Masses of products -- from cosmetics to clothing -- now contain nanoparticles, to kill microbes, lengthen shelf life or provide other wonderful properties. But new research from MIT and Harvard suggests they could also be damaging your DNA.
Researchers from the Harvard School of Public Health's Center for Nanotechnology and Nanotoxicology have found that that both silver and zinc oxide nanoparticles appear to cause substantial damage to DNA. The scientists used high-speed screening technology to analyse progressive DNA damage following exposure to the particles, allowing them to study the effects at a much higher rate and scale than ever before.
The research, published in ACS Nano, consider nanoparticles made of silver, zinc oxide, iron oxide, cerium oxide, and silicon dioxide. Zinc oxide and silver produced the greatest DNA damage, and at a concentration of 10 micrograms per milliliter they generated a large number of single-stranded DNA breaks.
More study is required though before it's known what levels of exposure to such nanoparticles could be unsafe for humans. Bevin Engelward, a professor of biological engineering at MIT, explains:
"The biggest challenge we have as people concerned with exposure biology is deciding when is something dangerous and when is it not, based on the dose level. At low levels, probably these things are fine. The question is: At what level does it become problematic, and how long will it take for us to notice?"
That, obviously, is the next challenge. Oh, and if you're interested, you'll find zinc oxide nanoparticles in sunscreen to block ultraviolet rays, and nanoscale silver in toys, toothpaste, clothing, and other products for its antimicrobial properties. Better go naked in the shade, then. [MIT]