Thiol-yne click synthesis of boronic acid functionalized silica nanoparticle-graphene oxide composites for highly selective enrichment of glycoproteins.

In this work, a facile novel strategy is developed for the preparation of 4-mercapto-phenylboronic acid functionalized silica nanoparticle-graphene oxide composite (GO@MPBA) via thiol-yne click reaction. The morphology, structure and composition of the resulting GO@MPBA was characterized by transmission electron microscopy, X-ray powder diffraction, Fourier transform infrared spectroscopy, Fourier transform Raman spectroscopy, Thermogravimetric analysis and X-ray photoelectron spectrometry. GO@MPBA exhibited the high binding capacity towards glycoproteins such as ovalbumin (1288.8mgg-1), immunoglobulin G (1144.1mgg-1), transferrin (592.1mgg-1) and horseradish peroxidase (392.4mgg-1), in contrast, the binding capacity of each non-glycoproteins (cytochrome c, deoxyribonuclease A, pepsin, trypsin, lysozyme and bovine serum albumin) is less than 50mgg-1. Furthermore, the GO@MPBA still remained a good binding capacity after the five times of adsorption-desorption cycles. The selective enrichment of glycoproteins from real egg white samples by GO@MPBA was demonstrated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis. This work could present a facile novel approach of surface modification to design environmentally friendly and more efficient adsorbents for the isolation and enrichment of glycoprotein from complex biological samples.