Ionic liquids skeleton typed magnetic core-shell molecularly imprinted polymers for the specific recognition of lysozyme

The novel ionic liquids skeleton typed magnetic core-shell molecularly imprinted polymers (Fe3O4-COOH@IL-MIP) were firstly constructed with 1-vinyl-3-aminoformylmethyl imidazolium chloride ionic liquid ([VAFMIM]Cl-IL) modified magnetic particles as the substrate materials, [VAFMIM]Cl-IL as functional monomer, 1,6-hexanediyl-3,3'-bis-1-vinylimidazolium dichloride ionic liquid as cross-linker and Lysozyme (Lys) as template protein via surface-imprinting technique. The structure of Fe3O4-COOH@IL-MIP were confirmed by transmission and scanning electron microscopy, dynamic light scattering, thermo-gravimetric analysis, fourier transform infrared spectrometry and X-ray diffraction. The adsorption mechanism was discussed from the perspective of amino acid residues of Lys. The maximum adsorption capacity of MIPs was 166.36 mg g-1 and imprinting factor was 2.67. The competitive adsorption experiments demonstrated the favorable recognition ability of MIPs toward Lys. Reusability studies indicated MIPs can be reused ten times without obvious loss of rebinding ability. The Lys conformation maintained intact after elution and the elution rate was as high as 74%. The adsorption experiment of egg white manifested that MIPs can effectively separate Lys in practical samples. Only ILs and Fe3O4 were utilized to fabricate MIPs, this strategy realized the goal of energy and cost saving while achieving simple synthesis of imprinted materials, and is expected to provide a new feasible idea to exploit synthetic methods for protein-MIPs.