A breakthrough in infection control: niaouli oil–chitosan hydrogels for enhanced wound healing

Abstract Wound healing remains a significant clinical challenge, especially in the context of rising antibiotic resistance and the demand for biocompatible, multifunctional wound care materials. In this study, we report for the first time the development and comprehensive characterization of Niaouli oil-loaded chitosan-based hydrogels (CS-N) as advanced wound dressings. The incorporation of Niaouli oil into the chitosan matrix was confirmed via FTIR, SEM, and XRD analyses, which revealed successful structural integration and altered crystalline patterns. Mechanical testing demonstrated that the addition of Niaouli oil did not significantly compromise the hydrogels’ mechanical integrity, with tensile strength values of 0.46 ± 0.020 MPa (CS), 0.46 ± 0.022 MPa (CS-N1), and 0.42 ± 0.018 MPa (CS-N2). The hydrogels also exhibited high entrapment efficiency (~ 90%) and a sustained release profile exceeding 48 h, with reduced swelling capacity compared to unloaded hydrogels. In vitro assays confirmed strong, dose-dependent antioxidant activity, with IC₅₀ values ranging from 6.94 to 8.65 mg/mL (DPPH) and 5.15–5.72 mg/mL (ABTS). The CS-N hydrogels were biocompatible with L929 fibroblasts and exhibited potent antibacterial activity against Staphylococcus aureus and Escherichia coli , with CS-N2 achieving the largest inhibition zones (30.0 ± 2.0 mm and 29.0 ± 1.0 mm, respectively). In vivo wound healing studies further demonstrated that CS-N hydrogels significantly accelerated wound closure in a concentration-dependent manner. By day 12, CS-N2-treated wounds exhibited less than 20% remaining wound area compared to over 40% in the control group. These results support the potential of Niaouli oil-loaded chitosan hydrogels as robust, multifunctional wound dressings combining mechanical stability with sustained antioxidant, antibacterial, and healing-promoting properties. Overall, this study presents a novel, multifunctional hydrogel system combining natural essential oils and biopolymer matrices, with potential for clinical translation in wound care.