Highly Water‐Soluble, Fluorescent, Conjugated Fluorene‐Based Glycopolymers with Poly(ethylene glycol)‐Tethered Spacers for Sensitive Detection of <i>Escherichia coli</i>

Abstract

Abstract Know your bacteria! Two fluorene‐based, conjugated polymers with oligo(ethylene glycol)‐ and poly(ethylene glycol)‐tethered spacers have been prepared by the Suzuki coupling polymerization reactions. β‐Glucose and α‐mannose residues were covalently attached to the conjugated polymers by post‐polymerization functionalization with thiol‐functionalized carbohydrates under basic conditions. Investigations on their use as biosensing materials for the detection of Escherichia coli are reported (see figure). magnified image Two bromide‐bearing, fluorene‐based, conjugated polymers with oligo(ethylene glycol)‐ and poly(ethylene glycol)‐tethered spacers have been prepared by the Suzuki coupling polymerization of bromide‐bearing, fluorene monomers. β‐Glucose and α‐mannose residues have been covalently attached to the conjugated polymers by post‐polymerization functionalization of the precursor polymers with thiol‐functionalized carbohydrates under basic conditions through thioether linkage. A glucose‐bearing glycopolymer with oligo(ethylene glycol)‐tethered spacers ( polymer A ) displays poor water solubility. However, glycopolymers with poly(ethylene glycol)‐tethered spacers ( polymers B and C ) are highly water‐soluble due to their long, flexible, hydrophilic spacers. Incubation of the ORN178 strain of Escherichia coli ( E. coli ) with α‐mannose‐bearing glycopolymer (polymer C ) results in the formation of fluorescent cell clusters, causing significant red shifts in UV/Vis absorption and fluorescent spectra of the polymer through multivalent cooperative interactions of the polymeric carbohydrates with the bacterial pili. In contrast, polymer C displays no interactions with a mutant ORN208 strain of E. coli .