Enhanced lateral flow immunoassay using ultrabright red-emitting AIE nanoparticles for simultaneous detection of Escherichia coli O157:H7 and Salmonella typhimurium

Abstract

Herein, we introduce a novel lighting-up fluorescence immunoassay, designated as d-AIENPs-LFIA, for the synchronous detection of Escherichia coli O157:H7 and Salmonella typhimurium utilizing ultrabright red-emitting aggregation-induced emission nanoparticles (AIENPs) as signal-amplification probes in a lateral flow immunoassay (LFIA). Under the developed conditions, the d-AIENPs-LFIA demonstrated exceptional sensitivity, enabling highly sensitive synchronous detection of E. coli O157:H7 and S. typhimurium within 15 min, with detection limits of 396 and 236 CFU/mL, respectively. This d-AIENPs-LFIA exhibited good reproducibility, with average recoveries of 83.68 % to 113.31 % and coefficients of variation below 15.83 %. Furthermore, the practical applicability of the d-AIENPs-LFIA was further demonstrated in complex food matrices, including lettuce, skim milk powder, and milk samples. Notably, by incorporating a pre-incubation step, the sensitivity of the d-AIENPs-LFIA was significantly enhanced to 1 CFU/mL within 6 h, offering substantial potential for routine rapid screening of foodborne pathogens.