The epidermis provides the main barrier between the human body and its environment, yet there are no good experimental model systems to study this barrier. Clonetics proposes to develop a model epidermis by culturing Normal Human Epidermal Keratinocytes (NHEK) on a suitably prepared membrane at the air-liquid interface. Stratified cell cultures of mouse or human keratinocytes are being investigated in several laboratories, but their availability is limited and the best cultures to date achieve only one-third barrier function. The Stratified Keratiniocytes on a Membrane (SKM) tissue model proposed will enable better research in transdermal drug delivery and toxicant permeation. Using preliminary results already in hand, Clonetics will demonstrate the feasibility of the SKM model and isolate the difficulties in producing the SKM for the research market. Initial work will concentrate on adequacy of substrate to promote uniform growth, culture protocols which promote stratification and differentiation, and lipid supplements to enhance lipid differentiation in the stratum corneum, the main barrier to trans-epidermal permeation. These results will yield a prototype which will be developed further in Phase II to supply the research community with a standardized viable epidermis in vitro.
