Complementary integration of highly sensitive aptasensor and portable hydrogel for colorimetric detection of dhurrin in sorghum based on enhanced laccase-like activity of CuCo-MOFs.

As a cyanogenic glycoside commonly found in grass family plants such as sorghum, dhurrin poses a serious threat to the food safety due to its hydrolysis product, hydrogen cyanide. But the equipment is expensive and the procedures complex, making it difficult to meet the demand for rapid on-site screening. This study develops a colorimetric aptasensor and its hydrogel format for rapid dhurrin detection in sorghum, based on aptamer-enhanced laccase-like activity of copper‑cobalt metal-organic frameworks. Dhurrin binding triggers aptamer detachment, weakening the enhancing effect of the aptamer on the laccase-like activity. The liquid-phase sensor achieves a low limit of detection (LOD) of 0.566 μg·mL-1, suitable for accurate quantitative analysis. The hydrogel sensor, with a higher LOD (200 μg·mL-1), provides stable color development within 20 min, offering good portability for on-site screening. This complementary system combines high sensitivity and specificity with operational simplicity, presenting a promising platform for rapid food hazard surveillance.