Integrated multi-channel microfluidic biosensing chip based on chain amplified enhanced fluorescence for determination of SEs

Staphylococcus aureus enterotoxins (SEs) are major foodborne contaminants that pose severe threats to public health. In this study, we developed a multi-channel microfluidic biosensing chip featuring a MNPs-ssDNA-AuNPs sandwich structure system, which integrated specificity aptamer-functionalized magnetic nanoparticles (MNPs) and ssDNA chain-amplified gold nanoparticles (AuNPs) signal probes. The chip achieved uniform liquid distribution, efficient fluid mixing, and high-throughput analysis, while multi-ssDNA probe design facilitated powerful fluorescence signals. Notably, the system enabled simultaneous detection of three classical serotypes-Staphylococcal enterotoxin A (SEA), B (SEA) and C 1 (SEC 1 )-on a single chip within 15 min. The biosensor exhibited highly sensitive and specific fluorescence responses in the range of 10 2 -10 7 fg/mL, with limits of detection of 9.19 fg/mL (SEA), 9.67 fg/mL (SEB) and 11.66 fg/mL (SEC 1 ). In addition, spiked recoveries in milk samples ranged from 89.00 % to 110.40 % (RSDs < 5 %). By overcoming the limitations of single-target detection paradigms, this study offers a convenient, sensitive and visual biosensing platform for rapid, high-throughput screening of SEs, which is essential for comprehensive risk assessment in food safety monitoring.