Synthesis and characterization of creatinine imprinted poly(4- vinylpyridine-co-divinylbenzene) as a specific recognition receptor

In this study, molecularly imprinted poly(4-vinylpyridine-co- divinylbenzene) (poly(4-VP-co-DVB)) as the specific receptor of creatinine was prepared by heated polymerization. 4-Vinylpyridine (4-VP) was used as the functional monomer. Creatinine was used as the template and divinylbenzene (DVB) was the cross-linking agent. After polymerization, water was applied to remove the imprinted creatinine from the polymer. Approximately 72% of the imprinted creatinine template was extracted. Solid-state ¹³C NMR was used to analyze qualitatively the imprinting effect of the synthetic polymer. Adsorption results of creatinine by the imprinted poly(4-VP-co-DVB) and the corresponding non-imprinted polymer were compared. Maximum imprinting ratio of 4.56, defined as the maximum binding capacity of the MIP to that of non-MIP, was achieved. The adsorption kinetics could be precisely described by Langmuir isotherms. The kinetic parameters, Q_m and K_m, with the respective values of 11.95 mg/g and 0.11 dL/g were obtained. Imprinting ratio of the creatinine imprinted poly(4-VP-co-DVB) was also obtained. Selectivity factors of the imprinted poly(4-VP-co-DVB) defined as the binding of creatinine with respect to the other analogs ranging from 2.0 to 4.0 were obtained. The major detection interference of creatinine for clinical applications may come from creatine. Therefore, the creatinine/creatine binary competitive adsorption experiment was also carried out to evaluate the specific recognition ability of the polymer. The binding specificity of the imprinted poly(4-VP-co-DVB) toward creatinine was thus confirmed.