Jd. Brewster et Rs. Mazenko, FILTRATION CAPTURE AND IMMUNOELECTROCHEMICAL DETECTION FOR RAPID ASSAY OF ESCHERICHIA-COLI O157-H7, Journal of immunological methods, 211(1-2), 1998, pp. 1-8
A new approach for rapid assay of bacteria in liquid samples is descri
bed. Cells were labeled by incubation with an enzyme-antibody conjugat
e and captured by filtration of the sample/conjugate mixture through a
0.2 mu m filter. The enzyme-labeled cells were detected by placing th
e filter on the surface of an electrode, incubating with enzyme substr
ate, and measuring the current produced by oxidation of the electroact
ive enzyme product. Assay time was 25 min and a detection limit of sim
ilar to 5000 cells/ml was obtained for E. coli O157:H7. Background cur
rent due to non-specific binding of conjugate to the filter was the pr
imary factor controlling the detection limit, and fewer than 50 cells
could be detected when very small sample volumes (10 mu l) were used t
o minimize background current. (C) 1998 Elsevier Science B.V.