Construction And Performance Research Of Graphene Multi-element Composite Electrochemical Sensor

Lung cancer is one of the most common kind of malignancy,posing the most serious threats to human health and causing death worldwide.Almost 80-85 % of lung cancers belong to non-small cell lung cancer(NSCLC),and not limited to 80 %of these cases are only distinguished on time of advanced stages.Presently,the highest expression specificity of cytokeratin fragment antigen 21-1(CYFRA 21-1)is considered to be the most important biomarker for the early-stage detection of NSCLC,because the content of CYFRA 21-1 in serum is closely related to the expression level of CYFRA 21-1 gene.Therefore,the efficient detection of CYFRA21-1 gene provides a promising pathway for early diagnosis of NSCLC,and developing genosensors for the ultrasensitive and rapid detection of specific DNA sequences has become particularly significant.In this work,a photocatalytic electrochemical DNA genosensor based on polyaniline nanofibers(PANI)and three-dimensional reduced graphene oxide(3D-r GO)qualified glassy carbon electrode has been successfully manufactured.It can ultrasensitively detect non-small cell lung cancer gene CYFRA 21-1 through photocatalytic reaction.Firstly,the flake graphite was oxidized to GO by Hummers’ method,then 3D-GO was prepared by hydrothermal method,and finally 3D-r GO was obtained by reducing it with hydrazine hydrate.The solution mixing method was used to prepare polyaniline nanofibers(PANI).After mixing the two equal masses and ultrasonic treatment,the PANI/3D-r GO nanocomposite is finally obtained.Using SEM,TEM,XRD and other methods to analyze and verify the material morphology,composition,bonding method.Taking advantage of the ability of ethidium bromide to intercalate double-stranded DNA(ds DNA)to generate singlet oxygen after illumination,a photocatalytic electrochemical DNA genosensor based on polyaniline nanofibers and three-dimensional reduced graphene oxide(3D-r GO)modified glassy carbon electrodes was constructed.It can be applied to indirect quantitative detection of the content of CYFRA 21-1,and the electrochemical performance of the sensor is studied using CV,DPV,and EIS.The theoretical LOD is 76.2 a M(3σ)and the peak currents are linear with the increasing concentrations of target DNA from 0.1 f M to 0.1 μM.This genosensor also possesses good specificity,acceptable stability and reproducibility toward CYFRA21-1,and was successfully applied for the detection of CYFRA21-1 in real serum samples.Therefore,this photocatalytic electrochemical genosensor provides a promising tool for early lung cancer diagnosis.