Construction Of Molecularly Imprinted Nanozymes Based On Molecular Self-assembly Technology And Its Application

Catalysts are often used in industrial production to increase production efficiency.However,the use of chemical catalysts causes environmental pollution and resource depletion.As a biocatalyst,the enzyme has the characteristics of environmental friendliness,high catalytic efficiency,high selectivity,mild conditions and so on.It is more in line with the concept of"green production".Although many different kinds of enzymes can be isolated through a series of studies,it is still difficult to widely used in industrial production due to strict use conditions.Enzyme immobilization is beneficial to improve the stability of the free enzyme and achieve the purpose of repeated use.The research of enzyme-immobilized vectors and methods is critical.The carrier should provide good microenvironment and increase the efficiency of enzyme catalysis.Especially in the multi-enzyme catalytic system,the optimal catalytic conditions of different enzymes are different.So it is difficult to ensure the different optimal catalytic conditions in the same reaction environment.Therefore,it is necessary to provide the enzymes with the suitable properties through special carrier materials.In this thesis we immobilized the magnesium-dependent metalloenzyme ?-galactosidase by molecular self-assembly technology,and successfully improved the rate and efficiency of enzyme catalysis.At the same time,different charged nanoparticles were synthesized to achieve the immobilization of multiple enzymes based on the molecular imprinting technique.The D-amino acid oxidase was immobilized on the positively-charged molecularly imprinted nanoparticles and the cytochrome c was immobilized on the negatively charged nanoparticles.At last,enzymes were provided with different acid-base microenvironments to improve catalytic performance of the respective enzymes in the cascade system.The research in this paper mainly includes:(1)Different ligands such as trimesic acid,cyclodextrin,and uracil were selected by molecular self-assembly techniques to immobilize magnesium-dependent ?-galactosidase.The nanoparticles were characterized by scanning electron microscopy and elemental analysis.The optimal catalytic conditions,reaction kinetics and stability of the immobilized enzymes were studied.The catalytic performance of the immobilized enzymes was significantly better.The results showed that the catalytic performance of the immobilized enzyme was significantly better than that of the free enzyme.(2)Molecular imprinting technique was used to prepare molecularly imprinted nanoparticles with different chargeability and the optimal conditions for synthesizing nanoparticles were explored.D-amino acid oxidase and cytochrome C were immobilized by using differently charged molecularly imprinted nanoparticles as a carrier.Charged nanoparticles provided special microenvironment for the enzyme and broadened the optimum pH of the two enzymes.The optimal reaction conditions,reaction kinetics and stability of the multi-enzyme catalytic system were tested and the superiority of the immobilized enzyme carrier and method was proved.The research showed that the catalytic performance of the immobilized enzyme was much better than that of the free enzyme.