Multimodal nanoenzyme-linked aptamer assay for Salmonella typhimurium based on catalysis and photothermal effect of PB@Au

A composite nanomaterial of Prussian blue@gold nanoparticles (PB@Au) with catalytic and photothermal properties was proposed, which combined with anti-matrix interference aptamers to achieve robust specificity and sensitivity in the detection of Salmonella typhimurium (S. typhimurium). The detection probe, PB@Au-Aptamer (PB@Au-Apt), was designed to exhibit high specificity for the target and catalyze the signal generation to produce a color change, thereby enabling rapid detection. Additionally, the excellent photothermal performance of the PB@Au catalytic system was utilized for multimodal sensitive detection in the multimodal nanoenzyme-linked aptamer assay. Moreover, the utilization of both catalytic and photothermal dual-mode detection was mutually verified to enhance detection accuracy. Under optimal conditions, the detection of S. typhimurium in a sample can be completed in 2 h. The developed assay exhibited exceptional specificity in detecting S. typhimurium, with an impressive detection limit down to 23 CFU·mL⁻¹. Furthermore, the assay exhibited excellent repeatability and stability. Real sample analyses have proven the high reliability and practicality of this assay, highlighting its significant potential for applications in food safety testing.