Scratching the Surface: Engineers Examine UV Effects On Skin Mechanics

http://www.sciencedaily.com/releases/2012/10/121005123900.htm

ScienceDaily (Oct. 5, 2012) — Researchers in Stanford's Department of Materials Science and Engineering are using models derived in mechanical labs to look closer at how ultraviolet radiation changes the protective functions of human skin.

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Schematic of the structure of human skin and penetration of different UV wavelengths. UVB penetrates mainly the epidermis. (Credit: Courtesy PNAS)

Reinhold Dauskardt, PhD, of Stanford's Department of Materials Science and Engineering has been studying skin for years. But when he sent his students to look for data on the mechanical properties of skin, they came back empty-handed. A lot was known about skin structure and disease, but few papers actually talked about its mechanical function -- its ability to stretch and resist tension without tearing. "That motivated us to get more interested in the skin itself," said Dauskardt.

He and his team, including Ph.D. student Krysta Biniek and postdoctoral researcher Kemal Levi, focused on the outmost layer of skin: the stratum corneum. It protects deeper layers from drying out or getting infected, and it's also our first line of defense against UV radiation. Their study was published October 1 in the Proceedings of the National Academy of Sciences (PNAS).

They found that beyond the well-documented DNA damage and cancer risk, UV rays also change the way the outermost skin cells hold together and respond to strain.