Various methods for the detection of E. coli O157:H7 in food have been developed in the past decades. However, current detection methods require specialized instruments and lengthy preparation time. In an effort to achieve a rapid and sensitive detection, we developed a radial chromatography (RC) biosensor integrated with gold nanoparticle (AuNP) conjugated with antibody for the detection of E. coli O157:H7. The immuno-AuNP binds to E. coli O157:H7 creating AuNP-E. coli O157:H7 complexes by specific antigen-antibody interaction. The AuNP-E. coli O157:H7 complexes can be identified clearly from free AuNP by RC based on their mobility on porous matrix. Thus, the AuNP complexed with target bacteria, E. coli O157:H7 could be discriminated from free AuNP by radial chromatography. The results showed that the developed RC biosensor is highly selective to E. coli O157:H7 over non-target bacteria, including Bacillus cereus, Staphylococcus aureus and Vibrio cholerae with a detection limit of 105 CFU/ml. When combined with a pre-concentration step using immunomagnetic beads, we could further enhance the detection limit down to 103 CFU/ml. In this study, we developed a novel method that is rapid, sensitive and applicable for qualitative and quantitative detection of E. coli O157:H7. The detection procedure is simple and the results can be easily determined by naked eyes, suggesting that this system is practical and can be applied to the field diagnosis in food industry for the detection of pathogenic bacteria.

• Soo-Yeon Park(Graduate school of biotechnology & Department of Food Science and Biotechnology, College of Life Sciences Kyung Hee University)
• Ki-Baek Jeong(Graduate school of biotechnology & Department of Food Science and Biotechnology, College of Life Sciences Kyung Hee University)
• Young-Rok Kim(Graduate school of biotechnology & Department of Food Science and Biotechnology, College of Life Sciences Kyung Hee University) Corresponding author