Deciphering Skin Mechanics to Develop Next Generation Therapies
Dr. Kemal Levi, Bio-X Consulting
Date: Friday, May 16, 2014
Place: EA 409
The stratum corneum (SC) is the principal mechanical interface between the epidermal and dermal layers and the exterior environment, and thus, plays a crucial role in determining the stress state in skin. The stresses in the SC provide a mechanical driving force for skin damage processes such as cracking and chapping, and affect fibrosis, scar formation and various tissue responses including inflammation and expression of growth factors. Although it is becoming increasingly clear over the years that the stress state of the tissue influences skin damage and healing processes, this connection still remains elusive due in part to a paucity of quantitative methods to characterize these stresses in vivo as a function of tissue condition and treatment. In the present study, we utilize thin-film mechanics methods together with finite element analysis (FEA) and digital image speckle correlation (DISC) to characterize the efficacy of skin care treatments on human skin in vivo. We show how most moisturizing treatments have a positive effect in alleviating drying strains and stresses immediately after application. In the long term, however, we show that there is substantial difference in the effects of moisturizers in alleviating skin stresses. In fact, some treatments actually increase the overall stress state of skin to a higher level which may actually lead to skin damage. The selected treatments include widely popular moisturizing products in the consumer care market, including humectants (e.g. glycerin based creams), occlusives (e.g. petroleum jelly) and emollients (e.g. jojoba oil). We also demonstrate that the stress state of skin is very sensitive to UV-induced alterations in the molecular conformation and organization of both the protein and lipid content of the tissue and describe how our thin-film mechanics methodology can be used to quantify UV-induced damage and sunscreen efficacy. This research has great implications in understanding both short term and long term effects of skin care treatments in alleviating and leading to dry skin damage. This research also has wide impacts on formulating better and more effective treatments both in the cosmetic and medical dermatology industries.
Dr. Kemal Levi is a researcher, entrepreneur and scientific consultant for medical device and biotech industries. He is the founder of Bio-X Consulting, a technology and consulting firm which partners with clients in technology innovation and development. He has authored numerous patents and publications in his field of expertise and is a frequent speaker on skin and polymer science. Dr. Levi received his doctorate in Materials Science and Engineering from Stanford University where he worked on mechanical and fracture behavior of polymer thin films and layered structures. These include human skin, fuel cell membranes and solar cells. The findings of his research have received wide claim in the area of dermatology science and thin films, been published in prestigious journals and as a book chapter in a medical dermatology textbook. The novel techniques he developed to characterize skin stresses and efficacy of skin care treatments have already been adopted by industry leaders and the dermatology science community.