Synergistic dual-recognition enabled by single-atom nanozyme and aptamer for ultrasensitive colorimetric detection of glyphosate

A dual-recognition strategy was developed to detect glyphosate. • The dual-recognition system incorporated Fe/Cu-N-C SAzymes and aptamers. • The LOD was 0.0581 μg/mL. • The method had high specificity and excellent tolerance to matrix effects. • Recovery rates of the proposed method ranged from 90.00% to 96.67%. While nanozyme-based inhibition strategies are attractive for on-site detection of pesticides, their sensitivity is primarily hampered by insufficient interactions at the nanozyme-pesticide interface. To address this, we developed a dual-recognition system that integrates a Fe/Cu-N-C single-atom nanozyme (SAzyme) with an aptamer for sensitive detection of glyphosate. The Fe/Cu-N-C SAzyme overcomes the low atomic exposure of conventional nanozymes by offering abundant metal atomic sites for glyphosate binding. Meanwhile, the surface-grafted aptamers on the SAzyme facilitate glyphosate enrichment on the SAzyme surface, thereby increasing the inhibition efficiency from 14.4% to 26.1%. Under optimized conditions, this enhancement translated into a detection limit of 0.0581 μg/mL, along with high specificity and excellent tolerance to matrix effects. Validation experiments with three spiked samples yielded recoveries ranging from 90.00% to 96.67%, comparable to the results of liquid chromatography-tandem mass spectrometry, demonstrating the reliability of this approach for glyphosate detection in foods. Download: Download high-res image (136KB) Download: Download full-size image