Multiplexed detection of mycotoxins in foods with a regenerable array.
The occurrence of different mycotoxins in cereal products calls for the development of a rapid, sensitive, and reliable detection method that is capable of analyzing samples for multiple toxins simultaneously. In this study, we report the development and application of a multiplexed competitive assay for the simultaneous detection of ochratoxin A (OTA) and deoxynivalenol (DON) in spiked barley, cornmeal, and wheat, as well as in naturally contaminated maize samples. Fluoroimmunoassays were performed with the Naval Research Laboratory array biosensor, by both a manual and an automated version of the system. This system employs evanescent-wave fluorescence excitation to probe binding events as they occur on the surface of a waveguide. Methanolic extracts of the samples were diluted threefold with buffer containing a mixture of fluorescent antibodies and were then passed over the arrays of mycotoxins immobilized on a waveguide. Fluorescent signals of the surface-bound antibody-antigen complexes decreased with increasing concentrations of free mycotoxins in the extract. After sample analysis was completed, surfaces were regenerated with 6 M guanidine hydrochloride in 50 mM glycine, pH 2.0. The limits of detection determined by the manual biosensor system were as follows: 1, 180, and 65 ng/g for DON and 1, 60, and 85 ng/g for OTA in cornmeal, wheat, and barley, respectively. The limits of detection in cornmeal determined with the automated array biosensor were 15 and 150 ng/g for OTA and DON, respectively.
Ngundi
Miriam M
MM
Center for Bio/Molecular Science and Engineering, Naval Research Laboratory, Washington, DC 20375, USA.
Shriver-Lake
Lisa C
LC
Moore
Martin H
MH
Ligler
Frances S
FS
Taitt
Chris R
CR
D015374:Biosensing Techniques / Q000379:methods* / Q000592:standards; D003257:Consumer Product Safety; D002523:Edible Grain / Q000737:chemistry*; D005504:Food Analysis; D005506:Food Contamination / Q000032:analysis*; D006801:Humans; D009183:Mycotoxins / Q000032:analysis / Q000302:isolation & purification*; D009793:Ochratoxins / Q000032:analysis / Q000302:isolation & purification; D012680:Sensitivity and Specificity; D013050:Spectrometry, Fluorescence / Q000379:methods; D014255:Trichothecenes / Q000032:analysis / Q000302:isolation & purification
D009183:Mycotoxins; D009793:Ochratoxins; D014255:Trichothecenes; C007262:deoxynivalenol