Nanozymes, nanomaterials with similar catalytic activity and enzymatic reaction characteristics to natural enzymes, can overcome natural enzymes’ disadvantages of high cost and poor stability, but they are faced with the problem of low catalytic activity, which to some extent restricts the rapid development of the interdisciplinary field of nanobiology. With the development of spherical aberration correction electron microscopy, different kinds of single-atom nanozymes (SAzymes) have been developed and rapidly become the research frontier in the field of nanozymes. SAzymes have uniformly dispersed active sites and precisely designed coordination structures, which imparts them with higher catalytic activity. This is particularly important for the development of sensitive, efficient and rapid food detection technologies. This article mainly reviews the development history of SAzymes, analyzes the latest research trends in the activity of SAzymes, and introduces in detail the recent progress in the application of SAzymes to rapid food detection. Finally, the challenges and future research directions of SAzymes are discussed.

“Lab on paper” is a paper-based microanalytical system with unique advantages such as high sensitivity, low cost, portability, and mass production, which breaks through the limitations of traditional detection technologies and shows great potential in the field of rapid on-site food detection. In this paper, the typical “labs on paper”, including chromatographic paper, chemical test chip, lateral flow assay (LFA), microfluidic paper-based analytical devices (μPADs), and synthetic biological paper, are systematically reviewed. Special emphasis is put on the application of “lab on paper” in the field of food detection. Finally, the advantages, challenges, and future prospects of paper-based analytic methods are discussed, which may provide theoretical support for better application of “lab on paper” in the field of food detection.

This study introduced an electrochemical sensor for the rapid, sensitive, and accurate detection of ciprofloxacin (CIP). The sensor utilized a screen-printed carbon electrode (SPCE) modified with Pd@Nb₂C nanocomposites, which were prepared through the in-situ reduction of palladium nitrate on Nb₂C nanosheets, resulting in a uniform distribution of Pd nanoparticles. Subsequently, they were drop-coated onto the SPCE surface, forming a Pd@Nb₂C/SPCE electrochemical sensing platform. The electrochemical analysis demonstrated the excellent electrochemical performance of the sensor. Pd@Nb₂C/SPCE showed a consistent linear correlation between redox peak current (I_P) and CIP concentration (c_CIP) in the range of 10–150 μmol/L, boasting a detection limit of 3 μmol/L. Notably, this technique tracked CIP in both whole and skimmed milk, achieving a high recoveries of 96.36%–105.40% (n = 3). Moreover, the sensor exhibited exceptional selectivity towards CIP, remaining unaffected by various interferences such as sulphonamide, amoxicillin, tetracycline, and chloramphenicol. These findings hold enormous promise for enabling real-time and rapid monitoring of CIP in milk.

Single-atom catalyst (SAC) is one of the newest catalysts, and attracts people’s wide attention in cancer therapy based on their characteristics of maximum specific catalytic activity and high stability. We designed and synthesized a Fe-N decorated graphene nanosheet (Fe-N₅/GN SAC) with the coordination number of five. Through enzymology and theoretical calculations, the Fe-N₅/GN SAC has outstanding intrinsic peroxidase-like catalytic activity due to single-atom Fe site with five-N-coordination structure. We explored its potential on lung cancer therapy, and found that it could kill human lung adenocarcinoma cells (A549) by decomposing hydrogen peroxide (H₂O₂) into toxic reactive oxygen species (ROS) under acidic microenvironment in three-dimensional (3D) lung cancer cell model. Our study demonstrates a promising application of SAC with highly efficient single-atom catalytic sites for cancer treatment.