Curcumin Liposome-Embedded Polyvinyl Alcohol/Chitosan Hydrogel Exhibiting pH-Responsive Sustained Drug Release and Antioxidant-Antibacterial Activity.

Curcumin (CUR), a natural polyphenolic compound with anti-inflammatory, antioxidant, and antibacterial properties, suffers from poor aqueous solubility and low bioavailability. To overcome these limitations, a novel pH-responsive colorimetric hydrogel (polyvinyl alcohol/chitosan/curcumin liposome [PVA/CS/CL]) was developed by incorporating CLs into a PVA/CS matrix. The optimized CL showed high encapsulation efficiency (95.04% ± 2.26%) and uniform particle size (121.51 ± 8.66 nm). The resulting hydrogel exhibited pH-dependent color changes (yellow to reddish-brown), improved mechanical strength (Young's modulus: 24.108 ± 1.572 kPa), and enhanced water retention (340.35% ± 20.12%). In vitro studies demonstrated pH-responsive drug release (61.37% ± 5.56% at pH 5.5 vs. 43.96% ± 4.10% at pH 7.4), following the Korsmeyer-Peppas kinetics. The hydrogel also showed excellent biocompatibility (cell viability > 88%), strong antibacterial activity (>90% inhibition), and high antioxidant capacity (1,1-diphenyl-2-picrylhydrazyl [DPPH] scavenging: 85.64% ± 4.68%). This dual-functional system provides a promising platform for wound management and inflammatory therapy.