Rapid, efficient and highly selective separation and enrichment of glycoprotein by surface-imprinted MOF nanoparticles loaded with high-density boric acid

Usually, glycoproteins are related to diseases or physiological processes; however, a serious challenge remains in realizing their highly specific recognition and enrichment via an imprinting strategy owing to their large molecular size, water solubility and high flexibility. Herein, we reported novel molecularly imprinted polymers based on a metal–organic framework (MOF) material, which achieved the specific enrichment of the target glycoprotein ovalbumin (OVA) by combining a boronate affinity strategy with directional surface imprinting technique. The MOF skeleton has a large specific surface area, thus resulting in a high loading density for the boric acid group (4.66 %) and a satisfactory adsorption capacity (482.56 mg/g). Boronate affinity strategy and the surface imprinting technique resulted in a high specificity of the target glycoprotein. Surface imprinting led to imprinting sites located on the shallow surface of nanoparticles, thus resulting in a rapid kinetic adsorption equilibrium (20 min). And the presence of an acyl group on phenylboronic acid led to the best enrichment effect under physiological pH (7.4). Furthermore, OVA in the real egg white was successfully analyzed, which confirmed the universality of this strategy.