Electrospun Multilayer Scaffolds Based on Poly (L-Lactic Acid) and Poly (Acrylonitrile) Reinforced with CaO Nanoparticles for Enhanced Skin Regeneration and Wound Healing

This study developed electrospun single-layer and multilayer wound-healing scaffolds based on poly (L-lactic acid) and polyacrylonitrile reinforced with calcium oxide nanoparticles to evaluate how composition and layer sequence affect structural, mechanical, antibacterial, and regenerative performance. The multilayer systems formed integrated five-layer architectures with continuous interfaces between PLA and PAN regions, while CaO incorporation increased surface area, introduced mesoporosity, and modified wettability. Mechanical testing showed that neat PLA was highly deformable but weak, whereas PAN was stiffer and stronger but less extensible; the multilayer hybrids produced intermediate mechanical behaviour that better balanced flexibility and strength. The PLA/PAN/CaO multilayer scaffold showed the best overall biological performance, with strong antibacterial effects against both S. aureus and E. coli, high HaCaT keratinocyte viability, faster in vitro scratch closure, and favorable in vivo subdermal biocompatibility with cellular infiltration, angiogenic response, and connective tissue integration. Overall, the work demonstrates that multilayer electrospinning of PLA, PAN, and CaO can generate bioactive wound dressings with coordinated mechanical and biological properties for skin regeneration.