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Keywords:

  • bacterial detection;
  • bioimaging;
  • biosensors;
  • conjugation;
  • fluorescence;
  • glycopolymers

Abstract

Thumbnail image of graphical 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).

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 (polymerA) displays poor water solubility. However, glycopolymers with poly(ethylene glycol)-tethered spacers (polymersB 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.