Optical waveguides – Accessories – External retainer/clamp
Reexamination Certificate
2000-05-19
2002-05-28
Sanghavi, Hemang (Department: 2874)
Optical waveguides
Accessories
External retainer/clamp
C385S115000, C385S120000
Reexamination Certificate
active
06396995
ABSTRACT:
FIELD OF THE INVENTION
This application relates generally to methods and apparatuses to obtain and analyze optically imaged samples including microbiological samples, and more specifically to methods and apparatuses for retaining at least one and preferably multiple randomly ordered microsphere arrays to solutions and to optical imaging systems for analysis.
BACKGROUND OF THE INVENTION
It is known in the art to use probe arrays and sensors in systems to detect the presence and/or concentration of specific substances in fluids and gases. Many such systems rely on specific ligand/antiligand reactions as the detection mechanism. Pairs of substances (e.g., ligand and antiligands) are known to bind preferentially to each other, but to exhibit little or no binding with other substances.
Many prior art techniques utilize such binding pairs to detect complexes of interest. Often one component of the complex is labeled so as to make the entire complex detectable, using, for example, radioisotopes, fluorescent and other optically active molecules, enzymes, etc. Detection mechanisms utilizing luminescence are especially useful. Within the past decade, considerable development of optical fibers and fiber strands for use in combination with light absorbing dyes for chemical analytical determinations has occurred. The use of optical fibers for such purposes and techniques is described by Milanovich et al., “Novel Optical Fiber Techniques For Medical Application”, Proceedings of the SPIE 28th Annual International Technical Symposium On Optics and Electro-Optics, Volume 494, 1980; Seitz, W. R., “Chemical Sensors Based On Immobilized Indicators and Fiber Optics” in C.R.C. Critical Reviews In Analytical Chemistry, Vol. 19, 1988, pp. 135-173; Wolfbeis, O. S., “Fiber Optical Fluorosensors In 5 Analytical Chemistry” in Molecular Luminescence Spectroscopy, Methods and Applications (S. G. Schulman, editor), Wiley & Sons, New York (1988); Angel, S. M., Spectroscopy 2 (4):38 (1987); Walt, et al., “Chemical Sensors and Microinstrumentation”, ACS Symposium Series, Vol. 403, 1989, p. 252, and Wolfbeis, O. S., Fiber Optic Chemical Sensors, Ed. CRC Press, Boca Raton, Fla., 1991, 2nd Volume.
When using an optical fiber in an in vitro/in vivo sensor, at least one light absorbing dye is located near the fiber distal end. An appropriate source provides light, typically through the fiber proximal end, to illuminate the dye(s). As light propagates along the length of the optical fiber, a fraction of the propagated light exits the distal end and is absorbed by the dye. The light absorbing dye(s) may or may not be immobilized, may or may not be directly attached to the optical fiber itself, may or may not be suspended in a fluid sample containing one or more analyses of interest, and may or may not be retainable for subsequent use in a second optical determination.
Upon being dye absorbed, some light of varying wavelength and intensity returns to be conveyed through the same fiber or through collection fiber(s) to an optical detection system where it is observed and measured. Interactions between the light conveyed by the optical fiber and the properties of the light absorbing dye can provide an optical basis for both qualitative and quantitative determinations.
Many different classes of light absorbing dyes are conventionally employed with bundles of fiber strands and optical fibers for different analytical purposes. The more common dye compositions that emit light after absorption are termed “fluorophores”, while dyes that absorb and internally convert light to heat (rather than emit as light) are termed “chromophores.”
Fluorescence is a physical phenomenon based upon the ability of some molecules to absorb light (photons) at specified wavelengths, and then emit light of a longer wavelength and at a lower energy. Substances able to fluoresce share a number of common characteristics: the ability to absorb light energy at one wavelength &lgr;
ab
, reach an excited energy state, and subsequently emit light at another light wavelength &lgr;
em
. Absorption and fluorescence emission spectra are unique for each fluorophore and are often graphically represented as two slightly overlapping separate curves.
The same fluorescence emission spectrum is generally observed irrespective of the wavelength of the exciting light. Thus, within limits, the wavelength and energy of the exciting light may be varied, but the light emitted by the fluorophore will consistently exhibit the same emission spectrum. Finally, the strength of the fluorescence signal may be measured as the quantum yield of light emitted. The fluorescence quantum yield is the ratio of the number of photons emitted in comparison to the number of photons initially absorbed by the fluorophore. For more detailed information regarding each of these characteristics, the following references are recommended: Lakowicz, J. R., Principles of Fluorescence Spectroscopy, Plenum Press, New York, 1983; Freifelder, D., Physical Biochemistry, second edition, W. H. Freeman and Company, New York, 1982; “Molecular Luminescence Spectroscopy Methods and Applications: Part I” (S. G. Schulman, editor) in Chemical Analysis, vol. 77, Wiley & Sons, Inc., 1985; The Theory of Luminescence, Stepanov and Gribkovskii, Iliffe Books, Ltd., London, 1968.
In contrast to fluorescence emitting materials, substances that absorb light but do not fluoresce usually convert the light into heat or kinetic energy. The ability to internally convert the absorbed light identifies the dye as a “chromophore.” Dyes that absorb light energy as chromophores do so at individual wavelengths of energy and are characterized by a distinctive molar absorption coefficient at that wavelength. Chemical analysis employing fiber optic strands, and absorption spectroscopy using visible and ultraviolet light wavelengths in combination with the absorption coefficient can determine concentration for specific analyses of interest using spectral measurement. The most common use of absorbance measurement via optical fibers is to determine concentration, which is calculated in accordance with Beers' law. Accordingly, at a single absorbance wavelength, the greater the quantity of the composition that absorbs light energy at a given wavelength, the greater the optical density for the sample. In this fashion, the total quantity of light absorbed directly correlates with the quantity of the composition in the sample.
Many recent improvements in the use of optical fiber sensors in qualitative and quantitative analytical determinations concern the desirability of depositing and/or immobilizing various light absorbing dyes at the distal end of the optical fiber. In this manner, a variety of different optical fiber chemical sensors and methods have been reported for specific analytical determinations, and for applications such as pH measurement, oxygen detection, and carbon dioxide analyses. These developments are exemplified by the following publications: Freeman, et al., Anal Chem. 53:98 (1983); Lippitsch et al., Anal. Chem. Acta. 205: 1, (1988); Wolfbeis et al., Anal. Chem. 60:2028 (1988); Jordan, et al., Anal. Chem. 59:437 (1987); Lubbers et al.e, Sens. Actuators 1983; Munkholm et al., Talanta 35:109 10 (1988): Munkholmetal., Anal. Chem. 58:1427(1986); Seitz, W. R., Anal. Chem. 56:16A-34A (1984); Peterson, et al., Anal. Chem. 52:864 (1980): Saari, et al., Anal. Chem. 54:821 (1982); Saari, et al., Anal. Chem. 55:667 (1983); Zhujun et al., Anal. Chem. Acta. 160:47 (1984); Schwab, et al., Anal. Chem. 56:2199 (1984); Wolfbeis, O. S., “Fiber Optic Chemical Sensors”, Ed. CRC Press, Boca Raton, Fla., 1991, 2nd Volume; and Pantano, P., 15 Walt, D. R., Anal. Chem., 481A-487A, Vol. 67, (1995).
More recently, fiber optic sensors have been constructed that permit the use of multiple dyes with a single, discrete fiber optic bundle. For example, U.S. Pat. Nos. 5,244,636 , 5,250,264, and 5,320,814 to Walt et al. disclose systems for affixing multiple, different dyes on the distal end of a fiber optic bundle. Applicants refer to and incorporate
Chee Mark S.
Dickinson Todd Alan
Pytelewski Richard J.
Stuelpnagel John R.
Wang Gan G.
Connelly-Cushwa Michelle R.
Flehr Hohbach Test Albritton & Herbert LLP
Illumina, Inc.
Sanghavi Hemang
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