Electrochemical aptasensor based on Ce3NbO7/CeO2@Au hollow nanospheres by using Nb.BbvCI-triggered and bipedal DNA walker amplification strategy for zearalenone detection

Herein, an electrochemical aptasensor combining Nb.BbvCI-triggered bipedal DNA walking strategy was constructed for ultrasensitive assay of zearalenone (ZEN). The aptasensor used Ce₃NbO₇/CeO₂ @Au hollow nanospheres as electrode modification material and PdNi@MnO₂/MB as the signal label. Importantly, the Ce₃NbO₇/CeO₂ synthesized by hydrothermal method were combined with Au nanoparticles and applied to the electrode surface. The as-prepared Ce₃NbO₇/CeO₂ @Au possessed a large surface area, excellent electrical conductivity, stability and more binding sites. PdNi@MnO₂ with high specific surface area and porosity combined with molecule methylene blue (MB) was introduced into electrodes as the signal label. The proposed aptasensor utilized the advantages of specific recognition of aptamers and target molecules to release bipedal DNA walker (w-DNA), and then the w-DNA was triggered by Nb.BbvCI and entered the cycle to release more signal probes. The feasibility of this strategy was recorded by the differential pulse voltammetry (DPV) method. Under the optimized conditions, the electrochemical aptasensor exhibited a wide linear dynamic range from 1 × 10^-4 to 1 × 10³ ng mL^-1 with a low detection limit of 4.57 × 10^-6 ng mL^-1. Moreover, the aptasensor had high selectivity, good stability, excellent repeatability and provided an effective method for the trace detection of ZEN in real samples.