Recent trends and advances in single-atom nanozymes for the electrochemical and optical sensing of pesticide residues in food and water

Abstract

Nowadays, single-atom nanozymes (SAzymes) and single-atom catalysts (SACs) have flourished in the field of catalysis owing to their high catalytic performance and exceptional atom utilization efficiency, thereby enhancing biosensing capabilities. In comparison to natural enzymes, SAzymes offer several advantages, including cost-effectiveness, ease of production, and robust catalytic activity, making them highly promising for biosensing applications. Notably, SAzymes demonstrate superior catalytic efficiency and selectivity compared with traditional nanozymes. In this context, this review delineates the enzyme-like characteristics of SAzymes aimed at enhancing food safety, with a focus on the primary factors that influence their catalytic efficacy. The discussion has been expanded to include the use of SAzymes for screening various pesticide residues, particularly organophosphate pesticides (OPPs), carbamates, acetamiprid, pyrethroids, and other pesticide types, which are present in agricultural food products. These applications are realized because of the exceptional properties of single-atom structures, including enhanced reaction kinetics, high active site density, and tunable electronic properties. The integration of SAzymes into sensing platforms holds great potential for the development of cost-effective, sensitive, and reliable tools for the real-time monitoring of pesticide residues. Finally, this paper highlights the current challenges and outlines potential opportunities for the advancement of SAzyme-based biosensing technologies.

Fig. 1. (a) Diagram of the catalytic reaction procedure of the peroxidase route of SAzymes. This figure has been reproduced from ref. with permission from the Royal Society of Chemistry, copyright 2019. (b) Suggested peroxidase-like catalytic performance of PMCS. This figure has been reproduced from ref. with permission from Wiley, copyright 2019.

Fig. 2. (a) The schematic illustration for the preparation of Fe SSN. (b) Modified colorimetric detection of glucose. (c) Integrated agarose-based hydrogel colorimetric detection of glucose. This figure has been reproduced from ref. with permission from Wiley, copyright 2020.

Fig. 3. Diagram of the synthesis of Mo_SA-NA-C and its morphological/crystalline features: (A) schematic of the synthesis method and (B) XRD spectrum, (C) HAADF-STEM elemental mapping and (D–F) HAADF-STEM images. This figure has been reproduced from ref. with permission from Elsevier, copyright 2021.

Fig. 4. Fabrication mechanism of SACe-N-C nanozyme bioactive paper for sensing organophosphorus carbamate pesticide residues (PPy nanowire: poly-pyrrole; CTAB: cetyltrimethyl ammonium bromide; APS: ammonium peroxydisulfate; OP: organophosphorus pesticides; CP: carbamate pesticides; AChE: acetyl-cholinesterase; ACh: acetylcholine; Ch: choline). This figure has been reproduced from ref. with permission from Elsevier, copyright 2022.

Fig. 5. (A) Solvothermal technique employed to synthesize CSACs immobilized on hybridized MOFs Fe₂O₃/MIL-100(Fe). (B) Chemiluminescent immunoassay technique used for the detection of carbendazim, with CSACs serving as signal assays. This figure has been reproduced from ref. with permission from Elsevier, copyright 2022.

Fig. 6. Diagram of the sensing principle of the Apt-CSNLFAs. (a) Configuration of LFAs; (b) representation of the local amplification of RCF; (c) differentiation between positive and negative tests for acetamiprid. This figure has been reproduced from ref. with permission from Elsevier, copyright 2023.

Fig. 7. Diagram illustrating the large-scale production of Fe–N/C SAzymes and the colorimetric system utilizing Fe–N/C SAzymes for the determination of OPs. This figure has been reproduced from ref. with permission from Elsevier, copyright 2024.

Fig. 8. (a) Diagram illustrating the construction procedure of the Fe–N/C SAzymes and the colorimetric sensing approach of OPs. This figure has been reproduced from ref. with permission from Elsevier, copyright 2023; (b) construction process of the colorimetry/electrochemical dual-mode aptasensor based on the Fe-SAzymes quantitative and qualitative identification of multiple OPs. This figure has been reproduced from ref. with permission from Elsevier, copyright 2024.