissipate heat while leaving surrounding tissue unharmed, a mechanism that serves as the basis for a variety of emerging biomedical technologies. Unfortunately, the challenges and costs of developing experimental setups commonly used to produce AMFs with suitable field amplitudes and frequencies present a barrier to researchers. This paper first presents a simple, cost-effective, and robust alternative for small AMF working volumes that uses soft ferromagnetic cores to focus the flux into a gap. As the experimental length scale increases to accommodate animal models (working volumes of 100s of cm3 or greater), poor thermal conductivity and volumetrically scaled core losses render that strategy ineffective. Comparatively feasible strategies for these larger volumes instead use low loss resonant tank circuits to generate circulating currents of 1 kA or greater in order to produce the comparable field amplitudes. These principles can be extended to the problem of identifying practical routes for scaling AMF setups to humans, an infrequently acknowledged challenge that influences the extent to which many applications of MNPs may ever become clinically relevant.

Polina Anikeeva

Matoula S. Salapatas Professor and Head, Department of Materials Science and Engineering
Professor, Brain and Cognitive Sciences
Director, K. Lisa Yang Brain-Body Center
Associate Investigator, McGovern Institute for Brain Research
Associate Director, Research Laboratory of Electronics

My goal is to combine the current knowledge of biology and nanoelectronics to develop materials and devices for minimally invasive treatments for neurological and neuromuscular diseases.