There is hope that nanotechnology in the form of silver nanoparticles will provide protection against drug-resistant bacteria in hospitals, but there is also concern that unregulated use of silver nanoparticles in commercial products will damage the environment. A mention on KurzweilAI.net led to this article by Monica Heger on SciAm.com News, provided originally by Scienceline. From “A Silver Coating in the Fight Against Microbes“:
A new technique in paint making could soon make almost any surface germ-free. Researchers have made paint that is embedded with silver nanoparticles, known for their ability to kill bacteria and other microbes, in the hopes that hospitals will coat their walls and countertops to fight infection.
According to the U.S. Centers for Disease Control and Prevention, more than 1 million people per year contract bacterial infections in hospitals. Silver itself is an excellent bacteria fighter, and in nanoparticle form it is even more potent at killing microorganisms. So far it has not shown any adverse effects in humans.
However, some scientists are concerned that silver nanoparticles may not be as harmless as they appear. Little research has been done on their health and environmental effects, and silver kills good microorganisms along with the bad. Also, there are currently no restrictions on using silver nanoparticles, which are already popping up in a range of consumer products that tout their antibacterial properties.
“Nanoparticles are very small and they are interacting with the bacteria and rupturing the cell wall,” says chemist George John of City College of New York and lead author of the study, published in the journal Nature Materials [abstract] last month. This rupturing kills the bacteria, he explains.
A silver nanoparticle is a small cluster of silver atoms less than 100 nanometers, or 100 billionths of a meter, wide. Because of their size, nanoparticles exhibit different properties than their bulkier counterparts. They have a high surface area to volume ratio, which makes them able to dissolve in paint. Nanoparticles are also being studied for their use in medicine, particularly in drug delivery, since they are able to pass easily through cell membranes.
…”It is more or less like a soaping or detergent effect,” says Lucian Lucia, associate professor of chemistry at North Carolina State University. The nanoparticle destroys the cell wall of the microbe.
Lucia and John both agree that bacteria cannot build up a resistance to silver nanoparticles as they can to antibiotics, because of the way the silver nanoparticle attacks — destroying the structure of the cells and killing them. Antibiotics, on the other hand, suppress the activity of bacteria but don’t necessarily kill them. “That’s the beauty of silver,” Lucia says. “There’s no way to develop a resistance to it.”
…Andrew Maynard, the chief science advisor for the Project on Emerging Nanotechnologies, funded by the Woodrow Wilson International Center for Scholars and the Pew Charitable Trust, is … concerned about the lack of research and regulation on the use of silver nanoparticles. He says this technology is cropping up in unlikely products, like socks, kitchenware and cosmetics, to name a few.
“You have an anti-microbial 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?”
And it is this question that Maynard wants answered before the technology is applied to any more commercial products. On the other hand though, Maynard acknowledges that the use of silver nanoparticles holds promise, particularly in hospital settings.
—Jim
