Study On Specific Rebinding Behavior Of Dually Imprinted Alginate Microspheres With Protein And Emulsion Templates

The macromolecular imprinting seems to distinguish from micromolecular imprinting mainly by the bulk effect, while the recognition between natural molecules is mostly determined by the assembling and coordination of regional structure. Hence in the study of macromolecular material and technology, molecular imprinting effect should be identified as a fundamental subject. In this paper, based on our pervious work, dually imprinted alginate hydrogel microspheres with protein and emulsion template are prepared and much emphasis is put on the systematical study on the difference between macromolecular imprinting and emulsion imprinting effects and their reaction to the structure and environmental factors.In this paper, the adsorption thermodynamics and the characteristic of protein and emulsion are first studied. The profiles of the molecular and emulsional imprinting efficiency are found similar at lower swelling ratio (SR<0.8 when controlled by ionic strength, SR<1.7 when controlled by temperature), suggesting both of the imprinting have the specific recognition effect based on steric dimension. The emulsion and molecular imprinted systems differ in the recognition mode at the fully swollen stage, resulting in the different trend variation of the two imprintings: the emulsion imprinting efficiency keeps a sustained growth while the latter reduces after the peak. The facts above suggest that the emulsion imprinting adsorbs by means of non-specific adsorption based on porous facial effect, and the molecular imprinting rebounds protein depending on the combination of shape complementary and site specificity, i.e. the specific rebinding effect. The peaks of the molecular imprinting efficiency curve may be characteristic for the specific rebinding effect, which is called molecular imprinting specific point. It is also indicated that the two types of imprintings differ in their behavior while cooperating in one system: the emulsion imprinting system achieves higher level in Na+ and weak basic surroundings, while the molecular imprinting efficiency is higher in Ca2+ and the isoelectric point of the protein molecular.Second the properties of dually imprinting adsorption in microspheres of different crosslinkages or pore diameters are studied. It is suggested that the crosslinkage is effective on the molecular diffusion, exchanging and binding through swelling and physical junctions, while the pore diameter works through specific area, tensiometric property and diffusion ability. Molecular imprinting efficiency is higher in the beads with higher HEC content, and takes less time getting equilibrium with bigger pores.Last the role of surrounding factors, i.e. ion strength, temperature and solution pH on the dually adsorption behavior is studied. It is suggested the molecular imprinting efficiency has its optimum value according to ionic strength and temperature, while the emulsion imprinting efficiency acts other wise. Moreover the dually imprinting efficiency according to pH has two peak values. The principle of target-interaction mode and its approaches in the dually imprinted hydrogel system are also discussed.