Dnazyme-Driven Bipedal DNA Walker and Catalytic Hairpin Assembly Multistage Signal Amplified Electrochemical Biosensor Based on Porous Aunps@Zr-Mof for Detection of Pb2+

Abstract

As a highly toxic and refractory heavy metal contaminant, Pb2+ has seriously endangered human health. The problems of low sensitivity and high cost of signal labeling often exist in common electrochemical biosensor. Herein, a Pb2+ electrochemical biosensor was constructed using DNAzyme-driven bipedal DNA walker and catalytic hairpin assembly as the multistage signal amplification strategy. Compared with Zr-MOF, the nanocomposite material gold nanoparticle @ zirconium-based metal organic framework (AuNPs@Zr-MOF) has larger porosity and specific surface area, which can effectively load methylene blue to amplify the current signal. The presence of Pb2+ triggers a dual signal amplification reaction to gradually accumulate the signal of MB/AuNPs@Zr-MOF on the electrode. The ingeniously designed sensing strategy enables analysis of Pb2+ with a wide linear range from 0.05 to 1000 nmol/L and a lower LOD of 4.65 pmol/L. In addition, the sensor has strong anti-interference ability and can accurately detect Pb2+ in various food samples.

Keywords: Electrochemical biosensor, Bipedal DNA Walker, Catalytic hairpin assembly, AuNPs@Zr-MOF, Lead ion