Abstract: Listeria monocytogenes , one of most problematic foodborne pathogens, is responsible for listeriosis in both humans and animals and mainly transmitted through the food chain. In this report, we propose a simple, rapid, and nearly instrument-free molecular technique using multiple cross displacement amplification (MCDA) label-based gold nanoparticles lateral flow biosensor (LFB) for specific, sensitive, and visual detection of L. monocytogenes . The MCDA-LFB method was carried out at a constant temperature (61°C) for only 20 min during the reaction stage, and then the amplification mixtures were directly detected by using LFB, eliminating the use of an electrophoresis instrument, special reagents, or amplicon analysis equipment. The whole procedure, from sample processing to result indicating, was finished within 1 h. The analytical specificity of MCDA-LFB method was successfully determined by distinguishing the target bacterium from other pathogens. The analytical sensitivity of the MCDA-LFB assay was 10 fg of genomic templates per reaction in pure culture, which was in complete accordance with MCDA by gel electrophoresis, real-time turbidity, and colorimetric indicator. The assay was also successfully applied to detecting L. monocytogenes  in pork samples. Therefore, the rapidity, simplicity, and nearly equipment-free platform of the MCDA-LFB technique make it possible for food control, clinical diagnosis, and more. The proof-of-concept assay can be reconfigured to detect various target sequences by redesigning the specific MCDA primers.
Keywords: Listeria monocytogenes , gold nanoparticles, MCDA, MCDA-LFB