April showers bring May patients who may be confused about the safety of sunscreens containing nanoparticles of titanium and zinc.
To help alleviate concerns, the Nanodermatology Society released a position statement on the safety of sunscreens containing nanoparticles. Dr. Adam Friedman, vice president of the Society and senior author of the position statement, spoke to our sister blog The Mole about the safety of nano-based sunscreens.
The Fears
The concern is that nanoparticles might interact directly with cell DNA and cause damage because of their size and their ability to not only penetrate the skin but to enter the body through the mucosa in the nose, or to be swallowed, Dr. Friedman said.
The Facts
Photo credit: Flickr user pni (Creative Commons)
Nanoparticle penetration is limited by size. “One of the things I tell people is that the materials they are using in bench research are different than what is used in over-the-counter products,” Dr. Friedman said. “Those used in consumer products are commonly coated, so they aggregate and don’t penetrate the skin as easily.”
“Thus far, everything that has been done in terms of topical application of the skin, the particles do not penetrate to the point where they could cause problems,” said Dr. Friedman. “Clearly, more needs to be done, and certain clinical situations need to be explored, such as penetration into damaged skin,” he noted. When the nanoparticles are aggregated in solution, they are trapped in the upper layers of the skin, where they are sloughed off over time.
“A lot of the fear with respect to the bodily harm from nanomaterials comes from the lung literature and occupational hazards with respect to people inhaling asbestos,” he noted.
Another concern about nano-based sunscreens is the potential impact on the environment, Dr. Friedman said. However, a hot-off-the press study in Science of the Total Environment by A. Johnson and colleagues found no impact of titanium oxide sunscreens on the environment.
—Heidi Splete (on Twitter @hsplete)