An antioxidative sodium alginate hybrid hydrogel with NIR-controlled NO releasing for diabetic wound healing via reduced inflammation and enhanced angiogenesis.

Chronic diabetic wounds are a great challenge for clinical management due to bacterial infection, prolonged inflammation and inadequate angiogenesis. Herein, a multifunctional sodium alginate (SA)-based hybrid hydrogel (Gel-S/PPB) is designed and synthesized that can integratedly combat bacterial infection and relieve oxidative stress for accelerated diabetic wound healing. The Gel-S/PPB is encapsulated by NIR-controlled NO-releasing polymeric nanoparticles (PPY-PDA-BNN6) with excellent photothermal and antioxidant performances and a dynamically crosslinked sodium alginate-derived hydrogel. Specifically, PPY-PDA-BNN6 nanoparticles comprising NO donor (BNN6) in conductive dopamine-pyrrole system possess excellent photothermal and NIR-responsive NO-releasing properties to combat bacterial infection, good electrical conductivity to promote intercellular electrical signaling and strong free radical scavenging ability to reduce oxidative stress levels. Thus, the developed Gel-S/PPB hydrogel could achieve on-demand bacterial management and tuning of the inflammatory microenvironment during the early stage, and efficient angiogenesis in the proliferative period. Moreover, this Gel-S/PPB hydrogel exhibits good shear-thinning and self-healing properties to enable a perfect wound coverage to adapt well to the moist wound microenvironment and provide sustained and effective treatment of the wound. Both in vivo and in vitro experiments demonstrated that this versatile hydrogel can accelerate diabetic wound healing and provides a promising alternative for the treatment of diabetic wounds.