Mechanically compliant multifunctional bioadhesive hydrogel for rapid wound repair

Bioadhesives in surgery are receiving increasing attention because of their ease of handling and desirable ability to promote wound closure; however, their mechanical mismatch with skin tissue and insufficient multifunctionality hinder clinical application. A mechanically compliant, multifunctional bioadhesive hydrogel (PATF) composed of polyacrylamide (PAM), alginate (Alg), tannic acid (TA), and ferric chloride (FeCl₃) has been developed for rapid wound repair. The covalently crosslinked PAM network provides structural integrity, while multiple noncovalent interactions (Alg/Fe³⁺ ionic bonds, hydrogen bonds, and TA/Fe³⁺ coordination) endows the hydrogel with skin-like modulus (∼25 kPa), improved toughness (328.9 kJ/m³), ultra-stretchability (∼2500% strain), and low hysteresis (<21%). PATF hydrogel exhibits outstanding conformational adhesion with the skin surface, 5.25-fold stronger than that of commercial 3M Tegaderm, and can be readily detached on demand in the presence of FeCl₃ solution. Furthermore, multifunction involving antioxidant capacity, photothermal therapy-mediated antibacterial efficacy, comparable conductivity to native skin tissues, and superior hemostatic performance enables PATF hydrogel (with near-infrared irradiation) to suppress inflammation, promote collagen deposition, and enhance angiogenesis, collectively accelerating healing of infected full-thickness skin wounds within 7 days. These integrated mechanically and biologically compliant properties make PATF hydrogel a versatile candidate for fast, effective wound repair. STATEMENT OF SIGNIFICANCE: This study develops a rationally designed mechanically compliant multifunctional bioadhesive hydrogel (PATF) through a hybrid crosslinking network. The covalently crosslinked PAM network ensures structural integrity, while multiple non-covalent interactions endow the PATF hydrogel with skin-like modulus, improved toughness, ultra-stretchability, and low hysteresis. It exhibits outstanding conformational adhesion with skin surface, which is 5.25-fold stronger than that of 3M Tegaderm, and could be detached easily on demand. Its antioxidant capacity, PTT mediated antibacterial efficacy, comparable conductivity to native skin tissues, and superior hemostatic performance enable PATF hydrogel to suppress inflammation, promote collagen deposition, and enhance angiogenesis, collectively accelerate infected full-thickness skin wound healing within 7 days and hair follicle regeneration, making it a promising candidate for wound management.