Construction and Performance Study of a Janus Dressing with Sustainable Drainage Function.

In the field of wound exudate management, Janus dressings with unidirectional fluid transport capabilities have garnered extensive attention. However, the hydrophilic layer tends to be saturated during application, which often leads to significant declines in the drainage efficiency. To address this issue, this study constructed a Janus dressing with a hydrophilic-hydrophobic wettability gradient that could continuously evaporate the fluid in the hydrophilic layer. The hydrophilic nanofibers of poly(vinyl alcohol)-MXene (PVA-MXene) were deposited onto a hydrophobic nanofiber layer of polyurethane-MXene (PU-MXene) by sequential electrospinning to form a Janus dressing with asymmetric wettability. The dressing can enable unidirectional transport of exudate from the wound bed to the hydrophilic layer to effectively prevent the rewetting of the wound by the expelled biological fluid. The incorporation of MXene endows the dressing with photothermal responsiveness, allowing it to continuously expel exudate at a stable evaporation rate and maintain a moisture-unsaturated state. In addition, the photothermal effect imparts antibacterial activity to the dressing to prevent wound infections. In the application study using a rat wound infection model under NIR irradiation, the dressing demonstrated anti-inflammatory effects, promoted collagen deposition and angiogenesis, and thus significantly accelerated the wound healing process. Our study offered an innovative approach to the development of Janus structure dressings and provided an effective solution for wound exudate management.