The Synergy\nbetween Antibiotics and the Nanoparticle-Based\nPhotodynamic Effect

Antimicrobial resistance (AMR) is a growing global health\nconcern,\nnecessitating innovative strategies beyond the development of new\nantibiotics. Here, we employed NdYVO<sub>4</sub>:Eu<sup>3+</sup> nanoparticles,\nwhich can persistently produce reactive oxygen species (ROS) after\nstopping the light, as a model of photodynamic nanoparticles and demonstrated\nthat the photodynamic effect can serve as an adjuvant with antibiotics\nto effectively reduce their minimum inhibitory concentration. These\npreirradiated nanoparticles could penetrate the bacterial cell membrane,\nsignificantly enhancing the potency of antibiotics. We showed that\nthe synergy effect could be attributed to disrupting crucial cellular\nprocesses by ROS, including damaging cell membrane proteins, interfering\nwith energy supply, and inhibiting antibiotic metabolism. Our findings\nsuggested that complementing the photodynamic effect might be a robust\nstrategy to enhance antibiotic potency, providing an alternative antibacterial\ntreatment paradigm.