ARS | Publication request: Indirect Competitive Immunoassay for Detection of Aflatoxin B1 in Corn and Nut Products Using the Array Biosensor

Submitted to: Biosensors and Bioelectronics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 31, 2005
Publication Date: February 21, 2006
Citation: Sapsford, K.E., Taitt, C.R., Fertig, S., Moore, M.H., Lassman, M.E., Maragos, C.M., Shriver-Lake, L.C. 2006. Indirect competitive immunoassay for detection of aflatoxin B1 in corn and nut products using the array biosensor. Biosensors and Bioelectronics. 21(12):2298-2305.

Interpretive Summary: Aspergillus flavus is a fungus capable of producing toxic metabolites (aflatoxins). Certain of the aflatoxins are carcinogenic and their presence in commodities and foods is regulated by the Food and Drug Administration. Testing of commodities for aflatoxins is routinely done with enzyme linked immunosorbent assays (ELISAs) or expensive chromatographic methods. This report describes the development of an array biosensor by researchers at George Mason University and the Naval Research Laboratory, and its application to detection of aflatoxin B1 in corn and nut products. The potential advantage of the array device is that it may be used to detect multiple, unrelated, toxins simultaneously.

Technical Abstract: Because of the potential health risks of aflatoxin B1 (AFB1), it is essential to monitor the level of this mycotoxin in a variety of foods. A competitive immunoassay has been developed using the Naval Research Laboratory (NRL) Array Biosensor, offering rapid, sensitive detection and quantification of AFB1 in buffer, corn and nut products. AFB1 spiked foods were extracted with methanol and Cy5-anti-AFB1 added to the resulting sample. The extracted sample/antibody mix was passed over a waveguide surface patterned with immobilized AFB1. The resulting fluorescence signal decreased as the concentration of AFB1 in the sample increased. The limit of detection for AFB1 in buffer, 0.3 ng/ml, was found to increase to between 1.5-5.1 ng/g and 0.6-1.4 ng/g when measured in various corn and nut products respectively.