Tailor-Made Boronic Acid Functionalized Magnetic Nanoparticles with a Tunable Polymer Shell-Assisted for the Selective Enrichment of Glycoproteins/Glycopeptides.

Biomedical sciences, and in particular biomarker research, demand efficient glycoproteins enrichment platforms. In this work, we present a facile and time-saving method to synthesize phenylboronic acid and copolymer multifunctionalized magnetic nanoparticles (NPs) using a distillation-precipitation polymerization (DPP) technique. The polymer shell is obtained through copolymerization of two monomers-affinity ligand 3-acrylaminophenylboronic acid (AAPBA) and a hydrophilic functional monomer. The resulting hydrophilic Fe3O4@P(AAPBA-co-monomer) NPs exhibit an enhanced binding capacity toward glycoproteins by an additional functional monomer complementary to the surface presentation of the target protein. The effects of monomer ratio of AAPBA to hydrophilic comonomers on the binding of glycoproteins are systematically investigated. The morphology, structure, and composition of all the synthesized microspheres are characterized by transmission electron microscopy (TEM), X-ray powder diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), and vibrating sample magnetometer (VSM). The hydrophilic Fe3O4@P(AAPBA-co-monomer) microspheres show an excellent performance in the separation of glycoproteins with high binding capacity; And strong magnetic response allows them to be easily separated from solution in the presence of an external magnetic field. Moreover, both synthetic Fe3O4@P(AAPBA) and copolymeric NPs show good adsorption to glycoproteins in physiological conditions (pH 7.4). The Fe3O4@P(AAPBA-co-monomer) NPs are successfully utilized to selectively capture and identify the low-abundance glycopeptides from the tryptic digest of horseradish peroxidase (HRP). In addition, the selective isolation and enrichment of glycoproteins from the egg white samples at physiological condition is obtained by Fe3O4@P(AAPBA-co-monomer) NPs as adsorbents.