Nanobody-based immunomagnetic separation platform for rapid isolation and detection of Salmonella enteritidis in food samples

Rapid separation and identification of Salmonella enteritidis (S. enteritidis) in food is of great importance to prevent outbreaks of foodborne diseases. Herein, by using O and H antigens as targets, an epitope-based bio-panning strategy was applied to isolate specific nanobodies towards S. enteritidis. This method constitutes an efficient way to obtain specific antibody fragments and test pairwise nanobodies. On this basis, a double nanobody-based sandwich enzyme-linked immunosorbent assay (ELISA) coupled with immunomagnetic sepa-ration (IMS) was developed to rapid enrich and detect S. enteritidis in food. The detection limit of the IMS-ELISA was 3.2 x 103 CFU/mL. In addition, 1 CFU of S. enteritidis in food samples can be detected after 4-h cultivation, which was shortened by 2 h after IMS. The IMS-ELISA strategy could avoid matrix interference and shorten the enrichment culture time, which has great potential for application in monitoring bacterial contamination in food.

Automated summary

By utilizing O and H antigens as targets, a bio-panning strategy was employed to isolate specific nanobodies against Salmonella enteritidis (S. enteritidis) for rapid separation and identification in food, which has significant importance in preventing foodborne disease outbreaks. A double nanobody-based sandwich enzyme-linked immunosorbent assay (ELISA) coupled with immunomagnetic separation (IMS) was developed based on this strategy, enabling rapid enrichment and detection of S. enteritidis in food. The IMS-ELISA strategy could effectively avoid matrix interference and shorten the enrichment culture time, demonstrating great potential for monitoring bacterial contamination in food.