"Certainly it is a very good antimicrobial product," says Zhiqiang Hu, a civil and environmental engineer at the University of Missouri–Columbia, who is studying the safety of silver nanoparticles. "But, it can kill the benign species [of bacteria] as well."
Hu says one of his major concerns is their potential effect on aquatic organisms. Many types of bacteria live in lakes and streams, and if silver nanoparticles were to get into these waters they could disrupt the aquatic ecosystem.
Hu is not the only one worried. Andrew Maynard, chief science advisor for the Project on Emerging Nanotechnologies, funded by the Woodrow Wilson International Center for Scholars and The Pew Charitable Trusts, is also concerned about the lack of research and regulation on the use of silver nanoparticles. He says this technology is cropping up in unlikely products, such as socks, kitchenware and cosmetics, to name a few.
"You have an antimicrobial agent appearing everywhere, including children's fluffy toys, with no knowledge about its health or environmental implications," Maynard says. "What are the chances of it taking out an ecologically important bacteria?"
It is this question that Maynard wants answered before the technology is applied to any more commercial products. On the other hand, Maynard acknowledges that the use of silver nanoparticles holds promise, particularly in hospital settings.
"I think there are multiple places in which it would be okay," Maynard says. Treating patients with wounds or creating a sterile environment in a hospital are two examples of what he sees as a good use.
"Silver is one of our best lines of defense against a number of microbes," he says. "And we need to think carefully before we put such a powerful agent in the market."
This article is provided by Scienceline, a project of New York University's Science, Health and Environmental Reporting Program.