Preparation Of Surface Molecular Imprinted Polymers Based On Magnetic Nanomaterials And Study Of The Recognition Property For The Proteins

In recent years, molecular imprinting technology (MIT) because of its outstanding performance such as predetermined structure, specific recognition and extensive practicability, have drawn increasing attention. So far, the research of MIT with small molecules has become mature. However, the development of the imprinting of biological macromolecules and proteins is relatively slow, and not yet mature. Some intrinsic properties of proteins hinder the advancement, such as the large molecular size, flexible structure and solubility. In this paper, three types of molecularly imprinted polymer (MIP) were synthesized by using the surface molecular imprinting technology in the presence of bovine hemoglobin as template. The performance of MIP was investigated via experiments. The main contents are as follows:(1) Preparation of surface molecularly imprinted polymer based on magnetic-graphene nano-composite carrier for the recognition and separation of bovine hemoglobinA surface molecularly imprinted polymer (Fe3O4@G-MIP) was prepared by surface molecular imprinting technique with magnetic-graphene (Fe3O4@G) as carrier, Acryl amide (AAm) as functional monomer, bovine hemoglobin (BHb) as template, respectively. Fourier transform infrared (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), raman spectroscopy(RS) and X-ray diffraction (XRD) were employed to characterize the resulted Fe3O4@G-MIP. The adsorption performance and specific selection property of Fe3O4@G-MIP for target molecules were studied by adsorption experiments combined with SDS-PAGE technique. The experimental results showed that the equilibrium adsorption concentration, theoretical maximum adsorption capacity, equilibrium adsorption time and imprinting factor of Fe3O4@G-MIP for BHb was 1.2 mg/mL,186.73 mg/g,21 h and 1.96, respectively. SDS-PAGE analysis results showed that the Fe3O4@G-MIP has good adsorption selectivity towards target protein BHb.(2) Preparation of surface molecularly imprinted polymer based on double bond-modified magnetic nanoparticles carrier for the recognition and separation of bovine hemoglobinWith C=C double bond of acrylic acid (AA) modified magnetic Fe3O4 nanoparticles (Fe3O4@AA) as carrier, itaconic acid (IA) and methyl acrylic acid (MAA) as the bifunctional monomers, combined with the advantage of surface imprinting technology and magnetic nanomaterials, the magnetic molecularly imprinted polymer (MIP-Fe3O4@AA) was prepared to recognize template protein BHb. The preparation process of polymer includes the surface modification of Fe3O4 nanoparticles and the synthesis of imprinted polymer layer. The influence of function monomers ratio was studied and optimized. The series adsorption experimental results showed that the imprinting effect became the best when the quality ratio of IA and MAA was 1:7. The thermodynamics adsorption equilibrium concentration of MIP-Fe3O4@AA was 1.0 mg/mL, the maximum theoretical adsorption capacity (Qmax) of MIP-Fe3O4@AA was calculated to be 117.27 mg/g, and the imprinting factor was 4.43. The recycling experiment results showed that the adsorption capacity of MIP-Fe3O4@AA for BHb was relatively stable in the previous four cycles and less reduced after five cycles, indicating the stability of MIP-Fe3O4@AA is excellent, and MIP-Fe3O4@AA can be reused in the practical application.(3) Preparation of thermosensitive surface molecularly imprinted polymer for the recognition and separation of bovine hemoglobinWith C=C double bond of acrylic acid (AA) modified magnetic Fe3O4 nanoparticles (Fe3O4@AA) as carrier, a new type of temperature-responsive imprinted polymer (TR-MIP-Fe3O4@AA) was prepared at 33.5? in the presence of BHb as template molecules, methyl acrylic acid (MAA) as functional monomer, and N-isopropyl acrylamide (NIPAAm) as thermosensitive monomer. The influence of pH for imprinting effect was studied and optimized, the results showed that under the neutral (pH=7.00) polymerization conditions, the resulting temperature-responsive imprinted polymer has the best imprinting effect for template protein BHb. Further more, the thermosensitivity, adsorption capacity and specific selectivity were investigated. The results suggested that the obtained TR-MIP-Fe3O4@AA has certain sensitivity to temperature change, TR-MIP-Fe3O4@AA has the maximum adsorption capacity and high imprinting factor under the condition of 33.5?. The dynamic adsorption equilibrium time of TR-MIP-Fe3O4@AA was 12 h, thermodynamics adsorption equilibrium concentration was 1.6 mg/mL. Selective experiments showed that TR-MIP-Fe3O4@AA could selective binding BHb with the imprinting factor as high as 6.39, which is much higher than that of other reference protein (the imprinting factor of BSA, OVA, and Lyz was 2.70,0.69 and 2.70, respectively). Competitive adsorption experiment and real sample experiment results indicated that the TR-MIP-Fe3O4@AA shows clearly specific recognition towards BHb. In addition, the TR-MIP-Fe3O4@AA could be reused more than four times, shows good stability and reused ability.