Facile synthesis of magnetic poly(styrene-co-4-vinylbenzene-boronic acid) microspheres for selective enrichment of glycopeptides

In this work, the composites of magnetic Fe3O4@SiO2@poly (styrene-co-4-vinylbenzene-boronic acid) microspheres with well-defined core-shell-shell structure were facilely synthesized and applied to selectively enrich glycopeptides. Due to the relatively large amount of vinyl groups introduced by 3-methacryloxy-propyl-trimethoxysilane on the core-shell surface, the poly(styrene-co-4-vinylbenzeneboronic acid) (PSV) was coated with high efficiency, resulting in a large amount of boronic acid on the outermost polymer shell of the Fe3O4@SiO2@PSV microspheres, which is of great importance to improve the enrichment efficiency for glycopeptides. The obtained Fe3O4@SiO2@PSV microspheres were successfully applied to the enrichment of glycopeptides with strong specificity and high selectivity, evaluated by capturing glycopeptides from tryptic digestion of model glycoprotein HRP diluted to 0.05 ng/L (1.25 x 10(-13) mol, 100 L), tryptic digest of HRP and nonglycosylated BSA up to the ratio of 1:120 w/w and the real complex sample human serum with 103 unique N-glycosylation peptides of 46 different glycoproteins enriched.