Ciprofloxacin and Purple Carrot Extract-Loaded Bilayer Nanofibrous Wound Dressings: A Multifunctional Platform for Controlled Release and Antibacterial Wound Care

Abstract

To effectively manage bacterial infections and support tissue regeneration, developing multifunctional, biocompatible, and stable wound coverings is critical. Here, bilayer nanofiber wound dressings were developed via electrospinning, comprising a ciprofloxacin-loaded (CIP) polyvinyl alcohol (PVA) layer and a purple carrot extract-loaded (PCrt) polyvinylpyrrolidone (PVP) layer, and cross-linked with glutaraldehyde (GLA). Compared to the PVA/CIP-PVP control, which exhibited restricted swelling (~2.65%) and limited CIP release (8.51%), incorporating hydrophilic PCrt (7% w/w) enhanced macroscopic swelling to 707.14% and provided diffusion-controlled antioxidant capacity (12.86% via DPPH). Kinetic modeling identified Quasi-Fickian diffusion, while the Peppas–Sahlin model mathematically proved that severe chain entanglement and hydrogen bonding locked the matrix (negative relaxation constant), suppressing proportional release efficiency to ~22.8%. Biologically, the PCrt-free control showed GLA-induced basal cytotoxicity (66.31% viability) and 0% antibacterial activity due to strict drug confinement. However, PCrt addition restored L929 fibroblast viability to safe levels (75–77%) via antioxidant phenolic protection. Crucially, PCrt incorporation effectively mobilized residual GLA and phenolic compounds, elevating bactericidal efficacy to 100% against both Escherichia coli and Staphylococcus aureus. Although these bilayer nanofibers show strong synergistic bactericidal effects, crosslinking strategies on the green concept should be developed to eliminate GLA-induced toxicity and ensure wound management in safe clinical conditions.