Multifunctional Oregano-Derived Plasma Polymer Coatings for Wound Healing Applications: An In Vitro Study

Chronic wounds, exacerbated by infection, aging, diabetes, and oxidative stress, remain a significant challenge in clinical management and impose a substantial burden on healthcare systems. This study presents oregano-derived plasma polymers (OPP) as a multifunctional surface coating for advanced wound healing applications. OPP coatings were fabricated using radiofrequency plasma-enhanced chemical vapour deposition and deposited on glass coverslips. Surface chemistry was characterised by x-ray photoelectron spectroscopy and Fourier-transform infrared spectroscopy, and hydrophilicity was assessed by water contact angle measurements. Antibacterial activity against Pseudomonas aeruginosa and Staphylococcus aureus was evaluated using LIVE/DEAD staining and confocal microscopy. Cytocompatibility, cell adhesion, and morphology were analysed using RAW 264.7 macrophage-like cells, as assessed by MTT assays and immunofluorescent staining for actin and nuclei. The immune response was evaluated by quantifying the cytokines, IL-4 and IL-6 using an enzyme-linked immunosorbent assay. Antioxidant properties were assessed by measuring lipopolysaccharide-induced intracellular reactive oxygen species via fluorescence imaging. The pro-regenerative potential was evaluated using in vitro scratch assays with human foreskin fibroblasts, monitored over 30 h with live-cell imaging. OPP surfaces retained key bioactive chemical groups and exhibited enhanced hydrophilicity. They significantly reduced bacterial viability (P. aeruginosa: ~90%, S. aureus: ~40%, p < 0.01) and supported macrophage adhesion, spreading, and viability. OPP downregulated IL-4 expression without elevating IL-6, suggesting a favourable immunomodulatory profile. OPP coatings inhibited LPS-induced reactive oxygen species production (p < 0.0001), demonstrating antioxidant activity. Scratch assays confirmed significantly accelerated fibroblast migration and wound closure on OPP surfaces (p < 0.05). OPP coatings combine antibacterial, anti-inflammatory, antioxidant, and pro-regenerative properties with excellent cytocompatibility, offering a scalable plant-based platform for advanced wound healing and next-generation nature-inspired biomaterials. This study is the first to demonstrate that oregano-derived plasma polymer coatings possess combined antibacterial, antioxidant, immunomodulatory, and pro-regenerative properties relevant to wound healing applications. Future work will focus on in vivo validation and manufacturability optimisation for clinical translation.