Dual-Responsive Biodegradable Chitosan/PEGDA-Alizarin Hydrogel Loaded with Pinostrobin for pH-Sensitive Wound Healing and Monitoring

Wound management including appropriate dressings, treatment, and early infection detection is critical for accelerating wound healing. We developed a smart hydrogel that gives a colorimetric response to pH changes and bacterial presence in vitro. Pinostrobin nanoemulsions were incorporated into the hydrogel matrix, and their biological activities were evaluated. A biodegradable temperature- and pH-responsive chitosan/PEGDA-alizarin (C/P-A) hydrogel was successfully fabricated through UV polymerization. The C/P-A hydrogels exhibited a color transition from yellow (acidic) to purple (alkaline) in response to pH changes. The high-molecular-weight chitosan-based hydrogel (C(H)1/P-A) demonstrated the greatest swelling capacity and pH responsiveness. Notably, the hydrogel released pinostrobin more rapidly under alkaline conditions. It also exhibited biodegradability in both lysozyme solution and environmental soils. The pinostrobin nanoemulsion showed 5-LOX inhibitory activity superior to nordihydroguaiaretic acid, which was maintained upon incorporation into the hydrogel. Additionally, the nanoemulsions demonstrated ROS scavenging activity comparable to ascorbic acid in LPS-induced HaCaT, and pinostrobin loaded in the hydrogel enhanced its activity. Incorporation of nanoemulsions further improved antibacterial activity against Staphylococcus aureus and promoted wound healing, outperforming allantoin. The hydrogel exhibited a color change to purple in the presence of S. aureus. These findings highlight the potential of this smart hydrogel as both a therapeutic and diagnostic platform for wound management.