Graphene oxide-based boronate polymer brushes via surface initiated atom transfer radical polymerization for the...

Biomedical sciences, and in particular biomarker research, demand efficient glycoprotein enrichment platforms. In this work, a facile and efficient method was developed to synthesize boronic acid polymer brushes immobilized on magnetic graphene oxide via surface initiated atom transfer radical polymerization (SI-ATRP) for the selective enrichment of glycoproteins from complex biological samples. The magnetic graphene oxide (GO@Fe₃O₄) nanocomposites were prepared by a solvothermal reaction, providing an ultrahigh surface area and allowing fast separation. Through the self-assembly procedure, the pyrene-based initiators (GO@Br) of SI-ATRP were easily functionalized on the GO sheet via noncovalent π-π interaction between pyrene and GO. Finally, the well-defined and high density poly(4-vinylphenylboronic acid) brushes (GO@PVPBA) via SI-ATRP were successfully fabricated. The morphology and structure of GO@Fe₃O₄, GO@Br, and GO@PVPBA nanocomposites were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), vibrating sample magnetometry (VSM), Fourier transform-infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). The selective recognition capability of GO@PVPBA nanocomposites was demonstrated by the selective enrichment of glycoproteins from a complex system consisting of standard proteins ovalbumin (OVA), transferrin (Trf), bovine serum albumin (BSA), and lysozyme (Lyz). Furthermore, the GO@PVPBA nanocomposite also exhibited a high binding capacity up to 514.8 and 445.9 mg g^-1 for OVA and Trf, respectively, and was applied to capture directly glycoproteins from the egg white samples.