Synthesis of a gelatin based molecularly imprinted hydrogel with high selectivity on adsorbing bovine serum albumin

Molecularly imprinted polymers are confronted with many challenges during application to separating proteins, this study synthesized a molecularly imprinted hydrogel (MIP hydrogel) for specifically separating bovine serum albumin (BSA) with high selectivity. By using the ionic liquid [VAFMIM]Cl as the structure functional monomer and N-isopropylacrylamide (NIPAM) as the thermo-sensitive functional monomer, the obtained gelatin based MIP hydrogel was porous, showed good mechanical properties and outstanding swelling ability. The methacrylation of gelatin improved the MIP hydrogel greatly on mechanical strength. The employment of NIPAM enabled the obtained MIP hydrogel thermo-responsive on swelling ability and adsorption capacity. The BSA adsorption capacity of MIP hydrogel was as high as 150.18 mg/g when the BSA initial concentration was used at 0.5 mg/mL, and the imprinting factor of MIP hydrogel was achieved as high as 5.17. The selectivity coefficients against bovine hemoglobin and lysozyme achieved as high as 11.83 and 9.39, respectively. In BSA/BHb mixture, the MIP hydrogel separation factor toward BSA was still as high as 23.97, and the MIP hydrogel adsorption capacity toward BSA was 4.64-fold larger than that of NIP hydrogel. The adsorption kinetics and isotherm study demonstrated the surface of the synthesized MIP hydrogel was homogenous, the adsorbing active sites were identical with equal energy, the BSA molecules were adsorbed monolayer on MIP hydrogel, the adsorption process was chemisorption and diffusion-controlled. The prepared MIP hydrogel was favorable and showed high potentiality on specific separation of BSA.