Enhancing the drug sensitivity of antibiotics on drug-resistant bacteria via the photothermal effect of FeTGNPs

The growing problem of bacterial resistance caused by the abuse of antibiotics is a serious challenge for the world. In order to make the clinically available antibiotics regain their bactericidal effect, our study introduced photothermal therapy (PTT) to assist antibiotics to annihilate drug-resistant bacteria. To achieve the synergistic effect, nanoparticles (FeTGNPs) with an antibiotic core (gatifloxacin complexing with tannins) and a photothermal shell (ferric iron coordinating with tannins) were prepared directly in aqueous solution by a convenient yet efficient one-pot synthesis. The excellent photothermal properties of the shell of FeTGNPs were used to break the mechanism of bacterial resistance, and the sustained-release of gatifloxacin from the core regained the killing effect against drug-resistant bacteria. From the results of antibacterial experiments, with the synergistic effect of APTT and antibiotics, FeTGNPs (400 μg/mL) could effectively kill methicillin-resistant Staphylococcus aureus (sterilizing rate up to 96.5 %) and gatifloxacin-resistant Staphylococcus aureus (sterilizing rate up to 98.7 %) than equivalent antibiotics. Moreover, under slightly acidic microenvironment, such as infection area, gatifloxacin could accelerate its release from the core of FeTGNPs. Therefore, FeTGNPs would be a highly effective antibacterial agent against drug-resistant bacterial infections in the future.