Skin barrier, structure, and properties

Abstract

Terrestrial life was only made possible through the adaptive evolution of a waterproof barrier in the integument of organisms. In man, like in all other land-living higher vertebrates, this barrier is constituted by a uniquely organized lipid material situated between the cells of the horny layer of skin. Not having a native reference for the molecular organization of the horny layer’s lipid material has until recently limited our fundamental understanding of the skin both in healthy and disease states, and hampered technological progress in areas such as development of treatments for skin disease, transdermal drug delivery, dealing with toxicity from topical exposure to chemicals, and the development of noninvasive diagnostic sensors.