Ultrasensitive aptasensor based on SERS-coupled immunochromatography for rapid detection of fenvalerate in food...

In this study, we developed an aptamer-mediated surface-enhanced Raman scattering (SERS)-coupled immunochromatographic assay (ICA) for the quantitative detection of pyrethroids. For this approach, core-shell gold nanoparticles (Au@Au NPs) were used as SERS probes by conjugating with aptamers, and fluorescent Raman reporter molecules (MPBN) were incorporated to yield stable, reproducible spectral signals. Leveraging the aptamers' specific recognition of the target analyte, Raman-labeled Au@Au NPs could be effectively captured by the test line of the immunochromatographic strip, thereby enabling the quantitative analysis of fenvalerate-with a limit of detection (LOD) as low as 0.4 ppb. Comparative experiments revealed that the detection sensitivity of this SERS-ICA method was 476 times higher than that of conventional lateral flow assays (LFA), showcasing a remarkable sensitivity advantage. To validate its practicality, spiked recovery experiments were conducted on three real samples, namely welsh onions, cowpeas, and kidney beans. The results showed that the spiked recoveries ranged from 78.3% to 112.5%, with relative standard deviations (RSD) between 1.7% and 20.1%. This fully confirms that the method possesses favorable specificity and accuracy, making it suitable for real-sample detection. This detection platform offers a new technical route for the rapid on-site monitoring of trace contaminants in food safety and environmental surveillance, holding broad application prospects.