Nanoflowers Versus Magnetosomes: Comparison Between Two Promising Candidates for Magnetic Hyperthermia Therapy

Elizabeth M Jefremovas,Inaki Orue,Luis Fernandez Barquin,Jose Angel Garcia,Lourdes Marcano,Alicia Muela,Cordula Gruttner,Lucia Gandarias,Ana Garcia-Prieto,Javier Alonso,Maria Luisa Fernandez-Gubieda,Eneko Garayo,Irati Rodrigo

doi:10.1109/access.2021.3096740

Abstract

Magnetic Fluid Hyperthermia mediated by iron oxide nanoparticles is one of the most promising therapies for cancer treatment. Among the different candidates, magnetite and maghemite nanoparticles have revealed to be some of the most promising candidates due to both their performance and their biocompatibility. Nonetheless, up to date, the literature comparing the heating efficiency of magnetite and maghemite nanoparticles of similar size is scarce. To fill this gap, here we provide a comparison between commercial Synomag Nanoflowers (pure maghemite) and bacterial magnetosomes (pure magnetite) synthesized by the magnetotactic bacterium <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Magnetospirillum gryphiswaldense</i> of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\langle D \rangle \approx ~40$ </tex-math></inline-formula> –45 nm. Both types of nanoparticles exhibit a high degree of crystallinity and an excellent degree of chemical purity and stability. The structural and magnetic properties in both nanoparticle ensembles have been studied by means of X–Ray Diffraction, Transmission Electron Microscopy, X–Ray Absorption Spectroscopy, and SQUID magnetometry. The heating efficiency has been analyzed in both systems using AC magnetometry at several field amplitudes (0–88 mT) and frequencies (130, 300, and 530 kHz).

Highlights

I N recent years, there has been an increasing number of works on iron oxide based magnetic nanoparticles for different kinds of biomedical applications, such as Drug Delivery, Magnetic Resonance Imaging (MRI), Magnetic Particle Imaging (MPI), and Magnetic Hyperthermia [1]–[6]
Magnetic Hyperthermia, which is mediated by magnetic nanoparticles (MNPs), constitutes a promising approach for cancer treatment
Different materials have been investigated as magnetic hyperthermia agents, iron oxide based MNPs have received most of the attention due to their chemical stability, high magnetization, relatively well–known metabolism, high biocompatibility, etc. [7], [15]

Summary

Introduction

I N recent years, there has been an increasing number of works on iron oxide based magnetic nanoparticles for different kinds of biomedical applications, such as Drug Delivery, Magnetic Resonance Imaging (MRI), Magnetic Particle Imaging (MPI), and Magnetic Hyperthermia [1]–[6]. As has been previously described [20], the heating efficiency of the MNPs is directly related to the “hysteresis losses” of the MNPs under an external AC field These losses are proportional to the hysteresis loop area, and are directly related to the magnetic behavior of the MNPs. there have been a few reports on the heating efficiency of MNPs made of iron oxide phases such as FeO [21], –Fe2O3 [22] or α–Fe2O3 [23], most of the current articles are based on MNPs composed of magnetite and/or maghemite, since these compounds are the only ones approved by the United States Food and Drug Administration (FDA) and the European Medicines Agency (EMA) for clinical use

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