Ultrasmall Ga-ICG nanoparticles based gallium ion/photodynamic synergistic therapy to eradicate biofilms and against drug-resistant bacterial liver abscess

Pyogenic liver abscess and keratitis are aggressive bacterial infections and the treatment has failed to eradicate bacteria in infectious sites completely owing to the currently severe drug resistance to existing antibiotics. Here, we report a simple and efficient one-step development of ultrasmall non-antibiotic nanoparticles (ICG-Ga NPs) containing clinically approved gallium (III) (Ga3+) and liver targeting indocyanine green (ICG) molecules to eradicate multi-drug resistant (MDR) bacteria thought the synergetic effect of photodynamic therapy and iron metabolism blocking. The ICG-Ga NPs induced photodynamic effect could destroy the bacterial membrane, further boost the endocytosis of Ga3+, then replace iron in bacteria cells to disrupt bacterial iron metabolism, and demonstrate the synergetic bacterial killing and biofilm disrupting effects. The ICG-Ga NPs show an excellent therapeutic effect against extended spectrum β-lactamases Escherichia coli (ESBL E. coli) and significantly improve treatment outcomes in infected liver abscess and keratitis. Meanwhile, the ultrasmall size of ICG-Ga NPs could be cleared rapid via renal clearance route, guaranteeing the biocompatibility. The protective effect and good biocompatibility of ICG-Ga NPs will facilitate clinical treatment of bacteria infected diseases and enable the development of next-generation non-antibiotic antibacterial agents.