Size matters: silver can get under your skin.

Jan 05, 2009

Filon, FL, F D’Agostin, M Crosera, G Adami, N Renzi, M Bovenzi and G Maina. 2008. Human skin penetration of silver nanoparticles through intact, damaged skin. Toxicology doi:10.1016/j.tox.2008.09.025.

Synopsis by Carys L. Mitchelmore

Researchers show for the first time that very small silver nanoparticles, now widely used in creams and other products to kill bacteria, can penetrate skin, especially if it is cut or damaged.

The silver nanoparticles can then potentially pass into the rest of the body.

It is not known, what, if any, damage would occur if the particles enter cells and tissues. Also unknown are any potential human health effects from everyday exposure to the small amounts of the materials that could penetrate the body's protective covering.

The findings raise concerns about the health and safety of topical applications using silver materials, especially since they are in consumer products and may be applied as antibacterials on open wounds.

Every nanoparticle has its own properties. Their small size -- less than a billionth of a meter -- gives them special properties that differ from larger versions of the same material.

Laboratory research shows that each type of material differs in how it reacts with cells and living material. Titanium dioxide and zinc oxide, for instance, do not pass through skin.

An explosion in small materials (called nanotechnology) is occurring. Many commercial products benefit greatly from these new manufactured structures that can make metals stronger and electronics more efficient.

However, some experts are concerned that the impact on human and environmental health has not been adequately tested. It is often the case that technological advances are significantly ahead of complete environmental and health assessments.

In this study, the researchers used a laboratory model skin system to see if silver nanoparticles could penetrate multiple skin layers. They applied a sweat solution with silver nanoparticles to both normal (intact) or damaged (abraded) skin. After 24 hours, the authors used a powerful microscope to verify where the particles ended up. Although the silver penetrated at low levels, it was detected under the "skin," particularily in the damaged skin model.