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

Abstract

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-thienyl-2,1,3-benzothiadiazole] 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.

Fluorescent Platforms Based on Organic Molecules for Chemical and Biological Detection

“…h) Differential fluorescence signals of PFDBT‐BIMEG used to distinguish pathogenic microorganisms within 1 min by 365‐nm excitation. Reproduced with permission . Copyright 2018, American Chemical Society.…”

“…Thus, the FRET‐based polymer enabled dual‐color imaging of membranes without inducing endocytosis (Figure c). Moreover, the BIM groups of the PFDBT‐BIMEG could induce both electrostatic attractions and salt bridge interactions in their binding process with gram‐negative bacteria, gram‐positive bacteria, and fungi . Depending on the different membrane structures of these microorganisms, different degrees of aggregation of PFDBT‐BIMEG on the membrane were reflected by a change of the FRET efficiency (Figure d–g).…”

Supramolecular Antibacterial Materials for Combatting Antibiotic Resistance

“…Therefore, it is meaningful to construct biosensors that can be employed for accurate discrimination of pathogens. Taking advantage of the outstanding light harvesting and light emitting, and amplification capability of water‐dispersive conjugated polymers, Wang and co‐workers spearheaded exploratory studies that led to remarkable results . In the effort, they synthesized a new type of cationic poly(phenylene vinylene) derivative and found that it can be used to discriminate between fungi, and Gram‐positive and Gram‐negative bacteria simply by the different fluorescent intensities that these organisms elicit in buffer solutions of varying ion strengths .…”

AIEgen‐Based Fluorescent Nanomaterials for Bacterial Detection and its Inhibition

“…Another group Wang and co‐workers developed a new system, poly[(9,9‐bis{6′‐[N‐(triethylene glycol methyl ether)‐di(1H‐imidazolium)‐methane]hexyl}‐2,7‐fluorene)‐co‐4,7‐di‐2‐thienyl‐2,1,3‐benzothiadiazole] tetrabromide (PFDBT‐BIMEG) for simple discrimination and inhibition of microbial pathogens by FRET mechanism . The positively charged PFDBT‐BIMEG has strong binding interaction with the negatively charged bacterial cell membrane at the aggregated state through electrostatic and salt bridge interactions.…”