Zwitterionic polymer chain-assisted lysozyme imprinted core-shell carbon microspheres with enhanced recognition and selectivity

Constructing imprinting materials with high recognition and selectivity for protein is an always challenge in protein imprinting technology (PIT). In this work, upon the participating of a zwitterionic polymer chain (Poly (1-vinyl-3-sulfopropylimidazolium), PVSP), a lysozyme imprinted core-shell carbon microsphere (CFC-PVSP@MIPs) was prepared by combining template immobilization method and surface imprinting technology. The carboxyl-functionalized carbon microspheres as substrate provided the CFC-PVSP@MIPs satisfactory adsorption capacity (68.1 mg g⁻¹), while the dopamine as a functional monomer and crosslinker allowed the imprinted microspheres to have a thin imprinted shell, thus endowing them a fast adsorption equilibrium rate (120 min). In addition, PVSP could be tightly bound to the imprinted layer through non-covalent interaction, which not only simplified the preparation process of CFC-PVSP@MIPs, but also reduced the non-specific adsorption of imprinted material on proteins. Therefore, the resulting CFC-PVSP@MIPs exhibited a more superior recognition ability towards lysozyme with imprinting factor value of 3.10, compared with the PVSP-free imprinted microsphere (imprinting factor value 1.93). Furthermore, benefiting from the characteristics of zwitterionic groups, CFC-PVSP@MIPs also revealed stronger selectivity in competitive adsorption studies of binary protein mixture samples. Consequently, the proposed strategy would be a promising and convenient way to obtain protein imprinted material with high recognition ability, thus would be conducive to further development and application of PIT.