Highly selective enrichment of N-linked glycan by carbon-functionalized ordered graphene/mesoporous silica composites

Abnormal protein glycosylation has been demonstrated to be associated with many diseases; therefore, it is very important to conduct a comprehensive structure analysis of glycan for prognosis and diagnosis of diseases, such as cancer. In this work, for the first time, carbon-functionalized ordered graphene/mesoporous silica composites (denoted as C-graphene@mSiO2) with large surface area and uniform pore size were designed and synthesized. By taking advantage of the special interaction between the carbon and glycans as well as size-exclusion ability, 25 N-linked glycans released from ovalbumin were observed clearly with strong MS signals and increased signal-to-noise (S/N) ratio. In addition, after enrichment with the C-graphene@mSiO2 composites, 48 N-linked glycans (S/N > 10) with sufficient peak intensities were obtained from only 400 nL of healthy pristine human serum. The facile and low-cost synthesis method as well as high selective enrichment ability of the novel C-graphene@mSiO2 composite makes it a promising tool for glycosylation research.