Study On Electrochemical Biosensor And Design Of Nickel Matrix Composite

In the past half century,biosensors had been extensively explored in many fields.The electrochemical biosensor had the most widely application in many fields owing to the advantages of high sensitivity,easy miniaturization,and manipulability in turbid solution.Regarding from the results of previous research,the sensitivity,stability and selectivity of electrochemical biosensor needed to be further improved.Therefore,the development of outstanding performance glucose sensors was a long-term work,and the high performance functional materials were attracted more and more attentions to construct glucose sensors.Recently,the transition metal material has been widely employed in the non-enzyme glucose sensing due to the low price,high activity and effective electron transfer at low potential.Among the transition metal material,the nickel based material was characterized by low cost,rich resources and excellent biocompatibility,which had aroused tremendous interest in glucose sensing.However,profound challenges remain on the nickel based electrode due to the deactivation of the catalyst in electrochemical reaction.Moreover,non-selectivity for the catalytic glucose oxidation was another limit of the nickel electrode in practical application.To overcome the defects,the nickel-based nanomaterials were modified in many aspects in this work.The main research achievements as followed:?1?The preparation of nickel nitride modified carbon-doped carbon spheres?Ni₃N/NCS?and the study on sensing performance of glucose.Ni₃N/NCS was prepared by the method of simultaneous nitridation using urea as nitrogen source.The results appeared that the electrocatalytic activity of Ni₃ N was notably improved by the combination of Ni₃ N and NCS.It had a sensitivity of 2024.18?A?m M^-1?cm^-2 in the liner range of 1?M-3000?M and 1256.98?A?m M^-1?cm^-2 in the range of 3000?M-7000?M.The corresponding detection limits were 0.1 ?M and 0.35?M respectively.Nevertheless,the Ni₃N/NCS sensor also has the excellent properties of anti-interference and detect glucose in the real serum.The significantly increased electrochemical performance may be owing to the rapid charge transfer and high conductivity brought by the synergistic reaction of Ni₃ N and nitrogen doped carbon sphere.?2?The design of non-enzymatic glucose sensor and research on glucose sensing properties based on nickel-based metal-organic-skeleton.Ni-BTC microsphere is designed by exploiting NiCl₂ and tribenzoic acid as materials via hydro-thermal preparation method.It is discovered that Ni-MOF/GCE has higher activity than Ni O/GCE related to direct electrocatalytic oxidation of glucose,which may result from the large specific surface area of the microsphere structure,the high porosity of MOF holder and the characteristic of multiple active sites.Two linear ranges of Ni-MOF/GCE are 5?M-3000?M and 3500?M-6000?M.The sensitivity in low concentration region is 932.68 ? A ? m M-1? cm-2 and the sensitivity in higher concentration region is 273.04 ?A?m M^-1?cm^-2.Moreover,Ni-MOF/GCE also represents prominent selectivity.?3?The fabrication of Ni₃N/C composite microspheres and characterization of glucose sensing with MOF as the precursor.Urea was used as nitrogen source and NiMOF precursor were used to form sol in ethanol,then burning in N2 atmosphere,Ni will be nitridated into Ni₃ N particles and MOF precursor can be carbonized into nitrogen-doped carbon.The addition of nitrogen enhanceed the conductivity of NiMOF and accelerated the transformation of electrons between the composite catalysts,which is more favorable to improve the detect sensitivity of Ni₃N-MOF/GCE to glucose.Ni₃N-MOF/GCE has two linear lines for glucose detection?0.001-3m M,R2 = 0.998 and 3-7m M,R2 = 0.991?.The sensitivity is 1511.59 ?A?m M^-1?cm^-2 and 783.75 ?A?m M-1? cm-2.Ni₃N/C composite microspheres also appeared the superior selectivity and feasibility for the detection of glucose in samples.?4?The construction of Au-Ni-MOF microspheres and study on glucose sensing performance.The Au-Ni-MOF composite was fabricated by loading Au nanoparticles on the Ni-MOF precursor with the rapid microwave assistant process.The excellent conductivity of Au NP significantly improved the enzyme-free glucose sensing performance of Au-Ni-MOF/GCE.The decorated electrode of Au-Ni-MOF indicates a wide linearity in the range of 0.005-7.4 m M and a high sensitivity of 1447.1 ?A?m M^-1?cm^-2.The coefficient of bimetallic system promotes the electrooxidation of glucose,which demonstrates that the sensing of polymetallic system will be a promising direction in the future research.