Au Nanorods Coated with pH-Responsive Polymers for Photothermal Therapy Against Multidrug-Resistant Bacteria

Overuse of antibiotics has led to an increased threat of drug-resistant pathogens and sustained chronic infections, suggesting an urgent need for effective strategies against drug-resistant bacterial infections. Herein, we developed au gold nanorods coated with pH-responsive polymers (GNR-DPArPEGMA) for photothermal therapy against multidrug-resistant bacteria. The size and zeta potential of GNR-DPArPEGMA was 78 nm and −37.96 mV, respectively. In subacidic conditions, the nanocomposite surface was positively (14.18 mV) charged, leading to better bacterial adhesion and antibacterial efficiency. The nanocomposites showed augmented in vitro photothermal efficiency up to 70 °C under 808 nm irradiation for 3 min, which further demonstrated an enhanced photothermal bacteria-killing efficiency. The in vivo assays showed that GNR-DPArPEGMA irradiated with near-infrared radiation could treat a drug-resistant Staphylococcus aureus-caused subcutaneous abscess and drug-resistant Pseudomonas aeruginosa-caused pneumonia while reducing the number of bacteria and attenuating inflammation in the infected sites. These results indicate that the nanocomposites could be used as a potential photothermal agent to combat drug-resistant bacterial infections in the future.