Fabrication of functionalized chitosan hydrogels triggered by charge interactions and pH response for bacterial capture and killing

Abstract

Functional hydrogels with antibacterial and tissue repair-promoting properties have attracted growing attention in wound treatment. We here designed a nanocomposite hydrogel consisting of a quaternary ammonium-functionalized chitosan matrix and curcumin (Cur)-loaded Zif-8 nanoparticles (Zif8@Cur). This hydrogel can capture and inactivate bacteria through quaternary ammonium group-induced electrostatic interactions and pH-triggered Cur release. Importantly, the property of pH-triggered Cur release at the infection site endowed this hydrogel with high antimicrobial activity at relatively low Cur content, thereby increasing drug bioavailability and mitigating toxic effects. In addition, with the variation in bacterial cell membrane permeability triggered by quaternary ammonium groups, the interference of Cur in intracellular homeostasis was enhanced and the antibacterial efficacy was significantly improved. Furthermore, the as-prepared hydrogel can effectively restrain wound inflammation and accelerate tissue repair, thereby showing valuable potential in treating microbial infections during wound healing.