Preparation Of Small Diameter Sensors For Continuous Clinical Monitoring

David R. Walt; Christiane Munkholm; David Jordan; Fred P. Milanovich; Paul F. Daley

doi:10.1117/12.937386

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1 April 1987 Preparation Of Small Diameter Sensors For Continuous Clinical Monitoring

David R. Walt, Christiane Munkholm, David Jordan, Fred P. Milanovich, Paul F. Daley

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Proceedings Volume 0713, Optical Fibers in Medicine II; (1987) https://doi.org/10.1117/12.937386
Event: Cambridge Symposium-Fiber/LASE '86, 1986, Cambridge, MA, United States

Abstract

We have prepared fluorescence-based fiber optic sensors which give rapid and reversible responses. Other investigators have previously prepared sensors in which a membrane, tubing, or a hollow fiber is used to contain a specific reagent near the distal end of the fiber. Such an approach produces fibers with limited signal magnitudes and slow response times. Furthermore, these sensors are cumbersome to assemble, and are difficult to miniaturize and calibrate. We have developed a technique for the covalent chemical modification of the fiber's distal surface which is easily adapted to the smallest diameter glass optical fiber (100 μm). The sensing layer is attached directly to the fiber surface. The layer is extremely thin and highly porous and provides high fluorescence intensity with nearly instantaneous response times. The fibers are moderately stable against bleaching and have long shelf-lives. Our initial efforts have concentrated on the preparation of pH-sensitive optical sensors that are useful in the pH range 4.0 to 8.0. These sensors are reversible in response to pH variation and possess signal-to-noise ratios over 250/1. The fibers are prepared using a glass surface modification followed by a polymerization step for dye immobilization. Both fluorescence and absorbance-based sensors have been prepared using this technique. The absorbance-based pH sensors have 100% response times of less than 3 seconds, are sensitive in the region of pH 6.0 to 8.0, and provide reliable measurement of pH with precision of better than 0.03 pH units.

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David R. Walt, Christiane Munkholm, David Jordan, Fred P. Milanovich, and Paul F. Daley "Preparation Of Small Diameter Sensors For Continuous Clinical Monitoring", Proc. SPIE 0713, Optical Fibers in Medicine II, (1 April 1987); https://doi.org/10.1117/12.937386

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