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Updated: Jul 29, 2025
Growing Magnetotactic Bacteria of the Genus Magnetospirillum: Strains MSR-1, AMB-1 and MS-1
Published on: October 17, 2018
Evaluation of cell disruption technologies on magnetosome chain length and aggregation behaviour from
Marta Masó-Martínez1, Benjamin Fryer1, Dimitri Aubert2
1Energy and Bioproducts Research Institute, Aston University, Birmingham, United Kingdom.
Abstract:
Magnetosomes are biologically-derived magnetic nanoparticles (MNPs) naturally produced by magnetotactic bacteria (MTB). Due to their distinctive characteristics, such as narrow size distribution and high biocompatibility, magnetosomes represent an attractive alternative to existing commercially-available chemically-synthesized MNPs. However, to extract magnetosomes from the bacteria, a cell disruption step is required. In this study, a systematic comparison between three disruption techniques (enzymatic treatment, probe sonication and high-pressure homogenization) was carried out to study their effect on the chain length, integrity and aggregation state of magnetosomes isolated from Magnetospirillum gryphiswaldense MSR-1 cells. Experimental results revealed that all three methodologies show high cell disruption yields (>89%). Transmission electron microscopy (TEM), dynamic light scattering (DLS) and, for the first time, nano-flow cytometry (nFCM) were employed to characterize magnetosome preparations after purification. TEM and DLS showed that high-pressure homogenization resulted in optimal conservation of chain integrity, whereas enzymatic treatment caused higher chain cleavage. The data obtained suggest that nFCM is best suited to characterize single membrane-wrapped magnetosomes, which can be particularly useful for applications that require the use of individual magnetosomes. Magnetosomes were also successfully labelled (>90%) with the fluorescent CellMask™ Deep Red membrane stain and analysed by nFCM, demonstrating the promising capacity of this technique as a rapid analytical tool for magnetosome quality assurance. The results of this work contribute to the future development of a robust magnetosome production platform.
Insights
Magnetosomes, biologically-derived magnetic nanoparticles (MNPs), were extracted from bacteria using three methods. High-pressure homogenization best preserved magnetosome chain integrity for potential applications.
Area of Science:
- Biotechnology and Nanotechnology
- Microbiology and Materials Science
Background:
- Magnetosomes are biologically-derived magnetic nanoparticles (MNPs) produced by magnetotactic bacteria (MTB).
- They offer advantages over synthetic MNPs, including narrow size distribution and high biocompatibility.
- Extraction of magnetosomes requires effective bacterial cell disruption.
Purpose of the Study:
- To systematically compare enzymatic treatment, probe sonication, and high-pressure homogenization for magnetosome extraction.
- To evaluate the impact of these methods on magnetosome chain length, integrity, and aggregation.
- To assess novel characterization techniques for magnetosome quality assurance.
Main Methods:
- Three cell disruption techniques: enzymatic treatment, probe sonication, and high-pressure homogenization.
- Characterization using Transmission Electron Microscopy (TEM), Dynamic Light Scattering (DLS), and nano-Flow Cytometry (nFCM).
- Fluorescent labeling of magnetosomes with CellMask™ Deep Red for nFCM analysis.
Main Results:
- All methods achieved high cell disruption yields (>89%).
- High-pressure homogenization preserved magnetosome chain integrity best, while enzymatic treatment caused more cleavage.
- Nano-flow cytometry (nFCM) proved effective for analyzing individual magnetosomes and quality assurance after fluorescent labeling.
Conclusions:
- High-pressure homogenization is optimal for preserving magnetosome chain integrity during extraction.
- Nano-flow cytometry (nFCM) is a promising tool for analyzing individual magnetosomes and ensuring quality.
- These findings support the development of robust platforms for magnetosome production.
