Facile synthesis of zwitterionic polymer-coated core-shell magnetic nanoparticles for highly specific capture of N-linked glycopeptides

Reversible Adsorption of Methylene Blue as Cationic Model Cargo onto Polyzwitterionic Magnetic Nanoparticles

The reversible electrostatic adsorption of the cationic dye methylene blue (MB) as a model compound to polydehydroalanine (PDha)-coated magnetic multicore nanoparticles (MCNP) is presented. The pH responsiveness of the zwitterionic coating material enables reversible switching of the net surface charge of the PDha@MCNP hybrid particles by changes in pH and thus allows reversible adsorption of MB at neutral pH and desorption at low pH values. The resulting hybrid materials can be very interesting systems in the context of water purification, and the reversible adsorption is studied using UV-vis spectroscopy under varying surrounding conditions. The particles are characterized using dynamic light scattering, zeta potential measurements, transmission electron microscopy, and thermogravimetric analysis.

Synthesis of zwitterionic hydrophilic magnetic mesoporous silica materials for endogenous glycopeptide analysis in human saliva

A novel zwitterionic hydrophilic magnetic mesoporous silica was prepared for endogenous glycopeptide enrichment prior to MS analysis. For the first time, the material was successfully applied in capturing endogenous glycopeptides from human saliva, indicating great potential of this strategy for glycopeptidome analysis.

Synthesis, Characterization, and Applications of Magnetic Nanoparticles Featuring Polyzwitterionic Coatings

Throughout the last decades, magnetic nanoparticles (MNP) have gained tremendous interest in different fields of applications like biomedicine (e.g., magnetic resonance imaging (MRI), drug delivery, hyperthermia), but also more technical applications (e.g., catalysis, waste water treatment) have been pursued. Different surfactants and polymers are extensively used for surface coating of MNP to passivate the surface and avoid or decrease agglomeration, decrease or modulate biomolecule absorption, and in most cases increase dispersion stability. For this purpose, electrostatic or steric repulsion can be exploited and, in that regard, surface charge is the most important (hybrid) particle property. Therefore, polyelectrolytes are of great interest for nanoparticle coating, as they are able to stabilize the particles in dispersion by electrostatic repulsion due to their high charge densities. In this review article, we focus on polyzwitterions as a subclass of polyelectrolytes and their use as coating materials for MNP. In the context of biomedical applications, polyzwitterions are widely used as they exhibit antifouling properties and thus can lead to minimized protein adsorption and also long circulation times.

Polymeric hydrophilic ionic liquids used to modify magnetic nanoparticles for the highly selective enrichment of N-linked glycopeptides

The low abundance of glycopeptides in biological samples makes it necessary to enrich them before further analysis. In this study, the polymeric hydrophilic ionic liquid-modified magnetic (Fe₃O₄@MPS@PMAC) nanoparticles were synthesized via a one-step reflux-precipitation polymerization. Owing to the excellent hydrophilicity and strong electrostatic interaction toward glycopeptides of the polymerized hydrophilic ionic liquid, [2-(methacryloyloxy) ethyl] trimethylammonium chloride (MAC), the synthesized Fe₃O₄@MPS@PMAC nanoparticles exhibited outstanding performance in glycopeptide enrichment with high detection sensitivity (10 fmol), large binding capacity (100 μg mg^-1) and satisfied enrichment recovery (approximately 82%). Furthermore, the newly developed Fe₃O₄@MPS@PMAC nanoparticles were applied for the glycopeptide enrichment of HeLa exosome proteins. A total of 1274 glycopeptides from 536 glycoproteins were identified in three replicate analyses of 50 μg of HeLa exosome proteins. These results demonstrate the potential of Fe₃O₄@MPS@PMAC nanoparticles for both glycoproteomic analysis and exosome research.

Cysteine-Functionalized Metal-Organic Framework: Facile Synthesis and High Efficient Enrichment of N-Linked Glycopeptides in Cell Lysate

Cysteine-functionalized metal-organic framework (MOF) was synthesized via a common and facile two-step method of in situ loading of Au nanoparticles on amino-derived MOF followed by l-cysteine (Cys) immobilization. Owing to the large specific surface area and ultrahigh hydrophilicity of this nanocomposite, excellent performance was observed in the enrichment of N-linked glycopeptides in both model glycoprotein and HeLa cell lysate. By using this nanocomposite, 16 and 31 glycopeptides were efficiently extracted from digest of horseradish peroxidase (HRP) and human serum immunoglobulin G (IgG), respectively. The short incubation time (5 min), large binding capacity (150 mg/g, IgG digest to material), good selectivity (1:50, molar ratio of IgG and bovine serum albumin (BSA) digest), high recovery (over 80%), and low detection limit (1 fmol) ensure the effectiveness and robustness of MIL-101(NH₂)@Au-Cys in complex HeLa cell lysate. As a result, 1123 N-glycosylation sites corresponding to 1069 N-glycopeptides and 614 N-glycoproteins were identified from the lysate. Compared with those of previously reported hydrophilic methods, to our knowledge, it was the best result. This work paves a new way for fast functionalization of MOF and also provides a novel idea for material design in sample preparation, especially in glycoproteome and related analysis.

Nanotechnology in Glycomics: Applications in Diagnostics, Therapy, Imaging, and Separation Processes

This review comprehensively covers the most recent achievements (from 2013) in the successful integration of nanomaterials in the field of glycomics. The first part of the paper addresses the beneficial properties of nanomaterials for the construction of biosensors, bioanalytical devices, and protocols for the detection of various analytes, including viruses and whole cells, together with their key characteristics. The second part of the review focuses on the application of nanomaterials integrated with glycans for various biomedical applications, that is, vaccines against viral and bacterial infections and cancer cells, as therapeutic agents, for in vivo imaging and nuclear magnetic resonance imaging, and for selective drug delivery. The final part of the review describes various ways in which glycan enrichment can be effectively done using nanomaterials, molecularly imprinted polymers with polymer thickness controlled at the nanoscale, with a subsequent analysis of glycans by mass spectrometry. A short section describing an active glycoprofiling by microengines (microrockets) is covered as well.

New Opportunities and Challenges of Smart Polymers in Post-Translational Modification Proteomics

Protein post-translational modifications (PTMs), which denote covalent additions of various functional groups (e.g., phosphate, glycan, methyl, or ubiquitin) to proteins, significantly increase protein complexity and diversity. PTMs play crucial roles in the regulation of protein functions and numerous cellular processes. However, in a living organism, native PTM proteins are typically present at substoichiometric levels, considerably impeding mass-spectrometry-based analyses and identification. Over the past decade, the demand for in-depth PTM proteomics studies has spawned a variety of selective affinity materials capable of capturing trace amounts of PTM peptides from highly complex biosamples. However, novel design ideas or strategies are urgently required for fulfilling the increasingly complex and accurate requirements of PTM proteomics analysis, which can hardly be met by using conventional enrichment materials. Considering two typical types of protein PTMs, phosphorylation and glycosylation, an overview of polymeric enrichment materials is provided here, with an emphasis on the superiority of smart-polymer-based materials that can function in intelligent modes. Moreover, some smart separation materials are introduced to demonstrate the enticing prospects and the challenges of smart polymers applied in PTM proteomics.

Sialic Acid-Responsive Polymeric Interface Material: From Molecular Recognition to Macroscopic Property Switching

Biological systems that utilize multiple weak non-covalent interactions and hierarchical assemblies to achieve various bio-functions bring much inspiration for the design of artificial biomaterials. However, it remains a big challenge to correlate underlying biomolecule interactions with macroscopic level of materials, for example, recognizing such weak interaction, further transforming it into regulating material's macroscopic property and contributing to some new bio-applications. Here we designed a novel smart polymer based on polyacrylamide (PAM) grafted with lactose units (PAM-g-lactose0.11), and reported carbohydrate-carbohydrate interaction (CCI)-promoted macroscopic properties switching on this smart polymer surface. Detailed investigations indicated that the binding of sialic acid molecules with the grafted lactose units via the CCIs induced conformational transformation of the polymer chains, further resulted in remarkable and reversible switching in surface topography, wettability and stiffness. With these excellent recognition and response capacities towards sialic acid, the PAM-g-lactose0.11 further facilitated good selectivity, strong anti-interference and high adsorption capacity in the capture of sialylated glycopeptides (important biomarkers for cancers). This work provides some enlightenment for the development of biointerface materials with tunable property, as well as high-performance glycopeptide enrichment materials.

Highly efficient enrichment of N-linked glycopeptides using a hydrophilic covalent-organic framework

A highly specific enrichment method for N-linked glycopeptides was successfully developed using a hydrophilic covalent-organic framework with excellent binding capacity, stability and reusability.

Facile synthesis of magnetic covalent organic frameworks for the hydrophilic enrichment of N-glycopeptides

Magnetic covalent organic frameworks were synthesized as novel hydrophilic materials for specific enrichment of glycopeptides.

Magnetic Nanospheres Encapsulated by Mesoporous Copper Oxide Shell for Selective Isolation of Hemoglobin

A novel strategy for the preparation of magnetic nanospheres encapsulated by mesoporous copper oxide shell, shortly termed as Fe₃O₄@mCuO, is reported via the calcination of Cu(NH₃)₄(NO₃)₂ into continuous mesoporous CuO shell onto the surface of Fe₃O₄ nanoparticles. The magnetic nanospheres are characterized to possess stable core-shell structure with a crystalline mesoporous CuO layer, exhibiting a CuO loading content of 25.2 ± 1.1% along with a favorable magnetic susceptibility. Fe₃O₄@mCuO nanospheres exhibit favorable selectivity on the adsorption of hemoglobin with a high adsorption capacity of up to 1162.5 mg g^-1. After adsorption, the high magnetic susceptibility allows convenient separation of the nanospheres by an external magnet. The retained hemoglobin could be readily recovered by using 0.5% (m/v) sodium dodecyl sulfate (SDS) as stripping reagent, providing a recovery of 78%. Circular dichroism spectra illustrate virtually no change in the conformation of hemoglobin after the process of adsorption/desorption. Fe₃O₄@mCuO nanospheres are further applied for the selective isolation of hemoglobin from human whole blood, achieving high-purity hemoglobin as demonstrated by SDS-PAGE (polyacrylamide gel electrophoresis) assays.

Facile synthesis of carboxymethyl-β-cyclodextrin conjugated magnetic nanoparticles for selective enrichment of glycopeptides

RATIONALE

Selective enrichment of glycopeptides prior to mass spectrometry (MS) analysis is essential due to the low abundance of the modified glycopeptides in complex samples, ion suppression effects during MS ionization and detection caused by the co-presence of non-glycosylated peptides, etc. Among different enrichment approaches, hydrophilic interaction liquid chromatography (HILIC)-based magnetic separation has become one of the most popular methods in recent years, due to its high efficiency and selectivity for glycopeptide enrichment.

METHODS

Herein, novel carboxymethyl-β-cyclodextrin (CMCD)-modified magnetic nanoparticles (MNPs) were synthesized via a carbodiimide activation method. CMCD was covalently bonded with the -OH group on the surface of MNPs through carbodiimide, and the proposed procedure provides a rapid and efficient alternative for glycopeptide enrichment due to its stable interaction, time-saving, and easy operation.

RESULTS

The prepared absorbents with a mean diameter of 15 nm demonstrated a strong magnetic response to an externally applied magnetic field. The results of thermogravimetric analysis showed the content of bound CMCD was 3 wt%. The outer CMCD layer conjugated on the Fe3 O4 core showed high hydrophilic surface property. In the analysis of a complex mouse liver sample, a total of 666 unique N-glycosylation sites corresponding to 494 glycosylated proteins were identified successfully.

CONCLUSIONS

The study demonstrated an easy-to-use CMCD-modified MNPs-based approach with high selectivity and high capacity in the enrichment of low-abundance glycopeptides from complex biological samples. Copyright © 2016 John Wiley & Sons, Ltd.

Post-synthetic modification of an amino-functionalized metal-organic framework for highly efficient enrichment of N-linked glycopeptides

A maltose-functionalized metal-organic framework (MOF), MIL-101(Cr)-maltose, was developed via a simple two step post-synthetic modification of MIL-101(Cr)-NH2. With the use of this nanomaterial, 33 glycopeptides were detected from the digest of human immunoglobulin G, demonstrating its high efficiency in glycoproteomic analysis. More importantly, the generic functionalization route from amino-derived MOFs opens a new perspective in material design in sample preparation.

Maturing Glycoproteomics Technologies Provide Unique Structural Insights into the N-glycoproteome and Its Regulation in Health and Disease

The glycoproteome remains severely understudied because of significant analytical challenges associated with glycoproteomics, the system-wide analysis of intact glycopeptides. This review introduces important structural aspects of protein N-glycosylation and summarizes the latest technological developments and applications in LC-MS/MS-based qualitative and quantitative N-glycoproteomics. These maturing technologies provide unique structural insights into the N-glycoproteome and its synthesis and regulation by complementing existing methods in glycoscience. Modern glycoproteomics is now sufficiently mature to initiate efforts to capture the molecular complexity displayed by the N-glycoproteome, opening exciting opportunities to increase our understanding of the functional roles of protein N-glycosylation in human health and disease.

Recent Advances in Clinical Glycoproteomics of Immunoglobulins (Igs)

Antibody glycosylation analysis has seen methodological progress resulting in new findings with regard to antibody glycan structure and function in recent years. For example, antigen-specific IgG glycosylation analysis is now applicable for clinical samples because of the increased sensitivity of measurements, and this has led to new insights in the relationship between IgG glycosylation and various diseases. Furthermore, many new methods have been developed for the purification and analysis of IgG Fc glycopeptides, notably multiple reaction monitoring for high-throughput quantitative glycosylation analysis. In addition, new protocols for IgG Fab glycosylation analysis were established revealing autoimmune disease-associated changes. Functional analysis has shown that glycosylation of IgA and IgE is involved in transport across the intestinal epithelium and receptor binding, respectively.

Hydrophilic GO/Fe3O4/Au/PEG nanocomposites for highly selective enrichment of glycopeptides

GO/Fe3O4/Au/PEG nanocomposites were synthesized via bonding gold nanoparticles on magnetic graphene oxide using polyethylenimine as the reducing and immobilizing reagent, followed by thiol-terminal polyethylene glycol immobilization. With the use of this nanocomposite, 255 glycopeptides, mapped to 127 different glycoproteins, were identified from human serum, demonstrating its great potential for glycosylation analysis.

Fabrication of Alkoxyamine-Functionalized Magnetic Core-Shell Microspheres via Reflux Precipitation Polymerization for Glycopeptide Enrichment

As a facile method to prepare hydrophilic polymeric microspheres, reflux precipitation polymerization has been widely used for preparation of polymer nanogels. In this article, we synthesized a phthalamide-protected N-aminooxy methyl acrylamide (NAMAm-p) for preparation of alkoxyamine-functionalized polymer composite microspheres via reflux precipitation polymerization. The particle size and functional group density of the composite microspheres could be adjusted by copolymerization with the second monomers, N-isopropyl acrylamide, acrylic acid or 2-hydroxyethyl methacrylate. The resultant microspheres have been characterized by TEM, FT-IR, TGA and DLS. The experimental results showed that the alkoxyamine group density of the microspheres could reach as high as 1.49 mmol/g, and these groups showed a great reactivity with ketone/aldehyde compounds. With the aid of magnetic core, the hybrid microspheres could capture and magnetically isolate glycopeptides from the digested mixture of glycopeptides and non-glycopeptides at a 1:100 molar ratio. After that, we applied the composite microspheres to profile the glycol-proteome of a normal human serum sample, 95 unique glycopeptides and 64 glycoproteins were identified with these enrichment substrates in a 5 μL of serum sample.

Selective removal of IgG from the urine of patients with proteinuria using a polymer coated core–shell magnetic nanoparticle

A synthetic monomer ofN-methacryloyl-l-aspartic acid plays a specific recognition role in magnetic separation of IgG from urinary protein sample using Fe₃O₄@SiO₂@MAsp-HEMA nanoparticles.

Reflux precipitation polymerization: a new synthetic insight in molecular imprinting at high temperature

Reflux precipitation polymerization was first used to fabricate monodispersed MIP microspheres, indicating electrostatic interaction was important for molecular imprinting at high temperature.

Anti-phagocytosis and tumor cell targeting micelles prepared from multifunctional cell membrane mimetic polymers

“Stealthy bio-missile” kinds of micelles were fabricated for developing advanced anticancer formulations by cell membrane mimicking.

A facile and cheap synthesis of zwitterion coatings of the CS@PGMA@IDA nanomaterial for highly specific enrichment of glycopeptides

Zwitterion coatings of CS@PGMA@IDA nanospheres have the combination of biospecific molecules with bioinert coatings that can selectively bind to glycopeptides

Au–cysteine modified macroporous adsorption resin: preparation and highly selective enrichment and identification of N-linked glycopeptides from the complex biological sample

Cysteine functionalized macroporous adsorption resin/gold nanoparticle was synthesized and applied to the highly selective enrichment and identification of N-linked glycopeptides.

Fishing the PTM proteome with chemical approaches using functional solid phases

Currently available chemical approaches for the enrichment and separation of a PTM proteome using functional solid phases were reviewed.

A dendrimer-assisted magnetic graphene–silica hydrophilic composite for efficient and selective enrichment of glycopeptides from the complex sample

A novel composite demonstrates the efficient hydrophilic enrichment of glycopeptides from the complex sample.