Magnetite pollution nanoparticles in the human brain

Maher, B. A., Ahmed, I. A.M., Karloukovski, V., MacLaren, D. A. , Foulds, P. G., Allsop, D., Mann, D. M.A., Torres-Jardón, R. and Calderon-Garciduenas, L. C. (2016) Magnetite pollution nanoparticles in the human brain. Proceedings of the National Academy of Sciences of the United States of America, 113(39), pp. 10797-10801. (doi: 10.1073/pnas.1605941113) (PMID:27601646)

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.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: MacLaren, Professor Donald
• Authors: Maher, B. A., Ahmed, I. A.M., Karloukovski, V., MacLaren, D. A., Foulds, P. G., Allsop, D., Mann, D. M.A., Torres-Jardón, R., and Calderon-Garciduenas, L. C.
• College/School: College of Science and Engineering > School of Physics and Astronomy
• Journal Name: Proceedings of the National Academy of Sciences of the United States of America
• Publisher: National Academy of Sciences
• ISSN: 0027-8424
• ISSN (Online): 1091-6490
• Published Online: 31 August 2016
• Copyright Holders: Copyright © 2016 National Academy of Sciences
• First Published: First published in Proceedings of the National Academy of Sciences of the United States of America 113(39):10797-10801
• Publisher Policy: Reproduced in accordance with the publisher copyright policy