Nano on (and in) the Brain

​by Michelle Muzzio, 2nd Year Chemistry PhD Student

Don’t worry, it is all in your head.
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Typically considered a trivial idiom, this phrase becomes a bit more alarming when “it” is magnetic nanoparticles and “it” is backed by experimental and theoretical data. A recent study published in PNAS by Maher et al. highlights the presence of exogenous (not of a biological origin) iron, cobalt, nickel, and even platinum nanoparticles in human brain samples. The work has been picked up by popular science outlets and major media alike such as Science Magazine, Newsweek, Chemical and Engineering News, and the Huffington Post. Crossing the publication-to-publicity barrier is a feat that most publications will never accomplish with their primary demographic being frazzled graduate students, uninspired postdocs, and curious-but-skeptical professors.

What then is the responsibility (if any) of the scientific papers that journey into the promised land of trending and retweeting? When science leaves the laboratory and then also leaves the carefully veiled community of publications and conference proceedings, the successful communication of science (or lack thereof) becomes a science in and of itself. 
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A transmission electron microscope (TEM) image of the particles found in human brain samples shows that their sizes are < 200 nm, and are monodisperse (have similar size and shape) compared with endogenous analogs.

Multiple comments about the PNAS article via the various news outlets highlight two alarming claims made by the article. First, the exogenous nanoparticles have been linked primarily to increased pollution. Second, the presence of the magnetic nanoparticles was shown to increase the probability of Alzheimer’s disease.

However, neither of these two claims came directly from the PNAS article.

Comments made on popular science pieces about the PNAS article range from genuine concern to sarcasm to anger to the occasional meme.

The Daily Mail article about the PNAS article did not include TEM images, XRD patterns, or any actual data. Instead, they included this photo of an older person looking distraught, in a way we as readers are meant to interpret as suffering from Alzheimer's disease caused by magnetic nanoparticles. Also included in the article was a photo of a car exhaust, insinuating pollution from the motor industry is the primary cause of the nanomaterials.

If you are confused, here is why. Maher et al. highlight that the presence of magnetic nanoparticles in the brain is not a positive thing. This is the first report confirming exogenous nanoparticles finding a way into the brain, and this ​is the story you should be reading about. They further cite research that the presence of metal ions has been linked to the formation of reactive oxygen species (ROS). From this, they cite additional research in which ROS have been linked to the increased probability of Alzheimer’s disease. The article concludes with a call for more research, but that’s it. Why then, does the Daily Mail title their popular science article about this research, “Is this behind the rising rates of Alzheimer’s?” Such an alarmist title is sure to make the casual reader click and read, but it also designs a reader’s response to an article before he or she even reads it and therefore, designs how a reader will forward (either electronically or by word-of-mouth) the information to family, friends, and colleagues.

​In the second to last paragraph of the article, the Daily Mail concludes that the PNAS article did not, in fact, conclusively link the magnetic nanoparticles to Alzheimer’s disease. However, the damage has already been done. The dramatic headline photo they chose of an older person looking distraught (obviously because of all the nanoparticles in her head?) will easily stick with a malleable reader able to understand the science if it was communicated properly, but instead fed a diluted filter of what the news thinks readers want to read.

Even more problematic is the source of the nanoparticles, which almost all of the popular science pieces attribute to increased pollution. While the PNAS article mentions roads, brake pads, and catalytic converters (platinum nanoparticles are extremely well-studied and utilized in the automotive industry) as potential sources of the exogenous nanoparticles, they also mention other potential sources that are not discussed in most of the popular science pieces. These include inkjet printers, open fires in homes, and graduate research in nanoparticle synthesis (alright, maybe that last one was not mentioned).

​Therefore, following the same logic of some of the popular science pieces, any story could be rewritten to potentially say office work and cozy nights curled up next to the fire increase the link to Alzheimer’s disease. But that would be ridiculous now, wouldn’t it?

​So maybe this is a harder problem than scientists are ready for. Scientists are expected to do good science and report it; it is not necessarily their concern how others (especially mainstream and social media) understand and communicate their science. Maybe it is also too hard of a problem for the journalists who are trying desperately to gain readership while remaining true to their source material. In the end, the burden of truth (fortunately or unfortunately) falls on the reader. It is all in your head, both nanoparticles and the ability to constantly question how science is being presented to you.

Maher et al. end the PNAS article by suggesting that more research must be done linking pollution (and other sources that were not mentioned in most popular science pieces) to nanoparticle presence in the brain, "In addition to occupational settings [including, for example, exposure to printer toner powders], higher concentrations of magnetite pollution nanoparticles are likely to arise in the indoor environment from open fires or poorly sealed stoves used for cooking and/or heating, and in the outdoor environment from vehicle (especially diesel) and/or industrial sources." Above could have been a headline photo for a popular science piece that focused on open flames, instead of pollution and Alzheimer's disease. Would you click on it?