Highly Efficient Solid-Phase Labeling of Saccharides within Boronic Acid Functionalized Mesoporous Silica Nanoparticles

Magnetic dendritic mesoporous silica nanoparticles based integrated platform for rapid and efficient analysis of saccharides

BACKGROUND

As an essential compound in living organism, saccharides have attracted enormous attentions from scientists in various fields. Understanding the distribution of saccharides in various samples is of great scientific importance. However, the low signal response and lack of specific recognition technology of saccharides and the complex matrix of samples make the analysis of saccharides a very challenge task. Thus, the development of a simple and straightforward strategy for the analysis of saccharides would represent a great contribution to the field.

RESULTS

In this study, by employing the sulfonyl functionalized magnetic dendritic mesoporous silica nanoparticles as the substrate, we develop an integrated platform for analysis of saccharides. The construction of the platform mainly relied on multi-functional boronic acid, which serves as separation and derivation ligands at the same time. In the general procedure, the boronic acid is first immobilized onto the surface of substrate, then the selective enrichment of saccharides can be realized via boronate affinity separation. Finally, by the rational choice of the solution, we are able to elute the labelled complex (boronic acid-saccharide) from the substrate, which can be direct subjected to HPLC-UV analysis. The reliable precision (<15 %), accuracy (80-100 %), reproducibility (<10 %), improved sensitivity (20x) and limited time-consuming (down to minutes) of the proposed platform are experimentally demonstrated.

SIGNIFICANCE AND NOVELTY

The successful quantification of different saccharides (alditols, glucose) in real samples is achieved. The proposed strategy is not only straightforward and fast, but also avoid the requirement of special equipment. With these attractive features, we believe that this strategy will greatly prompt the analysis of saccharides in various samples (eg. food, pharmaceutics and biosamples).

Enrichment of sialic acid-containing casein glycomacropeptide in protein hydrolysates using phenylboronic acid-functionalized mesoporous silica nanoparticles

Glycomacropeptide (GMP) is a bioactive peptide of high value, rich in glycosylation sites and with physiological and dietary therapeutic value. The enrichment and detection of GMP facilitates the accurate quantification and the identification of adulteration of GMP in food products. In GMP, sialic acid is an abundant glycosyl group and is mainly located at the end of the sugar chain. Here, we propose a novel GMP enrichment strategy based on the affinity of sialic acid for phenylboronic acid groups that shift with environmental pH. As an enrichment material, mesoporous silica nanoparticles were progressively modified with aminopropyl and phenylboronic acid groups. The developed material showed excellent selectivity for sialic acid in the presence of galactose and fucose as interferents. The adsorption behavior of sialic acid-containing GMP fits the Langmuir adsorption model, offering a recovery of 71.72% (in terms of sialic acid content) and a GMP relative purity of 0.957. Results from sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and size exclusion chromatography confirm that the enriched GMP contains almost no other unexpected proteins and peptides, indicating that the developed strategy holds promise for purifying GMP in various dairy systems.

Teamed Boronate Affinity-Functionalized Zn-MOF/PAN-Derived Molecularly Imprinted Hollow Carbon Electrospinning Nanofibers for Selective Adsorption of Shikimic Acid

Electrospun micro-/nanofibers with tailor-made specific binding sites are extremely popular due to their tremendous potential in separation applications. In this work, teamed boronate affinity (TBA)-functionalized molecularly imprinted hollow carbon electrospun nanofibers (MI-HCESNFs) derived from ZIF-8/PAN fibers with selective binding sites toward shikimic acid (SA) are presented. Each ingredient used in this strategy plays its own part: HCESNFs with excellent structural characteristics as the highly porous electrospun substrate, KH560 as the grafting material for the follow-up polyethyleneimine (PEI) modification, PEI as the dendritic platform to approach more boronic acid owing to its long chain with abundant amino groups, and TBA molecular group as the functional monomer to specifically bind with SA under the neutral condition. Benefiting from the porous structure, the high density of boronic acid, and the highly accessible imprinted sites on the surface, MI-HCESNFs show strong affinity and selectivity to the SA molecules. The adsorption capacity of MI-HCESNFs can reach 127.8 mg g-1, which is 3.1 times larger than that of the non-imprinted material. Besides, MI-HCESNFs are stable when treated with continuous ultrasonication and can be recycled eight times with a slight loss of 8.615% on the adsorption quantity. This work presents a new strategy to prepare boronate affinity adsorbents based on the electrospinning technique for the capture of SA and also proposes a path for the integration of molecularly imprinted polymers and electrospinning.

Connecting the Dynamics and Reactivity of Arylboronic Acids to Emergent and Stimuli-Responsive Material Properties

Over the past two decades, arylboronic acid-functionalized biomaterials have been used in a variety of sensing and stimuli-responsive scaffolds. Their diverse applications result from the diverse reactivity of arylboronic acids,...

Construction of DNA ligase-mimicking nanozymes via molecular imprinting

Enzyme mimics are of significant importance due to their facile preparation, low cost and stability to rigorous environment. Molecularly imprinted polymers (MIPs) have been important synthetic mimics of enzymes. However,...

Boronate carbon nanoparticles featuring efficient FRET for activatable two-photon fluorescence imaging of sialic acid surface-abundant tumor cells

Two-photon carbon-based nanoprobes hold great potential for biomedical applications as a result of their advantages of low fluorescence background, deep tissue imaging penetration and enhanced spatial resolution. However, the development of an activatable two-photon fluorescence carbon-based nanoprobe that simultaneously has the ability to target desired organs or cells is highly desired but remained a largely unsolved challenge. Herein, we developed boronate affinity BCNP@MnO2 nanocomposites, constructed by one step in situ growth of MnO2 nanosheets on the surface of aminophenylboronic acid-functionalized CNPs (BCNPs) via a redox reaction, which can feature efficient fluorescence energy transfer quenching to the BCNPs, allowing for tumor-specific affinity recognition and two-photon fluorescence activation imaging. By utilizing the inherent two-photon optical properties and sialic acid (SA) specific targeting ability of the BCNPs, good biocompatibility of the nanocomposites as well as highly sensitive and selective responses of MnO2 nanosheets towards GSH, the developed nanocomposites have demonstrated specific two-photon fluorescence activation imaging in target cancer cells and nude mouse tissues. Therefore, our proposed novel strategy could be used for monitoring GSH-triggered two-photon fluorescence activation events in SA-overexpressed cancer cells and has promising applications in both biological exploration and clinical diagnosis.

ANALYSIS OF CARBOHYDRATES AND GLYCOCONJUGATES BY MATRIX-ASSISTED LASER DESORPTION/IONIZATION MASS SPECTROMETRY: AN UPDATE FOR 2015-2016

This review is the ninth update of the original article published in 1999 on the application of matrix-assisted laser desorption/ionization (MALDI) mass spectrometry to the analysis of carbohydrates and glycoconjugates and brings coverage of the literature to the end of 2016. Also included are papers that describe methods appropriate to analysis by MALDI, such as sample preparation techniques, even though the ionization method is not MALDI. Topics covered in the first part of the review include general aspects such as theory of the MALDI process, matrices, derivatization, MALDI imaging, fragmentation and arrays. The second part of the review is devoted to applications to various structural types such as oligo- and poly-saccharides, glycoproteins, glycolipids, glycosides and biopharmaceuticals. Much of this material is presented in tabular form. The third part of the review covers medical and industrial applications of the technique, studies of enzyme reactions and applications to chemical synthesis. The reported work shows increasing use of combined new techniques such as ion mobility and the enormous impact that MALDI imaging is having. MALDI, although invented over 30 years ago is still an ideal technique for carbohydrate analysis and advancements in the technique and range of applications show no sign of deminishing. © 2020 Wiley Periodicals, Inc.

Insights into the structure-performance relationships of extraction materials in sample preparation for chromatography

Sample preparation is one of the most crucial steps in analytical processes. Commonly used methods, including solid-phase extraction, dispersive solid-phase extraction, dispersive magnetic solid-phase extraction, and solid-phase microextraction, greatly depend on the extraction materials. In recent decades, a vast number of materials have been studied and used in sample preparation for chromatography. Due to the unique structural properties, extraction materials significantly improve the performance of extraction devices. Endowing extraction materials with suitable structural properties can shorten the pretreatment process and improve the extraction efficiency and selectivity. To understand the structure-performance relationships of extraction materials, this review systematically summarizes the structural properties, including the pore size, pore shape, pore volume, accessibility of active sites, specific surface area, functional groups and physicochemical properties. The mechanisms by which the structural properties influence the extraction performance are also elucidated in detail. Finally, three principles for the design and synthesis of extraction materials are summarized. This review can provide systematic guidelines for synthesizing extraction materials and preparing extraction devices.

Oriented boronate affinity-imprinted inverse opal hydrogel for glycoprotein assay via colorimetry

A biomimetic antibody is described for colorimetric determination of glycoprotein, and horseradish peroxidase (HRP) is used as model analyte. Use is made of oriented surface imprinted inverse opal hydrogel particles functionalized with phenylboronic acid. The inverse opal hydrogel particles were negatively replicated from silica colloidal crystal beads (SCCBs), so that they were endowed with larger specific surface area than the bulk structure. Benefit from that, there were abundant surface molecularly imprinting sites in the hydrogel particles. Because the imprinting sites match the structure of the template molecules, they can recognize HRP with high selectivity and sensitivity. The recognized glycoprotein was bonded with the phenylboronic acid within the sites. The bonded HRP was determined by colorimetry of 3, 3', 5, 5'-tetramethylbenzidine (TMB) single-component solution at 450 nm, and it shows a 16.03 imprinting factor under optimized conditions. Alpha-fetoprotein (AFP) was also investigated and demostrated the value of this strategy in practical applications. The results show that the absorbance increases linearly in the 1-50 ng mL^-1 AFP concentration range and has a 1.32 ng mL^-1 detection limit. The assay of human serum was realized by the standard addition method. This strategy is promising to open new horizons for glycoprotein assay. Graphical abstract Schematic representation of the preparation of oriented boronate affinity-imprinted inverse opal hydrogel particles for glycoprotein assay.

Molecularly Imprinted Materials for Selective Biological Recognition

Molecular imprinting is an approach of generating imprinting cavities in polymer structures that are compatible with the target molecules. The cavities have memory for shape and chemical recognition, similar to the recognition mechanism of antigen-antibody in organisms. Their structures are also called biomimetic receptors or synthetic receptors. Owing to the excellent selectivity and unique structural predictability of molecularly imprinted materials (MIMs), practical MIMs have become a rapidly evolving research area providing key factors for understanding separation, recognition, and regenerative properties toward biological small molecules to biomacromolecules, even cell and microorganism. In this review, the characteristics, morphologies, and applicability of currently popular carrier materials for molecular imprinting, especially the fundamental role of hydrogels, porous materials, hierarchical nanoparticles, and 2D materials in the separation and recognition of biological templates are discussed. Moreover, through a series of case studies, emphasis is given on introducing imprinting strategies for biological templates with different molecular scales. In particular, the differences and connections between small molecular imprinting (bulk imprinting, "dummy" template imprinting, etc.), large molecular imprinting (surface imprinting, interfacial imprinting, etc.), and cell imprinting strategies are demonstrated in detail. Finally, future research directions are provided.

New insights into the structure-performance relationships of mesoporous materials in analytical science

Mesoporous materials are ideal carriers for guest molecules and they have been widely used in analytical science. The unique mesoporous structure provides special properties including large specific surface area, tunable pore size, and excellent pore connectivity. The structural properties of mesoporous materials have been largely made use of to improve the performance of analytical methods. For instance, the large specific surface area of mesoporous materials can provide abundant active sites and increase the probability of contact between analytes and active sites to produce stronger signals, thus leading to the improvement of detection sensitivity. The connections between analytical performances and the structural properties of mesoporous materials have not been discussed previously. Understanding the "structure-performance relationship" is highly important for the development of analytical methods with excellent performance based on mesoporous materials. In this review, we discuss the structural properties of mesoporous materials that can be optimized to improve the analytical performance. The discussion is divided into five sections according to the analytical performances: (i) selectivity-related structural properties, (ii) sensitivity-related structural properties, (iii) response time-related structural properties, (iv) stability-related structural properties, and (v) recovery time-related structural properties.

Efficient Synthesis of Five Types of Heterocyclic Compounds via Intramolecular Elimination Using Ultrasound-Static Heating Technique

An experimental technique, ultrasound-static heating, has been developed for the efficient synthesis of heterocyclic compounds. The technique involves ultrasonic irradiation and static heating processes. First, the ultrasonic irradiation process is performed to form an intermediate of the heterocyclic compound under mild conditions and the subsequent static heating process (heating the intermediate under solvent-free conditions without stirring) produces the target heterocyclic compounds via intramolecular elimination.

Specific enrichment combined with highly efficient solid-phase tagging for the sensitive detection of heparin based on boronic acid-functionalized mesoporous silica nanospheres

A combined specific enrichment and highly efficient solid-phase tagging approach is presented for heparin detection using boronic acid-functionalized mesoporous silica nanospheres as extraction sorbents and nanoscale reactors. It exhibits a faster reaction time (only 6 min), higher tagging-product purity and lower applicable sample concentration compared with liquid-phase tagging.

Ultrasensitive Electrochemical Detection of Glycoprotein Based on Boronate Affinity Sandwich Assay and Signal Amplification with Functionalized SiO2@Au Nanocomposites

Herein we propose a multiple signal amplification strategy designed for ultrasensitive electrochemical detection of glycoproteins. This approach introduces a new type of boronate-affinity sandwich assay (BASA), which was fabricated by using gold nanoparticles combined with reduced graphene oxide (AuNPs-GO) to modify sensing surface for accelerating electron transfer, the composite of molecularly imprinted polymer (MIP) including 4-vinylphenylboronic acid (VPBA) for specific capturing glycoproteins, and SiO₂ nanoparticles carried gold nanoparticles (SiO₂@Au) labeled with 6-ferrocenylhexanethiol (FcHT) and 4-mercaptophenylboronic acid (MPBA) (SiO₂@Au/FcHT/MPBA) as tracing tag for binding glycoprotein and generating electrochemical signal. As a sandwich-type sensing, the SiO₂@Au/FcHT/MPBA was captured by glycoprotein on the surface of imprinting film for further electrochemical detection in 0.1 M PBS (pH 7.4). Using horseradish peroxidase (HRP) as a model glycoprotein, the proposed approach exhibited a wide linear range from 1 pg/mL to 100 ng/mL, with a low detection limit of 0.57 pg/mL. To the best of our knowledge, this is first report of a multiple signal amplification approach based on boronate-affinity molecularly imprinted polymer and SiO₂@Au/FcHT/MPBA, exhibiting greatly enhanced sensitivity for glycoprotein detection. Furthermore, the newly constructed BASA based glycoprotein sensor demonstrated HRP detection in real sample, such as human serum, suggesting its promising prospects in clinical diagnostics.

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.

Determination of Glycoproteins by a Self-Assembled 4-Mercaptophenylboronic Acid Film on a Quartz Crystal Microbalance

Glycosylation plays an important part in many biological processes. However, many glycoproteins are either of low abundance or covered by other components in biological samples. Hence, developing new methods to measure the glycoproteins with both high efficiency and low detection limit is important. In this work, a self-assembled 4-mercaptophenylboronic acid film was coated on a quartz crystal microbalance chip. By optimizing the reaction time and the concentration of 4-mercaptophenylboronic acid, a sensor that specifically responded to glycoproteins was created. Then, several parameters for the prepared sensor were investigated and the working curve for representative glycoprotein-transferrin was established. The linearity range was from 50 to 400 ng/mL and the detection limit was 21.0 ng/mL. The sensor was used to detect transferrin in artificial urine samples. This sensor has a low detection limit of glycoproteins requiring only a small amount of samples, and thus has potential applications in both pharmaceutical and medical areas.

Highly efficient solid-phase derivatization of sugar phosphates with titanium-immobilized hydrophilic polydopamine-coated silica

Sugar phosphates are a type of key metabolic intermediates of glycolysis, gluconeogenesis and pentose phosphate pathway, which can regulate tumor energetic metabolism. Due to their low endogenous concentrations, poor chromatographic retention properties as well as ionization suppression from complex matrix interference, the determination of sugar phosphates in biological samples is very difficult. In this study, titanium-immobilized hydrophilic polydopamine-coated silica microspheres (SiO2@PD-Ti(4+)) were synthesized for highly efficient solid-phase derivatization of sugar phosphates. Sugar phosphates were selectively captured onto the surface of the SiO2@PD-Ti(4+) microspheres by chelating with phosphate groups, and then reacted with 3-amino-9-ethylcarbazole via reductive amination based on solid-phase derivatization, which could not only increase the retention and resolution of sugar phosphates on reversed-phase liquid chromatography (RPLC), but also improve the mass spectrometry (MS) sensitivity of sugar phosphates. The adsorption capacity of SiO2@PD-Ti(4+) microspheres towards glucose-6-phosphate is 0.76mg/g, which is much larger than that of commercial TiO2. Compared with the traditional liquid-phase derivatization, the solid-phase derivatization based on the SiO2@PD-Ti(4+) microspheres displayed several superiorities including shorter derivatization time (within 10min), higher product purity and much lower limit of detection (up to 38pmol/L). In addition, good linearity (R(2)≥0.99), excellent recovery (80.6-118%) and high precision (RSDs with 2.8-7.8%) were obtained when the developed method was used for quantitative analysis of sugar phosphates. Finally, the SiO2@PD-Ti(4+) microspheres combined with RPLC-MS were successfully applied to the determination of sugar phosphates from hepatocarcinoma cell lines and could even detect the trace sugar phosphates in thousands of cells.

Zirconium-doped magnetic microspheres for the selective enrichment of cis-diol-containing ribonucleosides

Zirconium-doped magnetic microspheres (Zr-Fe3O4) for the selective enrichment of cis-diol-containing biomolecules were easily synthesized via a one-step hydrothermal method. Characterization of the microspheres revealed that zirconium was successfully doped into the lattice of Fe3O4 at a doping level of 4.0 at%. Zr-Fe3O4 possessed good magnetic properties and high specificity towards cis-diol molecules, as shown using 28 compounds. For ribonucleosides, the adsorbent not only has favorable anti-interferential abilities but also has a high adsorption capacity up to 159.4μmol/g. As an example of a real application, four ribonucleosides in urine were efficiently enriched and detected via magnetic solid-phase extraction coupled with high-performance liquid chromatography. Under the optimized extraction conditions, the detection limits were determined to be between 0.005 and 0.017μg/mL, and the linearities ranged from 0.02 to 5.00μg/mL (R≥0.996) for these analytes. The accuracy of the analytical method was examined by studying the relative recoveries of the analytes in real urine samples, with recoveries varying from 77.8% to 119.6% (RSDs<10.6%, n=6). The results indicate that Zr-Fe3O4 is a suitable adsorbent for the analysis of cis-diol-containing biomolecules in practical applications.

Boronate affinity materials for separation and molecular recognition: structure, properties and applications

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.

Reversible control of pore size and surface chemistry of mesoporous silica through dynamic covalent chemistry: philicity mediated catalysis

Here, we report the synthesis of adaptive hybrid mesoporous silica having the ability to reconfigure its pore properties such as pore size and philicity in response to the external environment. Decyl chains were reversibly appended to the pore walls of silica through imine motifs as dynamic covalent modules to switch the pore size and philicity in response to pH. This switching of pore properties was used to gate the access of reactants to the gold nanoparticles immobilized inside the nanopores, thus enabling us to turn-on/turn-off the catalytic reaction. The use of such dynamic covalent modules to govern pore properties would enable the realization of intelligent hybrids capable of controlling many such chemical processes in response to stimuli.

Fabrication of a dendrimer-modified boronate affinity material for online selective enrichment of cis-diol-containing compounds and its application in determination of nucleosides in urine

A high binding capacity dendrimer-modified boronate affinity material (SiO₂@dBA) was synthesized and coupled with large-volume injection/online column-switching solid phase extraction to facilitate the determination process of cis-diols.