Hybrid Ag nanoparticles/polyoxometalate-polydopamine nano-flowers loaded chitosan/gelatin hydrogel scaffolds with synergistic photothermal/chemodynamic/Ag+ anti-bacterial action for accelerated wound healing

Bacterial infections significantly slow the wound healing process, thus severely threatening human health. Furthermore, traditional antibiotics may promote the development of multidrug-resistant bacteria. Therefore, developing novel bactericides and therapeutic strategies for bacterial infections is important to enhance wound healing. Herein, a three-in-one bactericidal flower-like nanocomposite was assembled using Ag nanoparticles/phosphotungstic acid-polydopamine nano-flowers (AgNPs/POM-PDA). The nanocomposite exhibited photothermal therapy (PTT) when exposed to NIR light via photothermal conversion by PDA. The resultant photothermal effect accelerated and controlled the Ag+ released from AgNPs. The chemodynamic therapy (CDT) was obtained via POM catalytic Fenton-like reaction. The combined PTT/CDT/Ag+ treatment achieved excellent synergistic anti-bacterial activity against both gram-negative E. coli and gram-positive S. aureus. A multifunctional wound dressing was then obtained by embedding the AgNPs/POM-PDA flower-like nanocomposite into the chitosan (CS)/gelatin (GE) biocomposite hydrogel. The synergy of AgNPs/POM-PDA nanocomposites and CS/GE hydrogel remarkably accelerated wound healing in vivo due to the excellent biocompatibility, hydroabsorptivity, and breathability of the hydrogel. In this study, a multifunctional agent was developed to synergistically combat bacterial infections and accelerate wound healing.