Construction Of Carbon-based Composite Nanomaterial Modified Electrode And Application In Electrochemical Detection Of Small Molecules In Biological Samples

Objective The content of biological small molecules in the body is related to metabolism in life activities and to various diseases.It is of great significance to develop new methods and devices for detecting small biological molecules with high sensitivity,high selectivity,low cost and portability.This paper builds an electrochemical analysis system based on a variety of nanocomposite modified electrodes for the detection of two small molecules dopamine(DA)and uric acid(UA)in biological samples.Methods In this paper,indium tin oxide conductive glass(ITO)is selected as the working electrode.After limiting the area of the working electrode,cyclic voltammetry(CV)and chronoamperometry(it)electrodeposition are used to modify the reduced graphene oxide / gold nanoparticles(ErGO/AuNPs))And poly 3,4-ethylene dioxythiophene /graphene oxide(PEDOT/GO)are used to improve the analytical sensitivity of the target detector.Finally,real-time quantitative detection of dopamine in rat cerebrospinal fluid and uric acid in human saliva samples was achieved.In addition,a three-electrode system was fabricated on the surface of polyethylene terephthalate(PET)film by screen printing carbon paste and silver / silver chloride paste,and the carbon nanotube composite nano-particles supported by platinum nanoparticles were modified on the working electrode.Materials(Pt-CNTs).The constructed analysis device was used to continuously monitor the release of dopamine from mouse pheochromocytoma(PC12)cells by real-time continuous monitoring of potassium ion,and evaluate the calcium channel opening effect of potassium ion induced by cadmium iodide(Cd I2).Results Electrochemical sensors using ErGO/AuNPs modified ITO as working electrodes,because the synergistic effect of ErGO/AuNPs greatly promoted electron transfer and improved catalytic activity.The detection of dopamine showed specificity,and the minimum detection limit could reach15 n M.And successfully applied to quantitative analysis of dopamine in rat cerebrospinal fluid.The PEDOT / GO paper-based analysis equipment provides a simple and reliable analysis platform.The disposable working electrode shows good electrocatalytic ability to uric acid,and has good reproducibility and stability.The analysis platform directly detects human saliva samples without pretreatment,and the uric acid level is consistent with the clinical test results.The current response of the constructed Pt-CNTs /SPE sensing platform to dopamine is linear in the concentration range of 0.05μM to 1 mM.The device is used to monitor the rapid release of dopamine in PC12 cells induced by K~+ in real time.Conclusions In this paper,we have constructed three electrochemical sensing platforms using carbon-based nanocomposite-modified electrodes.The electrochemical method was used to detect dopamine and uric acid,and was used for rapid detection of two biological molecules in situ in different biological samples.The research results in this paper indicate that the electrochemical analysis system constructed by nanocomposites has potential application prospects in bioanalysis,clinical monitoring and drug research.