DNA probe chip system for multiple detection of food poisoning microorganisms

A DNA probe chip system that can simultaneously analyze multiple genes at the place where a specimen is offered has been developed. Genes to be detected were extracted from food-contaminating microorganisms (Escherchia coli O157:H7 and Salmonella typhimurium in this study) and then amplified by multiplex polymerase chain reaction (PCR) (utilizing the reverse primers with fluorescein at each 5′-end). These DNA products were measured in a chip system containing capture probes specific to the respective product. The probes were synthesized to contain biotin at each 5′-end and bound onto spatially separated glass surfaces via biotin–streptavidin linkage. Upon addition of a PCR mixture after denaturation, hybridization between the capture probe and the DNA product occurred, which was sequentially monitored utilizing an immune reaction network. Provision of such simplified analytical protocol for multiple PCR products was achieved without a significant sacrifice in the detection sensitivities.