Magnetite pollution nanoparticles in the human brain
- Barbara A. Mahera,1,
- Imad A. M. Ahmedb,
- Vassil Karloukovskia,
- Donald A. MacLarenc,
- Penelope G. Fouldsd,
- David Allsopd,
- David M. A. Manne,
- Ricardo Torres-Jardónf, and
- Lilian Calderon-Garciduenasg,h
- Edited by Yinon Rudich, Weizmann Institute of Science, Rehovot, Israel, and accepted by Editorial Board Member A. R. Ravishankara July 25, 2016 (received for review April 13, 2016)
Significance
We identify the abundant presence in the human brain of magnetite nanoparticles that match precisely the high-temperature magnetite nanospheres, formed by combustion and/or friction-derived heating, which are prolific in urban, airborne particulate matter (PM). Because many of the airborne magnetite pollution particles are <200 a="" airborne="" alzheimer="" and="" as="" be="" because="" being="" brain="" by="" can="" causally="" crossing="" damaged="" damaging="" diameter="" directly="" discovery="" disease="" diseases="" enhanced="" enter="" examined="" exposure="" external="" fields="" hazard="" health.="" human="" implicated="" important="" in="" is="" linked="" magnetic="" magnetite="" might="" nanoparticles="" nanoscale="" need="" nerve="" neurodegenerative="" nm="" of="" olfactory="" oxygen="" p="" pm-derived="" possible="" production="" reactive="" respond="" ros="" s="" species="" such="" the="" they="" this="" through="" to="" toxic="" unit.="">
Abstract
Biologically formed nanoparticles of the strongly magnetic mineral, magnetite, were first detected in the human brain over 20 y ago [Kirschvink JL, Kobayashi-Kirschvink A, Woodford BJ (1992) Proc Natl Acad Sci USA 89(16):7683–7687]. Magnetite can have potentially large impacts on the brain due to its unique combination of redox activity, surface charge, and strongly magnetic behavior. We used magnetic analyses and electron microscopy to identify the abundant presence in the brain of magnetite nanoparticles that are consistent with high-temperature formation, suggesting, therefore, an external, not internal, source. Comprising a separate nanoparticle population from the euhedral particles ascribed to endogenous sources, these brain magnetites are often found with other transition metal nanoparticles, and they display rounded crystal morphologies and fused surface textures, reflecting crystallization upon cooling from an initially heated, iron-bearing source material. Such high-temperature magnetite nanospheres are ubiquitous and abundant in airborne particulate matter pollution. They arise as combustion-derived, iron-rich particles, often associated with other transition metal particles, which condense and/or oxidize upon airborne release. Those magnetite pollutant particles which are <∼200 nm in diameter can enter the brain directly via the olfactory bulb. Their presence proves that externally sourced iron-bearing nanoparticles, rather than their soluble compounds, can be transported directly into the brain, where they may pose hazard to human health.
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Des nanoparticules probablement issues de la pollution retrouvées dans le cerveau
De minuscules particules de magnétite, probablement issues de la pollution atmosphérique, ont été retrouvées dans le cerveau, selon une nouvelle étude, qui estime que ces nanoparticules pourraient jouer un rôle dans le développement de maladies neuro-dégénératives telles qu’Alzheimer/.../
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