Study On The Detection Of Pb²⁺ Based On Reduced Graphene Oxide-Gold Nanoparticles And Dnazyme System

Reduced graphene oxide（RGO）is a widely used carbon material with high specific surface area and good electrical conductivity.By adding gold nanoparticles（AuNPs）,a large number of active functional groups can be introduced on the surface of RGO,which is beneficial to improve its biological compatibility.Therefore,RGO materials have a broad application prospect in the detection of pollutants.This paper mainly explores the application of AuNPs-bound RGO in heavy metal detection.The RGO-AuNPs modified electrode is autonomously connected to a thiol-modified DNAzyme via the Au-S bond.The biosensor is specific to Pb²⁺.The DNAzyme self-hybridize to form a DNA hairpin structure.When Pb²⁺is present,the hairpin DNAzyme dissociate,the signal molecule ferrocene（Fc）is detached from the biosensor,and the redox electron pair ferricyanide added in the electrolyte can flow more smoothly on the electrode surface.In the absence of Pb²⁺,DNAzyme is not dissociated,which impedes the flow of redox electron pairs,resulting in changes in electrical signals on the electrode surface.The high conductivity and specific surface area of RGO and the strong chemical bond adsorption effect between DNAzyme and AuNPs are responsible for the amplified detection of Pb²⁺,which realize a detection range of 0.05–400,000.0 n M and a minimum detection limit of 0.015 n M.Moreover,the selectivity test results indicated that the biosensor had specificity for Pb²⁺,even if there was interference from other high-concentration metal ions.This simple biosensor also exhibited good responsiveness in actual sample detection,which provides a good application prospect for field detection of Pb²⁺in water.