Antibiotic-Free Phototherapy via an Indocyanine Green-DecoratedGold Nanoparticle/Manganese Dioxide Nanocomposite

Phototherapy treatment, as an alternative to antibiotic therapy, promises to be a noninvasive strategy to treat bacterial infections with a low likelihood of inducing bacterial resistance. However, the prolonged high temperature induced by photothermal therapy (PTT) and the limited reactive oxygen species (ROS) yield generated by photodynamic therapy (PDT) still limit clinical application. Here, we overcome the limitations of current PTT and PDT technologies through the effect of the red-shifted local surface plasmon resonance (LSPR) and oxygen vacancies to synthesize an indocyanine green-decorated gold nanoparticle/manganese dioxide (APIM) nanocomposite, improving photothermal stability and ROS generation. Under 808 nm laser irradiation, APIM nanocomposites achieved antibacterial efficiencies of up to 99.9% against Pseudomonas aeruginosa, Staphylococcus aureus, and Escherichia coli and 99% against tetracycline-resistant E. coli EIEC. Furthermore, the near-infrared (NIR)-mediated APIM nanocomposite could effectively treat S. aureus-infected wound <i>in vivo</i> without marked toxicity. Overall, synergistic PTT and PDT utilizing the APIM nanocomposite may provide a promising treatment for skin wound infection.