Huang_2026_Anal.Chim.Acta_1382_344856

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 x 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.