Scientists discover how to control the 'wettability' of skin

The outermost layer of our skin acts as a protective barrier between underlying living tissue and the external enviornments. But the 'wettability' of this tissue layer can influence the spreading of chemicals and how pathogenic microorganisms stick to the skin. Researchers have discovered a way to alter the wettability of skin using an ingredient commonly found in cosmetic cleansers, and it could lead to 'waterproof' skin, as well as super soaking skin to enhance spreading of a cosmetic product or ointment. The study, led by Binghamton University biomedical engineering professor Dr Guy German, showed that the wettability of the top skin layer - called the stratum corneum - can be controlled through treatment with solutions of a surfactant called sodium lauryl sulfate, at different PH values (a scale used to specify the acidity or basicity of an aqueous solution). 'In this study, we have demonstrated that we can alter the wettability of the human skin surface using an ingredient commonly used in cosmetic cleansers: anionic surfactants,' said Dr German. How does it work? The wettability of the top skin layer can be controlled through treatment with solutions of a surfactant called sodium lauryl sulfate, at different PH values (a scale used to specify the acidity or basicity of an aqueous solution). Surfactants are chemicals which are amphiphilic - meaning they have a 'head' end that is hydrophilic (attracted to water), and a 'tail' end that is repelled by water (hydrophobic). In acidic environments, the skin has a positive charge, and the negative charge of the head group binds with the positive charge of the skin, and the tails stick up.