Thermal analysis of human stratum corneum.

A thermal analysis technique has been developed and used to detect the melting of lipids and denaturation of proteins in stratum corneum. Trasitions were observed at 40 degrees C, 75 degrees C, 85 degrees C, and 107 degrees C. The transitions at 40 degrees C were attributed to the melting of lipids. The transition at 85 degrees C was identified as due to the denaturation of alpha-keratin, and the transition at 107 degrees C to the denaturation of a nonfibrous protein. It was found that alteration of the conformation of the nonfibrous protein changed the state of water absorbed, and that water contributed to the ordering of the lipid and protein. The thermal analysis technique may prove to be of value in studying the interaction of materials with skin.