Development, validation and characterization of a perfused ex vivo human skin model : FlowSkin ; Développement, validation et caractérisation d’un modèle ex vivo de peau humaine perfusé : FlowSkin

Organotypic models as human skin explants are the most complex and among the most representative of in vivo skin existing today to test the efficacy or the safety of molecules of therapeutic interest during preclinical studies. However, the loss of vascularization and lymphatic system in these models remains a major limitation in tissue homeostasis that impedes the prediction of skin responses to a treatment. In addition, exchanges of nutrients and oxygen being limited to diffusion, models lifetime is limited. Different strategies have been implemented to study and improve mass transport mechanism in such models. Microfluidics offers a great potential to control diffusion and convection mechanisms that permit molecular exchanges in skin models.The objective of this project is to develop, characterize and validate an ex vivo perfused human skin model. The purpose of this intra-tissue infusion is to promote the exchanges of nutrients, oxygen or drugs, but also to improve metabolic waste elimination.The first objective of my work consisted in implementing an intra-tissue flow in a human skin explant, and in setting up a process to maintain the perfused model in culture for several days. To this end, a porous device was implanted in the dermis of the ex vivo human skin model NativeSkin, developed by the company Genoskin. The implantable device is then connected to a microfluidic system allowing the infusion of compounds within the tissue.The second objective was to develop analysis methods of the diffusion of compounds in skin explants. Four methods have been developed: macroscopic and qualitative evaluation of the diffusion using a dye, the study of the diffusion in real time by X-ray radiography, the study of the diffusion in three dimensions by X-ray tomography, and finally the analysis of the diffusion of fluorescent dextrans of different molecular weights, on histological sections. A numerical model allowing to simulate the diffusion in the skin model has also been developed using COMSOL software, allowing to ...