| Life activity is being more deeply understood with the rapid development of science and technology.Protein is the core substance of life activity.The structure and function of protein has been concerned in the research of protein.The separation and purification of protein is an important part to produce protein reagents and other types of products.Traditional separation methods with consumption of electrolyte,organic extraction agent and energy do not meet the needs of sustainable development in the new era any more.Molecular imprinting is a preparation method in view of the material for protein specific adsorption.Protein molecularly imprinted polymers prepared by the technique have high adsorption capacity,imprinting efficiency and separation factor for proteins.Proteins with large molecular weights,complex distribution of surface functional groups and susceptible conformations easily affected by external environments are challenged while used as molecule templates.As a result,hydrogels with good biocompatibility and developed network structure are generally chosen as imprinting matrix.Alginate is a natural hydrogel material and many researches on its applications in the field of protein molecular imprinting has been reported.However,pure calcium alginate hydrogel has a limitation for protein adsorption capacity,imprinting efficiency and separation factor because of the poor flexibility of polysaccharide chains.Therefore it is important to study the modification of calcium alginate.Firstly,flexible chain segments,polyethylene glycol 600 and polyacrylamide,were grafted onto calcium alginate according to the molecular structure characteristics and chemical properties of calcium alginate hydrogel.The structure,surface morphology,thermal and swelling properties of modified materials were studied.The results showed that in virtue of the grafted segment,thermal stability of the two modified materials were improved.The swelling degree of calcium alginate grafted polyethylene glycol decreased while the swelling degree of calcium alginate grafted polyacrylamide increased.Secondly,investigations are carried out concerning hydrogel microspheres adsorption capacity,imprinting efficiency for template molecule bovine serum albumin(BSA)and separation factor against competitive molecule bovine hemoglobin molecule(BHb)before and after the modification.Unmodified imprinted hydrogel microspheres exhibited adsorption capacity of 4.96 mg/g,imprinting efficiency of 1.42 for BSA and separation factor of 1.75 against BHb.Polyethylene glycol 600 modified imprinted hydrogel microspheres showed adsorption capacity of 11.16 mg/g,imprinting efficiency of 2.78 for BSA and separation factor of 4.71 against BHb.Polyacrylamide modified imprinted hydrogel microspheres possessed adsorption capacity of 13.15 mg/g,imprinting efficiency of 2.12 for BSA and separation factor of 3.02 against BHb.The results showed that the introduction of flexible chain segments has increased the adsorption capacity,imprinting efficiency for BSA and separation factor against BHb.Finally,the reuse properties and desorption behavior of modified imprinted hydrogel microspheres were discussed.The samples remained specific adsorption capacity after 5 cycles.Desorption experiments revealed the differences between specific adsorption and non-specific adsorption on imprinted materials in the process of elution. |
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