• The classification of nanozymes and their catalytic mechanisms are introduced. • The activity regulation methods and composition of nanozymes are discussed. • Advancements in smartphone-integrated nanozymes for food analysis are summarized. Food analysis is vital for safeguarding food safety and ensuring product quality, particularly in global supply chains where hazards can emerge at any stage. Nanozymes not only have enzyme-mimetic catalytic activity analogous to natural enzymes, but also possess significant features, including high stability, affordability, and ease of modification, which have led to their widespread application in food analysis. Smartphone-integrated nanozyme systems are fully integrated analytical platforms rather than simple combinations of nanozymes and smartphone cameras; smartphones serve as core components by performing computational imaging, signal calibration, and quantitative analysis. Integrating nanozymes into smartphone-enabled sensing platforms has attracted widespread attention in point-of-care testing, owing to their excellent visual readout capability, cost-effectiveness, and user-friendly operation. These sensors enable rapid detection of harmful substances in food matrices, significantly improving detection efficiency and accuracy. By connecting to smartphone applications, users can access real-time detection results and gain in-depth insights into food safety through data analysis. The widespread adoption of such portable detection technologies not only strengthens safety guarantees for consumers but also provides food manufacturers with an effective tool for quality control, thereby enhancing transparency and trust throughout the entire food supply chain. This review offers a detailed introduction to the research background of smartphone-integrated nanozyme sensors. It then elaborates on the classification of nanozymes and their catalytic mechanisms, covering categories such as peroxidases, oxidases, catalases, hydrolases, and laccases. Additionally, it summarizes the regulatory methods for nanozymes’ catalytic activity, including material size, morphological characteristics, vacancy structures, surface modification, and chemical composition, as well as the material composition of nanozymes, such as metals, metal oxides/sulfides/salts, metal-organic frameworks, and carbon-based materials. The review also details the signal conversion mechanisms of smartphone-integrated nanozyme sensors, along with smartphone image processing, color space selection, and AI-assisted selectivity compensation. Afterwards, it discusses the applications of these sensors in food analysis, encompassing the detection of pesticides, antibiotics, hazardous ions, toxins, microorganisms, total antioxidant capacity, and other analytes. Finally, it presents perspectives on the current limitations and future research directions of smartphone-integrated nanozyme sensors, aiming to guide practical research and development in food analysis.
Geng et al. (Wed,) studied this question.