(520a) Understanding the Self-Assembly of Skin Lipids

McCabe, C., Vanderbilt University

The outermost layer of the skin (the stratum corneum) consists of skin cells embedded in a rich lipid matrix, whose primary role is to provide a barrier to foreign agents entering the body and to water leaving the body.  This lipid system is unique in biological membranes in that it is composed of ceramides, cholesterol, and free fatty acids, with phospholipids, which are the major components of most biological membranes, being completely absent. This unique composition enables the organization of the stratum corneum lipids into lamella, which in turn is believed to control barrier function.  While much is known about the nature of the skin lipids from extensive experimental studies, a clear understanding of how and why these molecules assemble into the structures observed through microscopy and biophysical measurements does not yet exist.  In order to probe the molecular level arrangement, we are performing atomistic and coarse-grained model simulations of key stratum corneum lipids and water. The development and validation of the coarse-grained models will be discussed alongside the results of self-assembly studies in simple mixed lipid systems that enable us to validate the models developed and work towards the study of a realistic stratum corneum system.