A ratiometric electrochemical aflatoxin B1 aptasensor based on DNA tetrahedral scaffold-corbelled 3D DNAzyme walker and AuNP/MOF/g-C3N4 hybrid electrode

Aflatoxin B 1 (AFB 1 ) has seriously threatened human health, so it is vital to construct an efficient detection strategy for AFB 1 analysis. An exquisitely designed ratiometric electrochemical aptasensor for sensitive detection of AFB 1 has been successfully developed in this work. DNA tetrahedral scaffold (DTS) is used to fix the DNA probes, 3D DNAzyme walker is employed to amplify the detection signals, and the composite material AuNP/ZIF-67/g-C 3 N 4 acts as the sensing surface of the detection electrode. In the presence of AFB 1 , the 3D DNAzyme walker induced the release of the oligonucleotide attached ferrocene (Fc) from the detection electrode and is simultaneously grafted the DNA-modified methylene blue (MB) onto the electrode, leading to a seesaw-like ratiometric electrochemical aptasensor. This ratiometric electrochemical aptasensor provides an outstanding AFB 1 analysis in the linear range of 2.0 fg·mL −1 to 1.0 ng·mL −1 with the limit of detection (LOD) 0.67 fg·mL −1 . It provides new idea for the analysis of other contaminants in foodstuffs.