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

Aflatoxin B1 (AFB1) has seriously threatened human health, so it is vital to construct an efficient detection strategy for AFB1 analysis. An exquisitely designed ratiometric electrochemical aptasensor for sensitive detection of AFB1 has been successfully developed in this work. DNA tetrahedrons (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-C3N4 acts as the sensing surface of the detection electrode. In the presence of AFB1, 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 AFB1 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 ideas for the analysis of other contaminants in foodstuffs.