Magnetotactic bacteria in biomedicine and environmental technology: A mini review

Magnetotactic bacteria (MTB) are a diverse group of aquatic microorganisms that biomineralize chains of intracellular magnetic nanoparticles called magnetosomes. These membrane-enclosed crystals of magnetite or greigite endow the cells with a permanent magnetic dipole, allowing them to align with external magnetic fields and to navigate along redox and oxygen gradients. Because magnetosomes are highly crystalline, single-domain nanoparticles with a narrow size distribution, strong magnetization and a biologically derived membrane, they have attracted considerable interest as natural magnetic nanomaterials. In this mini review, we summarize the main characteristics of representative MTB species, highlight the unique physicochemical properties of their magnetosomes, and discuss key applications in biomedicine, including targeted drug delivery, magnetic hyperthermia, magnetic resonance imaging, biosensing, and theranostic systems. In addition, environmental applications such as heavy-metal removal, wastewater treatment, bioseparation, and magnetic biosensors are reviewed. Current challenges related to large-scale cultivation, downstream processing, biosafety assessment, and industrial-scale magnetosome production are briefly outlined. Future perspectives for MTB-based microrobots, engineered magnetosome platforms, and bio-inspired multifunctional nanotechnologies are also discussed, emphasizing their growing importance in modern biomedical and environmental research.