Design And Manufacture Of Enzyme-free Biosensor Based On Two-dimensional Nanomaterials

Real-time detection of biochemical indicators such as glucose and cholesterol in human blood is conducive to the early prevention and screening of chronic diseases such as cardiovascular and cerebrovascular diseases and diabetes,and contributes to human health management.Since the enzyme electrode is easily affected by the environment and its cost is high,in this paper,based on two-dimensional transition metal nanomaterials,composite nanostructures are designed as enzyme-free sensing units.The main research contents of this paper are as follows:1.In order to solve the problem of easy inactivation of enzyme-containing sensors,cobalt（Co）/Molybdenum disulfide（Mo S₂）/reduced graphene oxide（r GO）ternary composites were prepared to achieve accurate enzyme-free detection of glucose.Co@Mo S2/r GO was prepared by the improved Hummers method and hydrothermal method.A sufficient conductive network was constructed benefitting from the large specific surface area of Mo S₂ and the excellent conductivity of graphene.The transition metal Co was doped to increase the active site of the structure and enhance the catalytic properties of glucose.Screen printing technology was introduced,and the topological structure of microelectrode was designed and optimized.The reliability was verified by exploring its electrochemical characteristics.Enzyme free glucose electrochemical sensor was prepared with ternary nanomaterials.2.In order to solve the problem that patients need to take blood and change the electrode for multiple times,MXene（Ti₃C₂T_x）/cuprous oxide（Cu₂O）self-supporting electrode was prepared to achieve simultaneous detection of glucose and cholesterol.A new transitional metal carbide MXene was introduced to replace Mo S₂ and r GO with its excellent electrical conductivity and large specific surface area.The self-supporting electrode was prepared by vacuum pumping and filtration,and Cu₂O was modified on the surface by electrodeposition.MXene was used to oxidize glucose at positive potential,and Cu₂O was used to oxidize cholesterol at negative potential.The relationship models between glucose/cholesterol concentrations and current signals were established,and the simultaneous detection of multiple substances without enzyme was realized through potential separation.3.In order to solve the problem of time-consuming and laborious detection for large biochemical instruments,MXene/Cu₂O screen printing electrode combined with a small workstation was developed to achieve a portable experimental platform for simultaneous detection of glucose and cholesterol.MXene/Cu₂O screen printing three-electrode system was assembled,and the mass production process was designed.The feasibility was confirmed through electrochemical tests.Combined with a small workstation,a portable multi-substance real-time enzyme-free biosensor was constructed to improve patients’compliance with daily testing.