Abstract
A fiber optic biosensor was used to detect the fraction 1 (F1) antigen from Yersinia pestis, the etiologic agent of plague. The instrument employs an argon ion laser (514 nm) to launch light into a long-clad fiber and measures the fluorescence produced by an immunofluorescent complex formed in the evanescent wave region. This sensing area is a short section (12.5 cm) at the end of the optical fiber from which the cladding has been removed and in which the silica core has been tapered. Capture antibodies, which bind to F1 antigen, were immobilized on the core surface to form the basis of the sandwich fluoroimmunoassay. The ability to detect bound F1 antigen was provided by adding tetramethylrhodamine-labeled anti-plaque antibody to form fluorescent complexes. The evanescent wave has a limited penetration depth (< 1 lambda), which restricts detection of the fluorescent complexes bound to the fiber's surface. The direct correlation between the F1 antigen concentration and the signal provided an effective method for sample quantitation. This method achieved a high level of accuracy for determining F1 antigen concentrations from 50 to 400 ng/ml in phosphate-buffered saline, serum, plasma, and whole blood, with a 5-ng/ml limit of detection. Subsequent blind studies, which included serum samples from patients, yielded results in good agreement with measurements by enzyme-linked immunosorbent assay. A major advantage of the fiber optic biosensor is that results can be generated within minutes while isolating the user from hazardous samples. These factors favor development of this biosensor into a facile and rapid diagnostic device.
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Selected References
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- Amante L., Ancona A., Forni L. The conjugation of immunoglobulins with tetramethylrhodamine isothiocyanate. A comparison between the amorphous and the crystalline fluorochrome. J Immunol Methods. 1972 May;1(3):289–301. doi: 10.1016/0022-1759(72)90006-3. [DOI] [PubMed] [Google Scholar]
- BAKER E. E., SOMMER H., FOSTER L. E., MEYER E., MEYER K. F. Studies on immunization against plague. I. The isolation and characterization of the soluble antigen of Pasteurella pestis. J Immunol. 1952 Feb;68(2):131–145. [PubMed] [Google Scholar]
- Bhatia S. K., Shriver-Lake L. C., Prior K. J., Georger J. H., Calvert J. M., Bredehorst R., Ligler F. S. Use of thiol-terminal silanes and heterobifunctional crosslinkers for immobilization of antibodies on silica surfaces. Anal Biochem. 1989 May 1;178(2):408–413. doi: 10.1016/0003-2697(89)90662-3. [DOI] [PubMed] [Google Scholar]
- Gosling J. P. A decade of development in immunoassay methodology. Clin Chem. 1990 Aug;36(8 Pt 1):1408–1427. [PubMed] [Google Scholar]
- Ogert R. A., Brown J. E., Singh B. R., Shriver-Lake L. C., Ligler F. S. Detection of Clostridium botulinum toxin A using a fiber optic-based biosensor. Anal Biochem. 1992 Sep;205(2):306–312. doi: 10.1016/0003-2697(92)90440-i. [DOI] [PubMed] [Google Scholar]
- Williams J. E., Arntzen L., Tyndal G. L., Isaäcson M. Application of enzyme immunoassays for the confirmation of clinically suspect plague in Namibia, 1982. Bull World Health Organ. 1986;64(5):745–752. [PMC free article] [PubMed] [Google Scholar]
- Williams J. E., Gentry M. K., Braden C. A., Leister F., Yolken R. H. Use of an enzyme-linked immunosorbent assay to measure antigenaemia during acute plague. Bull World Health Organ. 1984;62(3):463–466. [PMC free article] [PubMed] [Google Scholar]
- Williams J. E., Gentry M. K., Braden C. A., Tyndal G. L., Altieri P. L., Berman S., Robinson D. M. A monoclonal antibody for the specific diagnosis of plague. Bull World Health Organ. 1988;66(1):77–82. [PMC free article] [PubMed] [Google Scholar]