Thiourea-Cation Chelation Based Hydrogel and its Application as Antibacterial Dressing for the Repair of Diabetic Wound

For various chronic wounds, bacterial infection is one of the important reasons that hinder their healing. Ion-crosslinked antibacterial hydrogel dressings based on Ag+, Cu2+ and Zn2+, have made progress in clinical application. However, the toxicity of released metal ions cannot be ignored. Therefore, how to ensure the antibacterial performance of hydrogel dressing while reducing the amount of metal ions is a major challenge for the fabrication of metal ion based antibacterial hydrogel. In this study, a general method is proposed to design cationic ion-crosslinked hydrogel based on thiourea groups. Taking the hydrogel formed by mixing thiourea modified hyaluronic acid (H-ANCSN) with Ag+ (HA-NCSN/Ag+ hydrogel) as an example, the characteristics and application potential of this kind of hydrogel are thoroughly explored. Due to the strong cationic chelation characteristics of thiourea groups, HA-NCSN/Ag+ hydrogel can gel at low Ag+ concentration and achieve long-term slow release of Ag+ at stable concentration to balance the antibacterial and biocompatible properties. Moreover, this dynamic thiourea-Ag+ crosslinking also endowed the hydrogel with the property of "gelation and encapsulation first, injection to cover wound when necessary". Then, the mangiferin self-assembled nanoparticles are loaded into HA-NCSN/Ag+ hydrogel as the radical oxygen species scavenger. Thiourea-cation chelation is a universal method to prepare ionic crosslinking hydrogel. Mangiferin nanoparticle-loaded HA- NCSN/Ag+ hydrogel dressing recreated the microenvironment of diabetic wound, including long-term antibacterial, radical oxygen species scavenging, remodeling M1 macrophage to M2, and promoting angiogenesis, to promote the skin regeneration finally. image