Magnetosomes in Nature, Biomedicine and Physics

TL;DR

This paper explores the properties and detection methods of magnetosomes, biogenic magnetite particles in bacteria and fossils, focusing on their magnetic interactions and hysteresis behavior.

Contribution

It provides new formulas for describing magneto-dipole interactions of spheroidal magnetosomes and calculates their hysteresis loops considering random orientations.

Findings

Formulas for magneto-dipole interactions of spheroids.

Calculated hysteresis loops for randomly oriented magnetosome chains.

Insights into magnetic detection of biogenic magnetite in rocks.

Abstract

Magnetotactic bacteria synthesize linear chains of magnetite nanoparticles within their bodies, which allow the bacteria to navigate the Earth's magnetic field in search of the best habitat. Biogenic magnetite particles, called magnetosomes, are very promising for use in biomedicine. Magnetosome chains have also been found in ancient fossils and sediments. The study of magnetofossils provides valuable information about the Earth's biological past. The presence of biogenic magnetite in ancient rock samples can be detected by measuring ferromagnetic resonance spectra, first-order magnetization reversal curves, or quasi-static hysteresis loops. Theoretical analyses of these experiments generally assume that magnetosomes are spherical nanoparticles, although the shape of some types of magnetosomes is close to spheroidal one. In this work, simple formulas for describing the magneto-dipole interaction of oriented spheroids are obtained and quasi-static hysteresis loops of randomly oriented magnetosome chain assembly consisting of elongated spheroids are calculated.