Study On The Fabrication And Properties Of Tyrosinase Electrochemical Biosensor

Catechol has a role that cannot be ignored in chemical,food,pharmaceutical,etc.,but the large use of catechol has polluted the environment,food,and caused great harm to the human body.Therefore,finding a suitable method to detect catechol is of great significance in industrial production and environmental protection.The tyrosinase biosensor can convert the detection signal of catechol into an electrical signal in time,thereby achieving accurate detection of the concentration of catechol in the solution.Its fast,efficient,miniaturization,good reproducibility and low cost make it a research hotspot.However,there are still some problems in the tyrosinase biosensor that limit its application in practice,such as low detection performance,poor stability,and difficulty in analyzing complex actual components,etc.,which limit its application in practice.Based on the current research status of tyrosinase electrochemical biosensors,nanomaterials were prepared to efficiently immobilize tyrosinase to construct biosensors to achieve sensitive detection of catechol.Main tasks as follows:?1?Hafnium doped zinc oxide?Hf-ZnO?was prepared from tetrachloride hafnium?Hf Cl₄?and zinc nitrate by hydrothermal method.Tyr/Hf-Zn O/CS/GCE was obtained by modifying tyrosinase?Tyr??Hf-Zn O and chitosan?CS?onto Glassy carbon electrode?GCE?.The structure and properties of the Hf-Zn O was characterized by FESEM,XRD,DLS and XPS.Cyclic voltammetry?CV?was used to compare the response performance of zinc oxide with different amounts of hafnium doped to detection of catechol,and the optimal doping ratio was determined to be 3%.Electrochemical tests were conducted on the modified electrode Tyr/Hf-Zn O/CS/GCE by cyclic voltammetry?CV?and chronoamperometry?IT?.The results showed that the electrode modified by Tyr/Hf-Zn O/CS/GCE has the best detection ability for catechol at p H 5 and low potentials of–50 m V.The linear range of detection for catechol is 0.5?47?M,the sensitivity is 195?A/?M,and the detection limit is 0.1215?M?S/N=3?.The modified electrode has good stability and repeatability,and can effectively avoid the interference of urea,dopamine,ascorbic acid and other substances with similar electrical activity to catechol.?2?Titanium carbide?Ti₂C₃?is a new type of two-dimensional material,which has the advantages of good stability,good biocompatibility,good conductivity and large specific surface area.The alkalinization of titanium carbide?a-Ti₂C₃?with potassium hydroxide can further improve the conductivity and electron transfer ability of titanium carbide and its unique structure increases the fixed amount of tyrosinase.The Tyr/a-Ti₃C₂/CS/GCE biosensor was constructed by using the coating method to modify the tyrosinase and a-Ti₂C₃ materials on the surface of the glassy carbon electrode.The a-Ti₂C₃ was characterized by FESEM,XRD,XPS and so on.The cyclic voltammetry?CV?method was used to electrochemically test the modified electrode.The results showed that the alkalinized titanium carbide modified tyrosinase biosensor had better electron transport performance than the titanium carbide modified tyrosinase biosensor.According to the AC impedance analysis test?EIS?,the a-Ti₂C₃ has excellent conductivity,which can significantly reduce the resistivity of the modified electrode.The p H and work of the biosensor for catechol detection are optimized by single factor experiments Voltage,under optimized conditions,Tyr/a-Ti₃C₂/CS/GCE biosensor linear detection range for catechol is0.5?45?M,correlation coefficient R² is 0.998,sensitivity up to 215?A·m M^-1,detection limit is 0.02?M?S/N=3?.In addition,the repeatability and stability of the biosensor showed that the electrode has good repeatability and stability.After half a month of storage,the detection performance of catechol remains at91.23%.The relative standard deviation of 10 tests for diphenol was 1.14%.?3?ZnO is a good bioelectrode material with good biocompatibility,but the disadvantage of poor conductivity limits its further application in biosensing.The a-Ti₂C₃ has very good conductivity,and it combined with Zn O can effectively improve the conductivity of zinc oxide.The a-Ti₂C₃-Zn O composite material was prepared by physical mixing method?the mass ratio of a-Ti₂C₃ to Zn O is 1:4?,and the Tyr/a-Ti₂C₃-Zn O/CS/GCE biosensor was constructed.Factors such as p H,working potential and temperature of catechol detection by this biosensor are optimized,so that the prepared biosensor has the best detection performance for catechol.The detection range of the biosensor for catechol is 1.5?50?M,the correlation coefficient R² is 0.996,the sensitivity is203?A/m M,and the detection limit is 0.402?M?S/N=3?.The stability and repeatability tests were carried out.The results showed that the modified electrode had good repeatability and stability.The relative standard deviation of the test was 5 times under 10?M catechol substrate,and the relative standard deviation was only 1.02%.After placing the modified electrode in a refrigerator at 4°C for one month,the modified electrode still maintained an initial signal strength of 70.83%.In addition,the modified electrode has better selectivity.