Protein glycosylation is a key regulatory mechanism that controls many physiological and pathological processes. Analyses of glycoproteins in biological samples require challenging enrichment steps in light of sample complexity and low glycoprotein abundance. Here, in order to develop an efficient method to enrich glycoproteins, a magnetic carbon nanospheres (MCs) rich in amino group and polyboric acid sites was designed and prepared. The teamed boronate affinity was formed by the self-assembled of amino group and boric acid, which can specifically capture glycoprotein containing cis-diol under neutral conditions. Firstly, a simple green hydrothermal method led to the production of a carbon nanospheres matrix with abundant surface hydroxyl and carboxyl moieties. Then, MCs were synthesized by solvothermal method. Subsequently, the MCs were modified with polyethyleneimine and boric acid in turn to obtain the proposed composite. The hydrophilicity of amino group and its hydrogen bond with glycoprotein, as well as the cyclization reaction of boric acid with cis-1,2-diol, are utilized to specifically bind to glycoprotein. The prepared magnetic nanospheres exhibited binding to glycoproteins with rapid kinetics and strong affinity. Adsorption equilibrium was reached within 40 min, and the adsorption capacities for the glycoproteins ovalbumin, transferrin and horseradish peroxidase were found to be 493, 346 and 326 mg/g, respectively, while the adsorption capacities for the non-glycoproteins bovine serum protein and lysozyme were 60 and 30 mg/g, respectively. This novel nanoparticle provides a simple and efficient method for the enrichment and separation of glycoproteins from biological samples.
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