pH-responsive polysaccharide hydrogel with self-healing and bioadhesive Capabilities for targeted drug delivery in chronic disease therapy

This study engineered a pH‑responsive injectable polysaccharide hydrogel via dynamic Schiff base crosslinking of oxidized sodium alginate (ADA) and cationic guar gum (CG), enabling self‑healing and tissue bioadhesion. The hydrogel formed within 2–4 s and exhibited autonomous self‑healing without external intervention. It showed strong adhesion to bovine bone (10.62 kPa) and skin (1.6 kPa), and achieved sustained release of bovine serum albumin (BSA) and tetracycline hydrochloride (TC) over 120 h and 54 h, respectively, with markedly accelerated release under acidic pH (5.5). Notably, the TC‑loaded hydrogel demonstrated potent antibacterial activity against Staphylococcus aureus (inhibition zone 57.62 mm) while preserving > 70% L929 fibroblast viability. These results confirm that the CG/ADA hydrogel uniquely combines rapid gelation, pH‑programmable drug release, strong bioadhesion, and excellent cytocompatibility, providing a promising platform for the development of targeted therapeutic systems with potential applications in localized infections, diabetic wounds, and osteomyelitis.