A novel self-healing polydopamine-functionalized chitosan-arginine hydrogel with enhanced angiogenic and antibacterial activities for accelerating skin wound healing

Skin wound healing occurs via a series of orchestrated cellular and molecular events in a highly ordered manner, in which insufficient angiogenesis and infection at the wound site always retard the healing process. Hence, hydrogel wound dressing with multifunctional properties, including angiogenic and antibacterial properties, would be highly desired in practical application. In the present study, we developed a series of self-healing hydrogels based on L-arginine conjugated chitosan (CA), benzaldehyde group functionalized poly (ethylene glycol) (CHO-PEG-CHO), and polydopamine nanoparticles (pDA-NPs), named as CA-pDA, as an angiogenic and antibacterial dressing for wound repair. The CA-pDA hydrogels showed porous architecture, good adhesiveness and self-healing properties, as well as good biocompatibility. Particularly, the incorporation of pDA-NPs could enhance the mechanical property (~1.5–4.5 times) and pore size (~1.2 times) of pure CA hydrogel. The in vitro data demonstrated that CA hydrogel had limited capacities for inducing angiogenesis and inhibiting bacterial colony growth, while the two properties of the hydrogel could be enhanced by the incorporation of pDA-NPs. In addition, CA-pDA hydrogels, especially CA-pDA2, could accelerate wound healing with reduced scar formation in a large full-thickness skin defect (2 × 2 cm2) of a rat model. After 14 days post-surgery, the wound healing ratio in CA-pDA2 (~99%) was significantly higher than that in the control group (~79%). Collectively, the fabricated CA-pDA2 with enhanced angiogenic and antibacterial activities could have good potential for clinical wound dressing application.