Synergistic effect of metal ions pivot and macromolecular crowding reagents on affinity of molecularly imprinted polymer

Synergistic effect of metal ions pivot and macromolecular crowding reagents was first used for improving the affinity of molecularly imprinted polymer (MIP). The MIP monolith was synthesized with oleanolic acid as template, polymethyl methacrylate (PMMA) as macromolecular crowding agent and cobalt acetate as metal ion pivot. A ternary porogenic solvent composed of 1-butyl-3-methylimidazolium tetrafluoroborate, dimethyl sulf-oxide, PMMA/CHCl3 was developed to achieve desired polymers. The effect of synthetic parameters on the imprinting effect, including template content, crosslinker content, PMMA concentration, metal ion concentration was investigated. By comparing the imprinting effect of the MIPs with other MIPs prepared only using metal ion or crowder, the cooperative effect of metal ion as pivot and macromolecular crowding agent was demonstrated. The results indicated that the combination of metal ions pivot and macromolecular crowding is an effect method for improving the affinity of the MIP, based on noncovalent molecular imprinting, particularly valuable to the cages in which there is inadequate functionalities for the target molecule required for imprinting.