Trilayered hierarchical nanofibrous membrane with unidirectional water transport, sustained drug release and pH-responsive chromatic transition for wound dressing

Effective management of wound exudate is critical for promoting wound healing. However, conventional dressings often struggle to balance exudate regulation with bioactive functionality. In this study, a trilayered hierarchical nanofibrous dressing was developed via layer-by-layer electrospinning, featuring unidirectional water transport, bead-embedded drug delivery and pH-responsive chromatic transition for exudate management and wound monitoring. The trilayered composite dressing integrated a hydrophobic polyvinylidene fluoride/curcumin (PVDF/CUR) bottom layer providing controlled antioxidant release through distinct bead morphology and exudate drainage; anintermediate layer of polyvinylidene fluoride/polyacrylonitrile (PVDF/PAN) enabling directional water transfer; and a hydrophilic top layer composed of polyacrylonitrile/sodium polyacrylate/anthocyanin (PAN/SPA/An) for visual monitoring of wound pH and rapid exudate absorption. The mechanisms for unidirectional water transport and pH-responsive chromatic change were systematically elucidated. Results indicated that the trilayered hierarchical nanofibrous dressing with a layer mass ratio of 1:4:4 (bottom: intermediate: top) exhibited optimal unidirectional water transport performance, achieving a unidirectional transport index of 1325%. It also showed a sustained CUR release profile, with a cumulative release of 66.35% over 60 h, and retained excellent antioxidant activity with a DPPH radical scavenging efficiency of 98.9%. Furthermore, the dressing displayed pronounced color transitions across a broad pH range of 1–12. This work presents a multifunctional wound dressing with promising potential for postoperative care and wound therapy. Download: Download high-res image (278KB) Download: Download full-size image