Aptamer-locker probe coupling with truncated aptamer for high-efficiency fluorescence polarization detection of zearalenone

Zearalenone (ZEN) is a kind of mycotoxin with estrogen-like effect. The presence of ZEN in cereals is potentially harmful to the health of humans. Herein, for the first time, the binding mechanism of ZEN aptamer with 19 bases (Z19) were systematically studied by molecular dynamics, circular dichroism and isothermal titration calorim-etry. The binding driving forces, key bases of Z19 to ZEN, the conformational changes and thermodynamic in-formation were originally found. On this basis, by employing the inherent rapid nature of fluorescence polarization and target recycling induced by Exo III, a novel fluorescence polarization aptasensor was con-structed. The realized add and measure detection mode can be completed within one hour. Under the optimal conditions, the detection platform showed excellent analytical performance with a linear range of 0.01-100 ng/ mL and a limit of detection as low as 0.004 ng/mL. Moreover, the practicability and reliability of the constructed strategy were confirmed with standard HPLC-MS method in corn and wheat samples. The established aptasensor with enhanced sensitivity broaden the application scope of fluorescence polarization technique, especially in detection targets of low molecular weight.

Automated summary

In this study, the binding mechanism of a 19-base ZEN aptamer (Z19) with ZEN was systematically studied. The binding driving forces, key bases, conformational changes, and thermodynamic information were discovered. Based on this, a novel fluorescence polarization aptasensor was constructed using the rapid properties of fluorescence polarization and target recycling induced by Exo III. The aptasensor showed excellent analytical performance with a linear range of 0.01-100 ng/mL and a limit of detection as low as 0.004 ng/mL.