Macrochannel-aligned cryogels with oxygen release and antibacterial properties for MRSA-infected diabetic wound healing

Wounds in diabetic patients suffer from bacterial infection, reduced angiogenesis, and inadequate oxygen supply, which prolong healing time and form chronic wounds. Long-term hypoxia is one of the main causes of delayed wound healing. Therefore, it is particularly urgent to develop new dressings with oxygen release and antibacterial properties for the infected diabetic wound. In this paper, we developed oxygen-releasing and macrochannel-aligned cryogels based on acylhydrazone bond cross-linking between the adipic dihydrazide grafted hyaluronic acid (AHA) and oxidized dextran (OD). The aligned macroporous structure of cryogels formed by the unidirectional freezing technique is favorable for the release of oxygen. The incorporated calcium peroxide (CPO) can react with water to produce oxygen and hydrogen peroxide (H₂O₂), which can provide good antibacterial properties, while excess H₂O₂ can be decomposed into oxygen by catalase (CAT), achieving oxygen release for up to 10 days. The macrochannel-aligned cryogels have suitable mechanical properties, oxygen release property, good biological property, and antibacterial property resulting from H₂O₂ release. In the MRSA-infected diabetic full-thickness defect wound model, compared to the commercial dressing, the cryogel showed excellent bactericidal property and better wound healing by providing oxygen, regulating inflammation, accelerating collagen deposition, and promoting granulation tissue formation and vascularization. In brief, this study developed an efficient oxygen-releasing and antibacterial cryogel with an aligned macroporous structure, which may provide a new strategy for the management of chronic hypoxic infected diabetic wounds.