The idea of having magnetite particles in our brains, possibly making us sensitive to magnetic fields, sounds exciting. A career as a Marvel supervillain anyone? Sadly, the reality is much less attractive. We are absorbing tiny particles from air pollution, and those that reach the brain may be contributing to Alzheimer’s and other neurodegenerative diseases.
The presence of magnetic nanoparticles in the human brain was discovered in 1992, but little is known about where they come from or what effects they have. A new study indicates that most of the particles were formed in a high-temperature environment, suggesting they are not a product of some strange function within the human body. Their shape indicates they are probably a result of industrialization, rather than an external biological source.
Professor Barbara Maher of the University of Lancaster used a combination of magnetic analysis and electron microscopy to study the magnetite particles in brain samples taken from 37 people who once lived either in Mexico City or Manchester, England. She found what appear to be two distinct types of particles, which she attributes to different origins. One set is angular and appears to have grown inside the body.
However, in the Proceedings of the National Academy of Sciences Maher reports that the other type “displays [a] compelling similarity with the magnetite nanospheres formed by combustion, which are ubiquitous and prolific in urban, airborne particulate matter.” Specifically, some of the particles appeared to have been fused together in ways that are hard to explain without high temperatures.
Brain slices of people from Mexico city and Manchester, with magnetite nanoparticles circles. Maher et al/Proceedings of the National Academy of Sciences.