Study On Non-enzymatic Electrochemical Sensor For Dopamine Detection Based On RGO Nanomaterials

Dopamine（DA）is an important organic electrochemical neurotransmitter produced by the brain,and its concentration imbalance can seriously affect the health of the central nervous system,kidneys,and cardiovascular system,leading to a variety of mental diseases.Therefore,sensitive detection of DA is of great significance for the treatment and prevention of neurodegenerative mental diseases.In this paper,two non-enzymatic electrochemical DA sensors were constructed with two kinds of excellent reduced graphene oxide（rGO）nanocomposites as sensor detection probes,realizing high sensitivity and low-cost detection of DA.The research content includes the following aspects:（1）A non-enzymatic electrochemical sensor based on gold nanoparticles-functionalized porous ZnO microspheres-reduced graphene oxide nanocomposites（ZnO-rGO-AuNPs）.ZnO porous microsphere nanostructures were synthesized by a simple solution method,and the unique three-dimensional porous structure provided a larger specific surface area and higher porosity.The composite high conductivity of rGO as the carrier makes the solution and the electron transfer between the electrode were improved obviously.In order to enhance the electrical conductivity and biocompatibility of screen-printed electrodes（SPE）,a large number of AuNPs were grown on ZnO-rGO nanocomposites by the electrochemical deposition method.Under the optimized experimental conditions,the response current and the concentration of DA had a good linear relationship in the range of 0.5μM-100μM,and the detection limit of DA was0.294μM（S/N=3）.The detection results of clinical serum samples showed that the sensor had good stability（RSD=3.5%）and recovery（98.85-103.7%）,indicating that the sensor was expected to be used for clinical monitoring of DA in the future.（2）A dual-signal-amplifying dopamine sensor based on copper aluminate-reduced graphene oxide-tetraethylenepentamine-gold platinum bimetallic nanoparticles（Cu Al O₂-rGO-TEPA-Au Pt NPs）.Cu Al O₂-rGO-TEPA nanocomposites were prepared by hydrothermal method and high-temperature calcination method.Because rGO-TEPA induces excess oxygen to Cu Al O₂,resulting in a strong promoting effect between Cu Al O₂and rGO-TEPA,which can significantly improve the sensitivity and selectivity of the sensor.The electrodeposition of bimetallic Au Pt NPs on Cu Al O₂-rGO-TEPA nanocomposites not only provided more sites for the attachment of DA but also further improved the sensitivity of the sensor.Under the optimized experimental conditions,the logarithm of the response current was linearly related to the DA concentration in the range of 0.05μM-100μM,and the detection limit was 10.3 n M.The results showed that the DA sensor had good anti-interference,acceptable stability（RSD=2.57%）,a good recovery rate（97.38%-103.60%）,and the potential to be used in clinical DA detection.