Synthesis of l-phenylalanine imprinted hydrogels with anti-biofouling capability by using a novel zwitterionic functional monomer

A novel zwitterion was synthesized and used as a functional monomer in the synthesis of l-phenylalanine (l-phe) imprinted hydrogel (MIH). Molecular simulation demonstrated that the binding energy of the zwitterion with l-phe was −23.50 kcal mol−1 in the aqueous phase, which was higher than the binding energies of l-phe with other traditional functional monomers. Binding experiments also showed that MIH made using the zwitterion had a higher adsorption capacity and imprinting factor (IF) compared to MIHs made using either acrylic acid or 4-vinylpyridine. Optimization studies showed that the best recognition ability of MIH was obtained when the molar ratio of zwitterion to l-phe was 2:1 in the synthesis of MIH. Adsorption kinetics experiments showed that MIH could equilibrate within 120 min, and adsorption isotherms obtained experimentally demonstrated that MIH had a good adsorption capacity of 9.8 mg g−1 with a high imprinting factor of 2.0 in 0.3 mg mL−1 concentrated l-phe solution. Circular dichroism spectroscopy confirmed the excellent chiral resolution ability of MIH for racemic phenylalanine. Furthermore, MIH prepared using the zwitterion exhibited strong anti-fouling capability and could be utilized to extract l-phe from the protein solution.