A cascade catalysis-enhanced microfluidic platform for rapid foodborne pathogen detection using Pt@Zr-MOF nanozymes

Salmonella typhimurium (S. typhimurium) has become a major pathogen in the field of food safety, seriously threatening human health. Although mainstream diagnostic assays, including culture-based methods, enzyme-linked immunosorbent assay (ELISA), and molecular diagnostic technology, are generally reliable, each method presents significant practical limitations. Specifically, culture-based methods are labor-intensive and time-consuming; ELISA often lacks sufficient sensitivity for low-abundance detection; and molecular diagnostic technology requires complex nucleic acid extraction and specialized instrumentation. Therefore, the development of a specific, sensitive, and visual detection platform suitable for field deployment is crucial for preventing the spread of the disease. In this study, we developed a novel microfluidic detection platform (MIP) based on immunomagnetic beads (IMBs) and a platinum nanoparticle (PtNP)-decorated Zr-based metal-organic framework (Pt@Zr-MOF) for the rapid and portable detection of bacteria in food products. The platform utilizes colorimetric detection and microfluidic technology, providing an efficient and streamlined method for foodborne pathogen detection. The colorimetric method employs Pt@Zr-MOF with peroxidase-like activity, achieving a limit of detection (LOD) of 10 CFU mL^-1. Additionally, the microfluidic chip was designed for portable detection, offering a limit of quantification (LOQ) (10² CFU mL^-1), a wide linear range (10² to 10⁷ CFU mL^-1), and a short time (10 min, on-chip detection time) for spiked food matrices, including tap water, milk, and fruit juice. The MIP integrates microfluidic technology and nanozyme-induced cascade signal amplification for highly sensitive detection of S. typhimurium, offers a promising solution for fast and precise quantification of foodborne pathogens, especially in resource-limited settings, and provides a viable method for on-site food safety monitoring.