Ting, S. R. S. et al., Synthesis of glycopolymers, Polym. Chem., (original) (raw)
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Well-controlled amphiphilic block glycopolymers and their molecular recognition with lectins
Journal of Polymer Science Part A: Polymer Chemistry, 2010
The atom transfer radical polymerization of an unprotected glycomonomer, 2-{[(D-glucosamin-2N-yl)carbonyl]-oxy}ethyl methacrylate (HEMAGl) is firstly reported. Controlled polymerizations were performed with the CuBr/N,N,N 0 ,N 0 ,N 0pentamethyldiethylene triamine catalytic system with ethyl 2bromoisobutyrate and 1,2-bis(bromoisobutyryloxy) ethane as mono and difunctional initiators in DMF solutions (80% w/w) at 40 and 50 C, respectively. The polymerization of HEMAGl resulted in a controlled polymerization with linear kinetics, molecular weights which increase with conversion and narrow polydispersity indexes. Mono and difunctional PHEMAGl macroinitiators were used to synthesize the amphiphilic di and tri-block glycopolymers with n-butyl acrylate, verifying their living character. The self-assembly of these glycopolymers in distilled water and in 0.1M NaCl solutions was studied by dynamic light scattering, showing the role of hydrogen bonds and the hydrophobic parts. In addition, their interaction with Concanavalin A lectin was examined, demonstrating the influence of molecular weight and copolymer composition. V C 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3623-3631, 2010
Controlled Synthesis of O -Glycopolypeptide Polymers and Their Molecular Recognition by Lectins
Biomacromolecules, 2012
The facile synthesis of high molecular weight water-soluble Oglycopolypeptide polymers by the ring-opening polymerization of their corresponding N-carboxyanhydride (NCA) in very high yield (overall yield > 70%) is reported. The per-acetylated-O-glycosylated lysine-NCA monomers, synthesized using stable glycosyl donors and a commercially available protected amino acid in very high yield, was polymerized using commercially available amine initiators. The synthesized watersoluble glycopolypeptides were found to be α-helical in aqueous solution. However, we were able to control the secondary conformation of the glycopolypeptides (α-helix vs nonhelical structures) by polymerizing racemic amino acid glyco NCAs. We have also investigated the binding of the glycopolypeptide poly(α-manno-O-lys) with the lectin Con-A using precipitation and hemagglutination assays as well as by isothermal titration calorimetry (ITC). The ITC results clearly show that the binding process is enthalpy driven for both α-helical and nonhelical structures, with negative entropic contribution. Binding stoichiometry for the glycopolypeptide poly(α-manno-O-lys) having a nonhelical structure was slightly higher as compared to the corresponding polypeptide which adopted an α-helical structure.
Journal of Polymer Science Part A: Polymer Chemistry, 2008
Ethylene-vinyl alcohol copolymers, EVOH, with two different vinyl alcohol compositions have been functionalized with carboxylic acid groups by reaction with phthalic anhydride. Later on, the coupling reaction of three aminosaccharides (D-(þ)-glucosamine, D-(þ)-galactosamine, and D-(þ)-mannosamine) to functionalized EVOH copolymers has been carried out in dimethyl sulfoxide at 70 C to achieve water soluble glycopolymers. The structure of the resulting functionalized copolymers and the new glycopolymers was confirmed by 1 H and 13 C NMR. Likewise, the thermal behavior of glycopolymers has been performed by differential scanning calorimetry and thermal gravimetric analysis. In addition, their affinity to lectins, specifically to Concanavalin A and Ricinus Communis Agglutinin, has been evaluated.
Macromolecules, 2017
The weak binding between carbohydrates and proteins is a major constraint toward the development of carbohydrate-based therapeutics. To address this, here we report the synthesis of glycopolymer (GP)-grafted silica nanoparticles (SiNP) by using reversible addition−fragmentation chain transfer (RAFT) polymerization through the graf ting-f rom approach using a multistep process. GP chains of various lengths with controlled molecular weight and narrow polydispersities were grown on the RAFT agent anchored SiNP surface using mannosyloxyethyl methacrylate (MEMA) as a glycomonomer. Spectroscopic (FT-IR, NMR) and thermogravimetric studies confirmed the grafting of poly(MEMA) chains on the SiNP surface and also showed that the dry DMF is a better solvent as compared to water/ethanol mixture for carrying out the MEMA polymerization on SiNP surface. The mean diameter of the dry GP-grafted SiNPs (GP-g-SiNPs) obtained from microscopic studies was in the range 50−60 nm, whereas the hydrodynamic diameter as obtained using light scattering measurements varied between 90 and 165 nm depending on the chain length of poly(MEMA). Hydrolysis of silica cores using aqueous HF enabled characterization of cleaved polymer using GPC, and the obtained unimodal chromatogram and narrow PDI confirmed that the polymerization proceeded through the RAFT mechanism. GP-g-SiNPs displayed stronger binding to the mannose specific lectin, Concanavalin A, owing to the larger positive binding entropic contribution which resulted in an association constant that is 800-and 400-fold stronger than that of monomeric mannose and GP chains, respectively.
2013
A group of fluorescent statistical glycopolymers, prepared via reversible addition-fragmentation chain-transfer (RAFT)-based polymerizations, were successfully employed in lectin-mediated bacterial binding studies. The resultant glycopolymers contained three different monomers: N-(2hydroxyethyl) acrylamide (HEAA), N-(2-aminoethyl) methacrylamide (AEMA) and N-(2-glyconamidoethyl)methacrylamides possessing different pendant sugars. Low dispersities (≤1.32) and predictable degrees of polymerization were observed among the products. After the polymerization, the glycopolymers were further modified by different succinimidyl ester fluorophores targeting the primary amine groups on AEMA. With their binding specificities being confirmed by testing with lectin coated agarose beads, the glycopolymers were employed in bacterial binding studies, where polymers containing α-galactose or β-galactose as the pendant sugar were specifically bound by two clinically important pathogens Pseudomonas aeruginosa and Staphylococcus aureus, respectively. This is the first report of using RAFTbased glycopolymers in bacterial binding studies, and the ready access to tri-component statistical glycopolymers also warrants further exploration of their utility in other glycobiological applications. Keywords Glycopolymer. RAFT. Lectin. Bacterial binding Abbreviations RAFT Reversible addition-fragmentation chain-transfer DP Degree of polymerization CTA Chain transfer agent MEHQ Hydroquinone monomethyl ether AEMA N-(2-Aminoethyl) methacrylamide HEAA N-(2-Hydroxyethyl) acrylamide GPC Gel permeation chromatography PMA Poly-methacrylamide/acrylamide DMF Dimethylformamide GNL Galanthus nivalis lectin Mn Number-average molar molecular weight Mw Weight-average molar molecular weight Electronic supplementary material The online version of this article
Journal of the American Chemical Society, 2010
Dynamic glycopolymers have been generated by polycondensation through acylhydrazone formation between components bearing lateral bioactive oligosaccharide chains. They have been characterized as bottlebrush type by cryo-TEM and SANS studies. They present remarkable fluorescence properties whose emission wavelengths depend on the constitution of the polymer and are tunable by constitutional modification through exchange/incorporation of components, thus also demonstrating their dynamic character. Constitution-dependent binding of these glycodynamers to a lectin, peanut agglutinin, has been demonstrated.
Journal of the American Chemical Society, 2007
Synthesis of well-defined neoglycopolymer-protein biohybrid materials and a preliminary study focused on their ability of binding mammalian lectins and inducing immunological function is reported. Crucial intermediates for their preparation are well-defined maleimide-terminated neoglycopolymers (M n = 8-30 kDa; M w /M n = 1.20-1.28) presenting multiple copies of mannose epitope units, obtained by combination of transition-metal-mediated living radical polymerization (TMM LRP) and Huisgen [2+3] cycloaddition. Bovine serum albumin (BSA) was employed as single thiol-containing model protein, and the resulting bioconjugates were purified following two independent protocols and characterized by circular dichroism (CD) spectroscopy, SDS PAGE, and SEC HPLC. The versatility of the synthetic strategy presented in this work was demonstrated by preparing a small library of conjugating glycopolymers that only differ from each other for their relative epitope density were prepared by coclicking of appropriate mixtures of mannopyranoside and galactopyranoside azides to the same polyalkyne scaffold intermediate. Surface plasmon resonance binding studies carried out using recombinant rat mannose-binding lectin (MBL) showed clear and dose-dependent MBL binding to glycopolymer-conjugated BSA. In addition, enzyme-linked immunosorbent assay (ELISA) revealed that the neoglycopolymerprotein materials described in this work possess significantly enhanced capacity to activate complement via the lectin pathway when compared with native unmodified BSA.
Macromolecules, 2009
The preparation of poly(2-(2 0 ,3 0 ,4 0 ,6 0 -tetra-O-acetyl-β-D-galactosyloxy)ethyl methacrylateco-styrene) (P(AcGalEMA-co-S)) glycopolymer was performed via nitroxide-mediated polymerization using a methacrylic acid-based alkoxyamine with N-tert-butyl-N-(1-diethylphosphono-2,2-dimethylpropyl) (SG1) nitroxide as mediating agent. In the presence of a low proportion of styrene, the polymerization of the glycomonomer was conducted in a controlled fashion at 85°C. The synthesis of the diblock copolymers was investigated via two routes by using either P(AcGalEMA-co-S) or polystyrene macroinitiators capped with SG1 nitroxide to yield P(AcGalEMA-co-S)-b-PS and PS-b-P(AcGalEMA-co-S), respectively. The AcGalE-MA moieties on the diblock copolymer were deacetylated to afford carbohydrate-based amphiphilic diblock copolymer, polystyrene-block-poly(2-(β-D-galactosyloxy)ethyl methacrylate-co-styrene) (PS-b-P(GalEMAco-S)). The self-assembling properties of PS-b-P(GalEMA-co-S) amphiphilic diblock copolymers were thoroughly exploited to obtain micellar structures and porous films. Lectin binding assays were conducted using the UV-vis spectroscopy and dynamic light scattering to test the biofunctionality of the β-galactose moieties with peanut agglutinin (PNA) on the micelles. The polymer was used to prepare honeycomb structured porous films with bioactivity. Fluorescent PNA was eventually conjugated with the sugar moieties on the porous films. Most protein was conjugated to glycopolymer inside the pore, demonstrating that this procedure can be a simple route to pattern proteins onto surfaces.