Biodegradable chitosan–gelatin films incorporating Zanthoxylum limonella (Dennst.) Alston essential oil for antibacterial and hemostatic applications

The development of biodegradable and multifunctional films is a promising approach toward sustainable biomedical materials. In this study, chitosan–gelatin composite films incorporated with varying concentrations (0–2.5% w/w) of Zanthoxylum limonella essential oil were successfully fabricated and systematically characterized. The incorporation of essential oil increased film porosity and microstructural heterogeneity, as observed by scanning electron microscopy. Mechanical analysis revealed that tensile strength significantly improved from 17.21 ± 1.19 MPa in the control film to 39.04 ± 1.06 MPa at 2.0% essential oil concentration, while elongation at break increased from 70.41 ± 1.21% to 88.62 ± 1.72%. Essential oil addition enhanced surface hydrophobicity, indicated by the increase in contact angle from 56.41° to 72.99°, while water vapor permeability remained statistically unchanged. Fourier transform infrared spectroscopy and thermal analyses confirmed the physical incorporation of the essential oil without altering the chemical structure of the polymer matrix. The films exhibited dose-dependent antibacterial activity against Escherichia coli and Staphylococcus aureus. Minimum inhibitory concentration (MIC) and fractional inhibitory concentration index (FICI) analyses demonstrated synergistic effects at higher essential oil concentrations. Preliminary hemostatic evaluation showed enhanced blood absorption capacity from 325 ± 10% to 651 ± 20% and a reduction in whole blood clotting time from 10.53 ± 0.41 to 4.18 ± 0.38 min, comparable to the positive glass control. These biodegradable chitosan–gelatin films demonstrate promising antibacterial functionality and preliminary hemostatic potential.