An ultra hydrophilic dendrimer-modified magnetic graphene with a polydopamine coating for the selective enrichment of glycopeptides

Abstract

In recent MS-based glycoproteomics, the selective enrichment of glycopeptides from complex biological samples is essential. In this work, for the first time, a novel ultra hydrophilic dendrimer-modified magnetic graphene@polydopamine@poly(amidoamine) (magG@PDA@PAMAM) was synthesized via three simple and rapid steps. The magnetic composites combined large surface of graphene, strong magnetic responsiveness of Fe₃O₄ with double hydrophilic abilities of PDA and PAMAM. Especially PAMAM had long dendritic chains and abundant amino groups. When it was grafted onto magG@PDA, it strongly enhanced the hydrophilic properties of the magnetic composites. The PAMAM-functionalized magnetic composites were employed in the enrichment of glycopeptides, 15 glycopeptides from horseradish peroxidase (HRP) digestion were identified and the limit of detection was as low as 1 fmol μL⁻¹. Also, it showed a good selectivity when the background nonglycopeptides had a concentration 100 fold higher than the target glycopeptides. All the results proved that magG@PDA@PAMAM has great potential in the glycoproteome analysis of complex biological samples.