Janus medical sponge dressings with anisotropic wettability for wound healing

Excessive exudates around the wound often lead to severe infections and prolonged nonhealing of the wound, and various dressings have been studied to solve this medical problem. Herein, we present novel Janus polyurethane (PU) sponge dressings with anisotropic surface wettability and unidirectional liquid transportation capability for wound healing. The specific wettability dressings were fabricated by immobilized superhydrophobic silica (SiO 2 ) nanoparticles onto one surface of the superhydrophilic PU sponges with the assistance of polydopamine (PDA). Due to the draining force provided by the superhydrophilic part, the liquid could be transported unidirectionally through the superhydrophobic surface without wetting it. Based on this advantage, it was demonstrated that the Janus PU sponges could act as biomedical dressings to solve the problem of excessive wetting between the dressing and the wound, reduce the risk of infection, and accelerate the efficiency of the wound healing process. Thus, we believe that the novel Janus dressing is ideal for the management of excessive exudates around the wound and highly desirable for clinical applications.