Colorimetric aptasensor targeting zearalenone developed based on the hyaluronic Acid-DNA hydrogel and bimetallic MOFzyme

Zearalenone (ZEN) is a widespread nonsteroidal mycotoxin with estrogen-like activity. Sensitive and reliable quantification of ZEN in food is critical to ensure food safety and safeguard agricultural production. Herein, by combining the metal-organic frameworks-based nanozyme (MOFzyme) and hyaluronic acid (HA)-DNA hydrogel, a well-designed colorimetric aptasensor was developed. The HA-DNA hydrogel was deposited on the surface of the bimetallic MOFzyme via strand-induced hybridization chain reaction (HCR). Relying on the ZEN-specific aptamer integrated in hydrogel structure, the disintegration of the hydrogel network and the concomitant exposure of the encapsulated MOFzyme could be specifically triggered by the introduction of ZEN molecules. Moreover, the magnitude of hydrogel disintegration was positively correlated with the amount of ZEN, by which the quantification of ZEN can be effortlessly achieved. Benefiting from the delicate design, the satisfactory catalytic performance and stability of bimetallic MOFzyme and the appealing stimuli-responsiveness of DNA hydrogel, the developed aptasensor demonstrated superior analytical performance and ease of use. Under optimal conditions, the linear range of the aptasensor fell between 0.001 and 200 ng mL-1 with a limit of detection (LOD) of 0.8 pg mL-1. Furthermore, the aptasensor was successfully applied for the quantitative detection of ZEN in corn and soybean samples with recoveries ranging from 94.0% to 109.0%. The developed aptasensor is expected to be a prospective universal platform for accurately quantifying food or environmental hazards.