Click synthesis of glucose-functionalized hydrophilic magnetic mesoporous nanoparticles for highly selective enrichment of glycopeptides and glycans

Selective enrichment of glycopeptides from complex biological samples is essential for MS-based glycoproteomics, but challenges still remain. In this work, glucose-functionalized magnetic mesoporous nanoparticles (MMNs), which hold the attractive features of well-defined core/shell structure, high specific surface area (324 m2/g), narrow pore size distribution (2.2 nm) and high magnetic responsivity (69.1 emu g−1), were synthesized via click chemistry and applied to enrich glycopeptides and glycans. Taking advantages of the size-exclusive effect of mesopore against proteins and the hydrophilic interaction between glycans and glucose, the hydrophilic MMNs possessed high selectivity for glycopeptides at the digested mixtures of horseradish peroxidase (HRP), myoglobin and β-casein at molar ratio of 1:1:10, large enrichment capacity (as high as 250 mg/g), high sensitivity (50 fmol), excellent speed (5 min for enrichment) and high recovery of glycopeptides (as high as 94.6%). Additionally, the MMNs exhibited excellent performance in enrichment of N-linked glycans from the digested human serum that are made up of peptides, large proteins and other compounds. These outstanding features will give the hydrophilic MMNs high benefit for MS analysis of low-abundance glycopeptides/glycans.