Ultra technically-simple and sensitive detection for Salmonella Enteritidis by immunochromatographic assay based on gold growth

- The improved sensitivity was based on gold nanoparticles growth and accumulation.
- The results can be clearly distinguished by naked eyes even under a lower analyte level.
- An ultra technically-simple enhanced technology was provided.
- The user-friendly immunosensor exhibited excellent sensitivity, selectivity and practicability.

A signal amplified lateral flow immunoassay (LFIA) based on gold nanoparticles (GNPs) growth and accumulation for rapid detection of Salmonella Enteritidis (S. Enteritidis) was developed. The signal was amplified on account of the high catalytic activity of GNPs toward the reaction between HAuCl4 and NH2OH·HCl, which could produce new GNPs on the surface of the initial GNPs. The remarkable enhanced signal at the test and control lines can be clearly distinguished by naked eyes even under a lower analyte level. The lowest visible detection limit of the signal enhanced LFIA for S. Enteritidis was as low as 104 CFU/mL with excellent specificity, achieving a 100-fold improvement in sensitivity compared to the traditional GNP-based LFIA. Finally, for applicability demonstration the method was applied to milk for S. Enteritidis analysis. Except for incubation time, the process required only 6 h, which was obvious shorter than that of many reported methods.