Synthesis of poly(oxyethylene phosphoramidate)s and glycopolymers via Staudinger reaction: Multivalent binding studies with Concanavalin A

A new method for the preparation of poly(oxyethylene phosphoramidate)s and glycopolymers is developed via modification of poly(oxyethylene H‐phosphonate) which is a biodegradable, biocompatible and low toxic polymer. The phosphonate groups of the precursor are converted into tri‐coordinated phosphorus species yielding poly(oxyethylene trimethylsilyl phosphite). The latter is then reacted with different azides, including sugar azides, via Staudinger reaction to furnish the desired poly(oxyethylene phosphoramidate)s and such containing sugar moieties in the side chains attached to the P‐centers. 2002P NMR spectroscopy is applied as a powerful tool for determination of the conversion and structure of the reaction products. Studies on Concanavalin A binding to the obtained glycopolymers are performed using dynamic light scattering and analytical ultracentrifugation techniques. The viability of Human Embryonic Kidney 293 cell line is slightly affected when exposed to polyphosphoramidate glucoconjugate over a broad range of concentrations. The results obtained are encouraging for further investigations on the clustering and bio‐recognition properties of the synthesized glycopolymers. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 1730–1741     

Molecular recognition capability and rheological behavior in solution of novel lactone-based glycopolymers

Novel glycopolymers have been prepared from ethylene–vinyl alcohol copolymers, EVOH. For that purpose, three distinct aminosaccharides (N-(4-aminobutyl)-d-gluconamide (NABG), N-(4-aminobutyl)-O-β-d-galactopyranosyl-(1 → 4)-d-gluconamide (NABL) and N-(4-aminobutyl)-O-β-d-glucopyranosyl-(1 → 4)-d-gluconamide (NABM) have been synthesized. The previous functionalization of these EVOH copolymers is mandatory to activate their hydroxyl reactivity before the subsequent coupling reaction with the aminosaccharides. The activation with carboxylic acid groups by reaction with phthalic anhydride has been chosen in the current investigation because of its almost quantitative yield and the subsequent high modification extent reached (>60%). The glycopolymers that turned out water-soluble (i.e., those based on NABL and NABM) have shown a reversible network formation unusually described in glycopolymers. In addition, their capability to interact with lectins, particularly Concanavalin A and Ricinus communis Agglutinin, has confirmed the specificity of lectin recognition in these glycopolymers.     

One‐Pot Multicomponent Synthesis of Glycopolymers through a Combination of Host–Guest Interaction,Thiol‐ene,and Copper‐Catalyzed Click Reaction in Water

There is a common phenomenon that the heterogeneity of natural oligosaccharides contains various sugar units, which can be used to enhance affinity and selectivity toward a specific receptor, so the synthesis of heterogeneous glycopolymers is always an important issue in the glycopolymer field. Herein, this study conducts a one‐pot method to prepare polyrotaxane‐based heteroglycopolymers anchored with different sugar units and fluorescent moieties via the combination of host–guest interaction, thiol‐ene, and copper‐catalyzed click chemistry in water. Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, gel permeation chromatography, X‐ray diffraction, and Ellman's assay test are used in the paper to characterize the compounds. Quartz crystal microbalance‐dissipation (QCD‐D) experiments and bacterial adhesion assay are utilized to study the interactions of polyrotaxane‐based heteroglycopolymers with Con A and Escherichia coli . The results reveal that polyrotaxanes (PRs) with mannose and glucose present better specificity toward Con A and E. coli than PRs with glucose due to synergistic effects.     

One-pot synthesis of hyperbranched poly(amido amine) clicked with a sugar shell via Michael addition polymerization and thiol click reaction

This paper reports the production of glycopolymers via a simple and flexible method. A novel glycopolymer with a hyperbranched poly(amido amine) core and a sugar shell (HPAA-GLc) was synthesized by using thiol-ene click reaction via facile one-pot method. Hyperbranched poly(amido amine) with vinyl terminals was first synthesized by Michael addition polymerization of N,N′-methylene bisacrylamide (MBA) with 1-(2-aminoethyl) piperazine (AEPZ). Subsequently, thiol-ene click reaction between vinyl units of hyperbranched poly(amido amine) and thio-glucose was performed in situ. Based on the NMR result, all the vinyl groups reacted with thiol-glucose in 120 min. Strong photoluminescence emission was observed from the aqueous solution of HPAA-GLc.     

Comparison of systematically functionalized heterogeneous and homogenous glycopolymers as toxin inhibitors

Multivalent glycosylated polymers and particles display enhanced binding affinity toward lectins compared to individual glycans. The design of glycopolymers with selectivity toward pathogen‐associated lectins (toxins) for sensing or in antiadhesion therapy is complicated due to lectins having promiscuous binding profiles and can be considered to be pattern recognition “readers,” with the capability to bind to several different glycans. Here, heterogeneous glycopolymers bearing variable densities of two different monosaccharides are synthesized by a three‐step postpolymerization modification approach, enabling systematic control over composition. It is found that heterogeneous polymers displayed increased inhibitory activity, compared to homogeneous polymers, against a RCA₁₂₀ and the cholera toxin. This demonstrates that embracing heterogeneity in glycomaterials could result in improved performance or emergent properties. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57, 40–47     

Amphiphilic block glycopolymers via atom transfer radical polymerization: Synthesis,self‐assembly and biomolecular recognition

In this work the synthesis of poly(butyl acrylate)‐b‐poly(2‐{[(D ‐glucosamin‐2‐N‐yl)carbonyl]oxy}ethyl methacrylate) (PBA‐b‐PHEMAGl) diblock glycopolymer and poly(2‐{[(D ‐glucosamin‐2‐N‐yl)carbonyl]oxy}ethyl methacrylate)‐b‐poly(butyl acrylate)‐b‐poly(2‐{[(D ‐glucosamin‐2‐N‐yl)carbonyl]oxy}ethyl methacrylate) (PHEMAGl‐b‐PBA‐b‐PHEMAGl) was performed via atom transfer radical polymerization. Monofunctional and difunctional poly(butyl acrylate) macroinitiators were used to synthesize the well‐defined diblock and triblock glycopolymers by chain extension reaction with the glycomonomer HEMAGl. The self‐assembly of these glycopolymers in aqueous solution was studied by dynamic light scattering and transmission electron microcopy, showing the coexistence of spherical micelles and polymeric vesicles. In addition, the biomolecular recognition capacity of these micelles and vesicles, containing glucose moieties in their coronas, was investigated using the lectin Concanavalin A, Canavalia Ensiformis, which specifically interacts with glucose groups. The binding capacity of Concanavalin A with glycopolymer is influenced by the copolymer composition, increasing with the length of HEMAGl glycopolymer segment in the block copolymer. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Probing carbohydrate-lectin recognition in heterogeneous environments with monodisperse cyclodextrin-based glycoclusters

A series of β-cyclodextrin (βCD)-scaffolded glycoclusters exposing heterogeneous yet perfectly controlled displays of α-mannosyl (α-Man) and β-lactosyl (β-Lact) antennas were synthesized to probe the mutual influence of varying densities of the saccharide motifs in the binding properties toward different plant lectins. Enzyme-linked lectin assay (ELLA) data indicated that the presence of β-Lact residues reinforced binding of α-Man to the mannose-specific lectin concanavalin A (Con A) even though homogeneous β-Lact clusters are not recognized at all by this lectin, supporting the existence of synergic recognition mechanisms (heterocluster effect). Conversely, the presence of α-Man motifs in the heteroglycoclusters also resulted in a binding-enhancing effect of β-Lact toward peanut agglutinin (PNA), a lectin strongly binding multivalent lactosides but having no detectable affinity for α-mannopyranosides, for certain architectural arrangements. Two-site, sandwich-type ELLA data corroborated the higher lectin clustering efficiency of heterogeneous glycoclusters compared with homogeneous displays of the putative sugar ligand with identical valency. A turbidity assay was also consistent with the previous observations. Most revealingly, the lectin cross-linking ability of heterogeneous glycoclusters was sensitive to the presence of high concentrations of the non-ligand sugar, strongly suggesting that "mismatching" saccharide motifs may modulate carbohydrate-lectin specific recognition in a lectin-dependent manner when present in highly dense displays together with the "matching" ligand, a situation frequently encountered in biological systems.     

Controlled block glycopolymers able to bind specific proteins

The syntheses of a variety of amphiphilic block glycopolymers based on 2‐{[(D ‐glucosamin‐2‐N‐yl)carbonyl]oxy}ethyl acrylate and n‐butyl acrylate or methyl methacrylate by single‐electron transfer‐living radical polymerization (SET‐LRP) are described. In a first step, the homopolymerization of unprotected acrylic glycomonomer to obtain well‐controlled glycopolymers is studied. Posterior and based on these studies, di‐ and triblock glycopolymers were synthesized via SET‐LRP of the glycomonomer from different hydrophobic blocks, varying the hydrophilic block lengths. All the copolymers are characterized by nuclear magnetic resonance spectroscopy and GPC. Moreover, their water solution behavior by dynamic light scattering and their capacity of interaction with Concanavalin A lectin by turbidimetry are analyzed. The effect on the block glycopolymers behavior of hydrophobic block nature and the length of glycopolymer segments is evaluated. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013     

Relative Lectin Binding Properties of T‐Antigen‐Containing Glycopolymers: Copolymerization of N‐Acryloylated T‐Antigen Monomer vs. Graft Conjugation of Aminated T‐Antigen Ligands onto Poly(N‐acryloxysuccinimide)

Water‐soluble T‐antigen‐ (Galβ(1–3)‐GalNAcα) containing random glycopolymers were synthesized by two strategies: i) radical copolymerization of N‐acryloylated monomers with (NH₄)₂S₂O₈ and ii) graft conjugation of an end‐group‐aminated T‐antigen together with labeling reagent ( 16 ) by amidation onto poly(N‐acryloxysuccinimide) and its derivatives followed by quenching with NH₄OH. All glycoconjugates demonstrated antigenicity by double‐radial immunodiffusion assays with peanut lectin from Arachis hypogaea. The biocytin‐labeled terpolymer ( 23 ) also showed practical heterobifunctional antigenicity toward peanut lectin and streptavidin, giving the corresponding two precipitin bands in the assay.     

Synthesis of amphiphilic biodegradable glycocopolymers based on poly(ε‐caprolactone) by ring‐opening polymerization and click chemistry

Amphiphilic, biodegradable block glycopolymers based on poly(ε‐caprolactone) (PCL) with various pendent saccharides were synthesized by combination of ring‐opening polymerization (ROP) and “click” chemistry. PCL macroinitiators obtained by ROP of ε‐caprolactone were used to initiate the ROP of 2‐bromo‐ε‐caprolactone (BrCL) to get diblock copolymers, PCL‐b‐PBrCL. Reaction of the block copolymers with sodium azide converted the bromine groups in the PBrCL block to azide groups. In the final step, click chemistry of alkynyl saccharides with the pendent azide groups of PCL‐b‐PBrCL led to the formation of the amphiphilic block glycopolymers. These copolymers were characterized by ¹H NMR spectroscopy and gel permeation chromatography. The self‐assembly behavior of the amphiphilic block copolymers was investigated using transmission electron microscopy and atomic force microscope, spherical aggregates with saccharide groups on the surface were observed, and the aggregates could bind reversibly with Concanavalin A. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3583–3594, 2009     

Structural characterisation of a water-soluble polysaccharide from tissue-cultured Dendrobium huoshanense C.Z. Tang et S.J. Cheng

A water-soluble polysaccharide TC-DHPA4 with a molecular weight of 8.0 × 10⁵ Da was isolated from tissue-cultured Dendrobium huoshanense by anion exchange and gel permeation chromatography. Monosaccharide analysis revealed that the homogeneous polysaccharide was made up of rhamnose, arabinose, mannose, glucose, galactose and glucuronic acid with a molar ratio of 1.28:1:1.67:4.71:10.43:1.42. The sugar residue sequence analysis based on the GC-MS files and NMR spectra indicated that the backbone of TC-DHPA4 consisted of the repeated units:→6)-β-Galp-(1→6)-β-Galp-(1→4)-β-GlcpA-(1→6)-β-Glcp-(1→6)-β-Glcp-(→. The sugar residue sequences β-Glcp-(1→)-α-Rhap-(1→3)-β-Galp-(1→, β-Glcp-(1→4)-α-Rhap-(1→3)-β-Galp-(1→, β-Galp-(1→6)-β-Manp-(1→3)-β-Galp-(1→, and α-l-Araf-(1→2)-β-Manp-(1→3)-β-Galp-(1→ were identified as the branches attached to the C-3 position of (1→6)-linked galactose in the backbone.     

Synthesis of 8-Methoxycarbonyloctylβ-Glycosides of Tri-and Tetrasaccharides Related to Schizophyllan and Neoglycoproteins Therefrom

Abstract

The 8-methoxycarbonyloctyl β-glycosides of the trisaccharides O-β-d-Glcp-(1 → 6)- O-β-d-Glcp-(1 → 3)-d-Glcp and O-β-d-Glcp-(1 → 3)-O-[β-d -Glcp-(1 → 6)]-d-Glcp and of the tetrasaccharide O-β-d-Glcp-(1 → 3)-O-[β-d-Glcp-(1 → 6)]-O-β-d-Glcp-(1 → 3)-d-Glcp, corresponding to the fragments of schizophyllan, have been synthesized by using mono- to tetrasaccharide 1-thioglycosides as glycosyl donors, each bearing a participating benzoyl group in the 2-position, and N-iodosuccinimide and silver triflate as promoter. Saponification of the tri- and tetrasaccharide β-glycosides, followed by attachment to bovine serum albumin of the resulting sugar derivatives having a carboxyl group at the aglycon terminal, provided neoglycoproteins for immunological studies of the polysaccharide.     

Chemical modification of poly(hydroxyalkanoates). Copolymers bearing pendant sugars

Copolymers of poly(3‐hydroxyoctanoates) (PHAs) containing repeating units with unsaturated or brominated pendant side chains have been obtained from cultures of Pseudomonas oleovorans grown on mixtures of octanoic acid and undecenoic acid or 11‐bromoundecanoic acid as carbon sources. These polymers, bearing reactive functionalities, have been used to graft acetylated maltosyl units either by anti‐Markovnikov addition to the double bond or S_N2 substitution of the halogen. De‐O‐acetylation of the sugar moieties yielded PHAs with new properties.     

Glycopolymers resulting from ethylene–vinyl alcohol copolymers: Synthetic approach,characterization, and interactions with lectins

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 ‐(+)‐glucosamine, D ‐(+)‐galactosamine, and D ‐(+)‐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 ¹H and ¹³C 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. © Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7238–7248, 2008     

Molar Mass and Structural Characteristics of Poly[(lactide-co-(aspartic acid)] Block Copolymers

Summary: We report on various synthetic procedures for the preparation of biodegradable and biocompatible poly(lactide-co-aspartic acid) block copolymers based on natural monomeric units – lactic acid and aspartic acid. Multiblock poly(lactide-co-aspartic acid) copolymers of different comonomer composition were synthesized by heating a mixture of L-aspartic acid and L,L-lactide in melt without the addition of any catalyst or solvent and with further alkaline hydrolysis of the cyclic succinimide rings to aspartic acid units. Diblock poly(lactide-co-aspartic acid) copolymers with different block lengths were prepared by copolymerization of amino terminated poly(β-benzyl-L-aspartate) homopolymer and L,L-lactide with subsequent deprotection of the benzyl protected carboxyl group by hydrogenolysis. The differences in the structure, composition, molar mass characteristics, and water-solubility of the synthesized multiblock and diblock poly(lactide-co-aspartic acid) copolymers are discussed.     

Well‐defined pH‐sensitive block glycopolymers via reversible addition–fragmentation chain transfer radical polymerization: Synthesis,characterization, and recognition with lectin

pH‐Sensitive block glycopolymers of poly(2‐(diethylamino)ethyl methacrylate) (PDEAEMA) and poly(3‐O‐methacryloy‐α,β‐D ‐glucopyranose) (PMAGlc) were synthesized via reversible addition–fragmentation chain transfer (RAFT) radical polymerization based on protected glycomonomer 3‐O‐methacryloyl‐1,2:5,6‐di‐O‐isopropylidene‐D ‐glucofuranose (MAIpGlc). It was found that RAFT homopolymerization of MAIpGlc proceeded in a controlled fashion with 4‐cyanopentanoic acid dithiobenzoate as chain transfer agent. Using the dithioester‐capped PDEAEMA as macro‐RAFT agent, block copolymerization of MAIpGlc was in good control as indicated by the linear pseudo first‐order kinetic plot, the linear increment of number‐average molecular weights as well as narrow and symmetrical gel permeation chromatography peaks, and low polydispersities. Well‐defined diblock copolymers of DEAEMA and MAIpGlc were prepared successfully through the chain extension of PDEAEMA. The deprotection of MAIpGlc units in trifluoroacetic acid/H₂O solution afforded PDEAEMA‐b‐PMAGlc block glycopolymer. The self‐assembly behavior of PDEAEMA‐b‐PMAGlc in aqueous solution was investigated by using ¹H NMR, UV‐vis spectroscopy, dynamic light scattering, and transmission electron microscopy. The results demonstrated that spherical micelles with PDEAEMA as the hydrophobic cores and PMAGlc as the hydrophilic shells were formed in alkaline aqueous solution. These glucose‐installed micelles had specific recognition with Concanavalin A. The combination of pH‐sensitivity of PDEAEMA and biomolecular recognition of PMAGlc in one micellar system may create a multifunctional platform for targeted delivery, biomimetics, and biodection. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3350–3361, 2010     

Homogeneous graft copolymerization and characterization of novel artificial glycoprotein: Chitosan‐poly(L‐tryptophan) copolymers with secondary structural side chains

A novel series of artificial glycoprotein, peptide‐chitosan copolymers with secondary structural side chain have been synthesized by ring‐opening polymerization of L ‐tryptophan N‐carboxyanhydride under homogeneous conditions. Their chemical structures and polymerization degree (DP) were characterized by IR, ¹³C NMR, and XRD spectra. Distinctly secondary protein structure has been found in the poly‐L ‐tryptophan side chains of copolymers and with the lengthening of side chain (i.e., the increase of DP at the same time), its conformations could transfer from β‐sheet to α‐helix. The content of α‐helix reaches about 41% when DP of polytryptophan is 22. The solubility of graft copolymers in polar solvent strongly depends on the length of poly‐L ‐tryptophan side chains. Unique fluorescence emission at 360 nm has been observed in the glycopolymers and the intensity shows the positive‐correlation with the increasing of DP of polytryptophan. Importantly, the fluorescence effect can be quenched easily by the coordination with copper ions which provides the possibility on the biosensor design. In comparison with chitosan, glycopolymers also present impressively enhanced compressive strength and elastic modules when it is blended with epoxy E 44 to form epoxy‐copolymer hybrid resin. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 925–934, 2009     

Prepolymerization and postpolymerization functionalization approaches to fluorescent conjugated carbazole‐based glycopolymers via “click chemistry”

Facile prepolymerization and postpolymerization functionalization approaches to prepare well‐defined fluorescent conjugated glycopolymers through Cu(I)‐catalyzed azide/alkyne “Click” ligation were explored. Two well‐defined carbazole‐based fluorescent conjugated glycopolymers were readily synthesized based on these strategies and characterized by ¹H NMR, ¹³C NMR, IR spectra, and UV‐vis spectra. The “Click” ligation offers a very effective conjugation method to covalently attach carbohydrate residues to fluorescent conjugated polymers. In addition, the studies of carbohydrate–lectin interactions were performed by titration of concanavalin A (Con A) to D ‐glucose‐bearing poly(anthracene‐alt‐carbazole) copolymer P‐2 resulting in significant fluorescence quenching of the polymer due to carbohydrate–lectin interactions. When peanut agglutinin (PNA) was added, no distinct change in the fluorescent properties of P‐2 was observed. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2948–2957, 2009     

Synthesis of novel glycopeptide-polyoxazoline block copolymers by direct coupling between living anionic and cationic polymerization systems

A novel glycopeptide-containing block copolymer, poly[O-(tetra-O-acetyl-β-D -glucopyranosyl)-L -serine]-block-poly(2-methyl-2-oxazoline) ( 5 ), was synthesized by mutual termination of living polymerizations of a sugar-substituted α-amino acid N-carboxyanhydride (NCA) ( 1 ) and 2-methyl-2-oxazoline ( 3 ). 5 was deacetylated to provide the glycopeptide-polyoxazoline block copolymer, poly[O-(β-D -glucopyranosyl)-L -serine]-block-poly(2-methyl-2-oxazoline) ( 6 ).     

Syntheses and antitumor activities of monomer and medium molecular weight polymers. III. 3,6-endo-methylene-1,2,3,6-tetrahydrophthalimidopropanoyl-5-fluorouracil and its polymers

The new monomer, 3,6-endo-methylene-1,2,3,6-tetrahydrophthalimidopropanoyl-5-fluorouracil (ETPFU), was synthesized by the reaction of 5-fluorouracil (5-FU) and 3,6-endo-methylene-1,2,3,6-tetrahydrophthalimidopropanoyl chloride (ETPC). The homopolymer of ETPFU and its copolymers with acrylic acid (AA) and vinyl acetate (VAc) were prepared by photopolymerizations. The synthesized ETPFU and polymers were identified by Fourier transfer infrared (FTIR), ¹H nuclear magnetic resonance (NMR), and ¹³C-NMR spectroscopies. The contents of ETPFU units in poly(ETPFU-co-AA) and poly(ETPFU-co-VAc) were 26 and 32 mol %, respectively. The number average molecular weights of the synthesized polymers determined by gel permeation chromatography (GPC) were in range from 8,800 to 10,700. The in vitro cytotoxicities of the samples were evaluated with mouse mammary carcinoma (FM3A), mouse leukemia (P388), and human histiocytic lymphoma (U937) as a cancer cell line and mouse liver cells (AC2F) as a normal cell line. The in vivo antitumor activities of polymers against Balb/c mice bearing the sarcoma 180 tumor cells were greater than those of 5-FU at all doses tested. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 2113–2120, 1999