Magnetite in the human body: Biogenic vs. anthropogenic

Gieré, Reto

doi:10.1073/pnas.1613349113

Cited by 47 publications

(45 citation statements)

References 21 publications

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“…More recent work opined that the occurrence of magnetite nanoparticles in the brain is caused by the extraneous release of anthropogenic materials and air pollution. [ 66 ] One of the questions that arises from the discovery of externally derived magnetite in brain tissues is whether or not these nanoparticles adversely affect human health. A recent study reported that excessive accumulation of magnetic iron oxide nanoparticles in the cells of the central nervous system (particularly is astrocytes) may result in the disruption of normal iron metabolism/homeostasis, which is a hallmark characteristic of several neurodegenerative disorders.…”

Section: Microbe‐mediated Mineralization In Naturementioning

confidence: 99%

Microbe‐Mediated Extracellular and Intracellular Mineralization: Environmental, Industrial, and Biotechnological Applications

et al. 2020

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Bacteria play an important role in the calcification process of natural minerals and within organisms ( Table 1). It is Microbe-mediated mineralization is ubiquitous in nature, involving bacteria, fungi, viruses, and algae. These mineralization processes comprise calcification, silicification, and iron mineralization. The mechanisms for mineral formation include extracellular and intracellular biomineralization. The mineral precipitating capability of microbes is often harnessed for green synthesis of metal nanoparticles, which are relatively less toxic compared with those synthesized through physical or chemical methods. Microbe-mediated mineralization has important applications ranging from pollutant removal and nonreactive carriers, to other industrial and biomedical applications. Herein, the different types of microbe-mediated biomineralization that occur in nature, their mechanisms, as well as their applications are elucidated to create a backdrop for future research.

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Section: Microbe‐mediated Mineralization In Naturementioning

confidence: 99%

Microbe‐Mediated Extracellular and Intracellular Mineralization: Environmental, Industrial, and Biotechnological Applications

et al. 2020

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“…Such dimensions are smaller than diameters of crystals discovered in the brain. Transmission electron microscopy micrographs indicate that the particles in these samples are spherical [22], which means that they are not of the type of biogenic magnetite [23][24][25], but similar to the geometry of anthropogenic magnetite. Characteristics These two magnetic liquid samples were exposed sequentially, in volumes of V s = 2 ml each, in front of the portable transceiver, at distance D = 10 cm, at the measured incident magnetic field strength H = 0.22 A/m in air.…”

Section: Magnetic Fluid Characteristics and Its Dosimetric Response Tmentioning

confidence: 94%

H-Field Contribution to the Electromagnetic Energy Deposition in Tissues Similar to the Brain but Containing Ferrimagnetic Particles, During Use of Face-Held Radio Transceivers

Miclăuș¹,

Racuciu²,

Bechet³

2017

PIER B

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Abstract-A portable radio transceiver with rubber ducky antenna emitting at 446 MHz with an output power of 5 W was considered as near-field source of electric (E) and magnetic (H) field components when being used in the proximity of the user's face. By taking into account the significant content of ferrimagnetic nanoparticles recently identified to reside in the human brain, we assessed the specific absorption rate (SAR) of energy deposition due to H-component penetrating a presumptive forebrain. H-component SAR contribution to the total SAR is for the first time estimated in such a case, based on an original idea inspired from knowledge on magnetic fluids hyperthermia.

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“…The biogenic magnetite nanocrystals found in the human brain have several relevant properties [3,6,[11][12][13][14]: euhedral geometry (cuboctahedral or prismatic) manifesting crystallographic perfection; chemical purity; they can be encountered as either superparamagnetic (SPM) single-domain (SD) crystals -the most common or multi-domain (MD); the transition from the SPM phase to the SD one typically occurs at particle sizes of about 25-30 nm, while the SD to MD transition happens at sizes of about 70 nm. The large magnetic momentum of the SD nanocrystals makes it possible that they might affect biological processes -either through the H-field they generate or under the influence of an external H-field [12].…”

Section: Introductionmentioning

confidence: 99%

“…The crystals are intracellular, and occasionally they form chains, are bound to the cell membrane, and have a saturation magnetization M s = 4.5×10 5 A/m; occasionally, the crystals show unusual morphology [4]. The weight ratio between biogenic magnetite and the total crystals amounts in the brain is estimated at 1 : 500 [13]. The biogenic magnetite crystals in the human brain tend to display a rounded/spherical geometry and to have dimensions in the 5-35 nm range (median diameter in the 14-10 nm range), with a mean circularity of 0.92.…”

Section: Introductionmentioning

confidence: 99%

Would the Human Brain Be Able to Erect Specific Effects Due to the Magnetic Field Component of an Uhf Field via Magnetite Nanoparticles?

Miclăuș¹,

Iftode²,

Miclaus³

2018

PIER M

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Abstract-In 2016 a study reported observing a concentration of magnetite nanocrystals in human brains, with four orders of magnitude larger than previously thought. In the context of magnetite's role and function inside the human brain not being properly understood, this development prompts a question concerning the impact that a significant magnetic near-field component, in the hundreds of MHz range, might have on power loss in tissues having ferrimagnetic properties. This article highlights the importance of thorough research on possible thermal and non-thermal effects that could be caused by the magnetic field component to which one could be exposed while using certain communication devices near or in front of the head. Furthermore, this article provides preliminary estimations of magnetic contribution to the specific absorption rate (SAR) of energy deposition in tissues, using two approaches -one based on existing research concerning magnetic hyperthermia, and the other one based on a simulation model that takes into account the magnetic properties of tissues. By simulating the propagation of a 440 MHz wave in a "magnetic" (as opposed to pure dielectric) brain, we observed changes of the SAR values, and, more importantly, superficial hot spots appeared at the surface of small magnetite particles, distributed in the homogenous brain.

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Magnetite in the human body: Biogenic vs. anthropogenic

Cited by 47 publications

References 21 publications

Microbe‐Mediated Extracellular and Intracellular Mineralization: Environmental, Industrial, and Biotechnological Applications

Microbe‐Mediated Extracellular and Intracellular Mineralization: Environmental, Industrial, and Biotechnological Applications

H-Field Contribution to the Electromagnetic Energy Deposition in Tissues Similar to the Brain but Containing Ferrimagnetic Particles, During Use of Face-Held Radio Transceivers

Would the Human Brain Be Able to Erect Specific Effects Due to the Magnetic Field Component of an Uhf Field via Magnetite Nanoparticles?

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