Thermosensitive and Salt-Sensitive Molecularly Imprinted Hydrogel for Bovine Serum Albumin

Abstract

A novel stimuli-responsive protein imprinted polymer for selective recognition of bovine serum albumin is presented. N-[3-(Dimethylamino)propyl]-methacrylamide, which is positively charged in neutral solution and is able to self-assemble onto the template protein through electrostatic interaction, was chosen as the functional monomer. Polymerization was carried out in the presence of N-isopropylacrylamide as an assistant monomer, which resulted in a stimuli-responsive protein imprinted polymer. The template proteins were easily removed by treatment with 500 mmol L(-1) NaCl solution. The influences of the external stimuli, such as temperature and ionic strength, on the polymer affinity were investigated, and a clear conformational memory was observed. The association constant ( Ka) and binding capacity ( Qmax) for the specific interaction between the protein imprinted polymer and the template protein were determined by Scatchard plots and found to be 9.6 x 10(4) L mol(-1) and 4.7 micromol g(-1), respectively. Several proteins different in molecular weight and isoelectric point were employed as reference, and it was shown that the charge effect and the shape memory effect were the major factors affecting the imprint formation and template recognition. Finally, this imprinted polymer was used to purify the bovine serum albumin from the protein mixture and real sample, which demonstrated its high selectivity.

The preparation of bovine serum albumin surface-imprinted superparamagnetic polymer with the assistance of basic functional monomer and its application for protein separation

“…between Fe 3 O 4 @BSA-MIP and Fe 3 O 4 @NIP. Therefore, the differences of the adsorption capacities between Fe 3 O 4 @BSA-MIP and Fe 3 O 4 @NIP were negligible for all the proteins except template BSA and HAS, which were concordant with those reported by Zhao and coworkers [28].…”

“…Since BSA (MW 66.0 kDa) is nearly five times larger than Lyz (MW 13.4 kDa), it possesses larger molecular size and more flexible conformational transitions in imprinting process, the hydrogen bonds existing between BSA and the functional monomer (NIPAAm) are very weak, which causes the difficulty of stable BSA-monomer complexes formation in imprinting process. In a few successful larger protein imprinted polymer cases, the especial functional monomers [25][26][27][28] were used in the process of imprinting BSA, which forced the strong interaction with BSA, or BSA [21] and bovine hemoglobin (MW 64.5 kDa) [29] were directly covalently grafted on the surface of supports. Due to the additional strong interactions with larger proteins or their direct fixation on the supports, the larger protein-monomer complexes formed were more stable, which was helpful to form imprinting cavities and recognition sites in imprinting process.…”

Molecularly Imprinted Polymers with Stimuli-Responsive Affinity: Progress and Perspectives

“…The phase transition from soluble stretching polymer chain to insoluble coil-globule state is attributed to the decreasing enthalpic contribution of water hydrogen-bonded to the polymer chain in comparison to the enthalpic gain of the system with increasing temperature. Correspondingly, the phase transition from swollen state to collapsed state occurs in water when a moderate cross-linked PNIPAm network is used around the LCST [88,92]. This feature endows the MIPs containing PNIPAm blocks the fascinating property of regulatory binding capacity accompanied by the size changes of binding sites derived from temperature variation.…”

Molecularly imprinted beads with double thermosensitive gates for selective recognition of proteins

“…In the thermosensitive protein-imprinted system, minor functional groups interacting with the target molecule are dispersed in a loosely cross-linked thermosensitive polymer. Because the thermosensitive polymer undergoes a reversible swellingshrinking cycle in response to external temperature, which leads to a change in the structure of the binding sites, the rebinding ability is controllable by changing the temperature [26][27][28]. Stimulus-responsive protein-imprinted polymers with high specificity for a particular protein may become increasingly important in smart devices for drug-delivery systems, sensing systems, and molecular diagnostics.…”

“…Thus, stimulus-responsive gels with biocompatibility could have potential applications in the preparation of protein-imprinted polymers. Several encouraging publications have focused on the design of protein-imprinted materials based on stimulus-responsive gels [15,[26][27][28][29][30]. In the thermosensitive protein-imprinted system, minor functional groups interacting with the target molecule are dispersed in a loosely cross-linked thermosensitive polymer.…”