Double affinity integrated MIPs nanoparticles for specific separation of glycoproteins: A combination of synergistic multiple bindings and imprinting effect

The selective recognition, isolation, and subsequent enrichment of target glycoproteins are becoming more and more important in clinical diagnosis. In this work, nano-sized molecularly imprinted polymers integrated double affinity (i.e. metal ion affinity and boronate affinity) (D-MIPs) were prepared for specific separation of ovalbumin (OVA). Poly(styrene-glycidyl methacrylate) nanoparticles (PSG) with epoxy bonds were firstly grafted with iminodiacetic acid (IDA) by ring-opening reaction, and then the Cu2+ was chelated to prepare PSG/IDA-Cu2+. Subsequently, imprinted OVA molecules were pre-immobilized through Cu2+ ion affinity. Finally, a surface imprinting layer was formed though the gentle self-oxidization of a kind of boronic acid ligand (i.e. 3-aminophenylboronic acid, APBA). By washing out imprinted molecules, as-prepared D-MIPs posed higher monolayer binding capacity (138.92 mg g−1) and faster capture kinetics (30 min) for OVA, when compared with single affinity integrated MIPs (S-MIPs) and non-imprinted polymers (NIPs), and the chemical adsorption dominated double affinity was the rate-determining step for whole adsorption process. The imprinting factor (IF) of OVA, horseradish peroxidase (HRP) and bovine serum albumin (BSA) by the available D-MIPs were 4.44, 2.23 and 1.47, respectively, which confirmed the better selectivity for OVA. D-MIPs performed favorable regeneration ability and a promising application in actual sample. In addition, a combination of synergistic multiple bindings and imprinting effect, as the mechanism for enhancing specific separation, was also demonstrated.