Carboxymethyl chitosan-gelatin based films filled with whey protein-stabilized nanoscale essential oil for skin wound healing: In vivo and in vitro studies

Wound healing and antibiotic resistance present significant clinical challenges, underscoring the need for innovative bioactive wound dressings. This study prepared green-sustainable bioactive films by incorporating Litsea cubeba essential oil nanoemulsion (LCEO-NE) into a carboxymethyl chitosan-gelatin composite matrix, with essential oil in the films stabilized by whey protein for the first time. Fourier-transform infrared spectroscopy (FTIR) confirmed the interaction between the nanoemulsion and the matrix, resulting in altered absorption peaks. Scanning electron microscopy (SEM), X-ray diffraction (XRD), and thermogravimetric analysis (TGA) revealed that the addition of LCEO-NE increased the surface roughness, crystallinity, and thermal stability of the films. Furthermore, incorporating LCEO-NE significantly enhanced the physical properties and bioactivity of the films, with CGL-3 exhibiting optimal performance: tensile strength of 2.31 MPa, elongation at break of 72.31 %, strong antibacterial and antioxidant effects, excellent water absorption, biocompatibility, prolonged essential oil release (66 h), a water vapor permeability of 40.73 g/m 2 /h, and a contact angle of 82.23°. In vivo testing in a mouse model showed a 99 % wound healing rate by day 15 following treatment with the CGL-3 film, along with enhanced collagen deposition, accelerated epithelialization, and reduced inflammation. Overall, the CGL-3 film holds great promise for advanced wound care applications.