Research On Nonenzymatic Biosensor Based On Persimmon Tannin-Graphene-Pt-Pd Nanocomposite

The nonenzymatic sensor is constructed by some non-enzymatic substances with biocatalytic activity instead of enzyme modified electrodes,and it has been extensively applied in biological,clinical,and environmental field.Nanomaterial analogue enzyme is a kind of novel materials with catalytic enzymatic effects,which can greatly improve the sensitivity,stability and repeatability of non-enzymatic sensors.In this paper,two kinds of non-enzymatic sensors have been constructed with persimmon tannin-graphene-platinum/platinum-palladium nanoparticles as catalytic materials for the detection of hydrogen peroxide?H₂O₂?and glucose(C₆H₁₂O₆).And a portable H₂O₂ sensor was designed with STM32 as the control core.The main contents are as follows:?1?A nonenzymatic H₂O₂ biosensor based on persimmon tannin-reduced graphene oxide-platinum nanocomposite?PT-RGO-Pt NPs?was exploited.PT-RGO-Pt NPs were prepared by reduction procedure with PT as film-forming material and ascorbic acid as reducing agent.Scanning electron microscopy?SEM?,Fourier infrared spectroscopy?FT-TR?,Ultraviolet visible spectroscopy?UV-vis?and X-ray photoelectron spectros copy?XPS?were used to investigate structural and morphological properties of the catalysts.Under the optimal conditions,the PT-RGO-Pt NPs non-enzymatic biosensor exhibited outstanding catalytic activity toward H₂O₂.The amperometric response demonstrated a linear relationship with H₂O₂ concentration from 1.0 to 100?M with the regression equation of y?nA?=43.5518_x?M+207.8149 and the correlation coefficient of 0.9931.The limit of detection was 0.26?M and the response time was 3 s.The sensor has fast response speed,high stability and selectivity.?2?A nonenzymatic H₂O₂ biosensor was designed based on persimmon tannin-reduced graphene oxide-platinum-palladium nanocomposites?PT-RGO-Pt-Pd NPs?.The PT-RGO-Pt-Pd NPs were prepared by the reduction method using PT as the film-forming substance and characterized by SEM,FT-IR and UV-vis.H₂O₂ was catalyzed by nonenzymatic sensor of PT-RGO-Pt-Pd NPs and the linear relationship between the response signal of the sensor and the concentration of H₂O₂ in the range of 5.0-100?M was y_?A=0.99024x??M?+0.10549.The correlation coefficient was 0.9912 and a detection limit was0.059?M.?3?A non-enzymatic glucose biosensor was constructed with PT-RGO-Pt-Pd NPs modified on the surface of gold electrode.Utilizing the catalytic activity of PT-RGO-Pt-Pd NPs for glucose,the sensor response signal was plotted against glucose concentration.The results showed that the linearity curve of the sensor signal and glucose concentration in the range of 0.01-0.4M was y??A?=1.3046x?M?-0.00186,the correlation coefficient was 0.99873and the detection limit was 1.430?M.It has great potential for clinical blood glucose detection.?4?A portable H2O2 detection system was designed based on the principle of electrochemical method.The STM32 controlled drive circuit could provide adjustable potential excitation for the H2O2 detection system.H2O2 was decomposed in the reaction zone of the sensor and generated a micro current through I/V conversion voltage during the charge transfer process.And the signal was further amplified,filtered and displayed to build a portable H2O2 detection system.</sub>