A sprayable alginate hydrogel based on copper-tannic acid metal-polyphenol for promoting acute and infected wound healing

Bacterial-infected wounds may lead to delayed repair due to increased inflammation, especially wounds infected by drug-resistant bacteria, which remains a major clinical challenge. Sprayable hydrogels can treat large and irregular dynamic wounds and have attracted significant attention as wound dressings. Herein, sprayable hydrogels were formed by rapid crosslinking of atomized sodium alginate (SA) and high-concentration calcium ion solution, and copper-tannic acid metal-polyphenol network (CuTA) was loaded as the active ingredient. The hydrogel system achieved rapid crosslinking (10 s) through interaction with 10 % CaCl₂ solution, while deep eutectic solvent (DES) enhanced moisturizing capacity. In vitro studies demonstrated the broad-spectrum antibacterial effect of DES + Gel/CuTA sprayable hydrogel, with an inhibition rate of over 99 %. The excellent hemostatic performance of DES + Gel/CuTA sprayable hydrogel was also demonstrated, with the bleeding volume being less than 0.2 g, which was lower than 0.46 g in the control group. In three animal models of acute, infected and burn-infected skin wounds, DES + Gel/CuTA sprayable hydrogel showed significant effects in promoting wound healing. In conclusion, the developed sprayable hydrogels offered several advantages, including antibacterial and anti-inflammatory properties and promoting key stages of wound healing, such as cell migration, M2 polarization, collagen deposition, and angiogenesis. This sprayable hydrogel can resist infection and promote healing, showing its great potential in treating infected wounds.