An ELISA-on-a-Chip Biosensor System for Early Screening of Listeria monocytogenes in Contaminated Food Products

• Published in: Bulletin of the Korean Chemical Society 2009, Vol.30 (12), p.2993-2998
• Main Authors: Seo, Sung-Min, Cho, Il-Hoon, Kim, Joo-Ho, Jeon, Jin-Woo, Oh, Eun-Gyoung, Yu, Hong-Sik, Shin, Soon-Bum, Lee, Hee-Jung, Paek, Se-Hwan
• Format: Article
• Language: Korean
• ISSN: 0253-2964; 1229-5949

An enzyme-linked immunosorbent assay (ELISA)-on-a-chip (EOC) biosensor combined with cell concentration technology based on immuno-magnetic separation (IMS) was investigated for use as a potential tool for early screening of Listeria monocytogenes (L. monocytogenes) in food products. The target analyte is a well-known pathogenic foodborne microorganism and outbreaks of the food poisoning typically occur due to contamination of normal food products. Thus, the aim of this study was to develop a rapid and reliable sensor that could be utilized on a daily basis to test food products for the presence of this pathogenic microorganism. The sensor was optimized to provide a high detection capability (e.g., 5.9 ${\times}\;10^3$ cells/mL) and, to eventually minimize cultivation time. The cell density was condensed using IMS prior to analysis. Since the concentration rate of IMS was greater than 100-fold, this combination resulted in a detection limit of 54 cells/mL. The EOC-IMS coupled analytical system was then applied to a real sample test of fish intestines. The system was able to detect L. monocytogenes at a concentration of 2.4 CFU/g after pre-enrichment for 6 h from the onset of cell cultivation. This may allow us to monitor the target analyte at a concentration less than 1 CFU/g within a 9 h-cultivation provided a doubling time of 40 min is typically maintained. Based on this estimation, the EOC-IMS system can screen and detect the presence of this microorganism in food products almost within working hours.