Silver nanoparticle-base lateral flow immunoassay for rapid detection of Staphylococcal enterotoxin B in milk and honey.

A silver nanoparticle (AgNP)-based sandwich-type lateral flow immunoassay (LFIA) was evaluated for rapid detection of Staphylococcal enterotoxin B (SEB) in milk and honey. The role of trisodium citrate dihydrate (TSC) in the formation of Ag/TSC nanoparticles was established using UV–Vis spectroscopy. The association of silver with TSC in Ag/TSC nanoparticles was studied by the decrease in the intensity of anodic peak potential at 0.47 V and shift to 0.30 V in cyclic voltammetry (CV). The morphological, compositional and interaction studies of the AgNPs conjugated with the anti-SEB polyclonal antibody (Ag-sAb) was established using transmission electron microscopy (TEM) and X-ray photo electron spectroscopy (XPS) measurements. The visible detection limit and optical detection limit of the SEB test strip were 0.5 and 0.125 ppm, respectively, in SEB standard solution. This assay showed no cross-reaction with Staphylococcal enterotoxin A, Staphylococcal enterotoxin C or Salmonella typhi. Finally, the SEB test strip was effectively applied for the detection of SEB in spiked liquid milk and viscous honey, with optical detection limits of 0.25 and 0.5 ppm, respectively. Schematic illustration of citrate and the anti- Staphylococcal enterotoxin B polyclonal antibody conformation on the surface of silver nanoparticle. Unlabelled Image • Ag-based lateral flow immunoassay was evaluated for detection of Staphylococcal enterotoxin B. • The binding mode of Ag and antibody using FTIR and X-ray photoelectron spectroscopy method • ImageJ software was analyzed the optical densities of the test line and control lines. • The optical detection limits in liquid milk and viscous honey were 0.25 and 0.5 ppm. [ABSTRACT FROM AUTHOR]