Magnetic hyperthermia study of magnetosome chain systems in tissue-mimicking phantom

Magnetosomes produced by magnetotactic bacteria are biological membrane-enveloped magnetic nanoparticles. Extracted magnetosomes having the form of long chains as well as shortened chains with individual magnetosomes were prepared. The morphology (chain sizes) was modified in the sonication process and its impact was studied by transmission electron microscopy and dynamic light scattering. Fast magnetization saturation of magnetosome samples and the Verwey transition were detected by temperature-dependent magnetization measurements. To study the heating response to the applied alternating magnetic field (magnetic hyperthermia) magnetosomes were added into tissue-mimicking phantom. Temperature evolution and specific absorption rate (SAR) were measured and analyzed. It was found that embedding magnetosome chains in gel phantoms lead to a noticeable decrease in the efficiency of heating due to deterioration of Brownian mechanism.