Boronic Acid-Modified Magnetic Fe3O4@mTiO2 Microspheres for Highly Sensitive and Selective Enrichment of N-Glycopeptides in Amniotic Fluid

Targeted pH-responsive delivery of rosmarinic acid via phenylboronic acid functionalized mesoporous silica nanoparticles for liver and lung cancer therapy

Currently, chemotherapy is one of the most practiced approaches for the treatment of cancers. However, existing chemotherapeutic drugs have poor aqueous solubility, poor selectivity, higher systematic toxicity, and poor target accumulation. In this study, we designed and synthesized a boronic acid/ester-based pH-responsive nano-valve that specifically targets the microenvironment in cancer cells. The nano-valve comprises phenylboronic acid-coated mesoporous silica nanoparticles (B-MSN) loaded with polyphenolic compound Rosmarinic acid (ROS-B-MSN). The nano-valve was further coated with lignin (LIG) to achieve our desired LIG-ROS-BMSN nano-valve for targeted chemotherapy against Hep-G2 and NCI-H460 cell lines. The structure and properties of NPs were characterized by Fourier-transformed infrared spectroscopy (FTIR), Scanning Electron Microscopy (SEM) in combination with EDX, and Dynamic light scattering (DLS). The outcomes revealed that the designed LIG-ROS-BMSN were in the nanorange (144.1 ± 0.70 nm), had negative Zeta potential (-15.7 ± 0.46 mV) and had a nearly spherical morphology. In vitro, drug release investigations showed a controlled pH-dependent release profile under mild acidic conditions that could enhance the targeted chemotherapeutic response against cancer in mild acidic environments. The obtained LIG-ROS-BMSN nano valve achieved significantly lower IC50 values of (1.70 ± 0.01 μg/mL and 3.25 ± 0.14 μg/mL) against Hep-G2 and NCI-H460 cell lines as compared to ROS alone, which was (14.0 ± 0.7 μg/mL and 29.10 ± 0.25 μg/mL), respectively. The cellular morphology before and after treatment was further confirmed via inverted microscopy. The outcomes of the current study imply that our designed LIG-ROS-BMSN nanovalve is a potential carrier for cancer chemotherapeutics.

[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.

L-cysteine functionalized straticulate C3N4 for the selective enrichment of glycopeptides

The facile enrichment of glycopeptides or glycoproteins poses great challenges for glycoproteomic research. In this study, a novel hydrophilic material, named zwitterionic hydrophilic L-cysteine derivatized straticulate-C₃N₄ composites (LCAC), were synthesized and evaluated for the enrichment of N-glycopeptides. LCAC exhibited good biocompatibility, excellent hydrophilicity and selectivity, by virtue of the large surface of C₃N₄ and the zwitterionic property offered by cysteine. LCAC demonstrated excellent performance for N-glycopeptide enrichment with the sensitivity of 0.033 fmol/µL, selectivity of 1:100, and high recovery rate (∼85%). The performance of LCAC was demonstrated by the identification of 35 N-glycopeptides from IgG, as well as capturing 1809 human urine N-glycopeptides corresponding to 876 N-glycoproteins. Comparing the LCAC with our developed phenylboronic acid functionalized material showed a certain complementary due to the different binding mechanism. The simple production and enhanced hydrophilic properties make the material a promising choice for glycoproteomics researches.

Mass Spectrometry Approaches to Glycomic and Glycoproteomic Analyses

Glycomic and glycoproteomic analyses involve the characterization of oligosaccharides (glycans) conjugated to proteins. Glycans are produced through a complicated nontemplate driven process involving the competition of enzymes that extend the nascent chain. The large diversity of structures, the variations in polarity of the individual saccharide residues, and the poor ionization efficiencies of glycans all conspire to make the analysis arguably much more difficult than any other biopolymer. Furthermore, the large number of glycoforms associated with a specific protein site makes it more difficult to characterize than any post-translational modification. Nonetheless, there have been significant progress, and advanced separation and mass spectrometry methods have been at its center and the main reason for the progress. While glycomic and glycoproteomic analyses are still typically available only through highly specialized laboratories, new software and workflow is making it more accessible. This review focuses on the role of mass spectrometry and separation methods in advancing glycomic and glycoproteomic analyses. It describes the current state of the field and progress toward making it more available to the larger scientific community.