Research And Application Of Single Chamber Microcapsules And Three Chamber Microcapsules

At present,the carrier of immobilized biocatalysts is the polymer vesicles/microcapsules prepared by the LBL self-assembly process.This kind of nano-reactor for some simple catalytic system,for some of the more complex or incompatible elements of the system,has some limitations.In this research group,the microcapsules with hollow structure were prepared by electrospinning technology for the first time,and successfully used in the in-situ encapsulation of the multi-enzyme catalytic system in its inner chamber.An electrospun microcapsule with a hollow chamber can provide an extremely stable microenvironment for the entrapped enzyme compared to conventional nano-and micro-sPHeres,and is more conducive to the reaction with the substrate due to its good dispersibility.The research of this thesis mainly includes the following parts:1.Polyurethane(PU)hollow microcapsules were prepared by coaxial electrospinning.The composition of electrospinning liquid and the effect of doped polyelectrolyte on the morPHology and inner diameter of hollow microcapsules were investigated.The Polyurethane dissolved in N,N-dimethylacetamide(DMAC)was used as the external Phase electrospinning liquid(10wt%),and the content of 20%(cp)Glycerol solution as the internal Phase electrospinning liquid.The internal and external Phase flow rates were 0.05 mL/h and 1.0mL/h,the voltage is about 20 kV,the distance from the needle to the receiving plate is 40cm,the temperature is 25? and the humidity is 10%.Under these conditions,the hollow microcapsules with uniform structure can be prepared.2.Candida antarctica lipase(CALB),glucose oxidase(GOD)and horseradish peroxidase(HRP)were used as the model reaction to locate the inner chamber and the wall and the outer surface of the hollow microcapsules via coaxial electrospinning technology combined with LBL self-assembly and ion pairing technology.The results showed that the yield of single enzyme in the inner chamber and outer surface were kept above 68%,and the yield of single enzyme doped in the shell layer was also above 48%.The activity yield were maintained at 40%after 8 h at 60?,which was 12 times higher than that of the free system and remained nearly 70%after 8 times of repeated use.This method of assembly greatly improves the stability of the catalytic system,and has the advantages of simple operation,mild condition and easy preparation.The multi-enzyme catalytic system can be assembled on the polyurethane hollow microcapsules in a desired reaction sequence by simply adjusting the PH of the solution and selecting the appropriate surfactant.3.Three-chamber hollow microcapsules were prepared by designing specific spinneret and optimization of coaxial electrospinning parameters.The enzymes of three enzyme systems were in situ encapsulated in the three chambers of the microcapsules to construct a three chamber microcapsules-based multi-enzyme catalytic system.Three-chamber microcapsules with biocompatibility were first prepared by coaxial electrospinning,and its performance is characterized by the catalytic efficiency of the cascade reaction.The activity of single enzyme in the catalytic system was kept above 60%,and the active yield of the enzyme system was kept at 14.65%.The stability of the cascade reaction has also been greatly improved.This multi-chamber microcapsule,which can be separated by space,does not show its structural superiority in the study of immobilized three-enzyme catalytic system(CALB/GOD/HRP).It may be in the two-phase system or contain incompatible elements of the multi-enzyme catalytic system may be able to show its unique structural advantages.