Dopamine Sensors Based On Surface Acoustic Wave Devices

Dopamine plays an important role in the regulation of human movement,emotion,cognition and neuroendocrine.Dopamine concentration in the human body deviates from normal and has a close relationship with major human diseases.Therefore,the study of a simple and effective method for testing dopamine concentrations for the prevention and treatment of many diseases has important significance.In this paper,polylysine-titania-nickel composite sensing membrane was used to design and fabricate a dopamine sensor based on surface acoustic wave?SAW?resonator.The effects of polylysine-titania-nickel composite sensing membrane on the detection of dopamine was studied.The detection of dopamine was achieved.The SAW dopamine sensor with polylysine-graphene as the sensitive membrane for dopamine detection was also investigated.1.Designed polylysine-titanium dioxide-nickel composite membrane-modified SAW dopamine sensor.Cyclic voltammetry was used to deposit the polylysine-titania-nickel composite membrane on the SAW resonator,and the morphological characteristics of the components were characterized.In the mixed-sensitive membrane structure,polylysine has a large number of amino and oxygen-containing groups,and dopamine has hydroxyl and amino groups.When the sensitive membrane is adsorbed on dopamine by electric field,a large number of oxygen-containing groups on the surface of the titanium dioxide nanoparticles have a negative charge,which has electrostatic adsorption with the positively charged dopamine.Titanium dioxide and nickel catalyze the carboxylation of dopamine Process,the interaction between carboxylated dopamine and polylysine amino groups;and the nickel nanoparticles capture electrons and rapidly transfer electrons to the electrodes,thereby functioning as a fixed dopamine molecule.At the same time,the titanium dioxide nanoparticles and the nickel nanoparticles contribute a large specific surface area due to the small-size effect,thereby increasing the physical adsorption amount of dopamine.Allows the sensor to detect dopamine concentrations more sensitively.2.Design and test the dopamine program,test the dopamine with the prepared sensor,and study and analyze the factors that affect the dopamine test.Trace detection of dopamine concentration of 10^-8 mol/L was achieved.At the same time,the factors influencing the detection of dopamine concentration were analyzed,including the composition of sensitive membrane,the pH value of the solution,interferences and so on.The repeated experiments were carried out to reduce the influence of the unstable factors and the stability test for more than six months.3.Explore the poly-lysine-graphene mixed-sensitive SAW dopamine sensor.Bouquet-like graphene was prepared by chemical vapor deposition?CVD?method and characterized.The frequency response and frequency shift curves of dopamine at different concentrations were tested,and the effect of polylysine/graphene mixed sensitive membrane on detecting dopamine was analyzed.