This is hardly the first time, but nanoparticles are now being discussed again in connection with toxicity. The ramifications of nanoparticle use have come up in the past, and toxicity has often been the concern; however, the significance this go-round is that toxicity was said at one point to have been dispensed with at least in certain contexts. It appears that there are still some warnings that remain merited for those exposing themselves to certain uses of graphene nanoparticles, for example, or for some industrial uses of nanoparticles that researchers claim are imprudent. The health risks represented in this conversation are actually direr than one might think.

To address the more superficial concerns first (because priorities), graphene is something people may have already heard a lot about by now for its use in the form of nanoscale elements used by beauticians, engineers and everyone in between. We're talking about unimaginably thin tiles of carbon atoms being employed in water purification technologies, high-efficiency heating systems, certain heating, ventilation, and air conditioning units and other electronics. It's even used in the making of golf balls. A new study published in Chem, a peer-reviewed, scientific journal, strongly suggests that hair dyes are apparently also using these graphene nanoparticles, which presents quite the risk.

Think about how unsafe you can probably guess it is for toxic substances to come into such intimate, physical contact with your scalp in light of what's beneath that scalp. The risk factors involved should be fairly obvious, so the press release held by researchers at Northwestern University should probably surprise few people except for the extent of the misinformation. "Graphene finds new application as nontoxic, anti-static hair dye," they've just announced. Since the portrayal of graphene as a solution to a preexisting toxicity problem, stories have run in news media publications like Brinkwire and Science Magazine under headlines like "'Miracle material' graphene used to create the ultimate hair dye" and "Enough with the toxic hair dyes. We could use graphene instead" respectively.

According to the press release at Northwestern University, though, this celebration may have been premature. The early coverage suggested that the issue was decided and that graphene was the solution for which everyone had been waiting, especially environmentalists. EcoWatch's Andrew Maynard has studied environmental impacts of nanomaterials for many years, and he writes, "I find such overly optimistic pronouncements worrying, especially when they're not backed up by clear evidence."

Graphene, graphene oxide (the chemical form found in dyes) and other engineered nanomaterials aren't inherently bad, mind you. It's just that they have a tendency to be unpredictable in their reactions based on the particle shape, size, and chemistry, as well as how they're used. This is why experts have been warning against simply saying outright that these materials are just innocuous without extensive testing to prove the conditions in which their innocuousness could be verified. There's no preponderance of evidence that these materials are necessarily a threat to anyone, but there's no preponderance of evidence alluding to the safety of the materials either.

With that in mind, the new study does find that hair dyes are being manufactured with the inclusion of these nanoparticles, and the toxicity of these nanoparticles is a legitimate concern there, especially in light of yet another even more recent study published in Nature Nanotechnology this week. Scientists have demonstrated therein that, when exposed to metal nanoparticles in general, cellular barriers deploy messengers that can damage the DNA of other developing brain cells. This finding may actually prove pretty critical for drug target development when treating neurodegenerative conditions like Alzheimer's and Parkinson's, which are two examples of such diseases for which nanoparticles have been proffered as potential solutions in the form of delivery vehicles for medication.

The scientists who conducted the study were from the University of Bristol and Trinity College, and they collaborated on the study and its publication under the title "Nanoparticle-induced neuronal toxicity across placental barriers is mediated by autophagy and dependent on astrocytes." The role of nanoparticles, however, has been drastically broadening as of late in relation to chemotherapy, drug delivery, diagnostics, and imaging because they can easily maneuver cellular pathways. As such, though, they engage with cell membranes and end up modifying significant signaling pathways and processes. They also end up having an adverse effect on the health of cells that are directly exposed, and the cellular internalization of nanoparticles sometimes impinges on the health of adjacent cells somewhat like the radiation-induced bystander effect.

The research team for this study cultivated a layer of BeWo cells on a porous membrane in vitro because BeWo cells are a type of cell often used for placental barrier modeling. They exposed it not to graphene but to cobalt chromium nanoparticles; then, they took the media beneath the barrier and moved it onto human brain cell cultures whose DNA were subsequently damaged as a result. That's a pretty telling result, and we're talking about brain cells. Think about the findings from the graphene nanoparticle study with regard to hair dye, and consider the accessibility of brain cells for such fine materials that inherently seep through the scalp.

[researchpaper 리서치페이퍼=Cedric Dent 기자]