Graphene based soft nanoreactors for facile "one-step" glycan enrichment and derivatization for MALDI-TOF-MS analysis

Protein glycosylation is involved in the control of many important biological processes and structural alterations of the N-linked glycans are correlated with various kinds of disease. High-throughput N-glycan profiling is a key technique for elucidating the functions of glycans in biological process and disease development as well as discovering new diagnostic biomarkers. However, the low abundance of glycans existing in living organism, the competition/suppression effect of other highly abundant biological molecules and the inherent lack of alkalinity and hydrophobicity of glycans leads to particularly poor detection sensitivity in MS analysis. Here, we demonstrated the first "one-step" approach for highly efficient glycan enrichment and derivatization using reduced graphene oxide as nanoreactors and 1-pyrenebutyric hydrazide for glycan capture and derivatization, which resulted in a 33-fold increase in the glycan detection sensitivity in MALDI-TOF-MS and the identification of 48N-glycoforms from human plasma.