Construction Of Bienzyme-based MOF Nano-biosensor And Its Detection Performance

The construction of colorimetric biosensors based on Metal organic Frameworks(MOFs)nanomaterials to achieve rapid,accurate and sensitive detection of the target substances is a hot topic of current research.In this thesis,starting from the design and construction of hollow MOFs microcapsules and magnetic core-shell structured MOF-based nanozymes(MOFzymes),colorimetric biosensors are constructed by immobilizing enzymes in reasonable methods.The colorimetric biosensors can not only ensure the accuracy and sensitivity of the detection results,but also realize the reuse of the sensors,which is of great significance for expanding the application range of the colorimetric biosensors.The specific research work of this thesis mainly has the following two aspects:(1)The hollow zeolite imidazolate frameworks(ZIF-8)was prepared by a protein-induced soft-templating pathway,during which glucose oxidase(GOx)and horseradish peroxidase(HRP)were embedded in the capsule wall and cavity of hollow ZIF-8 respectively,to form nanocomposites(HRP@H-ZIF-8-GOx).The morphology structure and the bienzyme distribution of HRP@H-ZIF-8-GOx were investigated by scanning electron microscope(SEM),transmission electron microscope(TEM),X-ray diffraction(XRD),confocal laser scanning microscopy(CLSM),etc.HRP@H-ZIF-8-GOx is more conductive to catalyze the cascade reaction with glucose and 2,2?-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid)diammonium salt(ABTS)as the substrates comparing with other hollow ZIF-8 immobilized GOx and HRP.The temperature adaptability,thermal stability,mechanical stability and storage stability of HRP@H-ZIF-8-GOx are better than that of hollow ZIF-8 co-immobilized GOx and HRP.The performance of HRP@H-ZIF-8-GOx for colorimetric detection of glucose and phenol was investigated.The results indicate that the detection linear range of glucose concentration was 0-1500?M with a pretty low limit of detection(LOD,signal to noise ratio is 3)of 0.4457?M.And excellent selectivity and anti-interference ability were showed.The detection linear range of phenol concentration was 0-100?M and the LOD was0.8600?M.(2)Fe₃O₄ was prepared and coated with laccase-like catalytic active Cu/GMP(MOF formed by coordination of Cu²⁺and guanosinic acid(GMP))under mild aqueous conditions,and GOx was embedded in the formation Cu/GMP to construct enzyme-MOFzyme cascade biocatalyst(Fe₃O₄@Cu/GMP-GOx).The morphology and element composition of Fe₃O₄@Cu/GMP-GOx was characterized by SEM,fourier transform infrared spectroscopy(FTIR),X-ray photoelectron spectroscopy(XPS),etc.The mechanism of Fe₃O₄@Cu/GMP-GOx catalyzed cascade reaction was investigated.Fe₃O₄@Cu/GMP and Fe₃O₄@Cu/GMP-GOx showed better thermal stability,mechanical stability and storage stability than free GOx&HRP and laccase.The performance of Fe₃O₄@Cu/GMP-GOx in the colorimetric detection of glucose and arbutin was investigated.The results indicate that the detection linear range of glucose concentration was 0-800?M with a LOD of 5.516?M.And excellent selectivity and anti-interference ability were showed.When the arbutin concentration was in the range of 0-60?M and 100-400?M,the absorbance value was linearly correlated with the concentration of arbutin,and the LOD was 0.7660 ?M.