Facile synthesis of boronic acid-functionalized magnetic carbon nanotubes for highly specific enrichment of glycopeptides

Abstract

A stepwise strategy was developed to synthesize boronic acid functionalized magnetic carbon nanotubes (MCNTs) for highly specific enrichment of glycopeptides. The MCNTs were synthesized by a solvothermal reaction of Fe(3+) loaded on the acid-treated CNTs and modified with 1-pyrenebutanoic acid N-hydroxysuccinimidyl ester (PASE) to bind aminophenylboronic acid (APBA) via an amide reaction. The introduction of PASE could bridge the MCNT and APBA, suppress the nonspecific adsorption and reduce the steric hindrance among the bound molecules. Due to the excellent structure of the MCNTs, the functionalization of PASE and then APBA on MCNTs was quite simple, specific and effective. The glycopeptides enrichment and separation with a magnetic field could be achieved by their reversible covalent binding with the boronic group of APBA-MCNTs. The exceptionally large specific surface area and the high density of boronic acid groups of APBA-MCNTs resulted in rapid and highly efficient enrichment of glycopeptides, even in the presence of large amounts of interfering nonglycopeptides. The functional MCNTs possessed high selectivity for enrichment of 21 glycopeptides from the digest of horseradish peroxidase demonstrated by MALDI-TOF mass spectrometric analysis showing more glycopeptides detected than the usual 9 glycopeptides with commercially available APBA-agarose. The proposed system showed better specificity for glycopeptides even in the presence of non-glycopeptides with 50 times higher concentration. The boronic acid functionalized MCNTs provide a promising selective enrichment platform for precise glycoproteomic analysis.

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

“…At the present concentration of HRP (0.1 ng/μL), the S / N ratio was larger than 100, implying that the limit of detection for our method was at the level of 10 pg/μL. This value is comparable with those obtained by using core-satellite composite, Fe 3 O 4 @SiO 2 -APB, and APBA-MCNTs 23, 25, 28 . All the results revealed the striking advantage of the synergistic enrichment strategy.…”

“…5b). This detected number of glycopeptides is comparable with those by using enriching materials such as FDU-12-GA (5) and Fe 3 O 4 @SiO 2 -APB (3) 15, 28 , but much less than those by using core-satellite composite (17) and APBA-MCNTs (21) 23, 25 . We assume that this difference originates from the difference in experimental conditions, including content of boronic acid, instrument, and concentration of HRP used, etc.…”

“…Besides, this method isolates both N- and O-glycopeptides in an unbiased manner, thus complementing some limitations of other methods, such as biased glycol-enrichment with respect to lectin affinity and hydrazide chemistry, and insufficient selectivity and recovery related to hydrophilic interaction. Several types of materials have been developed to conjugate boronic acid groups for glycopeptide analyses, including agarose resin, mesoporous silica 15 , polymer particles 16 , magnetic particles 18–24 , carbon nanotubes 25 , and graphene oxide 26 . Each type of material has its own merit.…”

An ultra hydrophilic dendrimer-modified magnetic graphene with a polydopamine coating for the selective enrichment of glycopeptides

“…However, due to the poor ionization efficiency and low abundance of glycopeptides, the MS detection of glycopeptides is extremely difficult. The boronicacid-based enrichment method is equal to enrich both N-and O-glycopeptides, so several types of material modified with boronic acid groups, including magnetic carbon nanotubes, 16 gold nanoparticle@silica bubbles 17 and so on have been widely applied for glycopeptides enrichment. 6,7 Many methods for glycopeptide enrichment have been developed such as boronic acid-based specific enrichment, 8,9 hydrazide chemistry, [10][11][12] lectin affinity chromatography, 13 hydrophilic interaction liquid chromatography (HILIC).…”

Recent advances in applications of nanomaterials for sample preparation

“…By virtue of special affinity between guanidyl groups and phosphate groups, our group developed guanidyl functionalized graphene for selective enrichment of global phosphopeptides and multiphosphopeptides with consecutive phosphorylated residues [27]. Ju et al [28] modified CNTs with aminophenylboronic acid (APBA) for glycopeptide enrichment via the reversible covalent bonding between glycans and boronic acids. In addition to specific enrichment, immobilization of protease on CNPs has also been developed for fast protein digestion in proteome analysis [29].…”