Synthesis of highly water-soluble fluorescent conjugated glycopoly(p-phenylene)s for lectin and Escherichia coli

Biomacromolecules. 2006 Sep;7(9):2470-4. doi: 10.1021/bm0604404.

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.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Biocompatible Materials / chemistry*
  • Biotechnology / methods*
  • Concanavalin A / chemistry
  • Escherichia coli / metabolism*
  • Glucose / chemistry
  • Kinetics
  • Lectins / chemistry*
  • Macromolecular Substances
  • Magnetic Resonance Spectroscopy
  • Mannose / chemistry
  • Methylene Chloride / chemistry
  • Models, Chemical
  • Polymers / chemical synthesis*
  • Polymers / chemistry*
  • Spectrometry, Fluorescence

Substances

  • Biocompatible Materials
  • Lectins
  • Macromolecular Substances
  • Polymers
  • Concanavalin A
  • Methylene Chloride
  • polyphenylene sulfide
  • Glucose
  • Mannose