A disposable membrane strip immunosensor

As the safety in the food supply becomes critical, the demand for rapid, low volume, sensitive, and economic biosensing devices has dramatically increased. An immunosensor based on electrochemical sandwich immunoassay using polyaniline has been developed for detecting foodborne pathogens, such as Escherichia coli 0157:H7. The immunosensor design is based primarily upon the specific nature of labeled antibody-antigen binding. The architecture of the biosensor demonstrates the advantages of using lateral flow formal strip attached to a portable circuitry for signal measurement. The ability to change the specificity of the antibodies enables the biosensor to be used as a semi-quantitative detection device for other types of foodborne pathogens. Results show that the biosensor could detect as low as 10/sup 1/ bacterial cells per milliliter in less than 10 minutes. Additionally, the biosensor yields faster results, and is cheaper than conventional approaches. Details on the device fabrication and performance of the biosensor in detecting E. coli 0157:H7 are presented.