A few years ago, PBS interviewed Andrew Maynard, director of the Risk Science Center at the University of Michigan. He warned about the potential danger of nanomaterials, which are increasingly being used in everything from food products to sunscreen. Maynard wondered:
You take a substance and you make it very, very, small, and suddenly it begins to show new behaviors. It might show a very different chemical or biological behavior, so immediately you have to ask, "does that lead to new risks? Or it might simply be that if it’s very small it can get to new places…But as yet, we have remarkably little information on actual health effects. We just have this hint of doubt that there might be something new happening.
Maynard was right: the small size of nanomaterials does make them risky to human health. A new study published in Environmental Health Perspectives found that titanium dioxide nanoparticles and carbon nanotubes--two nanomaterials often found in lightweight sports equipment and paints--can cause lung inflammation in mice and rats. It isn’t the first study to show that these substances trigger inflammation, but it is the only study where researchers from multiple institutions across the U.S. were able to replicate the findings.
The researchers, who conducted the study as part of the NIEHS NanoGo Consortium, hope that their work will be used as a guidepost for future regulations of engineered nanomaterials (ENMs). They write:
We are only beginning to understand the mechanisms of toxicity for the increasing variety of emerging ENMs. Growing evidence indicates that nanosizing particles increases toxicity because of a proportional increase in surface area that is then available to generate ROS, a primary factor that drives cellular stress and disease pathogenesis (Nel et al. 2006). However, in addition to the obvious role of increased surface area and ROS generation, nanosized particles could be capable of moving across cellular barriers to interact with subcellular structures (e.g, mitochondria, microtubules, organelles, DNA) in potentially unique ways that we have yet to fully comprehend.
It’s possible that humanity is getting a little ahead of itself with today’s widespread use of nanomaterials. And we probably should have conducted these types of studies before unleashing nanomaterials upon the world. But that’s rarely what happens with toxic (and potentially toxic) materials, so we’ll have to be satisfied with the fact that scientists are working towards creating safety guidelines.
As the researchers note: "The disproportionate emphasis on nanotechnology research and development relative to issues of risk for human health and the environment could result in a new wave of occupational and environmental health crises. While many ENMs will present little or no risk, it is inevitable that at least some ENMs will pose a significant risk to human health and the environment."