Synthesis of water-compatible surface-imprinted composite microspheres with core–shell structure for selective recognition of thymopentin from aqueous solution

A novel water-compatible surface-imprinted core–shell microsphere, which had multiple non–covalent interactions with template molecule, was successfully prepared by the surface grafting polymerization method in acetonitrile–water systems with thymopentin as template through ionic liquid-functionalized polyethyleneglycolmethacrylate-co-vinylimidazole microsphere as the matrix. The average diameter of matrix was 1 μm ± 20 nm and the thickness of imprinted layer was about 50 nm. The results of static adsorption experiments indicated that ionic liquid-functionalized molecularly imprinted microspheres showed the good adsorption capacity and specific recognition for template peptide. The binding-isotherm analysis showed that Langmuir isotherm models gave a good fit in the range of concentrations, suggesting that there was only one kind of binding site in imprinted layer. Measurements of the binding kinetics revealed that surface-imprinted composite microspheres reached peptide-adsorption equilibrium in 60 min and the maximum adsorption capacity for TP5 was 38.4 mg g −1 . The effects of pH, salt concentration, and temperature on the adsorption capacities were investigated. The microspheres were found to have a high specificity for TP5 with little affinity for BSA and Hb. Finally, the core–shell microspheres can be reused with only 15.6 % decrease in TP5 adsorption capacity after six times.