Gelatin-St. John's Wort Oil Matrices: Material Properties for Potential Biomedical Applications

This study investigates physicochemical, mechanical, and thermal effects of St. John's wort (JW) oil on gelatin-based films for potential biomedical applications as there is limited research on gelatin biomaterials containing JW oil as sole bioactive component. Transparent films were fabricated at gelatin:JW oil ratios of 20:0, 20:1, 20:5 (w/w) designated as JW-0, JW-1, JW-2, respectively, via solution casting. Gas chromatography revealed that JW oil is rich in unsaturated fatty acids, predominantly linoleic and oleic acids, while FTIR confirmed their successful integration into the gelatin matrix through the fatty acid peak at 1743 cm^-1. Oil droplets, increasing with oil content was shown by SEM. JW oil improved water durability by reducing water aging by up to 8%. JW oil acted as a plasticizer, raising elongation at break (EAB) from 188% in JW-0 to 231% and 209% in JW-1 and JW-2, respectively. DSC indicated a higher T_max in JW-1 (116 °C) compared to JW-2 (110 °C), evidencing better thermal stability. In conclusion, JW oil can be effectively incorporated into gelatin as a single active component. Specifically, JW-1 formulation achieved an optimal balance between mechanical and structural integrity, flexibility, and thermal stability, underscoring its potential as a cost-effective, bioactive wound dressing material.