Algae-inspired chitosan-pullulan-based multifunctional hydrogel for enhanced wound healing

Chronic wounds caused by hyperglycaemia, hypoxia and bacterial infections are common complications in diabetic patients and chronic wound repair is extremely challenging in clinical practice. A series of hydrogels QPMP with good antioxidant and antimicrobial functions were prepared based on quaternized chitosan (QCS), oxidized pullulan polysaccharide (OP), dopamine-coated polypyrrole (PPY@PDA), and Chlorella vulgaris. The Schiff base cross-linking between the quaternized chitosan (QCS) and oxidized pullulan polysaccharide (OP) constitutes the basic skeleton of the hydrogel, and imparts a certain antimicrobial ability to the hydrogel. Chlorella vulgaris continuously produced oxygen under light conditions to relieve wound hypoxia and promote wound healing. The incorporation of PPY@PDA gave the hydrogel near-infrared (NIR) irradiation-assisted bactericidal activity and antioxidant activity, and as a conductive hydrogel, the hydrogel can be used to sense wound exudate and temperature changes, which can help to achieve the integration of diagnosis and treatment of wound healing. Most importantly, in a chronic wound model, the QPMP hydrogel was more effective in controlling the level of wound inflammation and promoting collagen deposition, angiogenesis, and early wound closure compared to the HeraDerm dressing. Therefore, this conductive oxygen-producing hydrogel is extremely beneficial for chronic wound healing in diabetes.