Ag Nanoparticles on MXene Nanosheets for Combined Ionic and Photothermal Therapy of Bacterial Infections

In view of the increasing bacterial resistance, 2D MXenes are promising alternatives to antibiotics. However, MXene-based photothermal therapy (PTT) suffers from unsatisfactory antibacterial efficiency and heat-resistant strains. Here, we prepared a Ti3C2 MXene and Ag hybridized antibacterial nanocomposite [MXene/metal-polyphenol networks (MPNs)/Ag] through the in situ reduction of Ag nanoparticles on MPN wrapped MXene matrix. The use of MPNs as the reducing agents of Ag+ and anchoring agents of Ag nanoparticles endowed MXene/MPN/Ag with a tight immobilization capacity and improved colloidal dispersion stability of Ag nanoparticles. The pH-triggered decomposition of MPNs led to the pH-responsive release of Ag to achieve combined MXene-based PTT and Ag-mediated therapy for enhanced antibacterial efficiency. In vitro antibacterial experiments revealed its satisfactory bactericidal activities against both planktonic bacteria and bacteria in stubborn biofilms. In vivo antibacterial assays solidly confirmed its high antibacterial therapeutic efficiency, strong anti-inflammatory ability, and good biosafety. Therefore, the in situ combination of Ag nanoparticles with MXenes offers a promising microenvironment-responsive 2D bactericidal candidate for infection that could be applied in future antibacterial treatments.