Rapid detection of Staphylococcus aureus in animal-derived foods using aptamer-based fluorescent lateral flow biosensors

Staphylococcus aureus (S. aureus), commonly found in animal-derived foods, poses a significant threat to food safety. Traditional detection methods often suffer from limited sensitivity and selectivity, are time-consuming, and involve complex procedures. In this study, fluorescent lateral flow biosensors (LFB) based on aptamer recognition were developed for the rapid and cost-effective detection of S. aureus. The method utilizes a Cy5-labeled aptamer (Cy5-Apt) as a signal recognition molecule. Detection is achieved through the competitive binding of S. aureus and a complementary strand to the aptamer, enabling the fluorescence intensity measurement on the LFB within 10 min. Key factors including the Cy5-Apt concentration, the length of the linker arm, the position and length of the complementary strand to the aptamer, BSA concentration, and buffer composition were optimized. The method showed good linear response for the quantitative detection of S. aureus in the concentration range of 2.8 × 10¹ to 2.8 × 10⁷ CFU mL⁻¹, and the limit of detection (LOD) was 1.65 CFU mL⁻¹. Application tests in milk and chicken meat confirmed the selectivity and sensitivity of this enzyme- and antibody-free approach. This aptamer-based method offers a promising solution for low-cost, rapid, and efficient detection of S. aureus in food safety applications.