Synthesis of Zwitterionic Polymer Particles via Combined Distillation Precipitation Polymerization and Click Chemistry for Highly Efficient Enrichment of Glycopeptide.

Because of the low abundance of glycopeptide in natural biological samples, methods for efficient and selective enrichment of glycopeptides play a significant role in mass spectrometry (MS)-based glycoproteomics. In this study, a novel kind of zwitterionic hydrophilic interaction chromatography polymer particles, namely, poly(N,N-methylenebisacrylamide-co-methacrylic acid)@l-Cys (poly(MBAAm-co-MAA)@l-Cys), for the enrichment of glycopeptides was synthesized by a facile and efficient approach that combined distillation precipitation polymerization (DPP) and "thiol-ene" click reaction. In the DPP approach, residual vinyl groups explored outside the core with high density, then the functional ligand cysteine was immobilized onto the surface of core particles by highly efficient thiol-ene click reaction. Taking advantage of the unique structure of poly(MBAAm-co-MAA)@l-Cys, the resulting particles possess remarkable enrichment selectivity for glycopeptides from the tryptic digested human immunoglobulin G. The polymer particles were successfully employed for the analysis of human plasma, and 208 unique glycopeptides corresponding to 121 glycoproteins were reliably identified in triple independent nano-LC-MS/MS runs. The selectivity toward glycopeptides of these particles poly(MBAAm-co-MAA)@l-Cys is ∼2 times than that of the commercial beads. These results demonstrated that these particles had great potential for large-scale glycoproteomics research. Moreover, the strategy with the combination of DPP and thiol-ene click chemistry might be a facile method to produce functional polymer particles for bioenrichment application.