Development of Nigella sativa essential oil loaded keratin/gelatin cryogel with antimicrobial and antioxidant properties for wound dressing

The effective management of infected and exudative wounds remains a persistent and critical challenge in clinical practice. Hydrogel-based dressings have emerged as a promising solution for wound healing due to their ability to mimic the native extracellular matrix. In this study, we developed an antimicrobial cryogel wound dressing composed of keratin, gelatin (Kr/Gel), and Nigella sativa essential oil (Kr/Gel@NS-EO). The formulation was engineered via a cryogelation process and strengthened through ionic crosslinking of sodium alginate. The physicochemical characterization using scanning electron microscope, Fourier-transform infrared spectroscopy, and tensile tests confirmed formation of a robust, porous, and fibrous cryogel structure. The material demonstrated optimal wound-dressing properties, such as high porosity, controlled solubility, appropriate moisture content, and favorable water vapor transmission rate that supports a moist environment. Biological evaluations demonstrated multifunctional efficacy. The cryogel showed broad-spectrum antimicrobial effectiveness against Escherichia coli, Staphylococcus aureus, and Candida species (minimum inhibitory concentration: 4–16 µL/mL), significant antibiofilm activity (65–80% inhibition), high biocompatibility (~ 95%), and potent antioxidant capacity (~ 60–100%). In conclusion, Kr/Gel@NS-EO cryogel combines targeted antimicrobial delivery, strong anti-biofilm action, excellent biocompatibility, and controlled release, making it a highly promising candidate for advanced wound management.