PaAP-Activatable NIR Probe for Diagnosing, Imaging, and Discovering Small-Molecule Therapeutics against Implant-Associated Biofilm Infections

Biofilm formation on medical implants causes implant-associated infections (IAIs), leading to high morbidity and mortality. Developing molecular tools for precise biofilm detection, along with novel strategies and agents to target biofilm-related IAIs, is crucial for improving treatment options and patient outcomes. <i>Pseudomonas aeruginosa</i> aminopeptidase (PaAP), a key biofilm-associated virulence factor, is a promising target for combating infections. Here, we developed a PaAP-activatable near-infrared (NIR) fluorescent probe, <b>Hcy-NEO-Leu</b>, for real-time, specific, and sensitive detection of PaAP activity. This probe enables noninvasive imaging of the <i>P. aeruginosa</i> biofilm in vitro and in vivo. The probe also identified <b>LY-58</b>, a lycorine derivative that disrupts biofilm formation without affecting bacterial growth or mammalian cell viability, enhancing tobramycin penetration and overcoming antibiotic resistance. This study introduces <b>LY-58</b> as a promising adjunctive therapy. In conclusion, the PaAP-activatable NIR imaging probe, combined with <b>LY-58</b>, offers innovative tools for the early diagnosis and effective treatment of IAIs.