Boronic acid-functionalized iron oxide magnetic nanoparticles via distillation–precipitation polymerization and thiol–yne click chemistry for the enrichment of glycoproteins

Abstract

In this work, a novel strategy is developed for the fabrication of phenylboronic acid functionalized iron oxide magnetic nanoparticles (MNPs) via distillation–precipitation polymerization and thiol–yne click chemistry. Firstly, silica was coated on the Fe₃O₄ MNPs using a sol–gel method to obtain Fe₃O₄@SiO₂. Subsequently, the vinyl groups were grated onto the silica-modified Fe₃O₄ surface using 3-methacryloyloxypropyltrimethoxysilane. Next, alkynyl groups as the clickable sites were modified on the MNPs to obtain the product Fe₃O₄@pPMA via distillation–precipitation polymerization of the vinyl end groups with propargyl methacrylate, ethylene glycol dimethacrylate. Finally, phenylboronic acid was grafted on the surface of Fe₃O₄@pPMA via thiol–yne click chemistry. The morphology, structure, and composition of all the synthesized phenylboronic acid functionalized Fe₃O₄ MNPs (Fe₃O₄@pPMA-MPBA) were characterized by transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy, X-ray powder diffraction (XRD), vibrating sample magnetometry (VSM), X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis (TGA). Three glycoproteins ovalbumin, transferrin, and horseradish peroxidase and two non-glycoproteins lysozyme and horse heart cytochrome are the chosen target proteins and their adsorption performance on Fe₃O₄@pPMA-MPBA is investigated. The Fe₃O₄@pPMA-MPBA MNPs exhibited outstanding advantages towards glycoproteins including high adsorption capacity, excellent specificity, repeatability and good enrichment recovery. Furthermore, the Fe₃O₄@pPMA-MPBA MNPs could efficiently enrich glycoproteins from real egg white samples. This study provides a feasible strategy for the surface functionalization of boronate affinity nanomaterials for the selective isolation and enrichment of glycoproteins.