Catalytic/fluorescent multifunctional nanostructures-based hydrogel suit for highly sensitive sensing of chlorpyrifos.

Developing rapid, integrated sensing platforms for on-site pesticide monitoring is critical for food safety evaluation. However, current field-deployable sensors often suffer from poor stability and matrix interference. Herein, a catalytic/fluorescent multifunctional nanostructure (Ru-CN/UCNPs@ZIF-8) was engineered by co-encapsulating oxidase-like Ru-CN and upconversion nanoprobes within a ZIF-8 framework. This integrated architecture enables the highly sensitive detection of chlorpyrifos via the specific inhibition of an acetylcholinesterase-mediated fluorescence recovery cascade. To realize on-site visualization, the sensing system was incorporated into a GelMA hydrogel. Coupled with smartphone imaging, this hydrogel platform achieved a quantitative limit of detection of 1 ng mL-1, exceptional 28-day storage stability, and reliable recoveries (88.78%-112.38%) in fruit and vegetable matrix extraction. Finally, to ensure stable signal acquisition under complex field conditions, a custom portable device featuring an independent excitation module and power supply was fabricated. By effectively isolating environmental light, this hardware-assisted strategy provides a highly stable and precise tool for rapid food safety screening.