A comparison of two- and three-dimensional models for the simulation of the permeability of human stratum corneum

The stratum corneum is the outermost layer of cells in mammalian epidermis. It is widely believed to play the key role for the barrier function of the skin. This study characterises how the cell geometry influences the permeability of the membrane. It is based on a diffusion model, which is evaluated using numerical simulation. Three different geometry concepts, i.e., ribbon, cuboid and tetrakaidekahedral type, in two and three space dimensions are compared. The results confirm that tetrakaidekahedral cells with an almost optimal surface-to-volume ratio provide a barrier, in which a minimal amount of mass is used very effectively. Additionally, the study supplies tools to quantify this and links the results to the theory of homogenization.