Application of sodium alginate and polyethylene glycol bilayer multifunctional hydrogel microneedles in infectious and diabetic wounds.

Chronic wounds are challenging to heal due to persistent infection, prolonged inflammation, and impaired angiogenesis, which can ultimately lead to severe disabilities. Current treatment strategies are unable to provide the comprehensive conditions needed for effective chronic wound healing. Herein, we proposed a multifunctional microneedle patch for chronic wound healing, consisting of a needle-like drug-loading gel (DG) constructed with polyethylene glycol (PEG) and a backing hydrogel (BHG) layer constructed with sodium alginate. This design combines the therapeutic effects of drug delivery with the protective benefits of a hydrogel. The needle-like DG layer effectively penetrates the bacterial biofilm, releasing Erythromycin, Vaccarin, Demethylsuberosin, and Cyanidin, agents with synergistic antibacterial, anti-inflammatory, pro-angiogenic, and antioxidant effects in a temperature response-dependent manner. Together, these components address multiple barriers to chronic wound healing. The DG layer also maintains a moist wound environment for the wound. The pH-responsive properties of Cyanidin visually indicate the wound healing status. The multifunctional microneedle patch (DG@BHG) significant enhances healing in both infected and diabetic wounds, leveraging the combined effects of drug action and hydrogel support. This approach presents a novel therapeutic strategy for chronic wound healing by addressing infection, inflammation, and angiogenesis simultaneously.