title: Synthesis of highly water-soluble fluorescent conjugated glycopoly(p-phenylene)s for lectin and Escherichia coli.
abstract: Two facile, convenient, and versatile synthetic approaches are used to covalently attach carbohydrate residues to conjugated poly(p-phenylene)s (PPPs) for highly water-soluble PPPs bearing alpha-mannopyranosyl and beta-glucopyranosyl pendants (polymers A and B), which highly fluoresce in phosphate buffer (pH 7.0). The post-polymerization functionalization approach is to treat bromo-bearing PPP (polymer 1) with 1-thiolethyl-alpha-D-mannose tetraacetate or 1-thiol-beta-D-glucose tetraacetate in THF solution in the presence of K(2)CO(3) at room temperature through formation of thioether bridges, affording polymer 2a or 2b. The prepolymerization functionalization approach is to polymerize a well-defined sugar-carrying monomer, affording polymer 2a. Polymers 2a and 2b were deacetylated under Zemplén conditions in methanol and methylene chloride containing sodium methoxide, affording polymers A and B, respectively. The multivalent display of carbohydrates on the fluorescent conjugated glycopolymer overcomes the characteristic low binding affinity of the individual carbohydrates to their receptor proteins. Titration of concanavalin A (Con A) to alpha-mannose-bearing polymer A resulted in significant fluorescent quenching of the polymer with Stern-Volmer quenching constant of 4.5 x 10(7). Incubation of polymer A with Escherichia coli (E. coli) lead to formation of fluorescently stained bacterial clusters. Beta-glucose-bearing polymer B displayed no response to Con A and E. coli.
authors.affiliation: Department of Chemistry, Michigan Technological University, Houghton, Michigan 49931.
authors.forename: Cuihua
authors.initials: C
authors.lastname: Xue
authors.forename: Sonali P
authors.initials: SP
authors.lastname: Jog
authors.forename: Pushpalatha
authors.initials: P
authors.lastname: Murthy
authors.forename: Haiying
authors.initials: H
authors.lastname: Liu
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry*; D001709:Biotechnology / Q000379:methods*; D003208:Concanavalin A / Q000737:chemistry; D004926:Escherichia coli / Q000378:metabolism*; D005947:Glucose / Q000737:chemistry; D007700:Kinetics; D037102:Lectins / Q000737:chemistry*; D046911:Macromolecular Substances; D009682:Magnetic Resonance Spectroscopy; D008358:Mannose / Q000737:chemistry; D008752:Methylene Chloride / Q000737:chemistry; D008956:Models, Chemical; D011108:Polymers / Q000138:chemical synthesis* / Q000737:chemistry*; D013050:Spectrometry, Fluorescence
chemical_list: D001672:Biocompatible Materials; D037102:Lectins; D046911:Macromolecular Substances; D011108:Polymers; D003208:Concanavalin A; D008752:Methylene Chloride; C041325:polyphenylene sulfide; D005947:Glucose; D008358:Mannose