This work deals with the study of the biological properties of bi-layered chitosan physical hydrogels within the context of third degree burns healing. These materials are elaborated thanks to the combination of two different gelification processes, without the use of any kind of chemical cross-linking agent. Chitosan physical hydrogels exhibit interesting antibacterial properties towards Gram+ and Gram- bacteria. Long term healing study shows that the use of physical hydrogels lead to a well-organized and well-vascularised regenerated skin, whose mechanical and aesthetic properties are similar to those of native skin. The main clinical benefit of this device is that it could be maintained during the all healing time, so as to prevent the risk of infection, the pain and the damages of neo-formed tissues. Skin has been studied with several approaches, namely aesthetic, clinical, mechanical, histological, immunohistological, and nanostructural (Small Angle X-ray Scattering) approaches. The detailed histological investigations confirm bi-layered hydrogels bioactivity and cellularizability: such devices can be considered as favourable media for tissue engineering.
