Freeze-Thawing Chitosan/Ions Hydrogel Coated Gauzes Releasing Multiple Metal Ions on Demand for Improved Infected Wound Healing

Imbalance of metal ions in the wound microenvironment is a key factor that leads to delayed wound healing. However, single metal administration to enhance wound repair is usually not enough due to the overlapping nature of the wound healing phases. Herein, a facile freeze-thawing strategy is developed to incorporate chitosan/ions hydrogel into medical gauzes to realize on-demand release of multiple ions to accelerate wound healing. In vitro study reveals that the gauzes can temporally release multiple metal ions on demand, and the released metal ions show effectiveness in killing bacteria and expediting cell migration. In vivo studies demonstrate that the metal ions loaded gauzes can efficiently enhance infected wound healing. Further histological analysis find that these metal ion-loaded gauzes accelerate wound healing by promoting granulation formation, collagen deposition and maturation, re-epithelization, angiogenesis, and inhibiting inflammation via regulating the expression of inflammatory factors (e.g., tumor necrosis factor-alpha) and polarization of macrophages. Thus, this novel metal ions delivery system has great potential in infected tissue repair and antibacterial applications.

Automated summary

The imbalance of metal ions in the wound microenvironment is a key factor leading to delayed wound healing. A novel freeze-thawing strategy has been developed to incorporate chitosan/ions hydrogel into medical gauzes for on-demand release of multiple ions to accelerate wound healing. Both in vitro and in vivo studies show that the metal ions released from the gauzes can effectively kill bacteria, promote cell migration, accelerate granulation formation, collagen deposition, re-epithelization, angiogenesis, and inhibit inflammation, thus enhancing infected wound healing.