The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Zhen Liu - One of the best experts on this subject based on the ideXlab platform.
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Boronate affinity materials for separation and molecular recognition structure properties and applications
ChemInform, 2015Co-Authors: Yang Chen, Zhen LiuAbstract:Boronate affinity materials, as unique sorbents, have emerged as important media for the selective separation and molecular recognition of cis-diol-containing compounds. With the introduction of boronic acid functionality, Boronate affinity materials exhibit several significant advantages, including broad-spectrum selectivity, reversible covalent binding, pH-controlled capture/release, fast association/desorption kinetics, and good compatibility with mass spectrometry. Because cis-diol-containing biomolecules, including nucleosides, saccharides, glycans, glycoproteins and so on, are the important targets in current research frontiers such as metabolomics, glycomics and proteomics, Boronate affinity materials have gained rapid development and found increasing applications in the last decade. In this review, we critically survey recent advances in Boronate affinity materials. We focus on fundamental considerations as well as important progress and new Boronate affinity materials reported in the last decade. We particularly discuss on the effects of the structure of Boronate ligands and supporting materials on the properties of Boronate affinity materials, such as binding pH, affinity, selectivity, binding capacity, tolerance for interference and so on. A variety of promising applications, including affinity separation, proteomics, metabolomics, disease diagnostics and aptamer selection, are introduced with main emphasis on how Boronate affinity materials can solve the issues in the applications and what merits Boronate affinity materials can provide.
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a high Boronate avidity monolithic capillary for the selective enrichment of trace glycoproteins
Journal of Chromatography A, 2015Co-Authors: Zijun Bie, Xianghua Pan, Qian Zhang, Zhen LiuAbstract:Abstract Boronate affinity materials, as effective sample enrichment sorbents for glycoproteomic analysis, have attracted increasing attention in recent years. However, most of Boronate affinity materials suffer from an apparent limitation, limited binding strength. As a result, extraction of glycoproteins of trace concentration is rather difficult or impossible. In this study, we present a high Boronate avidity monolithic capillary. Branched polyethyleneimine (PEI) was used as a scaffold to amplify the number of boronic acid moieties. While 2,4-difluoro-3-formyl-phenylboronic acid (DFFPBA), which exhibited ultrahigh affinity toward cis -diol-containing compounds, was employed as an affinity ligand. Due to the PEI-assisted synergistic multivalent binding, the monolithic column exhibited high Boronate avidity toward glycoproteins, with binding constants of 10 −6 –10 −7 M. Such binding strength was the highest among already reported boronic acid-functionalized materials that can be used for glycoproteomic analysis. Besides, the Boronate avidity monolithic column exhibited one additional beneficial feature, lowered binding pH (≥6.5). These features greatly favored the selective enrichment of trace glycoproteins from real samples. The feasibility for practical applications was demonstrated with the selective enrichment of trace glycoproteins in human saliva. As compared with other Boronate avidity/affinity materials, the Boronate avidity monolithic capillary exhibited the best performance.
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a Boronate affinity sandwich assay an appealing alternative to immunoassays for the determination of glycoproteins
Angewandte Chemie, 2014Co-Authors: Yang Chen, Zhen LiuAbstract:Immunoassay has been an essential tool in many areas, including clinical diagnostics. However, it suffers from drawbacks, such as poor availability of high specificity antibodies, limited stability of biological reagents, as well as damage to health and susceptibility of chemical labels to the sample environment. Here we present a new approach, a Boronate-affinity sandwich assay (BASA), for the specific and sensitive determination of trace glycoproteins in complex samples. BASA relies on the formation of sandwiches between Boronate-affinity molecularly imprinted polymers (MIPs), target glycoproteins, and Boronate-affinity surface-enhanced Raman scattering (SERS) probes. The MIP ensures the specificity, while the SERS detection provides the sensitivity. BASA overcomes the drawbacks of traditional immunoassays and offers a great prospect for application.
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off line hyphenation of Boronate affinity monolith based extraction with matrix assisted laser desorption ionization time of flight mass spectrometry for efficient analysis of glycoproteins glycopeptides
Analytica Chimica Acta, 2014Co-Authors: Zijun Bie, Yang Chen, Zhen LiuAbstract:Boronate affinity materials have attracted increasing attentions as sample enrichment platforms for glycoproteomic analysis in recent years. However, most of the Boronate affinity materials that have already employed for proteomic analysis are suffering from apparent disadvantages, such as alkaline pH for binding, weak affinity, and relatively poor selectivity. Benzoboroxoles are a unique class of boronic acids which have showed excellent binding properties for the recognition of cis-diol-containing compounds. Recently, a 3-carboxy-benzoboroxole-functionalized monolithic column had been reported and it had exhibited the best selectivity and affinity as well as the lowest binding pH among all reported Boronate affinity monolithic columns. In this study, an off-line hyphenation of this Boronate affinity monolithic column-based extraction with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) was developed and the powerfulness of this hyphenated approach in the analysis of glycoproteins and glycopeptides in complex samples was investigated. The approach was first applied to the analysis of glycopeptides in the tryptic digest of horseradish peroxidase (HRP). Totally 22 glycopeptides were identified. To the best of our knowledge, this is the best performance among all the boronic acid-functionalized materials. We further employed this approach to the analysis of intact proteins in human saliva. Totally 6 intact glycoproteins were successfully identified. As comparison, when the samples were analyzed without extraction, only a few glycopeptides were identified from the tryptic digest of HRP while no glycoproteins were found from the saliva samples.
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affinity tunable specific recognition of glycoproteins via Boronate affinity based controllable oriented surface imprinting
Chemical Science, 2014Co-Authors: Shuangshou Wang, Zijun Bie, Zhen LiuAbstract:The molecular imprinting of proteins is of great importance but remains a challenge. Particularly, efficient, universal and facile approaches for protein imprinting are limited. Here we report a new general approach, Boronate affinity-based controllable oriented surface imprinting, for the efficient and facile imprinting of glycoproteins. A glycoprotein template was first covalently anchored onto the surface of a boronic acid-functionalized substrate by Boronate affinity binding. The substrate surface was then deposited with a thickness-controllable imprinting coating generated by in-water self-copolymerization of dopamine and m-aminophenylboronic acid (APBA). After removal of the template with an acidic solution, 3D cavities complementary to the molecular shape of the template were formed in the imprinting layer. The imprinting layer was hydrophilic and showed limited residual boronic acid, thus non-specific binding was avoided. The approach has significant advantages, including high specificity, high imprinting efficiency, and widely applicable substrates (from 2D to 3D, from regular size to nanoscale). Uniquely, the prepared molecularly imprinted polymers can rebind the templates in dual modes: a high affinity mode (Boronate affinity interaction is on) and a low affinity mode (Boronate affinity interaction is off), and the overall binding strength can be tuned by adjusting the surrounding pH. Such an affinity-tunable dual-mode binding mechanism enables the binding strength to be adjusted while keeping the specificity, which allows for wider applications, and also sheds new light on the role of affinity-determining factors in molecular imprinting.
James P. Morken - One of the best experts on this subject based on the ideXlab platform.
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hydroxyl directed cross coupling a scalable synthesis of debromohamigeran e and other targets of interest
Journal of the American Chemical Society, 2015Co-Authors: Thomas P Blaisdell, James P. MorkenAbstract:A hydroxyl functional group positioned β to a pinacol Boronate can serve to direct palladium-catalyzed cross-coupling reactions. This feature can be used to control the reaction site in multiply borylated substrates and can activate Boronates for reaction that would otherwise be unreactive.
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Direct Stereospecific Amination of Alkyl and Aryl Pinacol Boronates
Journal of the American Chemical Society, 2012Co-Authors: Scott N. Mlynarski, Alexander S. Karns, James P. MorkenAbstract:The direct amination of alkyl and aryl pinacol Boronates is accomplished with lithiated methoxyamine. This reaction directly provides aliphatic and aromatic amines, stereospecifically, and without preactivation of the Boronate substrate.
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Direct Stereospecific Amination of Alkyl and Aryl Pinacol Boronates
2012Co-Authors: Scott N. Mlynarski, Alexander S. Karns, James P. MorkenAbstract:The direct amination of alkyl and aryl pinacol Boronates is accomplished with lithiated methoxyamine. This reaction directly provides aliphatic and aromatic amines, stereospecifically, and without preactivation of the Boronate substrate
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sequential pd catalyzed asymmetric allene diboration α aminoallylation
ChemInform, 2006Co-Authors: Joshua D Sieber, James P. MorkenAbstract:Pd-catalyzed enantioselective diboration of prochiral allenes provides adducts which participate in highly selective allylation reactions with primary imines. The allylation product is a vinyl Boronate which may be oxidized to give nonracemic Mannich products (87−97% ee). Alternatively, enantiomerically enriched homoallylic amine derivatives may be obtained by protonation and Suzuki cross-coupling of the vinyl Boronate.
William R Dichtel - One of the best experts on this subject based on the ideXlab platform.
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growth rates and water stability of 2d Boronate ester covalent organic frameworks
Chemical Communications, 2015Co-Authors: Brian J Smith, Nicky Hwang, Anton D Chavez, Jennifer L Novotney, William R DichtelAbstract:We examine the growth rates, activation energies, and hydrolytic stability of multiple 2D Boronate ester covalent organic frameworks by turbidity measurements, observing a 200-fold range in stability. The rate-determining step in Boronate ester 2D COF growth is not in-solution condensation, but rather interlayer polymer stacking through a nucleation–elongation process.
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a mechanistic study of lewis acid catalyzed covalent organic framework formation
Chemical Science, 2011Co-Authors: Eric L Spitler, Marissa R Giovino, Sarah L White, William R DichtelAbstract:Three Boronate ester-linked covalent organic frameworks (COFs) were synthesized using a new approach that employs polyfunctional boronic acid and acetonide-protected catechol reactants in the presence of the Lewis acid catalyst BF3·OEt2. This transformation avoids the use of unstable and insoluble polyfunctional catechols. The COF-5 and COF-10 hexagonal lattices were obtained from a triphenylene tris(acetonide) and the appropriate diboronic acid linker, whereas a square Ni phthalocyanine COF was prepared from the appropriate Ni phthalocyanine tetra(acetonide). The powder X-ray diffraction, infrared spectra, and measured surface areas of these materials matched or exceeded previously reported values. A mechanistic study of this transformation revealed that the dehydrative trimerization of boronic acids to boroxines and the formation of a nonproductive aryl boronic acid–BF3 complex strongly affect the rate of Boronate ester formation. Crossover experiments employing substituted Boronate ester derivatives suggest that esterhydrolysis is the most likely exchange mechanism during COF formation under BF3·OEt2-catalyzed conditions.
Zijun Bie - One of the best experts on this subject based on the ideXlab platform.
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a high Boronate avidity monolithic capillary for the selective enrichment of trace glycoproteins
Journal of Chromatography A, 2015Co-Authors: Zijun Bie, Xianghua Pan, Qian Zhang, Zhen LiuAbstract:Abstract Boronate affinity materials, as effective sample enrichment sorbents for glycoproteomic analysis, have attracted increasing attention in recent years. However, most of Boronate affinity materials suffer from an apparent limitation, limited binding strength. As a result, extraction of glycoproteins of trace concentration is rather difficult or impossible. In this study, we present a high Boronate avidity monolithic capillary. Branched polyethyleneimine (PEI) was used as a scaffold to amplify the number of boronic acid moieties. While 2,4-difluoro-3-formyl-phenylboronic acid (DFFPBA), which exhibited ultrahigh affinity toward cis -diol-containing compounds, was employed as an affinity ligand. Due to the PEI-assisted synergistic multivalent binding, the monolithic column exhibited high Boronate avidity toward glycoproteins, with binding constants of 10 −6 –10 −7 M. Such binding strength was the highest among already reported boronic acid-functionalized materials that can be used for glycoproteomic analysis. Besides, the Boronate avidity monolithic column exhibited one additional beneficial feature, lowered binding pH (≥6.5). These features greatly favored the selective enrichment of trace glycoproteins from real samples. The feasibility for practical applications was demonstrated with the selective enrichment of trace glycoproteins in human saliva. As compared with other Boronate avidity/affinity materials, the Boronate avidity monolithic capillary exhibited the best performance.
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off line hyphenation of Boronate affinity monolith based extraction with matrix assisted laser desorption ionization time of flight mass spectrometry for efficient analysis of glycoproteins glycopeptides
Analytica Chimica Acta, 2014Co-Authors: Zijun Bie, Yang Chen, Zhen LiuAbstract:Boronate affinity materials have attracted increasing attentions as sample enrichment platforms for glycoproteomic analysis in recent years. However, most of the Boronate affinity materials that have already employed for proteomic analysis are suffering from apparent disadvantages, such as alkaline pH for binding, weak affinity, and relatively poor selectivity. Benzoboroxoles are a unique class of boronic acids which have showed excellent binding properties for the recognition of cis-diol-containing compounds. Recently, a 3-carboxy-benzoboroxole-functionalized monolithic column had been reported and it had exhibited the best selectivity and affinity as well as the lowest binding pH among all reported Boronate affinity monolithic columns. In this study, an off-line hyphenation of this Boronate affinity monolithic column-based extraction with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) was developed and the powerfulness of this hyphenated approach in the analysis of glycoproteins and glycopeptides in complex samples was investigated. The approach was first applied to the analysis of glycopeptides in the tryptic digest of horseradish peroxidase (HRP). Totally 22 glycopeptides were identified. To the best of our knowledge, this is the best performance among all the boronic acid-functionalized materials. We further employed this approach to the analysis of intact proteins in human saliva. Totally 6 intact glycoproteins were successfully identified. As comparison, when the samples were analyzed without extraction, only a few glycopeptides were identified from the tryptic digest of HRP while no glycoproteins were found from the saliva samples.
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affinity tunable specific recognition of glycoproteins via Boronate affinity based controllable oriented surface imprinting
Chemical Science, 2014Co-Authors: Shuangshou Wang, Zijun Bie, Zhen LiuAbstract:The molecular imprinting of proteins is of great importance but remains a challenge. Particularly, efficient, universal and facile approaches for protein imprinting are limited. Here we report a new general approach, Boronate affinity-based controllable oriented surface imprinting, for the efficient and facile imprinting of glycoproteins. A glycoprotein template was first covalently anchored onto the surface of a boronic acid-functionalized substrate by Boronate affinity binding. The substrate surface was then deposited with a thickness-controllable imprinting coating generated by in-water self-copolymerization of dopamine and m-aminophenylboronic acid (APBA). After removal of the template with an acidic solution, 3D cavities complementary to the molecular shape of the template were formed in the imprinting layer. The imprinting layer was hydrophilic and showed limited residual boronic acid, thus non-specific binding was avoided. The approach has significant advantages, including high specificity, high imprinting efficiency, and widely applicable substrates (from 2D to 3D, from regular size to nanoscale). Uniquely, the prepared molecularly imprinted polymers can rebind the templates in dual modes: a high affinity mode (Boronate affinity interaction is on) and a low affinity mode (Boronate affinity interaction is off), and the overall binding strength can be tuned by adjusting the surrounding pH. Such an affinity-tunable dual-mode binding mechanism enables the binding strength to be adjusted while keeping the specificity, which allows for wider applications, and also sheds new light on the role of affinity-determining factors in molecular imprinting.
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magnetic nanoparticles with dendrimer assisted Boronate avidity for the selective enrichment of trace glycoproteins
Chemical Science, 2013Co-Authors: Heye Wang, Zijun Bie, Zhen LiuAbstract:Boronic acid-functionalized materials have been the subject of increasing attention in recent years due to their capability in the facile selective extraction of glycoproteins. However, boronic acids are associated with weak binding affinity, and it is thereby difficult for Boronate affinity materials to extract glycoproteins of low concentration. Here we present for the first time a Boronate avidity material, dendrimeric boronic acid-functionalized magnetic nanoparticles, with significantly enhanced binding strength towards glycoproteins. Due to the dendrimer-assisted multivalent synergistic binding, the Boronate avidity material exhibited dissociation constants of 10−5 to 10−6 M towards glycoproteins, which are 3–4 orders of magnitude higher than the affinities of single boronic acid binding. Such an avidity enabled the selective extraction of trace glycoproteins; an extractable concentration as low as 2 × 10−14 M was demonstrated. Meanwhile, the Boronate avidity material was tolerant of the interference of abundant competing sugars. Moreover, the dendrimeric boronic acid-functionalized magnetic nanoparticles exhibited two additional advantages: high binding capacity and fast binding/desorption speed. Due to these favourable features, the selective enrichment of trace glycoproteins by the Boronate avidity material became not only possible but also efficient. Efficient enrichment of trace glycoproteins from human saliva was demonstrated. The dendrimer-assisted synergistic binding strategy is also applicable to other types of boronic acid-functionalized materials and other types of functionalized materials.
Lawrence G Hamann - One of the best experts on this subject based on the ideXlab platform.
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regioselective synthesis and slow release suzuki miyaura cross coupling of mida Boronate functionalized isoxazoles and triazoles
Journal of Organic Chemistry, 2011Co-Authors: Jonathan E Grob, Jill Nunez, Michael A Dechantsreiter, Lawrence G HamannAbstract:The efficient preparation of heterocycles with a range of substitutions ortho to heteroatoms remains as a challenge in organic synthesis, particularly relevant to the construction of druglike molecules due to the ubiquitous presence of such moieties in that chemical space. Modular installation of heterocyclic building blocks using Suzuki–Miyaura cross-coupling is a conceptually useful strategy to address this challenge, though this has historically been met with technical difficulty due to issues of inaccessibility and instability of the requisite heterocyclic Boronates. Herein we report a mild and highly regioselective cycloaddition approach which affords convenient access to stable MIDA Boronate-functionalized isoxazoles and triazoles and their subsequent efficient Suzuki–Miyaura cross-coupling. This methodology is then further applied to a set of druglike compounds in an efficient one-pot telescoped sequence in line with green chemistry principles.