Hydrophilic maltose-modified magnetic metal-organic framework for highly efficient enrichment of N-linked glycopeptides

MOF-Based Platform for Kidney Diseases: Advances, Challenges, and Prospects

Kidney diseases are important diseases that affect human health worldwide. According to the 2020 World Health Organization (WHO) report, kidney diseases have become the top 10 causes of death. Strengthening the prevention, primary diagnosis, and action of kidney-related diseases is of great significance in maintaining human health and improving the quality of life. It is increasingly challenging to address clinical needs with the present technologies for diagnosing and treating renal illness. Fortunately, metal-organic frameworks (MOFs) have shown great promise in the diagnosis and treatment of kidney diseases. This review summarizes the research progress of MOFs in the diagnosis and treatment of renal disease in recent years. Firstly, we introduce the basic structure and properties of MOFs. Secondly, we focus on the utilization of MOFs in the diagnosis and treatment of kidney diseases. In the diagnosis of kidney disease, MOFs are usually designed as biosensors to detect biomarkers related to kidney disease. In the treatment of kidney disease, MOFs can not only be used as an effective adsorbent for uremic toxins during hemodialysis but also as a precise treatment of intelligent drug delivery carriers. They can also be combined with nano-chelation technology to solve the problem of the imbalance of trace elements in kidney disease. Finally, we describe the current challenges and prospects of MOFs in the diagnosis and treatment of kidney diseases.

Progress in Core-Shell Magnetic Mesoporous Materials for Enriching Post-Translationally Modified Peptides

Endogenous peptides, particularly those with post-translational modifications, are increasingly being studied as biomarkers for diagnosing various diseases. However, they are weakly ionizable, have a low abundance in biological samples, and may be interfered with by high levels of proteins, peptides, and other macromolecular impurities, resulting in a high limit of detection and insufficient amounts of post-translationally modified peptides in real biological samples to be examined. Therefore, separation and enrichment are necessary before analyzing these biomarkers using mass spectrometry. Mesoporous materials have regular adjustable pores that can eliminate large proteins and impurities, and their large specific surface area can bind more target peptides, but this may result in the partial loss or destruction of target peptides during centrifugal separation. On the other hand, magnetic mesoporous materials can be used to separate the target using an external magnetic field, which improves the separation efficiency and yield. Core-shell magnetic mesoporous materials are widely utilized for peptide separation and enrichment due to their biocompatibility, efficient enrichment capability, and excellent recoverability. This paper provides a review of the latest progress in core-shell magnetic mesoporous materials for enriching glycopeptides and phosphopeptides and compares their enrichment performance with different types of functionalization methods.

Water-stable hydrophilic metal organic framework composite for the recognition of N-glycopeptides during diabetes progression by mass spectrometry

A hydrophilic Al-MOFs composite was prepared using cheap and available reagents in water via a suitable large-scale production, an economical and environment-friendly method for capturing N-glycopeptides. The prepared Al-MOFs composite with high hydrolytically stable and hydrophilic 1D channels exhibits an ultralow detection limit (0.5 fmol/μL), and excellent reusability (at least 10 cycles) in the capture of N-glycopeptides from standard bio-samples. Interestingly, the Al-MOFs composite also shows remarkable performance in practical applications, where 300 N-glycopeptides ascribed to 124 glycoproteins were identified in 1 µL human serum and were successfully applied in profiling the differences of N-glycopeptides during diabetes progression. Moreover, 12 specific glycoproteins used as biomarkers to accurately distinguish the progression of diabetes are identified. The present work provides a potential commercial method for large-scale glycoproteomics research in complex clinical samples while offering new guidance for the precise diagnosis of diabetes progression.

In situ grown magnetic COF@MOF with a phosphoserine anchor for in-depth N-glycopeptide analysis in serum

A hydrophilic phosphoserine-functionalized magnetic organic framework composite (termed Fe3O4@COF@MOF-PS) was synthesized by an in situ growth strategy for effective capture of N-glycopeptides. Fe3O4@COF@MOF-PS exhibited high sensitivity (0.2 fmol μL-1), outstanding exclusion of size capability (1 : 10 000), good selectivity (1 : 2000), and reusability (at least 10 times). It also exhibited remarkable performance in the N-glycopeptide analysis in complex biological samples. Via nano-LC-MS/MS analysis, a total of 223 N-glycopeptides with 161 glycosylation sites assigned to 91 glycoproteins and 331 N-glycopeptides with 243 glycosylation sites assigned to 134 glycoproteins were identified in sera from cervical cancer patients and normal controls, respectively. Biological processes and molecular functional analyses indicate that the captured glycoproteins are of significant relevance to cervical cancer, for example, gene coverage or expression of cell adhesion and extracellular matrix structural constituents. Thus, Fe3O4@COF@MOF-PS not only efficiently captures N-glycopeptides, but also has the possibility of screening potential disease markers and elucidating the process of cervical cancer development.

State of the art on the separation and purification of proteins by magnetic nanoparticles

The need for excellent, affordable, rapid, reusable and biocompatible protein purification techniques is justified based on the roles of proteins as key biomacromolecules. Magnetic nanomaterials nowadays have become the subject of discussion in proteomics, drug delivery, and gene sensing due to their various abilities including rapid separation, superparamagnetism, and biocompatibility. These nanomaterials also referred to as magnetic nanoparticles (MNPs) serve as excellent options for traditional protein separation and analytical methods because they have a larger surface area per volume. From ionic metals to carbon-based materials, MNPs are easily functionalized by modifying their surface to precisely recognize and bind proteins. This review excavates state-of-the-art MNPs and their functionalizing agents, as efficient protein separation and purification techniques, including ionic metals, polymers, biomolecules, antibodies, and graphene. The MNPs could be reused and efficaciously manipulated with these nanomaterials leading to highly improved efficiency, adsorption, desorption, and purity rate. We also discuss the binding and selectivity parameters of the MNPs, as well as their future outlook. It is concluded that parameters like charge, size, core-shell, lipophilicity, lipophobicity, and surface energy of the MNPs are crucial when considering protein selectivity, chelation, separation, and purity.

Post-synthesis of covalent organic frameworks as a hydrophilic platform for specific detection of egg ovalbumin under physiological pH

Ovalbumin (OVA) is an important protein source in our daily life. Unfortunately, the food safety problem has become more and more serious, such as protein allergy and contaminated protein. Therefore, it is necessary to detect vital proteins efficiently and rapidly. Mass spectrometry (MS) is a powerful tool for the detection of proteins. Herein, dual amino acids functionalized covalent organic frameworks containing disulfide covalent bonds (COF@SS@GC, where G is glutathione and C is cysteine) were facilely prepared for OVA enrichment through hydrophilic interaction liquid chromatography (HILIC) under physiological pH. The results showed that COF@SS@GC had displayed sensitive detection (0.1 fmol), good selectivity (OVA: BSA = 1:100), adsorption capacity (311 mg/g), stability, reproducibility, linearity, LOQ level (42 μg/mL) and recovery ratio (64.83 %) for OVA. COF@SS@GC also demonstrated satisfactory purification ability in the enrichment of egg white, indicating that COF@SS@GC had great potential in the enrichment of protein from complex samples.

Analysis of carbohydrates and glycoconjugates by matrix-assisted laser desorption/ionization mass spectrometry: An update for 2019-2020

This review is the tenth 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 2020. 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. The review is basically divided into three sections: (1) general aspects such as theory of the MALDI process, matrices, derivatization, MALDI imaging, fragmentation, quantification and the use of arrays. (2) Applications to various structural types such as oligo- and polysaccharides, glycoproteins, glycolipids, glycosides and biopharmaceuticals, and (3) other areas such as medicine, industrial processes and glycan synthesis where MALDI is extensively used. Much of the material relating to applications is presented in tabular form. The reported work shows increasing use of incorporation of new techniques such as ion mobility and the enormous impact that MALDI imaging is having. MALDI, although invented nearly 40 years ago is still an ideal technique for carbohydrate analysis and advancements in the technique and range of applications show little sign of diminishing.

Advances in hydrophilic metal-organic frameworks for N-linked glycopeptide enrichment

The comprehensive profiling of glycoproteins is of great significance for the timely clinical diagnosis and therapy. However, inherent obstacles hamper their direct analysis from biological samples, and specific enrichment prior to analysis is indispensable. Among the various approaches for glycopeptide enrichment, hydrophilic interaction liquid chromatography (HILIC) has attracted special focus, especially for the development of novel hydrophilic materials, which is the key of HILIC. Metal-organic frameworks (MOFs) are a type of porous materials constructed from the self-assembly of metal and organic linkers. Advantages such as high surface area, flexible pore size, and easy modification render hydrophilic MOFs as ideal candidates for HILIC, which has inspired many studies over the past years. In this review, advances in hydrophilic MOFs for N-linked glycopeptide enrichment are summarized. According to the synthesis strategies, those materials are categorized into three classes, namely pristine MOFs, MOFs with chemical modifications, and MOFs-derived composite. In each categorization, the preparation and the function of different moieties are covered, as well as the enrichment performances of sensitivity, selectivity, and practical application. Finally, a summary and future perspective on the applications of hydrophilic MOFs for N-linked glycopeptide enrichment are briefly discussed. This review is expected to raise awareness of the properties of hydrophilic MOFs and offer some valuable information to further research in glycoproteomics.

Recent development in hydrophilic interaction liquid chromatography stationary materials for glycopeptide analysis

Protein glycosylation is one of the most important post-translational modifications, and aberrant glycosylation is associated with the occurrence and development of diseases. Deciphering abnormal glycosylation changes can identify disease-specific signatures to facilitate the discovery of potential disease biomarkers. However, glycosylation analysis is challenging due to the diversity of glycans, heterogeneity of glycosites, and poor electrospray ionization of mass spectrometry. To overcome these obstacles, glycosylation is often elucidated using enriched glycopeptides by removing highly abundant non-glycopeptides. Hydrophilic interaction liquid chromatography (HILIC) is widely used for glycopeptide enrichment due to its excellent selectivity and specificity to hydrophilic glycans and compatibility with mass spectrometry. However, the development of HILIC has lagged far behind hydrophobic interaction chromatography, so efforts to further improve the performance of HILIC are beneficial for glycosylation analysis. This review discusses recent developments in HILIC materials and their advanced applications. Based on the physiochemical properties of glycopeptides, the use of amino acids or peptides as stationary phases showed improved enrichment and separation of glycopeptides. We can envision that the use of glycopeptides as stationary phases would definitely further improve the selectivity and specificity of HILIC for glycosylation analysis.

Obtaining Water from Air Using Porous Metal-Organic Frameworks (MOFs)

Water collection from moisture in air, i.e., atmospheric water harvesting, is an urgent future need for society. It can be used for water production everywhere and anytime as an alternative water source in remote areas. However, water harvesting and collection usually relies on desalination, fog, and dewing harvesting, which are energy intensive. In this respect, metal-organic frameworks (MOFs) have broad applicability for water harvesting in water-scarce areas; therefore, the current discussion focuses on this approach. Furthermore, recent progress on MOFs for moisture harvesters is critically discussed. In addition, the design, operation, and water harvesting mechanisms of MOFs are studied. Finally, we discuss critical points for future research for the design of new MOFs as moisture harvesters for use in practical applications. MOF adsorbents offer excellent operating capacity in various temperature and pressure ranges. Rational water harvesters can thus be developed by adjusting structural properties such as the porosity, functionalities, and metal centers, thereby enabling new devices to produce water even in remote areas.

Hydrophilic glutathione-modified flower-like hollow covalent organic frameworks for highly efficient capture of N-linked glycopeptides

Highly efficient enrichment of N-glycopeptides from complicated biosamples based on mass spectrometry is essential for biomedical applications, especially in disease biomarker research. In this work, glutathione (GSH)-modified hierarchical flower-like hollow covalent organic frameworks loaded with Au nanoparticles (HFH-COFs@Au@GSH) were synthesized for N-glycopeptide enrichment. Due to the abundant accessibility sites, high specific surface area, and inherent high stability of the hierarchical flower-like hollow structure, a large number of Au NPs and hydrophilic GSH can be modified on the HFH-COFs. The HFH-COFs@Au@GSH displayed excellent hydrophilicity and remarkable enrichment performance for N-glycopeptides: low detection limit (0.1 fmol μL^-1), large adsorption capacity (200 μg mg^-1), great selectivity (1 : 1000, HRP to BSA), and good reusability (at least 5 times). Furthermore, the HFH-COFs@Au@GSH were successfully applied to capture N-linked glycopeptides in human serum, and 308 N-glycosylation peptides corresponding to 84 N-glycosylation proteins with 123 N-glycosylation sites were detected. Gene ontology analyses were used to elucidate the cellular component, biological process and molecular function of detected glycoproteins in human serum, demonstrating the great potential of the HFH-COFs@Au@GSH in N-glycopeptide enrichment for glycoproteomic analysis of complex biological samples.

A novel hydrophilic MOFs-303-functionalized magnetic probe for the highly efficient analysis of N-linked glycopeptides

The effective analysis of glycoproteomics in clinical complex samples is of vital importance for the diagnosis and therapy of diseases. In this study, a hydrophilic MOFs-303-functionalized magnetic probe (GO@Fe₃O₄@MOF-303) is designed and fabricated to profile N-linked glycopeptides. Owing to its strong magnetic property, large surface area (845 m² g^-1), excellent hydrophilicity and suitable porous structure, the GO@Fe₃O₄@MOF-303 probe exhibits an ultralow detection limit (0.1 fmol μL^-1), perfect size-exclusion effect (HRP digests/BSA protein/HRP protein, 1 : 1000 : 1000, w/w/w), a high binding capacity (200 mg g^-1) and excellent reusability in the capture of standard N-linked glycopeptides. More excitingly, the GO@Fe₃O₄@MOF-303 probe also shows remarkable performance in practical applications, where 274 N-linked glycopeptides from 101 glycoproteins were identified in total for healthy controls, while a total of 265 N-linked glycopeptides from 102 glycoproteins were identified in serum (1 μL) with hepatocellular carcinoma (HCC). In addition, we discovered 4 up-regulated and 19 down-regulated serum glycoproteins in HCC patients by the hierarchical clustering heatmap. All results demonstrated that the reusable GO@Fe₃O₄@MOF-303 probe has great potential in profiling different N-linked glycopeptides in complex clinical samples. This study not only developed a novel probe for the highly effective capture of N-linked glycopeptides but also contributed to further understanding the mechanism of HCC and provides guidance for the development of novel clinical diagnostic methods.

Preparation of a boronate affinity-functionalized metal–organic framework material for selective recognition and separation of glycoproteins at physiological pH

A boronate affinity functionalized metal–organic framework material was successfully prepared for the efficient and selective extraction of OVA glycoprotein from egg white samples and protein powder.

Synthesis of core-shell magnetic metal organic frameworks composite for efficient uranium (VI) removal

The combination of magnetic nanoparticles and metal-organic frameworks (MOFs) has demonstrated their prospective for pollutant sequestration. In this work, Fe3O4@SiO2@UiO-66 core-shell magnetic microspheres were synthesized and used for the removal...

A novel hydrophilic hydrogel with a 3D network structure for the highly efficient enrichment of N-glycopeptides

A novel super-hydrophilic hydrogel (ZIF-8/SAP) was first proposed and facilely fabricated to capture N-glycopeptides from complex biological samples with excellent selectivity and sensitivity.

Synthesis of metal-organic framework @molecularly imprinted polymer adsorbents for solid phase extraction of organophosphorus pesticides from agricultural products

The novel core-shell structural zeolitic imidazolate framework-8 @molecularly imprinted polymers were successfully synthesized by surface imprinting technique and used as adsorbents for solid-phase extraction of organophosphorus pesticides. The obtained hybrid composites were characterized by scanning electron microscopy, transmission electron microscopy and Fourier-transform infrared, and their adsorbing and recognition performance were evaluated by binding experiments. The results showed that zeolitic imidazolate framework-8 @molecularly imprinted polymers presented a typically core-shell structure with molecularly imprinted shell (about 50 nm) homogeneously polymerized on the surface of zeolitic imidazolate framework-8 core, and exhibited specific recognition towards organophosphorus pesticides with fast adsorption capacity. The adsorption and desorption conditions including sample loading solvent, sample pH, washing and elution solvent were optimized. Under optimum conditions, the solid-phase extraction based on zeolitic imidazolate framework-8 @molecularly imprinted polymers combined with high liquid chromatography-tandem mass spectrometry method for determining organophosphorus pesticides was established and exhibited good linearity (R² ≥ 0.9927) in the range of 1-200 µg/L. With spiked at three different concentration levels in agricultural products (cauliflower, radish, pear, muskmelon), the recoveries ranged from 82.5% to 123.0% with relative standard deviations lower than 8.24%. The developed method was sensitive, convenient and efficient. More importantly, this study could provide a promising strategy for designing new adsorbents with extremely fast mass transfer rate for other potential trace contaminants.

A review on recent advances in the enrichment of glycopeptides and glycoproteins by liquid chromatographic methods: 2016-Present

Among various protein post-translational modifications (PTMs), glycosylation has received special attention due to its immense role in molecular interactions, cellular signal transduction, immune response, etc. Aberration in glycan moieties of a glycoprotein is associated with cancer, diabetes, and bacterial and viral infections. In biofluids (plasma, saliva, urine, milk, etc.), glycoproteins are low in abundance and are masked by the presence of high abundant proteins. Hence, prior to their identification using mass spectrometry methods, liquid chromatography (LC)-based approaches were widely used. A general enrichment strategy involves a protein digestion step, followed by LC-based enrichment and desorption of glycopeptides, and enzymatic excision of the glycans. The focus of this review article is to highlight the articles published since 2016 that dealt with different LC-based approaches for glycopeptide and glycoprotein enrichment. The preparation of stationary phases, their surface activation, and ligand immobilization strategies have been discussed in detail. Finally, the major developments and future trends in the field have been summarized.

[Recent advances in functionalized magnetic nanomaterials for glycoprotein and glycopeptide enrichment]

Protein glycosylation is among the most common and important post-translational modifications, and plays an important regulatory role in many biological processes, including signal transduction, protein translation, and immune response. Abnormal protein glycosylation is also associated with numerous diseases, suggesting that glycoproteins may offer an array of useful disease biomarkers. Mass spectrometry (MS) has become an important analytical tool in glycoproteomics. However, the low abundance and weak ionization efficiency of glycopeptides have hindered direct mass spectrometric analyses, which remain considerably challenging. Glycoprotein and glycopeptide enrichment from complex biological samples is an important step in glycoproteomics. Diverse methods have recently been developed for specific glycoprotein and glycopeptide enrichment, including hydrophilic interaction liquid chromatography (HILIC), lectin affinity chromatography, boronate affinity chromatography, and hydrazide functional affinity chromatography. A variety of enrichment materials designed for the above strategies have been developed to meet the requirement of enriching low abundance glycoproteins and glycopeptides in complex samples. Magnetic solid phase extraction (MSPE) is an efficient sample pretreatment technology that offers advantages of simple operation, low cost, and high extraction efficiency. Functionalized magnetic nanomaterials have been widely used as adsorbents in glycoproteome studies. Since magnetic adsorbent is a key factor in MSPE, in this review, the preparation of magnetic nanomaterials functionalized with sugars, ionic liquids, lectins, boronate affinity ligands, metal organic frameworks, and covalent organic frameworks, and their applications in glycoprotein and glycopeptide enrichment are summarized. These functional magnetic nanomaterials possess high specific surface area and a large number of active adsorption sites, allowing different enrichment mechanisms, including HILIC, lectin affinity chromatography, and boronate and hydrazide functional affinity chromatography. These functional magnetic nanomaterials are mainly used to enrich glycoproteins and glycopeptides in serum, plasma, cells, tissues, saliva and other biological samples. Nearly 90 papers published in the last decade from the Science Citation Index (SCI) and Chinese core journals have been cited in this paper. Finally, the development and prospects of magnetic nanomaterials in glycoprotein and glycopeptide enrichment are also discussed.

Glutathione-functionalized two-dimensional cobalt sulfide nanosheets for rapid and highly efficient enrichment of N-glycopeptides

Protein glycosylation plays pivotal role in a variety of biological processes and has association with many diseases. The highly efficient glycopeptide enrichment is essential for the mass spectrometry-based glycoproteome research to reduce interference from non-glycopeptides. In this study, novel glutathione-functionalized two-dimensional cobalt sulfide nanosheets (Co-S@Au-GSH) were synthesized for rapid and highly effective enrichment of glycopeptides. By using this nanomaterial, 34 and 21 N-glycopeptides were effectively captured from human serum immunoglobulin G (IgG) and horseradish peroxidase (HRP) digests, respectively. In addition, the Co-S@Au-GSH showed remarkable performance in N-glycopeptide extraction with high selectivity (HRP: BSA = 1:500), low limit of detection (0.5 fmol/μL), high binding capacity (150 mg/g), good reusability, and great robustness. Moreover, it was successfully applied in complex serum samples, demonstrating its excellent enrichment performance. These results indicated that this nanomaterial has great potential in complicated practice samples in glycoproteome determination.

Facile synthesis of bifunctional polymer monolithic column for tunable and specific capture of glycoproteins and phosphoproteins

Efficiently tunable capture of the glycosylated/phosphorylated proteins is critical to meet the need of in-depth glycoproteome and phosphoproteome studies. Reported here is a new bifunctional polymer monolithic column by introducing benzeneboronic acid and phosphonic acid onto monolithic column (denoted as poly (EDMA-co-VPBA-co-VPA) monolith) for tunable and specific enrichment of glycoproteins and phosphoproteins via switching different mobile phases. Based on boronate affinity and immobilized metal affinity, the as-prepared poly (EDMA-co-VPBA-co-VPA) monolith exhibited superior performance in selective separation of small molecules and biomacromolecules containing cis-diol/phosphate groups or not. And the frontal chromatography analysis showed that the binding capacity of the poly (EDMA-co-VPBA-co-VPA) monolith towards horseradish peroxidase (HRP, glycoprotein) or β-casein (phosphoprotein) is four-fold higher than that of bovine serum albumin (BSA, non-glycosylated/phosphorylated protein). Furthermore, combined with mass spectrometry identification, the successful application in specific enrichment of glycopeptides/phosphopeptides from tryptic digests of HRP/β-casein and direct capture of low abundant endogenous phosphopeptides from human serum proved great practicability in complex samples. This study provides a novel insight for fabricating the monolithic columns with multifunctionalization to facilitate further post-translational modification (PTM)-proteomics development.

Gold nanoparticle-glutathione functionalized MOFs as hydrophilic materials for the selective enrichment of glycopeptides

Herein, a novel zwitterionic hydrophilic metal-organic framework (MOF)-functionalized material was synthesized through grafting l-glutathione (GSH) onto the Au which acts as the intermediate layer to modify the base material (PEI-ZIF-8) by the sulfhydryl group provided by GSH and the affinity provided by Au (denoted as PEI-ZIF-8@Au@GSH). The obtained product was employed to capture glycopeptides. Benefit from its excellent hydrophilic properties, abundant amphoteric ions, and unique large specific surface area, this material demonstrated amazing ability in the enrichment and identification of glycopeptides. As a result, the PEI-ZIF-8@Au@GSH displayed high sensitivity (as low as 2 fmol), excellent binding capacity (500 mg/g), outstanding enrichment selectivity (maximum mass ratio HRP to BSA is 1:1000) toward glycopeptides, and the ability to recycle at least five times. Furthermore, 35 and 51 glycopeptides were successfully detected from 5 μL human saliva and human serum respectively in the examination of the actual sample by MALDI-TOF MS. The above results indicated that the PEI-ZIF-8@Au@GSH had a satisfactory potential in the field of glycoproteomics.

Metal-organic frameworks as advanced materials for sample preparation of bioactive peptides

Development of novel affinity materials and separation techniques is crucial for the progress of modern proteomics and peptidomics. Detection of peptides and proteins from complex matrices still remains a challenging task due to the highly complicated biological composition, low abundance of target molecules, and large dynamic range of proteins. As an emerging area of analytical science, metal-organic framework (MOF)-based separation of proteins and peptides is attracting growing interest. This minireview summarizes the recent advances in MOF-based affinity materials for the sample preparation of proteins and peptides. Some newly emerging MOF nanoreactors for the degradation of peptides and proteins are introduced. An update of MOF-based affinity materials for the isolation of glycopeptides, phosphopeptides and low-abundance endogenous peptides in the last two years is focused on. The separation mechanism is discussed along with the chemical structures of MOFs. Finally, the remaining challenges and future development of MOFs in analyzing peptides and proteins in complicated biological samples are discussed.

Recognition of urinary N-linked glycopeptides in kidney cancer patients by hydrophilic carbohydrate functionalized magnetic metal organic framework combined with LC-MS/MS

A hydrophilic carbohydrate functionalized magnetic metal organic framework (Mag Zr-MOF@G6P) was synthesized via a facile one-step modification strategy for selective glycopeptide capture in virtue of hydrophilic interaction chromatography technique. The inherently hydrophilic Zr-MOF layer not only provides selective size-sieving pore structures but also offers large specific surface area to afford abundant affinity sites. Hydroxyl-rich glucose-6-phosphate was immobilized onto the Zr-MOF via a straightforward coordination manner to regulate its surface property, for the purpose of enhancing its hydrophilicity. Benefitting from the merits of Zr-MOF and glucose-6-phosphate, the as-designed composite exhibits good selectivity (the mass ratio of HRP digests to BSA digests was up to1:200) and low limit of detection (0.1 fmol μL^-1) towards the recognition of glycopeptides from standard samples. More excitingly, glycopeptides in urine of healthy people and patients with kidney cancer were successfully enriched and identified by the combined liquid chromatography-mass spectrometry/mass spectrometry technology (LC-MS/MS). Further gene ontology analysis of molecular function and biological process revealed that 13 original glycoproteins of the identified glycopeptides from urine of patients significantly participate in diverse cancer-associated events, including collagen binding, immunoglobulin receptor binding, antigen binding, and complement activation process. Graphical abstract.