Antioxidant, hemostatic, and injectable hydrogels with photothermal antibacterial activity to accelerate full-thickness wound regeneration

Abstract

Developing injectable hydrogel dressings with multifunctional properties, including antibacterial and antioxidant ability, and good mechanical properties to treat infected full-thickness skin wounds is of particular importance in clinical applications. The incorporation of metal ions, such as Zn²⁺, Ca²⁺, and Fe²⁺, confers the hydrogels with unique properties, including conductivity, bioactivity, and tunability. In this study, a multifunctional near-infrared (NIR) active hydrogel, named Alg–HA–Zn–PDA, was fabricated via the incorporation of polydopamine (PDA) nanoparticles into hyaluronic acid (HA) and alginate (Alg) crosslinked by Zn²⁺. This hydrogel exhibited high porosity, good mechanical properties, and high water content, which is an essential requirement in the adsorption of exudates during the healing process. PDA endowed the hydrogels with antioxidant activity and hemostatic ability, and made the hydrogels NIR active. Zn²⁺ could contribute to the antibacterial and healing effects of the hydrogels. The antibacterial activity of Alg–HA–Zn–PDA, with and without NIR irradiation against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), showed that the NIR light irradiation could result in heat generation and destroy the bacteria. Furthermore, in vivo treatment in a S. aureus-infected full-thickness skin defect model demonstrated that the Alg–HA–Zn–PDA hydrogel possesses excellent wound closure capacity in the presence of NIR irradiation. In summary, we concluded that the developed antibacterial, hemostatic, and antioxidant hydrogel is an excellent candidate for wound dressing for the repair of full-thickness skin defects.