The New Attempt at Modeling of the Three-Dimensional Geometry of the Epidermal Skin Layer and the Diffusion Processes of Nanomolecular Drug Carriers in Such Structures.

Nanoparticles are presently considered the efficient carriers of medicals, cosmetics, and pharmaceuticals in the human organism. There is a lot of research carried out on the delivery of these materials in a non-invasive way. Such a method is very safe in times of global illnesses and pandemics. The most frequently investigated route is the approach to delivering nano-media through the skin as the result of diffusion processes. The stratum corneum, the outermost layer of skin, is the most resistive barrier to such a form of penetration. In this work, a new model is proposed to predict nanoparticles' transport through this layer. It introduces the concept of the three-dimensional model of the stratum corneum, which allows to define the skin surface area from which diffusion occurs. This structure was replaced by the single capillary, resulting from theoretical considerations. Modeling of the diffusion process of nanoparticles as the result of Brownian motion in such a capillary was performed numerically using COMSOL Multiphysics package programs. Further, using the dimensions of such a capillary, a new model of diffusion was developed in which the parameters allow to determine the effective diffusion coefficient as a function of nanoparticle size and the viscosity of a liquid. As a result, the proposed models provide a new and efficient approach to the determination of the nano-molecules' transport phenomena through the skin layer.