title: Synthesis and characterization of water-soluble conjugated glycopolymer for fluorescent sensing of concanavalin A.
abstract: A neutral polyfluorene derivative that contains 20 mol% 2,1,3-benzothiadiazole (BT) is synthesized by Suzuki cross-coupling polymerization. A cationic conjugated polymer A and an alpha-mannose-bearing polymer B are subsequently obtained through different post-polymerization methods. As a result of the charged pendant groups or sugar-bearing groups attached to the polymer side chains, both A and B show good water-solubility. The titration of Concanavalin A (Con A) into polymer aqueous solution leads to different fluorescent responses for polymers A and B. Polymer A does not show any obvious fluorescence change upon interaction with Con A, whereas polymer B shows fluorescence increase in BT emission intensity when Con A is added. This is because of the specific interaction between alpha-mannose and Con A, which induces polymer aggregation, and then facilitates energy transfer from the phenylene-fluorene segments to the BT units. A practical calibration curve ranging from 1 nM to 250 nM is obtained by correlating the changes in BT emission intensity with Con A concentration. The advantage of polymer B-based Con A macromolecular probe is that it shows signal increase upon Con A recognition, which is significantly different from other conjugated polymer-based fluorescence quenching assays.
authors.affiliation: Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore, 117576 Singapore.
authors.forename: Jianbing
authors.initials: J
authors.lastname: Shi
authors.forename: Liping
authors.initials: L
authors.lastname: Cai
authors.forename: Kan-Yi
authors.initials: KY
authors.lastname: Pu
authors.forename: Bin
authors.initials: B
authors.lastname: Liu
mesh_terms: D002241:Carbohydrates / Q000737:chemistry*; D003208:Concanavalin A / Q000737:chemistry*; D005453:Fluorescence; D008968:Molecular Conformation; D011108:Polymers / Q000138:chemical synthesis* / Q000737:chemistry*; D012995:Solubility; D014867:Water / Q000737:chemistry*
chemical_list: D002241:Carbohydrates; D011108:Polymers; D014867:Water; D003208:Concanavalin A