Asymmetric porous composite hydrogel patch for microenvironment-adapted repair of contaminated abdominal wall defects

Effective antibacterial property and long-term mechanical support are essential for the repair of complex abdominal wall defects associated with infection. However, clinically available repair materials often fail to meet these requirements, resulting in high surgical failure rate and complications. In this study, an asymmetric porous composite hydrogel patch (cCS/PVA@BAC) with antibacterial, anti-adhesion, pro-healing, and durable mechanical support properties is designed for the efficient repair of contaminated abdominal wall defects. By stepwise phase-conversion and soaking method, robust and stable polyvinyl alcohol hydrogel (PVAH) is integrated with the biocompatible multicomponent hydrogel made of chitosan and carboxymethyl chitosan (cCS), and benzalkonium chloride (BAC) is loaded to enhance the antibacterial property. The cCS layer of cCS/PVA@BAC has an extracellular matrix-like porous structure, which can promote fibroblasts adhesion and wound healing. In contrast, the PVAH layer on the other side with a smooth and dense structure, which can reduce fibroblasts adhesion and prevent visceral adhesion. In addition, the composite hydrogel patch has good anti-swelling and anti-deformation properties as well as stable mechanical strength, thus can withstand high intraperitoneal pressure in the wet internal microenvironment. The loaded BAC can efficiently kill bacteria and improve the local inflammatory microenvironment. With these advantages, cCS/PVA@BAC can significantly reduce inflammation, promote tissue remodeling, and accelerate the healing of contaminated abdominal wall defects in the rat model. These findings suggest a potential use of multifunctional hydrogel patch as an ideal material for effective repair of contaminated soft tissue defects.