The Synthesis And Research Of The Electrochemical Biosensor Based On Metal-organic Frameworks

An enormous variety of porous metal-organic frameworks?MOFs?have been designed and reported by choosing different central metal ions and organic ligands.These MOFs possess many merits including large surface area,regular porosity,tunable structures and become increasingly more diverse and targeted applications.Some studies have shown modified electrodes fabricated by utilizing MOFs possessed of excellent electrochemistry properties.In this dissertation,some MOFs were successfully synthesized by simple method and utilized to immobilize enzyme/protein/antibody to construct different biosensors.1.A core-shell structrue MOF of ZnO@ZIF-8 was prepared by a simple self-template method and characterized through Scanning Electron Microscopy?SEM?and X-ray diffraction?XRD?.Then,the strategy of bifunctional electrochemistry platform based on heterogeneous composite ZnO@ZIF-8 and ionic liquid?IL?composite film for nitrite?NO₂-?and immunoassay human IgG biosensors was proposed.On the one hand,the electrocatalytic ability to NO₂-of myoglobin?Mb?modified electrode?ZnO@ZIF-8/IL/Mb-CPE?was studied,and a linear response from 10.5 to 833 ?? with a detection limit of 3.5 ?? was achieved.On the other,a label-free immunosensor for the determination of human IgG was proposed using ZnO@ZIF-8/IL composite film as immobilization matrix.The differential pulse voltammetry?DPV?response of the developed immunosensor was found proportional with logarithmic of human IgG concentrations in the two ranges of 0.1-10 and 10-400 ng/mL.The detection limit of IgG was calculated as 0.03 ng/mL.2.A Zr?IV?-organic framework with 2,5-thiophenedicarboxylate ligand?Zr-tdc?was synthesized by hydrothermal method.Zr-tdc was characterized by SEM,UV-visiblespectroscopy?UV-vis?and N2 adsorption-desorption measurements.Subsequently,Zr-tdc was dispersed by IL to develop a steady composite film on carbon paste electrode?CPE?used as matrix to immobilize glucose oxidase?GOD?.The direct electrochemistry of GOD was researched by cyclic voltammetry?CV?and electrochemical impedance spectroscopy?EIS?.The surface coverage of active GOD,heterogeneous electron transfer rate constant?ks?and Michaelis-Menten constant?KM?of immobilized GOD were 4.18×10-9 mol cm-2,1.34 s-1 and 0.16 mM,respectively.3.A bimetallic organic frameworks of Cu-Ni-BTC and its derivative CuO@NiO were synthesized and studied for electrochemical sensing.The electrocatalytic properties of Cu-Ni-BTC modified electrode for catechol?CT?,resorcinol?RS?and hydroquinone?HQ?were investigated by CV and DPV.The DPV results showed detection limits were0.2 ?M,0.3 ?M,and 0.08 ?M for CT,RS and HQ,respectively.Then,CuO@NiO was synthesized by the calcination of Cu-Ni-BTC in the air at 500?.A biocompatible platform based on CuO@NiO and IL composite film was applied to immobilize Mb.Spectroscopic and electrochemical examinations revealed that Mb remained its bioactivity and achieved fast electron transfer on the surface of CuO@NiO/IL composite film.The CuO@NiO/IL/Mb-CPE showed excellent electrocatalytic activity towards NO₂-in the range of 1.0-3636 ?M with a low detection limit of 0.4 ?M.