A Dual-Mode Electrochemical Aptasensor for Ochratoxin A Detection in Red Wine Based on a Target-Induced Displacement Strategy

Ochratoxin A (OTA) is a mycotoxin frequently found in wine, and its presence at elevated levels poses a significant threat to food safety and human health. However, existing detection methods often suffer from high cost, complex operation, or insufficient sensitivity and specificity. To bridge this technological gap, we developed a label-free dual-mode electrochemical aptasensor for OTA detection in red wine, based on the specific competitive binding between OTA and its aptamer. The sensor integrates a dual-signal cross-validation strategy, combining electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry (DPV), for OTA detection in red wine samples. The sensor exhibited a good linear response within the OTA concentration range of 0.01-10 ng/mL. This dual-mode detection provides complementary insights into the interfacial electron transfer mechanism, demonstrating that conformational changes induced by competitive binding can be reliably monitored via both voltammetric signals. In spiked red wine samples, the recovery of OTA ranged from 94.6% to 103.9%, with relative standard deviations (RSD) below 10%. This approach not only meets the requirements for OTA detection in wine but also offers the advantages of simple sample pretreatment and compatibility with portable electrochemical workstations, laying a foundation for on-site rapid detection and practical field applications.