Dual detection of Escherichia coli and Staphylococcus aureus via lateral flow immunoassay sensor utilizing porous surface Ag@Au micron particles

Early detection and diagnosis are essential for effectively preventing and treating complex pathogenic bacterial infections. This study presents an innovative approach for on-site, ultrasensitive pathogen detection by integrating a uniquely designed probe binding mode with novel nanomaterial structures within a lateral flow immunoassay (LFIA) platform. Through a galvanic replacement reaction, gold is non-uniformly deposited onto a silver core, resulting in the formation of Ag@pore-Au structures. The abundant nanopores and porous surface of these structures create a high density of "hot spots", significantly enhancing their surface-enhanced Raman scattering (SERS) performance. We systematically characterized the SERS and detection capabilities of the synthesized Ag@pore-Au Raman-dye micron particles (MPs) probe. The results conclusively demonstrated that this structural probe exhibits a robust SERS signal, paving the way for its successful application in LFIA. By integrating the Ag@pore-Au Raman-dye MPs probe into the LFIA platform, we achieved rapid, quantitative detection of Escherichia coli and Staphylococcus aureus. This enhanced platform overcomes the limitations of traditional LFIA, notably its high detection limit of 10 CFU/mL and its inability to provide quantitative results. Furthermore, a dual-channel detection mode enabled the simultaneous and specific identification of both bacterial strains. The platform's efficacy was validated through successful detection in real sample matrices. This research offers novel insights and methodologies for pathogen detection in the medical field, providing an effective solution for on-site pathogen diagnosis and real-time environmental monitoring.