| Taken the advantage of good biocompatibility,high stablility and good selectivity from polymer and large specific surface area and strong electrocatalytic activity from inorganic nanoparticles,the polymer-inorganic nanoparticle composites could show great significance in fabrication of electrochemical biosensor.Consideration of this,in this dissertation,a series of electrochemical biosensors based on polymer-inorganic conductive composites were prepared through the combination of conductive polymer with inorganic nanomaterials.Several techniques were used to study their structures,morphologies and properties,such as the transmission electron microscopy?TEM?,scanning electron microscopy?SEM?,FTIR,X-ray diffraction spectrometry?XRD?,X-ray photoelectron spectroscopy?XPS?,cylic voltammetry?CV?,etc.The main contents and results of this dissertation were summarized as follows:?1?Ultrasensitive electrochemical sensing of dopamine using p-TSA doped polypyrrole/Fe3O4 or Fe3O4@MOFs nanocomposites decorated reduced graphene oxide sheetsA hybrid nanocomposite consisting of polypyrrole?PPy?nanospheres doped with p-toluenesulfonate?p-TSA?was prepared and deposited on sheets of reduced graphene oxide?rGO?.The rGO sheets were first coated with Fe3O4 particles,and pyrrole was then polymerized on their surface to obtain architecture of the type PPy/Fe3O4/rGO.Addition of p-TSA during polymerization led to the formation of p-TSA-doped PPy to obtain doped-PPy/Fe3O4/rGO.Moreover,the MOFs?ZIF-8?were coated on the surface of Fe3O4 to get the Fe3O4@ZIF-8/rGO nanocomposite.Two kinds of nanocomposites were placed on a glassy carbon electrode to give an electrochemical sensor?doped-PPy/Fe3O4/rGO/GCE and Fe3O4@ZIF-8/rGO/GCE?for dopamine?DA?,respectively.Both sensors have a wide linear range,a low detection limit,and good selectivity for DA over ascorbic acid and uric acid.It also gave satisfactory results in the determination of DA in spiked samples of urine and serum.?2?Preparation of magnetic Fe3O4/PPy@MOFs nanocomposite for glucose oxidase immobilization and used as glucose electrochemical biosensorThe MOFs?ZIF-8?coated Fe3O4/PPy magnetic nanocomposite?Fe3O4/PPy@ZIF-8?,with large surface area and high conductivity,was prepared by polymerizing the pyrrole on Fe3O4 nanoparticle and self-assembling the ZIF-8 on the obtained magnetic Fe3O4/PPy.Due to the outstanding specific area and pore volume of MOFs,the glucose oxidase?GOx?can be effectively immobilized on the Fe3O4/PPy@ZIF-8 to fabricate a potentiometric glucose biosensor.The as-prepared GOx/Fe3O4/PPy@ZIF-8/GCE biosensor exhibited extraordinary electro-detection performance for glucose with wide linear range from 1×10-6 M to 2×10-3 M and the limit of detection was 0.33×10-6 M?S/N=3?.Furthermore,the prepared biosensor also showed good selectivity for glucose detection and satisfactory result in real samples detection.?3?Preparation of graphene nano-sheets bonded PDA/MOFs microcapsules immobilized glucose oxidase as mimetic multi-enzyme system for electrochemical sensing of glucoseA novel amperometric biosensor for glucose detection was fabricated based on the mimetic multi-enzyme system by combing the mimetic enzyme?metal-organic frameworks,MOFs?and glucose oxidase?GOx?.The microcapsule constructed with polydopamine?PDA?and ZIF-8 using CaCO3 templates could be utilized not only to provide the biocompatible and non-toxic microenvironment to immobilized GOx,but also as the efficient mimetic enzyme because of the peroxidase-like property of ZIF-8.The reduced graphene nano-sheets?rGO?were bonded to PDA/ZIF-8 microcapsules to accelerate the electron transfer between microcapsule and electrode.The mimetic multi-enzyme system was fabricated when GOx was immobilized in the as-prepared microcapsule,and the developed GOx/PDA/ZIF-8@rGO/GCE biosensor exhibited extraordinary electro-detection performance for glucose with two wide linear ranged from 1×10-6 M to 1.2×10-3 M and 1.2×10-3 M to 3.6×10-3 M.Moreover,the good selectivity for glucose and satisfactory results in real samples detection by the prepared biosensor were also demonstrated.?4?Mn2O3/Ni?OH?2 electro-deposited graphene nano-sheets/ sulfonated polyimides membrane for electrochemical sensing of glucoseA novel nonenzymatic glucose sensor was fabricated based on the Mn2O3/Ni?OH?2 alloy nanocomposite electro-deposited sulfonated polyimides/graphene nano-sheets membrane?SPI/rGO?.Firstly,Mn2O3 nanorod array was prepared on SPI/rGO membrane using pulse reverse potential electrodeposition.Then Ni?OH?2 nanoparticle was also deposited on the membrane to get SPI/rGO-Mn2O3/Ni?OH?2.The electrochemical behaviors of resulted sensor were investigated by cyclic voltammetry and chronoamperometry in alkaline solution.Combination the outstanding electrocatalytic activity of Mn2O3/Ni?OH?2 and high conductivity of SPI/rGO,the resulted sensor showed remarkable advantages for glucose detection,the linear range of detection was from 1×10-6 M to 1.8×10-3 M.Other detection performance of the prepared biosensor,like high sensitivity,long-term stability and reproducibility were also demonstrated. |
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