Iron decoration in binary graphene oxide and copper iron sulfide nanocomposites boosting catalytic antibacterial activity in acidic microenvironment against antimicrobial resistance.

The strong antimicrobial resistance (AMR) of multidrug-resistant (MDR) bacteria and biofilm, especially the biofilm with extracellular polymeric substance (EPS) protection and persister cells, not only renders antibiotics ineffective but also causes chronic infections and makes the infectious tissue difficult to repair. Considering the acidic properties of bacterial infection microenvironment and biofilm, herein, a binary graphene oxide and copper iron sulfide nanocomposite (GO/CuFeSx NC) is synthesized by a surfactant free strategy and utilized as an alternative smart nanozyme to fight against the MDR bacteria and biofilm. For the GO/CuFeSx NC, the iron decoration facilitates the well distribution of bimetallic CuFeSx NPs on the GO surfaces compared to monometallic CuS NPs, providing synergistically enhanced peroxidase (POD)-like activity in acidic medium (pH 4 ∼ 5) and intrinsic strong near infrared (NIR) light responsive photothermal activity, while the ultrathin and sharp structure of 2D GO nanosheet allows the GO/CuFeSx NC to strongly interact with the bacteria and biofilm, facilitating the catalytic and photothermal attacks on the bacterial surfaces. In addition, the GO in GO/CuFeSx NC exhibits a "Pseudo-Photo-Fenton" effect to promote the ROS generation. Therefore, the GO/CuFeSx NC can effectively kill bacteria and biofilm both in vitro and in vivo, finally eliminating the infections and accelerating the tissue repair when treating the biofilm-infected wound. This work paves a new way to the design of novel nanozyme for smart antibacterial therapy against antimicrobial resistance.