Bovine serum albumin recognition via thermosensitive molecular imprinted macroporous hydrogels prepared at two different temperatures

A novel temperature-sensitive molecular imprinted hydrogel composed of 2-acrylamido-2-methyl-propanosulfonic acid (AMPS), N-isopropylacrylamide (NIPAm) and acrylamide (AAm) has been prepared by free-radical cross-linking copolymerization in aqueous solution under two different temperatures (25 °C and −20 °C). Bovine serum albumin (BSA, pI 4.9, MW 66.0 kDa) is used as the template protein. The influence of the external temperature stimuli on the affinity of the hydrogels was investigated, and the optimal binding conditions were tested. The adsorption capacity (Qmax) and association constant (K) for the specific interaction between the hydrogel and the template protein were determined by Langmuir isotherm plots. Several types of reference protein, which are different in molecular weights and isoelectric points were chosen to investigate the selectivity of the hydrogels. It was shown that the shape memory and the charge effect were the major factors for the recognition. This imprinted hydrogel was used to specifically adsorb the BSA from the protein mixture and real sample, which demonstrated its potential selectivity.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► The preparation of thermo-sensitive molecular imprinted hydrogel (MIH) for the template BSA. ► Choosing 2-acrylamido-2-methyl-propanosulfonic acid (AMPS), N-isopropylacrylamide (NIPAm) and acrylamide (AAm) as the monomers. ► Temperature, functional monomer and cross-linking degree were optimized respectively. ► The MIH were characterized by FT-IR and SEM, and investigated by different adsorption experiments. ► The selectivity of the MIH was verified by direct adsorption of single reference protein, protein mixture and real sample.