Research On Enzyme-free Bimetallic Synergistic Catalytic Sensor For Glucose Detection

With changes in lifestyle,the number of obese people has increased and the amount of exercise has decreased.The most common chronic diseases in almost all countries include basic diseases such as diabetes.Therefore,it is of great significance to prepare a simple glucose sensor with high sensitivity,good selectivity and good stability.Due to the poor stability of the enzyme glucose sensor and the complicated preparation process,the research on the enzyme-free glucose sensor has received more extensive attention.Due to the special properties of nanomaterials,it is a current research hotspot for the preparation of enzyme-free glucose sensors.This article used copper nanoparticles（CuNPs）,cobalt nanoparticles（CoNPs）,gold nanoparticles（AuNPs）and the active substance ferrocene formyl glutathione（Fc-ECG）with diverse physiological activities and unique properties as materials,Respectively prepared Fc-ECG/CuNPs/GE,Fc-ECG/CoNPs/GE and AuNPs/CuNPs/GE glucose sensors.The main research work was as follows:（1）Study on enzyme-free sensor Fc-ECG/CuNPs/GE for glucose detection:CuNPs were deposited on GE（gold electrode）by i-t method,and ferrocene derivative Fc-ECG was uniformly dropped on CuNPs/GE to construct Fc-ECG/CuNPs/GE electrochemical sensor.SEM and electrochemistry were used for characterization.Under the optimized conditions,the DPV（differential pulse method）was used to detect glucose,and the relationship between glucose with different concentrations and the peak current is obtained.The peak position was at 0.6 V.The fitting equation was:I=1.69792+15.35783c,where c was the concentration of Glu,and I was the current value,the linear range was 0.4～2.3 mM,R²=0.99196,the sensitivity was 217.2688μA·mM^-1·cm^-2,and the detection limit was 0.1333 mM.The combination of CuNPs and Au can increase the catalysis of glucose.The bimetal was combined with ferrocene derivatives with good electrochemical performance to use their synergistic effect to improve the electrocatalytic oxidation performance of glucose.The catalytic mechanism of glucose was:the electron e generated by the oxidation reaction of Fc was transferred to the cathode,which promoted the reduction reaction of Fc⁺on the cathode.Glucose（Glu）in the alkaline electrolyte solution was added to be oxidized to gluconolactone on the anode.（2）Study on enzyme-free sensor Fc-ECG/Co NPS/GE for glucose detection:The CV method was used to deposit CoNPs on GE,and the active material Fc-ECG was modified on the electrode CoNPs/GE surface.Characterized by SEM and electrochemistry.The DPV method was used to detect Glu,the peak position was about 0.3 V,and the peak current was fitted to the glucose concentration.The fitted equation was:I=-8.65946+26.76856c,the linear range was 0.7～4 mM,R²=0.99627,the sensitivity was 378.6977μA·mM^-1·cm^-2,and the detection limit was 0.2333 mM.CoNPs and Au can increase the catalytic performance of Glu.The bimetal combines with ferrocene derivatives with good electrochemical performance to use their synergistic effect to improve the electrocatalytic oxidation performance of Glu.The catalytic mechanism of Glu was:the electron e generated by the oxidation reaction of Fc was transferred to the cathode,which promoted the reduction reaction of Fc⁺on the cathode.Glu added in the alkaline electrolyte solution was oxidized to gluconolactone on the anode.（3）Study on dual-alloy AuNPs/CuNPs/GE of non-enzyme sensor for glucose detection:The i-t method was used to deposit CuNPs and then AuNPs on GE to prepare AuNPs/CuNPs/GE electrochemical sensors.Then perform SEM,CV and EIS characterization.The i-t method was used to detect Glu with different concentrations,and the linear relationship between the concentration of Glu and the response current was obtained.The linear equation was:I=-0.44853+0.05397c,the linear range of 10～17 mM,R²=0.99436,the sensitivity was 763.5193μA·mM^-1·cm^-2,and the detection limit was 3.3333mM.AuNPs and CuNPs synergistically catalyzed Glu with Au.The catalytic mechanism of Glu was:the electron e generated by the metal oxidation reaction flows to the positive electrode,from the positive electrode to the negative electrode of the power supply,and then reached the cathode,which promoted the reduction reaction on the cathode,and the oxidation reaction of Glu occurs on the anode.,generate gluconolactone.（4）For the sensor Fc-ECG/CuNPs/GE,the linear range was 0.4～2.3 mM,the sensitivity was 217.2688μA·mM^-1·cm^-2,the detection limit was 0.1333 mM,and the recovery rate for actual sample detection was 87.39%～107.65%,the RSD was less than 6.45%,the repeatability RSD was 6.44%,the stability RSD was 4.30%,and the reproducibility RSD was 2.23%.For the sensor Fc-ECG/CoNPs/GE,the linear range was 0.7～4 mM,the sensitivity was 378.6977μA·mM^-1·cm^-2,the detection limit was 0.2333 mM,and the recovery rate for actual sample detection was 100.00%～106.88%,the RSD was lower than1.39%,the repetitive RSD was 3.16%,the stable RSD was 2.23%,and the reproducible RSD was 1.84%.For the sensor AuNPs/CuNPs/GE,the linear range was 10～17 mM,the sensitivity was 763.5193μA·mM^-1·cm^-2,and the detection limit was 3.3333 mM.The recovery rate for actual sample detection was 100.09%～102.69%,the RSD was less than0.22%,the reproducible RSD was 6.89%,the stable RSD was 2.66%,and the reproducible RSD was 1.34%.The widest range of sensor AuNPs/CuNPs/GE,the sensor Fc-ECG/CuNPs/GE has the lowest detection limit,and the sensor AuNPs/CuNPs/GE has the highest sensitivity.