How does our top layer of skin -- the thin stratum corneum -- manage to keep water inside our bodies and microbes out, all while maintaining strength and elasticity, at just a fraction of the thickness of a sheet of paper?
In the first tests of its kind, scientists at the University of Bath are using a tiny "microneedle" with atomic force microscopy to probe the surface of the top layer of human skin and solve some of these mysteries.
Until now, researchers were able to use this form of microscopy only to analyze the surface of corneocytes, the cells that form the outer layer of the epidermis. Now, by adding a nanoneedle to the end of the probe, they can delve below the surface and shine a light on the cell structure within.
As they report in the Journal of Investigative Dermatology, the scientists are already seeing in their human volunteers a clear difference between the softer, external layer of corneocyte and the more rigid, internal structure. As they continue to employ their new technique, they hope this mechanical scan of the skin will shed light on the biomechanical changes that occur through aging, skin disease, environmental factors, and so on
"A deeper understanding of the biomechanics of skin barrier function, and the relationships between this role and the physical properties of human skin cells, may lead to the development of new therapeutic or cosmetic products to restore or reinforce the skin," Professor Richard Guy from the Department of Pharmacy & Pharmacology said in a school news release. "This would benefit, for example, individuals with dry or eczema-prone skin and, perhaps, the ever-increasing aging population whose skin becomes progressively fragile over time."
As for the needle.... Any volunteers? Come on, it's for science!