Construction of phosphatase- and laccase-mimicking Cascade catalysis for ultrasensitive colorimetric detection of Profenofos

Nanozyme-based dephosphorylation reactions show potential for monitoring organophosphorus pesticides (OPs) but require efficient sensing platforms. Herein, a novel dual-mode cascaded amplification sensing strategy was established for the rapid detection of profenofos by employing metal-organic framework-based nanozymes (Ce-UiO-66/Zn) and carbon-dot-based nanozymes (Ce-CDs/MnO 2 ). Based on the high phosphohydrolase-like activity of Ce-UiO-66/Zn, profenofos could be rapidly hydrolyzed and the hydrolysis product would be further oxidized by Ce-CDs/MnO 2 with laccase-like activity, and the oxidative product was coupled with 4-aminoantipyrine to form a red product for colorimetric detection. Additionally, this cascade reaction was also used in the exploration of a smartphone sensing platform due to its obvious color change, which was used to visually analyze profenofos in different food samples and achieved ideal recovery rates. This study provides new insight into development of highly sensitive and selective biosensors, food safety and environmental on-site monitoring.