Conjugated Polymer with Aggregation-Directed Intramolecular Forster Resonance Energy Transfer Enabling Efficient Discrimination and Killing of Microbial Pathogens

Rapid and effective differentiation and killing of microbial pathogens are major challenges in the diagnosis and treatment of infectious diseases. Here, we report a novel system based on the conjugated polymer poly[(9,9-bis{6'-[N-(triethylene glycol methyl ether)-di(1H-imidazolium)-methane]hexyl}-2,7-fluorene)-co-4,7-di-2-thieny1-2,1,3-benzo-thiadiazole] tetrabromide (PFDBT-BIMEG), which enables efficient microbial pathogen discrimination and killing. The functional side chains of PFDBT-BIMEG enabled both electrostatic and salt bridge interactions with microorganisms. Microorganism binding events caused a change in the aggregation structure of PFDBT-BIMEG, which could be recognized by a change of its fluorescence signal by intramolecular Forster resonance energy transfer (FRET). This sensing strategy allowed rapid and sensitive distinction of microbial pathogens within 15 min. We performed linear discrimination analysis that featured this advance to confirm that the polymer PFDBT-BIMEG could accurately classify microbial pathogens. Owing to the different adhesion mechanism of PFDBT-BIMEG to the surface of the microorganisms, we applied different sterilization strategies for each kind of microbial pathogen. The microbial pathogens could be efficiently killed by reactive oxygen species produced from PFDBT-BIMEG under irradiation, avoiding the use of any other antibacterial agents. This methodology, which combines pathogen discrimination and killing, represents a promising alternative to current diagnostic platforms.