Construction And Performance Of Electrochemical Nano-biosensor For BPA

In recent years,bisphenol A is everywhere in polymer materials,fine chemical products and daily life.Because the pollutants migrated from bisphenol A can enter the human body and cause harm to the human body,the detection of bisphenol A content has also become a meaningful work.Traditional fluorescence spectrometry,high performance liquid chromatography(HPLC)and enzyme-linked immunosorbent assay(ELISA)methods have gradually failed to meet the requirements of specific and rapid detection,so electrochemical biosensor detection of BPA has become the main detection method.In this experiment,the way and process of synthesis of the materials,the microscopic morphology,the electrochemical properties they have,the application to the emerging DNA tetrahedral structure,and the understanding of the conformational changes of the aptamer to construct the electrochemical nanobiosensor.A polished glassy carbon electrode was used as a substrate,reduced graphene oxide was loaded by the current-time profile method,and gold nanoparticles were generated by reducing chloroauric acid on graphene using a step-pulse method to construct DNA tetrahedra as a scaffold to which a highly specific bisphenol a nucleic acid aptamer was attached.Measurements were made by electrochemical detection.The main experimental results and conclusions of this paper are as follows:1)The graphene oxide loaded gold nanoparticle assembled glassy carbon electrodes show better conductivity than bare glassy carbon electrodes and graphene loaded glassy carbon electrodes,which can make it easier for electrons to reach the electrode surface and thus enhance the sensitivity of the electrode response;2)Analyse and compare the changes in differential pulse voltammetric response currents before and after the BPA concentration at 0 and 1?M concentrations,with three parameter indices(nucleic acid aptamer probe fixation time,time required to detect BPA,and aptamer/MCH concentration ratio).Under optimal conditions,a minimum detection limit of 2 nmol L^-1 was obtained,with a linear range of 0.01-1?mol/L.3)Bisphenol A was prepared as standard solutions at different concentrations and added to the milk for spiked recoveries.The results showed that the spiked recoveries were in the range of 96%-112%with standard deviations not higher than 3.9%.