Sustainable collagen-based films cross-linked with Vitex agnus-castus for enhanced water retention and thermal stability

This study presented a sustainable methodology for designing collagen-based biomaterials by using natural reinforcing agents and environmentally friendly cross-linking to improve water absorption, water retention and thermal stability − key features for biomedical and environmental applications. Collagen films were enhanced with keratin and natural polysaccharides (carboxymethyl cellulose, microcrystalline cellulose, acacia gum, soy protein, and carrageenan), then cross-linked by Vitex agnus-castus (VAC) extract as an eco-friendly alternative for synthetic cross-linkers. Glutaraldehyde was used for comparative analysis. A series of comprehensive analyses were conducted, including Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and water absorption testing. Among all compositions, films containing 30% acacia gum and 3% VAC demonstrated the highest water absorption and retention capacity (5.90 g/g after 48 h) and enhanced thermal stability, with the minimal weight loss observed at 600 °C. FTIR analysis confirmed enhanced molecular connections through cross-linking, while DSC results validated increased structural resilience. The results indicated that VAC serves as both a structural and functional cross-linker, facilitating the creation of biodegradable, thermally resilient, and moisture-retentive films. This natural system presents significant potential for wound dressing and other biomedical applications within a sustainable material framework.