Surfactant treatments influence drying mechanics in human stratum corneum

We describe a high-throughput method capable of quantifying the elastic modulus and drying stress of ex vivo samples of human stratum corneum. Spatially resolved drying deformations in circular tissue samples are measured, azimuthally averaged and fitted with a profile based on a linear elastic model. Our approach enables the comparison of the physical effects of different cleansers. We find that cleansing can cause dramatic changes to the mechanical properties of stratum corneum. In some cases, cleansing can lead to an order of magnitude increase in elastic modulus and drying stress. We expect that these mechanical properties have a direct impact on cracking and chapping skin as well as the milder sensation of perceived tightness often experienced after washing. Mechanical drying studies are also combined with drop wetting studies and pyranine staining experiments. This combination of techniques allows one to establish a multidimensional profile of stratum corneum including stiffness, susceptibility to drying, hydrophilicity and barrier functionality.