Antibacterial and immunomodulatory core–shell nanofibrous membranes accelerate skin wound repair and regeneration

Complex skin wounds are complicated by infection, inflammation, and delayed regeneration, necessitating wound dressings with antibacterial, immunomodulatory, and regenerative properties. Here, we developed a coaxial core–shell nanofibrous membrane that integrates structural and bioactive components within a multifunctional dressing. The membrane comprised poly(lactic acid) (PLA) reinforced with nano-hydroxyapatite (nHA) as the structural core and poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) as the bioactive-loaded outer shell. Formulations included: PLA/PVDF-HFP (PPN0B0), PLA–3% nHA with 2% curcumin and 4% vitamin B12 (PPN3B2), and PLA–3% nHA with 4% curcumin and 8% vitamin B12 (PPN3B4). Membranes were characterized by field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FTIR), water contact angle (WCA), and tensile testing, followed by in vitro and in vivo biological evaluation. Bioactive incorporation reduced fiber diameter from 423 nm (PPN0B0) to 392 nm (PPN3B2) and 382 nm (PPN3B4) and decreased WCA from 137° to 98°. PPN3B4 showed 79% wound closure at 24 h in a scratch assay and the strongest antibacterial activity against Pseudomonas aeruginosa . PPN3B2 and PPN3B4 significantly reduced TNF-α ( p < 0.01), while IL-1β expression was reduced ( p < 0.05), and IL-10 and Arg-1 increased ( p < 0.05), consistent with an M2-associated gene-expression profile but not definitive macrophage polarization. In vivo , PPN3B4 achieved 100% wound closure by day 21, compared to 94% for the positive control and 76% for the negative control, with no evident acute systemic toxicity during the 72-h observation period. PPN3B4 showed the most favorable multifunctional response, supporting its evaluation as a wound-dressing platform.