Cu−N4 Active Site Sensing Platform for Point-of-Care Colorimetric Detection of Environmental Organophosphorus Pesticide

Background Organophosphorus pesticides contamination significantly threatens the ecological environment. Therefore, developing sensitive and efficient point-of-care detection methods is essential. Results In this work, Cu−N 4 single-atom nanozymes on nitrogen-doped carbon (Cu SAs/NC) with dual enzyme-mimicking activities (peroxidase-like and oxidase-like) were prepared for point-of-care detection of parathion using acetylcholinesterase inhibition-based colorimetric sensing mechanism. Cu SAs/NC shows high catalytic activity with high turnover number (K cat ) of ∼24.07 min −1 and K cat /K m of ∼1.35×10 5 M −1 min −1 . Experimental findings in combination with density functional theory simulations demonstrate that Cu centers in Cu SAs/NC play a pivotal role in intermediate binding optimization, which contributes to a decreased reaction energy barrier. Hence, a colorimetric sensing platform based on Cu SAs/NC was constructed for point-of-care detection of parathion, achieving a detection limit of 0.79 ng mL −1 . Significance This study provides a novel strategy for structuring single-atom nanozymes with enhanced enzyme-mimicking activity, showing great promise for advanced environmental protection.