A series of glycopolymers were prepared through combining ring-opening metathesis polymerization (ROMP) and CuAAC reaction. Firstly, a wide range of exo-7-oxanorbornene derivative glycomonomers without protecting groups were synthesized via a copper(I)-catalyzed azide-alkyne Huisgen cycloaddition (CuAAC) reaction, including alpha-D-mannose, beta-D-glucose, and beta-D-galactose. A series of well-defined glycopolymers were then obtained from various types and proportions of the above glycomonomers using ring-opening metathesis polymerization (ROMP) with the 3rd Grubbs catalyst in homogeneous organic solvent. Molecular weight and polydispersity index (PDI) of the glycopolymers were characterized by NMR spectroscopy and GPC, from which the well-controlled molecular weight (M-n = 1.3 x 10(4) - 2.7 x 10(4)) in narrow distribution (PDI = 1.22 similar to 1.45) was confirmed. Turbidity measurement, dynamic light scattering (DLS), and isothermal titration calorimetry (ITC) were carried out to investigate the specific recognition of glycopolymers with concanavalin A (Con A). Turbidimetric study suggested a stronger binding ability of glycopolymers with Con A at higher ratio of alpha-Dmannose in glycopolymers. In comparison, those composed solely of beta-D-galactose (P9) or beta-D-glucose (P5) could not bind to Con A. Dynamic light scattering experiments demonstrated that the particle sizes of glycopolymers containing alpha-D-mannose approached 1000 nm with the addition of Con A (originally 100 nm), while the glycopolymers without alpha-D-mannose showed little size variation. Binding constants (K-a) of the three glycopolymers P3 (50 mol% alpha-D-mannose, 50 mol% beta-D-glucose), P7 (50 mol% alpha-D-mannose, 50 mol% beta-D-galactose), and P11 (50 mol% alpha-D-mannose, 50 mol% non-sugar motif) with Con A were 1.58 x 10(6), 2.23 x 10(6), and 2.05 x 10(5) L/mol, respectively, as measured by isothermal titration calorimetry. P11 exhibited much weaker ability to bind with Con A than P3 and P7 did, which implied a synergistic effect of beta-D-glucose and beta-D-galactose on the recognition of alpha-D-mannose with Con A.
[1]Shanghai Inst Technol, Sch Chem & Environm Engn, Shanghai 201418, Peoples R China;
[2]Fudan Univ, Dept Polymer Sci, State Key Lab Polymer Mol Engn, Shanghai 200433, Peoples R China;
[3]Chinese Acad Sci, Shanghai Inst Organ Chem, Key Lab Organ Funct Mol Synth & Assembly Chem, Shanghai 200032, Peoples R China
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