Long‐Term Stability, Biocompatibility, and Magnetization of Suspensions of Isolated Bacterial Magnetosomes

• Published in: Small (Weinheim an der Bergstrasse, Germany) Germany), 2023-05, Vol.19 (19), p.e2206244-n/a
• Main Authors: Mickoleit, Frank, Jörke, Cornelia, Richter, Reinhard, Rosenfeldt, Sabine, Markert, Simon, Rehberg, Ingo, Schenk, Anna S., Bäumchen, Oliver, Schüler, Dirk, Clement, Joachim H.
• Format: Article
• Language: English
• Subjects: Bacteria; Biocompatibility; long‐term stability; magnetic nanoparticles; Magnetic saturation; magnetization; Magnetosomes; Nanoparticles; Nanotechnology; Particle size distribution; Room temperature; Stability
• ISSN: 1613-6810; 1613-6829
• DOI: 10.1002/smll.202206244

Magnetosomes are magnetic nanoparticles biosynthesized by magnetotactic bacteria. Due to a genetically strictly controlled biomineralization process, the ensuing magnetosomes have been envisioned as agents for biomedical and clinical applications. In the present work, different stability parameters of magnetosomes isolated from Magnetospirillum gryphiswaldense upon storage in suspension (HEPES buffer, 4 °C, nitrogen atmosphere) for one year in the absence of antibiotics are examined. The magnetic potency, measured by the saturation magnetization of the particle suspension, drops to one‐third of its starting value within this year—about ten times slower than at ambient air and room temperature. The particle size distribution, the integrity of the surrounding magnetosome membrane, the colloidal stability, and the biocompatibility turn out to be not severely affected by long‐term storage. The stability and integrity of isolated bacterial magnetosomes upon long‐term storage are examined with regard to physicochemical parameters, as well as their biocompatibility. Although magnetization curves indicate a time‐dependent reduction of the magnetically active core diameter, our investigations demonstrate that the particles can be stored for at least one year.