Monday, 11 October 2004 - 10:55 AM

This presentation is part of : Active Materials

Model of Water and Solute Transport through Swelling Epidermis: An Active Poroelastic Model

Cibele V. Falkenberg and John G. Georgiadis. University of Illinois at Urbana-Champaign, Department of Mechanical & Industrial Engineering, 1206 W. Green St., Urbana, IL 61801

Our research program focuses on the role of human skin as a thermal or a mass barrier. Since the hydration of the epidermis is extremely variable in response to external factors and the dermis and hypodermis are very permeable, we hypothesize that the overall barrier function is controlled by the epidermis which can swell by absorbing water supplied by the microcirculation or from the environment. The epidermis is stratified in three layers with the outmost layer (stratum corneum) composed mainly of dead keratinocytes. In this project, we extend the triphasic model we developed for the composite extracellular water-active cell phase-extracellular matrix to accommodate a poroelastic contribution from the swelling stratum corneum layer. The mathematical model accounts for active transport of electrolytes across the membrane of the live cells (keratinocytes) and the extracellular matrix. The volume of the cell phase is regulated by the fluxes of water and Na, K and Cl ions across the cell membrane and is controlled according to the time-delay scheme introduced in the model of Hernandez & Cristina (1998). A parametric numerical study of the response of the active stratified triphasic layer exposed to osmotic shocks reveals novel traveling waves. The generation of such waves in live tissue consisting of non-excitable cells might prove to serve an important physiological function akin to that exhibited by specialized excitable cells (neurons).

*Hernandez & Cristina, Am J Physiology 275:C1067-1080 (1998)

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