Luminescence Fiber-Optic Biosensor

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Abstract
A novel type of biosensors involving immobilized bioluminescence enzymes and a fiber-optic probe has been developed. The enzymes were immobilized on preactivated Nylon membranes placed in close contact with the tip of a bundle of optical glass fibers. The fiber-optic sensor was immersed in a stirred and thermostated cell protected from ambient light by a PVC jacket. The light emitted by the luminescence reactions was conducted through the fiber bundle to the photomultiplier tube of a luminometer. With immobilized firefly luciferase from Photinus pyralis, light emission could be linearly related to ATP concentration in the range 2.8 × 10−10 − 1.4 × 10−6 M. When co-immobilizing bacterial luciferase and oxidoreductase from Vibrio fischeri, NADH measurements could be performed from 3 × 10−10 M to 3 × 10−6 M. The luminol chemiluminescence reaction catalyzed by immobilized horseradish peroxidase has also been used for hydrogen peroxide determination. The standard curve was linear from 2 × 10−8 M to 2 × 10−5 M H2O2. Extension to other analytes with additional enzymes is under investigation.