Ultrathin, flexible, and piezoelectric Janus nanofibrous dressing for wound healing

The healing process of infected skin lesions is often delayed by many factors including bacterial infection, excessive accumulation of wound exudate, poor local perfusion, and low cell recruitment. Development of wound dressing for efficient wound management and promotion of wound healing is a great challenge. Herein, we constructed a Janus nanofiber dressing with the comprehensive capacities of bacterial killing, piezoelectrical stimulation for promoting fibroblast migration, and wound exudate removal via unidirectional liquid delivery. The rationally designed Janus nanofibrous dressing with ultrathin, flexible, breathable, and piezoelectric characteristics is fabricated via the facile layer-by-layer electrostatic spinning technology. The hydrophilic layer of the dressing is composed of randomly arranged polycaprolactone/gelatin (PCL/Gel) nanofibers, while the hydrophobic layer consists of well-aligned Ag nanoparticles (Ag NPs)-doped piezoelectric polyvinylidene fluoride (PVDF/Ag) nanofibers. The in vitro and in vivo experimental results demonstrate that the Janus dressing can not only drain excess wound exudate out of the wound unidirectionally and kill local bacteria, but also generate dynamic piezopotential under normal body motions to promote fibroblast proliferation and migration, collagen deposition, angiogenesis, and re-epithelialization, which accelerates rapid wound healing on mice. The smart Janus dressing will provide a new approach for acceleration of wound healing and wound management.