Structurally optimized photo-crosslinkable casein-PEG hydrogels for enhanced encapsulation and functional stability...

Casein-based gel delivery systems often exhibit limited loading efficiency and functional performance under conventional formulation approaches. We present a novel UV-induced photo-crosslinking strategy for generating porous casein-polyethylene glycol gels, enhancing resveratrol stabilization and enabling controlled delivery during processing and storage. Structural characterization by FTIR and ¹³C NMR supported the formation of an enhanced covalent network via ester and amide linkages. Formulation optimization showed that 10% casein achieved a crosslinking degree of 93.32 ± 0.43% (p < 0.05), accompanied by rapid gelation (18 s) and a sixfold increase in storage modulus compared with the control, while gel electrophoresis profiles supported controlled degradation behavior. Resveratrol was efficiently encapsulated at 96.31 ± 1.40%, as evidenced by reduced fluorescence intensity in the cross-linked matrix, and the optimized gel retained 86% of the drug during storage. The optimized formulation exhibited enhanced antioxidant performance, with 27.03% higher DPPH radical-scavenging activity and 46.12% higher ABTS response compared to the non-crosslinked system, highlighting that structurally engineered casein-based gels can significantly enhance encapsulation efficiency and the controlled release of sensitive bioactives in pharmaceutical applications.