Regulation Metals On Enzyme Polymer Microgel Immobilization System

Enzyme catalysts have been widely used in the analysis and detection of small biomolecules,metal ions,enzyme activity,and cancer markers due to their high catalytic efficiency,good selectivity,and simple and convenient operation.With the rapid development of nanotechnology,enzyme has been immobilized to enhance their stability for biological functions.As a polymer immobilization material,microgel has good biocompatibility,and its internal micro water environment can effectively guarantee the activity of enzymes.Moreover,the functional groups on the microgel are conducive to the coordination of metal ions to form catalytic metal complexes.In this paper,different kinds of enzyme metal microgel were synthesized,and a series of enzyme metal catalysts with simple operation,high cost performance and strong specificity were developed.The specific content is as follows:Firstly,Chapter 1 introduces the types and characteristics of enzyme catalysts and metal catalysts,as well as the problems of enzyme metal catalysis in immobilized systems and proposes solutions to these problems.For immobilized enzymes,there is a relative contradiction between their stability and activity.Easy immobilization methods with good initial activity often experience a sharp decrease in enzyme activity due to changes in time or system environment;However,stable immobilized enzyme systems often have poor initial enzyme activity.Balancing the relationship between the two or simultaneously enhancing both is crucial for immobilizing enzyme systems.In this paper,these two contradictions was solved by immobilizing the third important factor of enzymes-adjustability.Synthesize the existing immobilization methods and immobilization materials,use the organic material microgel to immobilize the enzyme,and coordinate metal ions on the surface of the microgel to synthesize composite microgel materials to adjust the immobilized enzyme molecules.Chapter 2 first employs the synergistic approach of metal and enzyme molecules to jointly perform ester catalytic functions.Adjust the type and content of gel network and metal ions to form zinc ion esterase microgel.This system combines the advantages of enzyme and metal catalysis.First,imidazole group funionalized esterase microgel was synthesized by free radical polymerization,and then zinc ion complex was formed on the surface of the microgel to realize the strategy of metal and enzyme co catalysis.Among them,enzyme catalysis has a more significant catalytic effect under mild conditions,while metals exhibit better catalytic performance in extreme environments.By changing the temperature,pH,solvent and other conditions,it is proved that such zinc esterase microgel has the high efficiency of ester catalysis in various environments.This immobilization method ensures both catalytic activity and catalytic stability.From an application perspective,we have prepared biodiesel and demonstrated its excellent catalytic performance and recycling ability in practical applications.Chapter 3:Adjusting the catalytic effect and catalytic system through the pH response of metals.In order to make the system catalyze at the two-phase interface,we constructed an amphiphilic metal chitosan microgel material,and formed Pickering lotion for ester catalysis at the interface.Such Pickering lotion has temperature response(through temperature sensitive polymer)and pH response(through metal coordination).The formation and demulsification of Pickering lotion can be effectively regulated by the temperature sensitive polymer in the temperature regulated microgel;Similarly,the coordination state of metal ions on the surface of microgel can adjust the state of Pickering lotion with pH switch reversible emulsification and demulsification of metal microgel system such as Pickering.Such metal ions not only have catalytic ability,but also have the ability to regulate recovery.This system expands the ability of enzyme/metal catalyzed systems in two-phase catalysis and expands the application of metal ions in catalysis.In chapter 4,the structure of microgel was modified,and an Fe-based microgel with tubular channels was constructed,which realized the strategy of enzyme metal cascade catalytic detection.Taking inspiration from intermediate pathways in the life system,we constructed a catalytic system that could stabilize intermediates and achieve multi-step efficient catalysis.First,we constructed a polyfunctional glucose oxidase/chitosan/polymer microgel with macromolecular crosslinker chitosan.Iron ions were coordinated on the surface of the microgel,and the iron based microgel with tubular channels was formed by chitosan to guide iron ions to coordinate inside for glucose detection.This spatially stable tubular channel facilitates the transport of intermediate products and ensures the stability of intermediate products.We proved the high sensitivity and low detection limit of iron based microgel through optical signal detection and electrical signal detection.This strategy provides a precise and reliable practical tool for real-time glucose detection,and is also of great significance for cascade catalytic detection.In chapter 5,the full text is summarized.In the enzyme immobilization system based on microgel,metal ions play the roles of co catalysis,cascade catalysis and auxiliary catalysis respectively.Such a system provides a new idea for the enzyme/metal catalytic system.At the same time,in the future work,the degradation of metal residues and microgel is an important problem to solve,which requires more refined design of enzyme/metal microgel catalytic system to complete industrial application.