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

Mickoleit, Frank; Jörke, Cornelia; Richter, R.; Rosenfeldt, Sabine; Markert, Simon; Rehberg, Ingo; Schenk, Anna S.; Bäumchen, Oliver; Schüler, Dirk; Clement, Joachim H.

doi:10.1002/smll.202206244

Cited by 5 publications

(5 citation statements)

References 73 publications

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“…In DLS measurements, an increased overall particle diameter was measured (75.4 ± 10.9 nm), which can be explained by the formation of a hydration shell in aqueous environments. The determined zeta potential of the particles of −37.3 ± 5.4 mV is in accordance with previous analyses, 23,37 indicating a negative particle surface charge.…”

Section: ■ Resultssupporting

confidence: 91%

“…Potential cytotoxic effects of magnetosomes on the viability of mammalian cells (cancer cell lines or primary cells) have been evaluated in several studies, and dependent on the cell line tested, an overall good biocompatibility at the cell culture level has been reported . For instance, for the cancer cell lines FaDu, BeWo, and HCC78 as well as for hPC–PL primary cells we have previously demonstrated that particle amounts of up to 400 μg Fe mL –1 can be safely applied without severe effects on the cell vitality or increased cell death events. − However, as the magnetosome-producing bacterial strain M. gryphiswaldense has a Gram-negative type of cell wall, which contains lipopolysaccharides (LPS) in its outer membrane, further toxicity factors have to be addressed, such as blood stability and endotoxicity.…”

Section: Introductionmentioning

confidence: 99%

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Assessing Cytotoxicity, Endotoxicity, and Blood Compatibility of Nanoscale Iron Oxide Magnetosomes for Biomedical Applications

Mickoleit,

Pfister,

Friedrich

et al. 2024

ACS Appl. Nano Mater.

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Magnetosomes are biogenic magnetic nanoparticles with unique material properties, such as high crystallinity and strong magnetization as well as uniform and tunable shapes and sizes. In particular, the ability to genetically modify their enveloping membrane could render isolated magnetosomes as versatile tools for a variety of potential applications in the biomedical field. However, the biocompatibility of the bacterially produced particles has so far not been fully been assessed. In this study, different biocompatibility and toxicity factors of magnetosomes isolated from the model organism Magnetospirillum gryphiswaldense were investigated and tested with THP-1, Jurkat cells, and primary human-derived material such as peripheral blood mononuclear cells (PBMCs). The obtained data demonstrate generally good biocompatibility for all tested magnetosome concentrations as well as high blood compatibility. Only slight but not significant complement activation was observed, with no indications for plasma coagulation or hemolysis. However, the presence of lipopolysaccharides originating from the Gram-negative cell wall of M. gryphiswaldense caused activation of PBMCs expressed as significant cytokine release. Thus, this endotoxicity represents an issue for possible in vivo applications, which needs to be addressed in future studies. Nevertheless, the results show that, overall, magnetosomes have high potential for different (bio)medical applications and are already well-suited for the fields of in vitro diagnostics.

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Section: ■ Resultssupporting

confidence: 91%

Section: Introductionmentioning

confidence: 99%

Assessing Cytotoxicity, Endotoxicity, and Blood Compatibility of Nanoscale Iron Oxide Magnetosomes for Biomedical Applications

Mickoleit,

Pfister,

Friedrich

et al. 2024

ACS Appl. Nano Mater.

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“…Magnetosomes can be isolated with intact membranes; however, the latter cannot fully prevent oxidation of the magnetite cores of purified particle suspensions. Thus, even under storage conditions (HEPES buffer at 4 °C under a nitrogen atmosphere), a drop of the saturation magnetization to one-third of its initial value was observed over a period of one year [ 25 ].…”

Section: Resultsmentioning

confidence: 99%

“…The magnetic properties of magnetosomes (b-NPs) have been investigated in various studies [ 25 , 29 , 30 , 31 , 32 , 33 ]. Due to their particle diameters, b-NPs are near the transition range between superparamagnetic and ferrimagnetic/stable single-domain behavior (at ~30 nm).…”

Section: Resultsmentioning

confidence: 99%

Comparing the Colloidal Stabilities of Commercial and Biogenic Iron Oxide Nanoparticles That Have Potential In Vitro/In Vivo Applications

et al. 2023

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For the potential in vitro/in vivo applications of magnetic iron oxide nanoparticles, their stability in different physiological fluids has to be ensured. This important prerequisite includes the preservation of the particles’ stability during the envisaged application and, consequently, their invariance with respect to the transfer from storage conditions to cell culture media or even bodily fluids. Here, we investigate the colloidal stabilities of commercial nanoparticles with different coatings as a model system for biogenic iron oxide nanoparticles (magnetosomes) isolated from magnetotactic bacteria. We demonstrate that the stability can be evaluated and quantified by determining the intensity-weighted average of the particle sizes (Z-value) obtained from dynamic light scattering experiments as a simple quality criterion, which can also be used as an indicator for protein corona formation.

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“…While in terms of metallic composition, magnetosomes are characterized by the presence of an iron oxide core, in the absence of a specific treatment, some other non-metallic and non-toxic elements have been observed in small quantities (< 1.5 10 –4 % Fe per element in average) such as Na, Ca, Mg and K which could under their cationic form surround the negatively charged magnetosome surface [ 46 ]. Such impurities in the magnetosome membrane could be eliminated by removing the magnetosome membrane from the inorganic core to improve the particle purity [ 40 , 50 ].…”

Section: Discussionmentioning

confidence: 99%

Set-up of a pharmaceutical cell bank of Magnetospirillum gryphiswaldense MSR1 magnetotactic bacteria producing highly pure magnetosomes

Chades,

Le Fèvre,

Chebbi

et al. 2024

Microb Cell Fact

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We report the successful fabrication of a pharmaceutical cellular bank (PCB) containing magnetotactic bacteria (MTB), which belong to the Magnetospirillum gryphiswaldense MSR1 species. To produce such PCB, we amplified MTB in a minimal growth medium essentially devoid of other heavy metals than iron and of CMR (Carcinogenic, mutagenic and reprotoxic) products. The PCB enabled to acclimate MTB to such minimal growth conditions and then to produce highly pure magnetosomes composed of more than 99.9% of iron. The qualification of the bank as a PCB relies first on a preserved identity of the MTB compared with the original strain, second on genetic bacterial stability observed over 100 generations or under cryo-preservation for 16 months, third on a high level of purity highlighted by an absence of contaminating microorganisms in the PCB. Furthermore, the PCB was prepared under high-cell load conditions (9.108 cells/mL), allowing large-scale bacterial amplification and magnetosome production. In the future, the PCB could therefore be considered for commercial as well as research orientated applications in nanomedicine. We describe for the first-time conditions for setting-up an effective pharmaceutical cellular bank preserving over time the ability of certain specific cells, i.e. Magnetospirillum gryphiswaldense MSR1 MTB, to produce nano-minerals, i.e. magnetosomes, within a pharmaceutical setting.

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

Abstract: The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/smll.202206244.

Cited by 5 publications

References 73 publications

Assessing Cytotoxicity, Endotoxicity, and Blood Compatibility of Nanoscale Iron Oxide Magnetosomes for Biomedical Applications

Assessing Cytotoxicity, Endotoxicity, and Blood Compatibility of Nanoscale Iron Oxide Magnetosomes for Biomedical Applications

Comparing the Colloidal Stabilities of Commercial and Biogenic Iron Oxide Nanoparticles That Have Potential In Vitro/In Vivo Applications

Set-up of a pharmaceutical cell bank of Magnetospirillum gryphiswaldense MSR1 magnetotactic bacteria producing highly pure magnetosomes

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