Multifunctional protocatechuic acid–polyacrylic acid hydrogel adhesives for wound dressings

Multifunctional hydrogel adhesives are highly desirable in wound healing applications, yet their preparation often requires complex material system design to achieve. Herein, a straightforward one-pot two-step polymerization method is developed to prepare adhesive hydrogels for wound dressing based on protocatechuic acid (PCA), polyacrylic acid (PAA), and polyamidoamine-epichlorohydrin (PAE), where PCA provides the catechol groups for strong adhesion, PAA serves as the primary polymer matrix, and PAE acts as a bridge connecting PCA and PAA. This design results in a PAA-PAE-PCA hydrogel having a remarkable instant 90-degree peeling interfacial toughness of 431 J m^-2 on porcine skin, which is further amplified to 615 J m^-2 after 30 minutes. The hydrogel also possesses the desired features for wound dressing, such as self-healing, antioxidant, anti-UV and antibacterial properties, good cytocompatibility, strong adhesion in use and weak adhesion on removal, as well as reversible and wet adhesion. Finally, in vivo data reveal that the PAA-PAE-PCA hydrogels can significantly accelerate wound healing, as evidenced by a noticeable reduction in the wound area and a diminished inflammatory response. Collectively, these results endorse the obtained multifunctional hydrogel as a promising candidate for wound healing and related fields.