The development of protein chip using protein G for the simultaneous detection of various pathogens

A protein chip using protein G for the simultaneous detection of various pathogens such as Escherichia coli O157:H7, Salmonella typhimurium, Yersinia enterocolitica, and Legionella pneumophila was developed. In order to endow the orientation of antibody molecules on solid surface, protein G was introduced. The protein G on gold (Au) surface modified with 11-mercaptoundecanoic acid (MUA) was arrayed and then four different kinds of monoclonal antibodies (Mabs) against pathogens (E. coli O157:H7, S. typhimurium, Y. enterocolitica, and L. pneumophila) on protein G spots were selectively arrayed using a microarrayer, and its spatial density was over 2400 spots cm2. Using the constructed protein chip, the various pathogens such as E. coli O157:H7, S. typhimurium, Y. enterocolitica, and L. pneumophila could be detected by a sandwich method and its lowest detection limit for E. coli O157:H7 was 102 CFU/ml. The proposed fabrication technique of protein chip for the detection of various pathogens could be applied to construct other protein chips with a high efficiency.