SERS-Based Immunochromatographic Assay for Sensitive Detection of Escherichia coli O157:H7 Using a Novel WS2-AuDTNB Nanotag

HighlightsWhat are the main findings?Developed a novel WS2-Au nanocomposite coupled with 5,5′-dithiobis-(2-nitrobenzoic acid) (DTNB) and antibodies as sensitive surface-enhanced Raman scattering (SERS) nanotags forE. coliO157:H7 detection.Demonstrated a broad linear detection range (8 × 102–8 × 107CFU/mL), a low detection limit (175 CFU/mL), high specificity and good accuracy in real food samples (milk, pork).What are the implications of the main findings?A rapid assay for qualitative and quantitative detection ofE. coliO157:H7, overcoming limitations of traditional ICA methods.A cost-effective, user-friendly surface-enhanced Raman scattering (SERS)-based immunochromatographic assay (SERS-ICA) platform with great potential for point-of-care testing and detection of other foodborne pathogens.E. coliO157:H7 contamination in food and the environment poses a serious threat to human health. Rapid and sensitive identification of foodborne pathogens remains challenging. Here, we prepared tungsten disulfide (WS2)–Au nanocomposites coupled with the Raman signal molecule 5,5′-dithio-bis-(2-nitrobenzoic acid) (DTNB) and antibodies to replace the conventional colloidal gold nanoparticles and applied SERS-active nanotags in the SERS-ICA method for highly sensitive detection ofE. coliO157:H7. The large surface area and numerous effective SERS hotspots of WS2-Au nanotags provide superior SERS signals. Under optimized conditions, this ICA achieves the quantitative detection ofE. coliO157:H7 in a broad linear range of 8 × 102–8 × 107CFU/mL and at a low detection limit of 175 CFU/mL. In addition, the test strip indicates high specificity forE. coliO157:H7 identification, favorable reproducibility, and shows good accuracy in the detection of actual food samples, such as milk and pork. The proposed assay can be used for rapid qualitative and quantitative detection ofE. coliO157:H7 and has great potential for field application.