Chemical and photothermal synergistic antimicrobial treatment for enhanced wound healing based on light/pH responsive nanocomposites†

Recently, the advancements in the field of responsive nanomaterials have created new possibilities for restraining the overuse of antibiotics. In this research, we present the fabrication of linear maltodextrin and cyclodextrin polymer (LM-CD) modified graphene oxide (GO) nanocomposites, which were subsequently loaded with levofloxacin (LVN) and oxytetracycline (OXY). The as-prepared nanocomplexes (GO–LM-CD@LVN and GO–LM-CD@OXY) exhibited remarkable synergistic antibacterial efficacy through the combined effects of photothermal therapy and pH-responsive drug delivery, effectively eradicating multidrug-resistant Escherichia coli and Staphylococcus aureus, while concurrently reducing the dosage of antibiotics. The bactericidal rate of 20 μg mL⁻¹ by GO–LM-CD@LVN and GO–LM-CD@OXY against the aforementioned bacteria was nearly 100% upon NIR irradiation, demonstrating exceptional photothermal properties. In addition, the photochemotherapy effect of GO–LM-CD@LVN was verified by wound healing experiments in mice. The results demonstrated that the application of GO–LM-CD@LVN under NIR irradiation for 10 days resulted in a wound healing rate of approximately 19% higher than that of the blank control group, indicating a remarkable and rapid therapeutic effect. Furthermore, histological analysis using H&E staining revealed no significant impact on the visceral tissues of mice treated with GO–LM-CD@LVN. Collectively, GO–LM-CD is anticipated to serve as a novel photothermal/pH-responsive nanocarrier for achieving efficient antibacterial effects through the synergistic interplay between photothermal materials and antibacterial drugs.