Ultrasensitive and enzyme-free SERS aptasensor for foodborne S. aureus detection

Rapid and reliable detection of Staphylococcus aureus ( S. aureus ), a major foodborne pathogen, remains a critical challenge in food safety surveillance. Here, we present a hybrid electrospinning–CHA–SERS biosensing platform that integrates aptamer-functionalized electrospun nanofibers with catalytic hairpin assembly (CHA)-mediated assembly of gold nanoparticles (GNPs) for ultrasensitive detection of S. aureus . The electrospun nanofibers enable efficient bacterial enrichment through their high-surface-area architecture, while CHA-triggered GNPs aggregation generates dense plasmonic “hotspots” for remarkable Raman enhancement. This synergistic design achieves a record-low detection limit of 9.2 CFU/mL, along with high specificity and stability in complex food matrices. Demonstrated in real samples, this work establishes a new signal amplification paradigm that couples enzyme-free nucleic acid assembly with SERS enhancement, offering a powerful strategy for intelligent food safety monitoring and rapid pathogen diagnostics.