A new multivalent glycopolymer platform for lectin recognition is introduced in this work by combining the controlled growth of glycopolymer brushes with highly specific glycosylation reactions. Glycopolymer brushes, synthetic polymers with pendant saccharides, are prepared by surface‐initiated atom transfer radical polymerization (SI‐ATRP) of 2‐O‐(N‐acetyl‐β‐d ‐glucosamine)ethyl methacrylate (GlcNAcEMA). Here, the fabrication of multivalent glycopolymers consisting of poly(GlcNAcEMA) is reported with additional biocatalytic elongation of the glycans directly on the silicon substrate by specific glycosylation using recombinant glycosyltransferases. The bioactivity of the surface‐grafted glycans is investigated by fluorescence‐linked lectin assay. Due to the multivalency of glycan ligands, the glycopolymer brushes show very selective, specific, and strong interactions with lectins. The multiarrays of the glycopolymer brushes have a large potential as a screening device to define optimal‐binding environments of specific lectins or as new simplified diagnostic tools for the detection of cancer‐related lectins in blood serum.
Group transfer polymerization was used to synthesize several series of hydrophilic random and model networks. Cationic random networks were prepared both in bulk and in tetrahydrofuran (THF) using a monofunctional initiator and simultaneous polymerization of monomer and branch units, while a bifanctional initiator was employed in THF for the synthesis of model networks comprising basic or acidic chains. Upon polymerization of the monomer, the latter initiator gives linear polymer chains with two “living” ends, which are subsequently interconnected to a polymer network by the addition of a branch unit. Homopolymer network star polymers were also synthesized in THF by a one‐pot procedure. The synthesis involved the use of a monofunctional initiator and the four‐step addition of the following reagents: (i) monomer, to give linear homopolymers; (ii) branch unit, to form “arm‐first” star polymers; (iii) monomer, to form secondary arms and give “in‐out” star polymers; and, finally (iv) branch unit again, to interconnect the “in‐out” stars to networks. Different networks were prepared for which the degree of polymerization (DP) of the linear chains between junction points was varied systematically. For all networks synthesized, the linear segments, the “arm‐first” and the “in‐out” stars were characterized in terms of their molecular weight (MW) and molecular weight distribution (MWD) using gel permeation chromatography (GPC). The degrees of swelling of both the random and model networks in water were measured and the effects of DP, pH, and monomer type were investigated. 相似文献
Cell surface carbohydrates, usually binding with other biomacromolecules (such as lipids and proteins), are involved in numerous biological functions, including cellular recognition, adhesion, cell growth regulation, and inflammation. Synthetic carbohydrate-based polymers, so-called glycopolymers, are emerging as important well-defined tools for investigating carbohydrate-based biological processes and for simulating various functions of carbohydrates. In this study, a novel two-step sequence for the generation of a glycopolymer layer tethered on a polypropylene microporous membrane is described. First, a UV-induced graft polymerization of 2-aminoethyl methacrylate hydrochloride (AEMA) was carried out on the membrane to generate an amino-functionalized surface, and the effects of polymerization factors (monomer/initiator concentration and UV irradiation time) on the grafting density were studied. Second, sugar moieties were bound with the grafted functional layer to form glycopolymer by the reaction between the amino groups on the membrane surface and carbohydrate lactones. Chemical analysis by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy combined with surface morphology observation by scanning electron microscopy confirmed the graft polymerization of AEMA and the formation of glycopolymer. The decreases of water contact angle and protein adsorption on the membrane revealed the enhancement of hydrophilicity and protein resistance due to the typical characteristics of the glycopolymer tethered on the surface. These results indicated that the novel sequence reported in this work is a facile process to form glycopolymer-modified surfaces. 相似文献
Flavan-3-ols consist of flavan-3-ol monomers and polymers with different degrees of polymerization (DP). In this study, flavan-3-ol extracts from grape seeds were well separated into three fractions including monomers, oligomers (2 < DP < 10) and polymers (DP > 10), by means of normal-phase HPLC-MS. The different patterns of these three fractions were analyzed in three Vitis vinifera cultivars ('Shiraz', 'Cabernet Sauvignon' and 'Marselan') seeds from veraison to harvest. The results showed: (1) polymers were the main form of flavan-3-ols in grape seeds and monomers accounted for only a small proportion; (2) the contents of flavan-3-ol monomers in the seeds of three grape cultivars all exhibited a gradually decreasing trend with a little fluctuation, whereas the patterns of the change of contents of oligomers and polymers were extremely different among grape cultivars; the contents of flavan-3-ol oligomers were enhanced in the seeds of 'Cabernet Sauvignon', but were reduced in the other two cultivars; (3) with regard to the proportion of flavan-3-ols with a certain DP to total flavan-3-ols, both flavan-3-ol monomers and flavan-3-ols with low DP fell in proportion, while the flavan-3-ols with high DP increased correspondingly. These findings indicate that flavan-3-ol polymerization in developing seeds is variety-dependent and may be genetically regulated. 相似文献
We report the synthesis and characterization of sugar-containing microspheres consisting of poly(divinylbenzene) (PDVB) cores onto which chains of galactose- or mannose-bearing polymers have been grafted. PDVB particles prepared by distillation polymerization with a diameter of 2.4 μm containing residual surface vinyl groups were used as starting material. “Grafting from”, “grafting through” and “grafting to” techniques were performed and special interest was laid towards the resulting grafting densities. The surface modification via “grafting from” was conducted by reversible addition fragmentation chain transfer (RAFT) polymerization directly from the surface, whereas thiol-ene chemistry was used to affix glycopolymer chains onto the particle surface. The resulting sugar-covered microspheres were analyzed towards their protein recognition activity with a series of lectins. 相似文献
The A–A/B–B step‐growth copolymerization between a monomer immobilized in the crystalline state and a monomer mobile in the solution state is demonstrated. One of the two monomers was immobilized as organic ligands of the metal–organic framework (MOF) and polymerized with the mobile guest monomer, resulting in the formation of linear polymers. The polymerization behavior was completely different from that of the solution polymerizations. In particular, the degrees of polymerization (DP) converged to a specific value depending on the MOF structures. The inevitable termination is caused not by imperfectness of the polymerization reaction, but by the selection of the two polymerization partners among the several adjacent immobilized monomers. This is fully supported by the Monte Carlo simulation on the basis of the polymerization mechanism. Precise immobilization of monomers in the supramolecular assemblies is a promising way for the controlled A–A/B–B step‐growth polymerization. 相似文献
A new class of supramolecular and biomimetic glycopolymer/poly(epsilon-caprolactone)-based polypseudorotaxane/glycopolymer triblock copolymers (poly(D-gluconamidoethyl methacrylate)-PPR-poly(D-gluconamidoethyl methacrylate), PGAMA-PPR-PGAMA), exhibiting controlled molecular weights and low polydispersities, was synthesized by the combination of ring-opening polymerization of epsilon-caprolactone, supramolecular inclusion reaction, and direct atom transfer radical polymerization (ATRP) of unprotected D-gluconamidoethyl methacrylate (GAMA) glycomonomer. The PPR macroinitiator for ATRP was prepared by the inclusion complexation of biodegradable poly(epsilon-caprolactone) (PCL) with alpha-cyclodextrin (alpha-CD), in which the crystalline PCL segments were included into the hydrophobic alpha-CD cavities and their crystallization was completely suppressed. Moreover, the self-assembled aggregates from these triblock copolymers have a hydrophilic glycopolymer shell and an oligosaccharide threaded polypseudorotaxane core, which changed from spherical micelles to vesicles with the decreasing weight fraction of glycopolymer segments. Furthermore, it was demonstrated that these triblock copolymers had specific biomolecular recognition with concanavalin A (Con A) in comparison with bovine serum albumin (BSA). To the best of our knowledge, this is the first report that describes the synthesis of supramolecular and biomimetic polypseudorotaxane/glycopolymer biohybrids and the fabrication of glucose-shelled and oligosaccharide-threaded polypseudorotaxane-cored aggregates. This hopefully provides a platform for targeted drug delivery and for studying the biomolecular recognition between sugar and lectin. 相似文献