Due to the globalization of food supply have been growing, there have been a great demands for food safety and quality assuarance for on-site detection. On-site detetction isuue is the process should be fast, simple, user-friendly and require minimal equipments. Herein, we developed a Radial chromatography (RC) biosensor integrated with the immuno-gold nanoparticles-coated magnetic nanoparticle (AuNPs@Fe3O4) for specific separation and detection of the target bacteria, E. coli O157:H7, in sample. The immuno-AuNPs@Fe3O4 specifically binds to E.coli O157:H7 creating AuNP@Fe3O4-E.coli complexes and captured bacteria were concentrated by magnet. The complex can be identified with inner ring derived from the difference of mobility of free AuNPs@Fe3O4 on the RC sensor. Our results show that AuNPs@Fe3O4 based RC sensor has high sensitivity to the target bacteria over non-target bacteria with a detection limit of 103 CFU/ml. Our system offers a rapid and sensitive means of detecting E.coli O157:H7 with naked eyes, which can be applied to the field diagnosis.

• Sang-Mook You(Graduate School of Biotechnology & Department of Food Science and Biotechnology, Kyung Hee University, Yongin Korea)
• Ke Luo(Graduate School of Biotechnology & Department of Food Science and Biotechnology, Kyung Hee University, Yongin Korea)
• Young-Rok Kim(Graduate School of Biotechnology & Department of Food Science and Biotechnology, Kyung Hee University, Yongin Korea)