Rapid detection and identification of biological and chemical agents by immunoassay, gene probe assay and enzyme inhibition using a silicon-based biosensor
We. Lee et al., Rapid detection and identification of biological and chemical agents by immunoassay, gene probe assay and enzyme inhibition using a silicon-based biosensor, BIOSENS BIO, 14(10-11), 2000, pp. 795-804
A rapid biosensor assay procedure that utilizes biotin-streptavidin mediate
d filtration capture onto nitrocellulose membrane, in conjunction with a si
licon-based light-addressable potentiometric sensor (LAPS) was developed fo
r detection and identification of biological and chemical threat agents. Sa
ndwich immunoassays, nucleic acid hybridization assays and enzyme inhibitio
n assays are described. For immunoassays, the lower limits of detection (LO
D) per 100-mu l sample were approximately 5 pg/ml for protein (Staphylococc
al enterotoxin B), 2 ng/ml for virus (Newcastle disease virus), and 20 ng/m
l for vegetative bacteria (Brucella melitensis). In a dual gene probe assay
format, the LOD was 0.30 fmol (1.8 x 10(8) copies per 60-mu l) of single s
tranded target DNA. Enzyme inhibition assays on the LAPS using acetylcholin
esterase were able to detect soman and sarin in aqueous samples at 2 and 8
pg (100 and 600 pM), respectively. The assays were easy to perform and requ
ired a total time equal to the reaction period plus about 15 min for filter
ing, washing and sensing. The assay format is suitable for detection of a w
ide range of infectious and toxic substances. New assays can be developed a
nd optimized readily, often within 1 or 2 days. (C) 2000 Elsevier Science S
.A. All rights reserved.