A compact fiber-optic immunosensor for Salmonella based on evanescent wave excitation
| Autor: | Stephen V. Letcher, A. G. Rand, Chonghua Zhou, Steven Auger, Philip E. Pivarnik |
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| Rok vydání: | 1997 |
| Předmět: |
Materials science
Optical fiber business.industry Metals and Alloys Condensed Matter Physics Laser Signal Fluorescence Surfaces Coatings and Films Electronic Optical and Magnetic Materials law.invention Wavelength Optics law Materials Chemistry Fiber Electrical and Electronic Engineering business Instrumentation Biosensor Diode |
| Zdroj: | Sensors and Actuators B: Chemical. 42:169-175 |
| ISSN: | 0925-4005 |
| Popis: | A compact fiber-optic evanescent-wave sensing system that features all-fiber optical design and red semiconductor-laser excitation has been developed and tested. A 2 × 2 fiber coupler directs the input light to the SMA-connected sensing fiber tip and the fluorescent signal back to a CCD fiber spectrophotometer. In this system, the fluorescent signal is confined in the fiber system so the signal-to-noise ratio is greatly improved and the system can be operated in ambient light conditions. A diode laser as the source has the advantages of small volume, ruggedness, low cost and stability; more importantly, since biological matrices demonstrate minimal fluorescent background at the laser wavelength of 650 nm, this system can reduce the background signal of non-essential biomolecules. To illustrate the biosensor's diagnostic capabilities, a sandwich immunoassay to detect Salmonella was developed. Tapered fiber tips with different shapes and treatments were studied and optimized. The system could detect Salmonella with a concentration as low as 104 colony-forming units per milliliter (CFU ml−1). |
| Databáze: | OpenAIRE |
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