(NHI Nanoblog) Rats that swallowed super-small silver particles for nearly a month had bits of the metal in their brains, lungs, liver, kidneys, and digestive tracts, according to a new study by Danish scientists.
The paper, published in the journal Particle and Fibre Toxicology, concludes that more research is needed to decode why these ultra-tiny “nanoparticles” do what they do. But the study adds to a growing pile of research suggesting that nanosilver — increasingly used in clothing and other products as an anti-microbial agent — might do some worrisome things while it’s killing germs.
The researchers gave groups of rats nanosilver and silver acetate, which is commonly used as a pesticide. They chose to give the rats the silver orally “because of the use of silver nanoparticles in products related to food and food contact materials,” according to the paper.
After 28 days, the rats were euthanized and various tissues examined. The scientists found lower concentrations of silver in the rats that received the nanosilver, but concentrations of the substance in several places. They also found that the “granules” in the tissues included selenium and sulfur, raising questions about whether the silver particles dissolve in some way as they move through the body.
Nanotechnology leverages super-small particles (a nanometer is a billionth of a meter) to create products with amazing properties. These materials can make better batteries or lighter and stronger bike frames, as well as new medical instruments and medicines that can save lives.
These “nanomaterials” are believed to hold great promise for a wide variety of applications. But shrinking these substances can change their properties, and scientists are struggling to figure out whether, how and why that shift can make them dangerous in the process.
Nanosilver has become widely used, especially in health and fitness products. Studies show that the silver particles come out in the wash, which has potentially big implications for the water supply. Spray products that contain nanosilver release it into the air, and there are also questions about whether nanosilver in soil could disrupt naturally-occurring bacteria.
