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

Abstract

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.