Electrospun nanofibrous membrane-functionalized dual-responsive self-healing hydrogel dressings based on chitosan and hyaluronic acid encapsulating gallic acid-loaded Eu-MOF clusters for fluorescent monitoring and efficient healing of diabetic wound.

Abstract

Diabetic chronic wounds are difficult to heal because of persistent infection, oxidative stress, inflammation, and hyperglycemia. Herein, a bilayer multifunctional dressing (GCP/GAEu@H) was developed for wound monitoring and diabetic wound repair. The lower layer comprised a glucose- and pH-responsive self-healing hydrogel formed from phenylboronic acid-modified chitosan (CS-PBA) and oxidized hyaluronic acid (OHA) through dynamic boronate ester and Schiff base linkages. The upper layer was a glutaraldehyde-crosslinked chitosan/poly(vinyl alcohol) (CS/PVA) electrospun nanofibrous membrane. This bilayer configuration increased the tensile strength to 278.94 kPa, provided strong resistance to compressive fatigue, and preserved structural integrity over 50 compression cycles at 60% strain. The incorporated GA-loaded Eu-MOF (GAEu) clusters supplied pH-sensitive fluorescence for real-time assessment of wound status and enabled acid-responsive release of active species. Antibacterial efficiencies against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) exceeded 99%, and 70% of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals were scavenged within 30 min. In addition, it displayed good hemocompatibility and cytocompatibility. Animal experiments revealed enhanced collagen deposition and angiogenesis, together with 98.8% wound closure by day 12. These findings offer an alternative route for designing intelligent dressings for diabetic wounds.