Optimizations needed for lateral flow assay for rapid detection of pathogenic E. coli

Abstract

Lateral flow assay (LFA), or the immunochromatographic strip test, is popular to use for rapid and sensitive immunoassays.Gold nanoparticles (GNPs), due to tunable optical characteristics and easy manipulation of size or shape, represent an attractiveapproach for LFA technology. Since most enterohemorrhagic infections result from water and food contaminations ofEscherichia coli O157:H7, selective and rapid detection of this organism in environmental and biological complexes is necessary. In this study, optimizedparameters of antibody (Ab)-based LFA for rapid detection of pathogenicE. coliO157:H7 are described. GNPs were used as visualizingagents. The measuring parameters include the Ab concentration on the capture lines, the concentration of gold conjugate, and flowrate. M180 and 36 nm were the ideal membrane and GNP size, respectively, for bacterial detection of LFA. The target,E. coliO157:H7,could be detected with a visual limit of detection of 10 5cfu/mL in 3 5 min. Selectivity of the system was very high and the target wasrecognized by developed strips, regardless of its presence singly or in mixed bacterial samples.