Synthesis of a hydrophilic maltose functionalized Au NP/PDA/Fe3O4-RGO magnetic nanocomposite for the highly specific enrichment of glycopeptides

Abstract

The development of methods to isolate and enrich low-abundance glycopeptides is an important prerequisite for glycoproteomics research. In this study, a hydrophilic maltose functionalized Au nanoparticle (NP)/polydopamine (PDA)/Fe₃O₄-reduced graphene oxide (RGO) nanocomposite has been successfully synthesized in mild conditions. The bioadhesive polydopamine film was prepared by self-polymerization on the surface of Fe₃O₄–graphene oxide, which not only prevents the agglomeration of the graphene sheets and enhances the specific surface area, but also facilitates the Au NP immobilization. A great number of loading Au NPs possess the highly available surface area for the immobilization of the high density of the thiol-terminated maltose via Au–S bonds. The resulting Au NP-maltose/PDA/Fe₃O₄-RGO nanocomposite exhibits excellent environmental stability, good biocompatibility and water dispersibility. Furthermore, the highly loaded Fe₃O₄ NPs make the enrichment very convenient. With all of these advances, the novel Au NP-maltose/PDA/Fe₃O₄-RGO nanocomposite presents selective enrichment of the glycopeptides from a low concentration of horseradish peroxidase tryptic digest (0.1 ng μL⁻¹).