Fluorescent Peptide Probe for Specific Detection and In Vivo Imaging of Fusobacterium Nucleatum.

Fusobacterium nucleatum (F. nucleatum), an opportunistic oral anaerobic pathogen, is closely associated with various oral disorders and colorectal cancer (CRC). Current detection methods for this bacterium suffer from technical complexity and labor intensiveness. In this study, we engineered TPAI-YQPVPE, a peptidic fluorescent probe, by conjugating an aggregation-induced emission (AIE) fluorophore (TPAI) with the F. nucleatum-targeting peptide YQPVPE. This probe binds specifically to FomA, a major outer membrane protein of F. nucleatum, enabling its selective accumulation and robust fluorescence emission, even in complex biological environments. Its specificity and detection were validated both in vitro and in vivo in an F. nucleatum infection model, where the probe achieved precise localization at F. nucleatum inoculation foci and exhibited excellent biocompatibility. This AIE-based peptidic probe established a specific and noninvasive detection platform for F. nucleatum, which might represent a promising tool for the early screening and diagnosis of F. nucleatum-associated CRC.