Preparation And Properties Of Protein Imprinted Polyampholyte Hydrogel Materials

With the deepening of protein research.many proteins discovered by scientists in human serum are closely related to human health,which makes the adsorption and separation of proteins become a hot topic again.Molecularly imprinted polymers as a new type of adsorption and separation materials are expected to break the bottleneck of protein separation.Polyacrylamide hydrogel materials have been widely used in the preparation of protein molecularly imprinted materials and specific adsorption related property studies because of the advantages of non-toxic and good biocompatibility etc..The recognition between protein and polyacrylamide gel material mainly depends on the hydrogen bond interaction force.In hydrophilic environment,this hydrogen bond interaction force is greatly weakened,and the specificity of the imprinting sites also decreased.Thereby the recognition performance of the imprinted material is affected.This work aims at the obvious problem that the recognition performance of the protein imprinted material in the hydrophilic environment is affected by electrical charge.The polyampholyte hydrogel materials were prepared by the introduction of positive and negative charge groups on the polyacrylamide gel network skeleton by means of radical polymerization for specific adsorption and selective recognition of proteins.In this paper,BSA was used as a template for the preparation of imprinted(MIPAHs)and non-imprinted(NIPAHs)polyampholyte hydrogel materials.The optimum preparation process was obtained by investigating the effects of the amount of structural and functional monomers,the amount of crosslinking agent,the charge density ratio,the adding amount of template BSA,and the elution method on the adsorption capacity and imprinting efficiency.Then the structure,morphology,thermal properties and swelling properties of the MIPAHs and NIPAHs gel materials were studied.The results showed that the introduction of protein template led to changes in the structure and properties of the gels.Swelling test also indicated that the swelling properties of the gels were closely related to the crosslinking structure.Secondly,the effects of external environmental conditions such as the ionic strength and temperature of the adsorbent on the adsorption capacity and imprinting efficiency were investigated.When the ambient temperature was 25 ℃.MIPAHs have high adsorption capacity and the optimum imprinting efficiency for BSA;The presence of free anion and cation in the adsorption solution will reduce the specific adsorption of the imprinting hydrogels.Adsorption kinetics indicated that the adsorption rate of the imprinted hydrogel material decreased with time and reaching a dynamic equilibrium of adsorption at about 150 min.Adsorption thermodynamic investigation showed that the adsorption amount of MIPAHs was related to the initial concentration of BSA adsorption solution.When the initial concentration was about 4 mg/mL,the thermodynamic adsorption equilibrium of hydrogels was achieved.Finally,the influence of the ionic strength of absorbent and the crosslinking structure on the adsorption selectivity of the imprinted materials and the reuse of the gels were investigated.The experimental results showed that the adsorption selectivity of the imprinted materials on the template molecules was related to the ionic strength of absorbent,the crosslinking structure of the gels,the protein molecular weight and the isoelectric point etc..The reuse performance test also showed that the elution of the template had exerted certain damage to the structure of the imprinting sites.