Gold nanoparticle-based paper sensor for multiple detection of 12 Listeria spp. by P60-mediated monoclonal antibody

<p>The genus of <i>Listeria</i> 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 <i>Listeria</i> spp. The selected pair was found to be sensitive to both the P60 protein and cell body of the genus <i>Listeria</i>. On this basis, a rapid paper sensor was established for sensitive <i>Listeria</i> spp. detection. The developed paper sensor broadly cross-reacted with the 12 tested strains of <i>Listeria</i> and the sensitivity in PBS buffer was 10<sup>3</sup>–10<sup>4</sup> 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 <i>Listeria</i> 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.</p>