Gold nanoparticle-based paper sensor for multiple detection of 12 Listeria spp. by P60-mediated monoclonal antibody
The genus of Listeria consists of heterologous species and its presence in the food chain is an indicator of poor hygiene. However, a portable and simple paper sensor for detection of listeria spp. with high accuracy was still unknown. In this study, we prepared a pair of monoclonal antibodies (mAbs) that specifically recognize the P60 protein on the cell surface of Listeria spp. The selected pair was found to be sensitive to both the P60 protein and cell body of the genus Listeria. On this basis, a rapid paper sensor was established for sensitive Listeria spp. detection. The developed paper sensor broadly cross-reacted with the 12 tested strains of Listeria and the sensitivity in PBS buffer was 103–104 colony-forming units (CFU) judged by the gray values of the test line. No cross-reaction with any other gram-positive or gram-negative strains tested was observed. A study using milk samples showed that this paper sensor could detect samples contaminated with low levels of the tested Listeria spp. (1–9 CFU/mL) after 8 h of enrichment and further concentrate for approximately 10 times by centrifugation. The results were in accordance with those obtained using the polymerase chain reaction method.
