"Double-sided protector" Janus hydrogels for skin and mucosal wound repair: applications, mechanisms, and prospects

Skin and mucous membranes serve as crucial barrier tissues within the human body. Defective wound healing not only inflicts pain but also heightens the risk of infection and impairs immune function. Janus hydrogels possess two-sided distinct asymmetric structures that endow them with diverse properties such as high water absorbency, flexibility, anti-adhesion ability etc. These hydrogels also exhibit great potential in biofluid transport, drug delivery and promoting tissue repair. Currently, research efforts predominantly concentrate on the preparation techniques, properties, and biomedical applications. This review summarized its structural characteristics and different forms of designations, and focused on the possible mechanisms, the existing problems and improvement strategies for the skin and mucous tissues wound, aiming to provide new design ideas for repairing complex skin and mucous membrane tissue defects.