Surface glycosylation of polymer membrane by thiol-yne click chemistry for affinity adsorption of lectin

Electrochemical impedance spectroscopy reveals a new mechanism based on competitive binding between Tris and protein on a conductive biomimetic polydopamine surface

A novel mechanism was developed to study the interaction of mussel inspired polydopamine surfaces with bovine serum albumin using electrochemical impedance spectroscopy.

Application of Porous Materials to Carbohydrate Chemistry and Glycoscience

There is a growing interest in using a range of porous materials to meet research needs in carbohydrate chemistry and glycoscience in general. Among the applications of porous materials reviewed in this chapter, enrichment of glycans from biological samples prior to separation and analysis by mass spectrometry is a major emphasis. Porous materials offer high surface area, adjustable pore sizes, and tunable surface chemistry for interacting with glycans, by boronate affinity, hydrophilic interactions, molecular imprinting, and polar interactions. Among the materials covered in this review are mesoporous silica and related materials, porous graphitic carbon, mesoporous carbon, porous polymers, and nanoporous gold. In some applications, glycans are enzymatically or chemically released from glycoproteins or glycopeptides, and the porous materials have the advantage of size selectivity admitting only the glycans into the pores and excluding proteins. Immobilization of lectins onto porous materials of suitable pore size allows for the use of lectin-carbohydrate interactions in capture or separation of glycoproteins. Porous material surfaces modified with carbohydrates can be used for the selective capture of lectins. Controlled release of therapeutics from porous materials mediated by glycans has been reported, and so has therapeutic targeting using carbohydrate-modified porous particles. Additional applications of porous materials in glycoscience include their use in the supported synthesis of oligosaccharides and in the development of biosensors for glycans.

Glycopolymer monoliths for affinity bioseparation of proteins in a continuous-flow system: glycomonoliths

Macroporous materials, called glycomonoliths, were prepared from saccharide-containing monomers, and applied for affinity bioseparation of proteins in a continuous-flow system.

Synthesis, Photo-physical and Electrochemical Properties of Dendrimers with (S)-BINOL Core and Benzothiazole Surface Unit

Chiral dendritic architectures with benzothiazole as surface group, 1,2,3-triazole as a bridging unit, and (S)-BINOL (1,1-bi-2-naphthol) as a core unit were synthesised in good yields via a convergent synthetic strategy. The chiroptical properties of the dendrimers revealed that the specific rotation increased in the order of dendrimers 4 > 3 > 2 > 1. All the dendrimers showed excellent optical and electrochemical response, and hence would find application in dye-sensitised solar cells.

Synthesis and characterization of novel barbwire-like graft polymers poly(ethylene oxide)-g-poly(ε-caprolactone)4 by the ‘grafting from’ strategy

Novel barbwire-like graft polymers PEO-g-PCL₄ were synthesized by combination of ring opening polymerization (ROP) and Glaser coupling with thiol–yne addition reaction via the “grafting from” strategy.

Synthesis of hyperbranched polymers and their applications in analytical chemistry

This review focuses primarily on the recent developments in the synthesis of hyperbranched polymers and their application in analytical chemistry.

When functionalization of PLA surfaces meets Thiol-Yne photochemistry: case study with antibacterial polyaspartamide derivatives

In this work we wish to report on the covalent functionalization of polylactide (PLA) surfaces by photoradical thiol-yne to yield antibacterial surfaces. At first, hydrophilic and hydrophobic thiol fluorescent probes are synthesized and used to study and optimize the conditions of ligation on alkyne-PLA surfaces. In a second part, a new antibacterial polyaspartamide copolymer is covalently grafted. The covalent surface modification and the density of surface functionalization are evaluated by SEC and XPS analyses. No degradation of PLA chains is observed, whereas covalent grafting is confirmed by the presence of S2p and N1s signals. Antiadherence and antibiofilm activities are assessed against four bacterial strains, including Gram-negative and Gram-positive bacteria. A strong activity is observed with adherence reduction factors superior to 99.98% and biofilm formation decreased by 80%. Finally, in vitro cytocompatibility tests of the antibacterial surfaces are performed with L929 murine fibroblasts and show cell viability without promoting proliferation.

Efficient asymmetric synthesis of 1-cyano-tetrahydroisoquinolines from lipase dual activity and opposite enantioselectivities in α-Aminonitrile resolution

Dual promiscuous racemization/amidation activities of lipases leading to efficient dynamic kinetic resolution protocols of racemic α-aminonitrile compounds are described. α-Amidonitrile products of high enantiomeric purity could be formed in high yields. Several lipases from different sources were shown to exhibit the dual catalytic activities, where opposite enantioselectivities could be recorded for certain substrates.

Glycosylation of the polypropylene membrane surface via thiol-yne click chemistry for lectin adsorption

Glycosylated membrane, as one of the most important affinity membranes, permits affinity separation/purification of proteins based on carbohydrate-protein interactions. It is an important scientific issue to screen facile method for fabricating the glycosylated membrane surface with high glycosyl density. Such a surface can be fabricated by the direct covalent immobilization of carbohydrate ligands on the surfaces of microporous polypropylene membrane (MPPM). First, alkyne-functionalized membrane surface was fabricated by plasma pretreatment combined with UV-induced graft polymerization of 3-(trimethylsilyl) propargyl methacrylate. Then, the glycosylated membrane surface was directly fabricated with the thiol-yne click reaction to ensure rapid process, improved efficiency, and high glycosyl density. Chemical and physical properties of the membrane surface were characterized by ATR/FT-IR, XPS, FESEM and water contact angle measurement. Static lectin adsorption indicates that the glycosylated membrane can specifically adsorb lectin concanavalin A (Con A) other than peanut agglutinin (PNA). Break through curves from dynamic Con A adsorption show the membrane has unique properties such as strong specificity, high adsorption capacity, and reversible binding capability. We suggest that the prepared glycosylated membrane is of great potentials in affinity membrane chromatography for rapid and high-resolution separation/purification of lectins.

Facile functionalization of polyesters through thiol-yne chemistry for the design of degradable, cell-penetrating and gene delivery dual-functional agents

Synthesis of polyesters bearing pendant amine groups with controlled molecular weights and narrow molecular weight distributions was achieved through ring-opening polymerization of 5-(4-(prop-2-yn-1-yloxy)benzyl)-1,3-dioxolane-2,4-dione, an O-carboxyanhydride derived from tyrosine, followed by thiol-yne "click" photochemistry with 2-aminoethanethiol hydrochloride. This class of biodegradable polymers displayed excellent cell penetration and gene delivery properties with low toxicities.

Glycopolymer brushes for the affinity adsorption of RCA120: effects of thickness, grafting density, and epitope density

The interactions between glycopolymer brushes and lectin are very important for the development of affinity membrane chromatography in protein separation. Here, we report the combination of surface-initiated atom transfer radical polymerization (SI-ATRP) and surface plasmon resonance (SPR) to investigate the relationship between the structure of glycopolymer brushes and the affinity adsorption of lectin. The glycopolymer brushes were fabricated from self-assembly of 11-mercapto-1-undecanol (MUD)/1-undecanethiol (UDT) mixture, immobilization of ATRP initiators, and then SI-ATRP of 2-lactobionamidoethyl methacrylate (LAMA). Brush thickness and grafting density were adjusted by controlling polymerization time and thiol ratio in MUD/UDT mixture, respectively. Sugar epitope density was also controlled through copolymerization of 2-hydroxylethyl methacrylate (HEMA) with LAMA. Ricinus communis agglutinin (RCA(120)), one kind of lectin that can bind galactose specifically, was chosen to study the effects of brush architectures on lectin adsorption. SPR results indicate not only the thickness but also the grafting density and the epitope density of glycopolymer brushes can achieve the best performance of sugar cluster effect in affinity adsorption of lectin. In addition, the mass transport effect is crucial in the adsorption process. We propose that it is important to keep the balance between the sugar cluster effect and the mass transport effect in the preparation of high-performance affinity membrane chromatography.

Thiol-yne coupling: revisiting old concepts as a breakthrough for up-to-date applications

Radical thiol-yne coupling (TYC) has emerged as one of the most appealing click chemistry procedures, appearing as a sound candidate for replacing/complementing other popular click reactions such as the thiol-ene coupling (TEC) and the Cu-catalysed azide-alkyne cycloaddition (CuAAC). Radical TYC is indeed a metal-free reaction suitable for biomedical applications, and its mechanistic features often make it more efficient than its TEC sister reaction and more suitable for multifaceted derivatisations in the materials chemistry and bioconjugation realms. This article reviews the fascinating results obtained in those fields in very recent years.

Photogenerated lectin sensors produced by thiol-ene/yne photo-click chemistry in aqueous solution

The photoinitiated radical reactions between thiols and alkenes/alkynes (thiol-ene and thiol-yne chemistry) have been applied to a functionalization methodology to produce carbohydrate-presenting surfaces for analyses of biomolecular interactions. Polymer-coated quartz surfaces were functionalized with alkenes or alkynes in a straightforward photochemical procedure utilizing perfluorophenylazide (PFPA) chemistry. The alkene/alkyne surfaces were subsequently allowed to react with carbohydrate thiols in water under UV-irradiation. The reaction can be carried out in a drop of water directly on the surface without photoinitiator, and any disulfide side products were easily washed away after the functionalization process. The resulting carbohydrate-presenting surfaces were evaluated in real-time studies of protein-carbohydrate interactions using a quartz crystal microbalance (QCM) flow-through system with recurring injections of selected lectins, with intermediate regeneration steps using low pH buffer. The resulting methodology proved fast, efficient and scalable to high-throughput analysis formats, and the produced surfaces showed significant protein binding with expected selectivities of the lectins used in the study.