Polyoxometalate-based heterojunction with NIR light-facilitated photocatalytic W6+/W5+ redox cycling for enhanced bacteria-infected wound healing

Abstract

Background: Metal-based nanomaterials with shifting or mixed redox states have been widely applied for combating against bacteria-infected diseases by virtue of their peroxidase (POD)-like catalytic activity, which can decompose endogenous overexpressed hydrogen peroxide (H2O2) into highly oxidized hydroxyl radical (·OH) via the Fenton or Fenton-like reaction. However, the compromised POD-like catalytic activity in biofilm microenvironment (BME) restrains their therapeutic efficiency. Results: Herein, a polyoxometalate-based heterojunction (GdP5W30@WS2) with shifting or mixed redox states (W6+/W5+) is devised to achieve boosted reactive oxygen species (ROS) generation by near-infrared (NIR) laser-facilitated W6+/W5+ redox cycling for effective biofilm eradication and accelerated bacteria-infected wound healing. On the one hand, under the exposure to NIR laser, WS2 as electron donor could be stimulated to transfer electrons to GdP5W30, which promotes the reduction from W6+ to W5+ active sites on the surface of the GdP5W30. Consequently, the regenerated W5+ active sites could catalyze endogenous overexpressed H2O2 to persistently generate ROS, which displays enhanced POD-like catalytic activity for chemodynamic therapy (CDT) by NIR-driven photocatalytic W6+/W5+ redox cycling. Moreover, GdP5W30@WS2 also displays favorable glutathione (GSH)-activated photothermal performance by W6+-triggered GSH exhaustion for sufficient ROS generation, thereby facilitating the synergistic therapeutic efficiency of photothermal therapy (PTT) and CDT. Conclusions: We expect that the present work will promote the development of the heterojunction with shifting or mixed redox states for biofilm elimination based on NIR-facilitated enzyme-like catalytic activity, which may act as a candidate for the BME-activated synergistic therapy.