Application of Microscopic Highly Hydrophilic Silica-Based Nanocomposites with High Surface Exposure in the Efficient Identification of Intact N-Glycopeptides.

Abstract

Glycosylation of proteins regulates the life activities of organisms, while abnormalities of glycosylation sites and glycan structures occur in various serious diseases such as cancer. A separation and enrichment procedure is necessary to realize the analysis of the glycoproteins/peptides by mass spectrometry, for which the surface hydrophilicity of the material is an important factor for the separation and enrichment performance. In the present work, under the premise of an obvious increase of the surface silicon exposure (79.6%), the amount of surface polar silanol is remarkably generated accompanying the introduction of the active amino groups on the surface of silica. The microscopic hydrophilicity, which is determined with water physical-adsorption measurements and can directly reflect the interaction of water molecules and the intrinsic surface of the material, maximally increases by 44%. This microscopically highly hydrophilic material shows excellent enrichment ability for glycopeptides, such as extremely low detection limits (0.01 fmol μL-1), remarkable selectivity (1:8000), and size exclusion effects (1:8000). A total of 677 quantifiable intact N-glycopeptides were identified from the serum of patients with cervical cancer, and the glycosylation site and glycan structure were analyzed in depth, indicating that this novel material can show a broad practical application in cervical cancer diagnosis.