Label-free dual-target electrochemiluminescence aptasensor based on interdigitated electrodes for rapid on-site detection of mycotoxins in grain.

Abstract

Mycotoxins are widespread contaminants in grains and agricultural products, posing risks to food safety and public health. However, rapid on-site multi-mycotoxin monitoring remains challenging due to complex procedures and reliance on laboratory-based instruments. Here, we developed a miniaturized label-free ECL microfluidic aptasensor integrating MEMS-fabricated Au/Pt interdigitated electrodes and a PDMS chip, enabling rapid dual-channel analysis of ochratoxin A (OTA) and zearalenone (ZEN) using a portable ECL detection system. Finite element simulation-guided electrode optimization enhanced electrochemical performance, while stepwise quantum dot-aptamer assembly reduced signal-probe preparation and assembly complexity. Target-induced steric hindrance generated quantitative ΔECL responses. The sensor achieved detection limits of 0.42 ng/mL (OTA) and 0.85 ng/mL (ZEN), with consistency and repeatability RSDs below 3.8% and 3.3%, respectively, and > 95% signal retention after two weeks. Recoveries of 88.87-106.61% in spiked rice and corn samples validated its reliability. This platform can be extended to other mycotoxins, enabling rapid on-site screening during grain storage and transportation.

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