Researchers assess risks posed by nanoparticles

Credit: Adelaide Cole/Art Editor Credit: Adelaide Cole/Art Editor

Tiny particles, some 100,000 times smaller than the thickness of a sheet of paper, are playing an increasingly important role in our lives. Nanoparticles, as they’re called, can be found in eyeglasses, tires, and even sunscreen. Recently, Carnegie Mellon researchers have been discussing nanoparticles’ prevalence in the natural world and their potential to greatly alter the way we live.

As part of a larger consortium of faculty members from universities known as the Center for Environmental Implications of NanoTechnology (CEINT), professor Greg Lowry in the department of civil and environmental engineering recently teamed up with professor Elizabeth Casman in the department of engineering and public policy to discuss the prevalence of nanoparticles in nature and their implications in the environment. Their recent study, published last month, focuses on the prevalence, dynamic qualities, and environmental effects of nano particles.

Nanoparticles are microscopic molecules that are the building blocks for many engineered products and are typically 100 nanometers in size, although some are even as small as one nanometer. Nanoparticles have been engineered by scientists for years, but their presence and effects in nature had remained a mystery.

Cue James Hutchison. Hutchison, of the University of Oregon, experimented with the interaction between silver nanoparticles under a variety of conditions. He found that silver nanoparticles reacted differently under various environmental conditions, and arrived at the idea that nanoparticles are abundant in nature.

Casman explained, “When these silver nanoparticles were placed in water, there was a production of more nanoparticles. The results indicated the idea that nanoparticles are ubiquitous in the natural world.”

This information stirred some curiosity within CEINT. As Casman noted, “This revelation inspired us to discuss, ‘What do we know about how nanoparticles can be formed in nature?’ ” The researchers mapped out what they already knew, including the idea that many nanoparticles that are found in nature are nearly identical to those engineered, and that nanoparticles played significant roles in natural processes.

The dynamic nature of nanoparticles was also an important topic of discussion. When introduced to the environment, their incredibly high surface area relative to their volume makes them prime candidates for dynamic changes in nature. “We realized that nanoparticles out of the jar, when they interact ... they don’t stay that way,” Casman said.

The new influx of information also spurred the researchers to consider the toxicity and environmental effects that come with nanoparticles, specifically with nanophases.

“Nanophases” are as small or smaller than nanoparticles and display completely different properties than their larger counterparts. For example, some nanophases of metals can be more than five times harder than their respective metal nanoparticles.

Casman and Lowry stress that nanophases must be accounted for when discussing the impact of humans producing nanomaterials, as ignoring them could lead to an underestimation of environmental risk, among other things. In an email, Lowry stated, “The potential effects of these materials on the environment and human health are unknown and must be determined prior to their widespread use in commerce.”

Despite all of this newfound information, there is still plenty that is not known about nanoparticles. “There is a lot of interesting chemistry that has yet to be worked out,” Casman noted.

More information on nanoparticles will help scientists understand how to assess toxicity, environmental impact, and environmental risks that occur when humans produce nanoparticles. Furthermore, nanotechnology may play an integral role in the future. As Lowry said, “Nanotechnology will impact areas such as nanomedicine, [and] it can help make the transportation industry more fuel efficient.” Lowry also mentioned that nanotechnology can help water treatment. The possibilities seem endless.

Indeed, nanotechnology may someday affect nearly everything we interact with. For now, however, scientists must continue to try to understand more about these enigmatic materials.