Detection of small molecules by an evanescent wave fiber optic biosensor
- Naval Research Lab., Washington, DC (United States). Center for Bio/Molecular Science and Engineering
Detection of small molecules is important in environmental analyses as most pollutants are low molecular weight compounds. Utilizing the specificity of antibodies, the rapid signal transduction of optical fibers and the signal-to-noise discrimination of fluorescence, an evanescent wave fiber optic-based biosensor was modified for the detection of these molecules. To facilitate the isolation of personnel and equipment from hazardous environments, long partially clad optical fibers are employed. Antibodies were immobilized on the 10 cm sensing region at the distal portion of the optical fiber probe. A 200 {micro}l sample chamber was fabricated from a capillary tube. The core of the fiber in the sensing region is tapered for maximum signal recovery. A competitive immunoassay was performed. Basically, the small molecule competes with a fluorescently-labelled analog for the capture antibody binding sites. As the level of analyte increases in the sample, the fluorescent signal decreases. Two assays for the small molecules, trinitrotoluene (TNT) and polychlorinated biphenyl (PCB) will be described. Detection levels of 10 ng/ml TNT (8 ppb) have been achieved with this sensor.
- OSTI ID:
- 276368
- Report Number(s):
- CONF-950209--
- Country of Publication:
- United States
- Language:
- English
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