Hydrophilic arginine-functionalized mesoporous polydopamine-graphene oxide composites for glycopeptides analysis

Analysis of carbohydrates and glycoconjugates by matrix-assisted laser desorption/ionization mass spectrometry: An update for 2021-2022

The use of matrix-assisted laser desorption/ionization (MALDI) mass spectrometry for the analysis of carbohydrates and glycoconjugates is a well-established technique and this review is the 12th update of the original article published in 1999 and brings coverage of the literature to the end of 2022. As with previous review, this review also includes a few papers that describe methods appropriate to analysis by MALDI, such as sample preparation, even though the ionization method is not MALDI. The review follows the same format as previous reviews. It is divided into three sections: (1) general aspects such as theory of the MALDI process, matrices, derivatization, MALDI imaging, fragmentation, quantification and the use of computer software for structural identification. (2) Applications to various structural types such as oligo- and polysaccharides, glycoproteins, glycolipids, glycosides and biopharmaceuticals, and (3) other general areas such as medicine, industrial processes, natural products and glycan synthesis where MALDI is extensively used. Much of the material relating to applications is presented in tabular form. MALDI is still an ideal technique for carbohydrate analysis, particularly in its ability to produce single ions from each analyte and advancements in the technique and range of applications show little sign of diminishing.

Determination of alectinib and its active metabolite in plasma by pipette-tip solid-phase extraction using porous polydopamine graphene oxide adsorbent coupled with high-performance liquid chromatography-ultraviolet detection

Alectinib is known as an effective targeted drug, which has excellent therapeutic effect on non-small cell lung cancer and can significantly prolong the survival of patients. Therapeutic drug monitoring is necessary due to the photo-instability of alectinib and the individual differences in patients. In this work, a porous polydopamine graphene oxide composite (PDAG) was prepared by a simple surface modification method. A PDAG-based pipette-tip solid-phase extraction (PT-SPE) coupled with HPLC-UV detection was proposed for the separation and detection of alectinib and its active metabolite M4 in plasma. The method was methodologically validated and showed good linearity in the range of 50-5000 ng mL-1 (R2 > 0.9995). The limit of detection (LOD) was 4.8 ng mL-1 and 3.9 ng mL-1 for alectinib and M4, respectively, and the limit of quantitation (LOQ) was 16.1 ng mL-1 and 13.1 ng mL-1, respectively. The intra-day and inter-day precision expressed by coefficient of variation was less than 4.8 %. The recovery of this method ranged from 84.9 % to 103.5 % with a standard deviation of less than 4.3 %. In conclusion, the established method is accurate, stable and inexpensive, and can be used to monitor the levels of alectinib and M4 in plasma, which provide technical and data support for exploring optimal individualized remedial dosing regimens.

Dual-functionalized two-dimensional metal-organic framework composite with highly hydrophilicity for effective enrichment of glycopeptides

Protein glycosylation research is currently focused on the development of various functionalized materials that can effectively enrich the levels of glycopeptides in samples. However, most of these materials possess limited glycopeptide-specific recognition sites because of large steric hindrance, unsuitable mass transfer kinetics, and relatively low surface areas. Herein, a highly hydrophilic two-dimensional (2-D) metal-organic framework (MOF) nanosheet modified with glutathione (GSH) and l-cysteine (l-Cys) (denoted as Zr-Fc MOF@Au@GC) has been synthesized for efficient glycopeptide enrichment. Using this composite material, 39 and 44 glycopeptides from horseradish peroxidase (HRP) and human serum immunoglobulin G (IgG) digests were detected, respectively, which represents a higher efficiency for glycopeptide enrichment from model glycoprotein digests than has been previously reported. The material Zr-Fc MOF@Au@GC exhibited ultra-high sensitivity (0.1 fmol/µL), excellent selectivity (weight ratio of HRP tryptic digest to bovine serum albumin (BSA) tryptic digest = 1:2000), good binding capacity (200 mg/g), satisfactory reusability, and long-term storage capacity. In addition, 655 glycopeptides corresponding to 366 glycoproteins were identified from human serum samples. To the best of our knowledge, this is the largest number of glycoproteins detected in human serum samples to date. These results indicated that Zr-Fc MOF@Au@GC has the potential to be used for the enrichment of glycopeptides in biological samples and the analysis of protein glycosylation.

Surface functionalization modification of ultra-hydrophilic magnetic spheres with mesoporous silica for specific identification of glycopeptides in serum exosomes

Protein glycosylation of human serum exosomes can reveal significant physiological information, and the development of large-scale identification strategies is crucial for the in-depth investigation of the serum exosome glycoproteome. In this study, using surface functionalization techniques, an ultra-hydrophilic mesoporous silica magnetic nanosphere (denoted as Fe₃O₄-CG@mSiO₂) was synthesized for the quick and accurate detection of glycopeptides from HRP digests. The Fe₃O₄-CG@mSiO₂ nanospheres demonstrated outstanding enrichment capability, high sensitivity (5 amol/μL), good size exclusion effect (HRP digests/BSA proteins, 1:10,000), stable reusability (at least 10 times), and an excellent recovery rate (108.6 ± 5.5%). Additionally, after enrichment by Fe₃O₄-CG@mSiO₂, 156 glycopeptides assigned to 64 proteins derived from human serum exosomes were successfully identified, which demonstrates that the nanospheres have great potential for the research of the large-scale serum exosome glycoproteome.

Construction of boric acid-functionalized metal-organic frameworks for glycopeptide recognition in the serum of cervical cancer patients

RATIONALE

Cervical cancer is one of the most common malignant tumors in women, and it is essential to explore potential biomarkers such as glycopeptides closely related to cancer in physiological samples of cervical cancer patients. Sample pretreatment is required before direct detection using mass spectrometry because there are certain limitations. Meanwhile, it is still highly desired to promote the functionalization and application of metal-organic framework (MOF)-derived materials.

METHODS

Using a post-synthesis modification method, a novel type of boric acid-functionalized MOF probe (designated as UiO-66@PEI@Au@B(OH)₂ ) is prepared for recognition of glycopeptides. The results are obtained using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and nano-liquid chromarography-tandem mass spectrometry.

RESULTS

The UiO-66@PEI@Au@B(OH)₂ probe exhibits a low detection limit (0.6 fmol μL^-1 ), an excellent recovery rate, comparatively good reusability and selectivity (HRP digests:BSA digests = 1:500). When UiO-66@PEI@Au@B(OH)₂ is used to selectively capture glycopeptides from the serum of a healthy person and a cervical cancer patient, 101 glycopeptides corresponding to 54 glycoproteins and 108 glycopeptides corresponding to 57 glycoproteins are detected, respectively.

CONCLUSIONS

The successful preparation of UiO-66@PEI@Au@B(OH)₂ provides a path for the investigation of the functionalization of MOF-derived materials. The excellent performance of UiO-66@PEI@Au@B(OH)₂ not only demonstrates the huge potential of functionalized MOFs in the glycoproteome, but also opens up new phases of the application of MOF-based materials.