The research, which was led by Guy German, assistant professor of biomedical engineering at the university, looked into the effects of the anionic surfactant sodium lauryl sulfate, showing significant results on the outermost layer of the skin.
Specifically, the research showed that the wettability of the outer skin layer can be controlled through treatment with a variety of formulations based on the surfactant that were buffered to different pH values.
Controlling microorganisms and sensory attributes
The research team believes the discovery could not only have a significant impact controlling microorganisms coming into contact with the skin, but could also have an influence on the all=important sensory area.
"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 German.
"Skin acts as the first line of defense to the outside world and the wettability of skin plays an important role in contact inhibition of microorganisms, as well as the sensory perception of cosmetic products."
The results of the research were published in Colloids and Surfactants B: Biointerfaces journal, and underline the aim of the team to advance research that already exists demonstrating the wettability of wool and hair, into the skin care arena.
Focus on hydrophobic and hydrophilic properties
The research focused on the fact that surfactants are amphiphilic – containing both hydrophobic and hydrophilic groups, with the outcome of the research on the skin demonstrating that these small molecules can be flipped upside down.
"In acidic environments, the skin actually has a positive charge. The negative charge of the head group actually binds with the positive charge of the skin, and the tails stick up,” said German.
“When the tails stick up, that means that you’ve got a really hydrophobic surface. But when you go to alkaline conditions, you don’t get that positive charge in the skin anymore, and the tails avoid water by sticking to the skin. The exposed head groups then make the skin much more hydrophilic."
The team of researchers claim that this is the first time anyone has been capable of directly controlling the physical properties of skin through chemical interactions between keratin in the skin and surfactants.
Moving forward, the team says it wants to build on the research findings to eventually alter bacterial growth behavior on skin, or improve adhesion of biointegrated electronics and sensor systems