The Construction Of A Novel Ratio Electrochemical Sensor And Its Application In Biochemical Analysis

The detection of doxorubicin hydrochloride(DOX)and other major anti-tumor drugs,dopamine(DA)and other disease markers which are important molecules in biological body,is of great significance to human health and clinical biochemical analysis.Common analytical methods,such as fluorescence,colorimetric,electrophoresis,chromatography et al.are facing with problems of costly and complex sample preparation process.Electrochemical sensors attracted widespread attention due to their high sensitivity,fast response,simple,low cost,in vivo testing et al.Conventional single-signal electrochemical sensors are heavily dependent on the technical conditions of laboratory testing,which greatly limits the development and application of electrochemical sensing technology.Ratiometric electrochemical sensors introduce inherent calibration mechanism that can effectively reduce the background electrical signal within the sensor system,thereby improving the accuracy,reproducibility and sensitivity of sensing system.Therefore,based on ratiometric electrochemical technology,DOX and DA are detection in the subject,the specific researches are as follows:1.A new dual-ratiometric electrochemical DOX sensor based on bare glassy carbon electrode to detect the target in conventional electrolyte was designed.In this study,three substances with different oxidation peak potentials were selected,ferrocene(Fc,0.15 V)and methylene blue(MB,-0.26 V)were served as internal reference substances,and DOX(-0.62 V)as analyte.Then,a mixed electrolyte system of Fc,MB,DOX was prepared.The square wave voltammetry curves of the electrolyte solutions containing the fixed concentrations of Fc,MB and different concentrations of DOX were measured by directly using the bare glassy carbon electrode as the dual-signals sensing platform.The experimental results showed that the sensing system owned a wide linear range and a low detection limit similar to or even better than other modified electrodes.In addition,the dual-ratiometric electrochemical sensor showed good selectivity and stability,and can be used for the detection of DOX in real serum and saliva samples.2.A novel label-free ratiometric electrochemical DA aptasensor based on gold nanoparticles/electrochemical reduction of graphene-Nile blue(Au NPs/ERGO-NB)nanocomposites modified GCE was constructed.Based on the excellent conductivity of the AuNPs/ERGO-NB nanocomposites,specificity of the aptamers toward the analytes,and double-signal current ratio(IDA/INB)as the signal output the ratiometric electrochemical aptasensor exhibits long-term stability and excellent reproducibility,enabling high sensitivity,selectivity,and accurate detection for DA.Additionally,the as-prepared sensor owned the real sample detection capability and can be applied to the analysis of DA in real serum samples.More importantly,the analytical method can be easily extended to the design of novel electrochemical sensors for the detection of other electroactive substances by combining specific receptors and target targets.