Researchers in the Materials Science and Engineering (MatSci) department examined the effects of ultraviolet (UV) rays on skin cells and found that the rays loosen bonds between neighboring skin cells, causing the skin to become more brittle.

The researchers, led by MatSci Assoc. Chair Reinhold Dauskardt, doctoral student Krysta Biniek and postdoctoral researcher Kemal Levi, concentrated their attention on the stratum corneum – the outermost layer of the skin – and how UVB radiation affects those skin cells. UVB rays are the type of UV rays that most frequently cause sunburns and skin cancer.

Dauskardt’s team was initially interested in the behavior of the material that solar panels are made of but eventually applied the same investigative techniques to skin cells.

Skin is largely composed of dead skin cells – corneocytes – connected by wax-like substances that hold the corneocytes together and prevent water from penetrating the skin. They found that greater exposure to UVB rays caused the lipids in the wax like substances to be more poorly bonded together, increasing the skin’s tendency to absorb water and decreasing its resistance to tearing under pressure.

However, when the team mounted skin cells onto opposing grips and pulled them apart, they found that skin cells that had been exposed to more UVB were no less resistant to being pulled apart than samples with less UVB exposure.

The research team also characterized UVB rays as a “double-whammy” because they not only damage the connective material but also damage the cells such that they cannot repair the connective material.

The study was published Oct. 1 in the Proceedings of the National Academy of Sciences.

–Alice Phillips