Polystyrene Microsphere-Labeled Lateral Flow Assay for the Visual Detection of Foodborne Pathogens

With the increasing emphasis on food safety and health, it has become particularly important to develop rapid, sensitive and low-cost detection methods for foodborne pathogens. Lateral flow assay (LFA) has shown great potential in the field of point-of-care testing (POCT) due to its rapidity, portability and low cost. However, traditional gold nanoparticles (AuNPs)-labeled LFAs face challenges such as insufficient signal strength when detecting nucleic acids. In this study, LFA labeled with polystyrene microspheres was constructed targeting the specific nuc gene of Staphylococcus aureus for the detection of double-stranded PCR products. Unlike traditional AuNPs that pair antibodies through physical adsorption, polystyrene microspheres adopt a covalent coupling strategy, significantly enhancing probe stability and signal strength. Under the optimized conditions, the detection limit was calculated to be 7.28 × 102 CFU/mL, which was approximately 10 times higher than that of the AuNP-based strip. This method demonstrated excellent specificity, reproducibility (RSD < 5%) and stability. In the practical application of artificially contaminated milk samples, the detection performance of polystyrene microsphere-based strips was better than that of AuNP-based strips. This study provides an efficient and easy-to-operate solution for the visual detection of foodborne pathogens.