Magnetic properties of bacterial magnetosomes as potential diagnostic and therapeutic tools

Hergt, R.; Hiergeist, R.; Zeisberger, Matthias; Schüler, Dirk; Heyen, Udo; Hilger, Ingrid; Kaiser, Werner A.

doi:10.1016/j.jmmm.2005.01.047

Cited by 296 publications

(238 citation statements)

References 10 publications

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“…Magnetite has a cubic spinel lattice structure with a unit cell containing 32 4 . The magnetism exhibited by magnetite MNPs is a result of the superexchange interaction between the (A) and [B] site cations, which yields antiparallel magnetic moments between the two sublattices.…”

Section: Introductionmentioning

confidence: 99%

Controlled cobalt doping in biogenic magnetite nanoparticles

Byrne

Coker

Moise

et al. 2013

J. R. Soc. Interface.

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Cobalt-doped magnetite (Co x Fe 32x O 4 ) nanoparticles have been produced through the microbial reduction of cobalt-iron oxyhydroxide by the bacterium Geobacter sulfurreducens. The materials produced, as measured by superconducting quantum interference device magnetometry, X-ray magnetic circular dichroism, Mössbauer spectroscopy, etc., show dramatic increases in coercivity with increasing cobalt content without a major decrease in overall saturation magnetization. Structural and magnetization analyses reveal a reduction in particle size to less than 4 nm at the highest Co content, combined with an increase in the effective anisotropy of the magnetic nanoparticles. The potential use of these biogenic nanoparticles in aqueous suspensions for magnetic hyperthermia applications is demonstrated. Further analysis of the distribution of cations within the ferrite spinel indicates that the cobalt is predominantly incorporated in octahedral coordination, achieved by the substitution of Fe 2þ site with Co 2þ , with up to 17 per cent Co substituted into tetrahedral sites.

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Section: Introductionmentioning

confidence: 99%

Controlled cobalt doping in biogenic magnetite nanoparticles

Byrne

Coker

Moise

et al. 2013

J. R. Soc. Interface.

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“…Magnetotactic bacteria take up soluble iron species that they use to biomineralize chains of magnetite nanocrystals, known as magnetosomes, in intracellular membrane vesicles 2 . The nanocrystals have nearly perfect mineral crystal structures with consistent species-specific morphologies, leading to well-defined magnetic properties 2,3,9,12,18,19 . As a result, magnetotactic bacteria are one of the best model systems for investigating the molecular mechanisms of biomineralization.…”

mentioning

confidence: 99%

“…Magnetite biomineralization by magnetotactic bacteria is a topic of great interest in nanotechnology [7][8][9][10][11][12] , functional materials [11][12][13][14][15][16] , and astrobiology 17 . Magnetotactic bacteria take up soluble iron species that they use to biomineralize chains of magnetite nanocrystals, known as magnetosomes, in intracellular membrane vesicles 2 .…”

mentioning

confidence: 99%

Correlative Electron and Fluorescence Microscopy of Magnetotactic Bacteria in Liquid: Toward In Vivo Imaging

et al. 2015

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Magnetotactic bacteria biomineralize ordered chains of uniform, membrane-bound magnetite or greigite nanocrystals that exhibit nearly perfect crystal structures and species-specific morphologies. Transmission electron microscopy (TEM) is a critical technique for providing information regarding the organization of cellular and magnetite structures in these microorganisms. However, conventional TEM can only be used to image air-dried or vitrified bacteria removed from their natural environment. Here we present a correlative scanning TEM (STEM) and fluorescence microscopy technique for imaging viable cells of Magnetospirillum magneticum strain AMB-1 in liquid using an in situ fluid cell TEM holder. Fluorescently labeled cells were immobilized on microchip window surfaces and visualized in a fluid cell with STEM, followed by correlative fluorescence imaging to verify their membrane integrity. Notably, the post-STEM fluorescence imaging indicated that the bacterial cell wall membrane did not sustain radiation damage during STEM imaging at low electron dose conditions. We investigated the effects of radiation damage and sample preparation on the bacteria viability and found that approximately 50% of the bacterial membranes remained intact after an hour in the fluid cell, decreasing to ,30% after two hours. These results represent a first step toward in vivo studies of magnetite biomineralization in magnetotactic bacteria.B iomineralization is a widespread biological phenomenon occurring in living organisms ranging from single cells to complex multicellular organisms. Biomineralization of inorganic materials in single cell organisms is an ideal system for studying fundamental mechanisms of biomineralization 1 . Model systems range from prokaryotic organisms, such as magnetite formation in magnetotactic bacteria 2-4 , to eukaryotic organisms, such as silica biomineralization in diatoms 5,6 . Understanding biomineralization in these organisms in terms of crystal nucleation and growth, as well as the involvement of biological macromolecules and cellular processes, is of fundamental interest to scientists as similar principles can be used to develop synthetic nanomaterials.Magnetite biomineralization by magnetotactic bacteria is a topic of great interest in nanotechnology 7-12 , functional materials [11][12][13][14][15][16] , and astrobiology 17 . Magnetotactic bacteria take up soluble iron species that they use to biomineralize chains of magnetite nanocrystals, known as magnetosomes, in intracellular membrane vesicles 2 . The nanocrystals have nearly perfect mineral crystal structures with consistent species-specific morphologies, leading to well-defined magnetic properties 2,3,9,12,18,19 . As a result, magnetotactic bacteria are one of the best model systems for investigating the molecular mechanisms of biomineralization. Magnetite biomineralization in these bacteria is a complex process involving a number of steps including cellular uptake and reduction of ferric ions, complexation of the iron with membrane proteins, an...

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“…As a result, the total magnetic energy of such single-domain nanoparticle has 8 equivalent energy minima separated by relatively low energy barriers. This makes these nanoparticles promising for application in biomedicine [4,5].…”

Section: Introductionmentioning

confidence: 99%

Specific Absorption Rate of Assembly of Magnetite Nanoparticles with Cubic Magnetic Anisotropy

Nesmeyanov¹,

Gubanova²,

Belyaeva³

et al. 2018

KEn

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The presence of strong magnetic dipole interaction in assemblies of fractal clusters of nearly spherical magnetite nanoparticles, which arise in a biological media loaded with magnetic nanoparticles, leads to a significant decrease of the specific absorption rate of these assemblies in alternating magnetic field. However, the specific absorption rate of the assembly can be increased if the nanoparticles are covered by non magnetic shells of sufficiently large thickness comparable with the nanoparticle diameter.

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Magnetic properties of bacterial magnetosomes as potential diagnostic and therapeutic tools

Cited by 296 publications

References 10 publications

Controlled cobalt doping in biogenic magnetite nanoparticles

Controlled cobalt doping in biogenic magnetite nanoparticles

Correlative Electron and Fluorescence Microscopy of Magnetotactic Bacteria in Liquid: Toward In Vivo Imaging

Specific Absorption Rate of Assembly of Magnetite Nanoparticles with Cubic Magnetic Anisotropy

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