A GSH Functionalized Magnetic Ultra-thin 2D-MoS2 nanocomposite for HILIC-based enrichment of N-glycopeptides from urine exosome and serum proteins.

Protein N-glycosylation plays crucial roles in many biological processes and has close association with the occurrence and development of various cancers. Therefore, it is necessary to analyze the abnormal changes of N-glycopeptides in complex biological samples for biomarker discovery. However, due to their low abundance and poor ionization, N-glycopeptides identification in complex samples by mass spectrometry (MS) is still a challenging task. In this work, a novel magnetic hydrophilic material was prepared by serial functionalization of ultra-thin two-dimensional molybdenum disulfide with Fe3O4 nanoparticles, gold nanowire and glutathione (MoS2-Fe3O4-Au/NWs-GSH) for efficient N-glycopeptides enrichment. The advantage of using the new nanocomposite is threefold. First, the introduction of magnetic Fe3O4 nanoparticles efficiently simplifies the enrichment process. Second, the gold nanowire modification enlarges the surface area of the nanocomposites to facilitate interaction with N-glycopeptides. Third, the employment of highly hydrophilic glutathione leads to specific HILIC-based retention of N-glycopeptides. Low femtomolar detection sensitivity and 1:1000 enrichment selectivity can be achieved using MoS2-Fe3O4-Au/NWs-GSH enrichment and bio-mass spectrometry analysis. Successful applications in human urine exosome and serum proteins were demonstrated by the enrichment and identification of 1250 and 489 N-glycopeptides, respectively. This remarkable data set of N-glycoproteome indicates the application potential of the novel nanocomposites for N-glycopeptides enrichment in complex biological samples and for related glycoproteome studies.