Optical assay: method and apparatus
First Claim
1. An optical assay method comprising the following steps:
- providing a coated metallic medium, the coating thereof being sensitized for a specific assay species;
generating in the metallic medium a resonant signal at optical frequency, the power of this signal extending into the sensitized coating;
providing coupling between said resonant signal and a monitored optical beam;
exposing the coated metallic medium to a fluid assay sample; and
,measuring any changes in the optical beam to detect a response to the presence of the specific assay species in the fluid sample.
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Accused Products
Abstract
An optical assay apparatus of the type comprising an optic waveguide and a coating sensitized to a specific assay species. The light signal response of the apparatus is enhanced by coupling a resonant metallic medium to the waveguide and to the sensitized coating. To this end, a metal coated transparent buffer layer may be interposed between the waveguide and the sensitized coating. Alternatively, a metallized optically matched grating can be used in place of the buffer layer or the metallic medium can be of particulate form, with each particle having a sensitized coating.
In using the optical assay apparatus, the sensitized coating is exposed to a fluid assay sample. A light beam is directed onto the sensitized coating and reflected onto a detector. The detected light is monitored for any change indicating the presence of the specific assay species in the fluid sample.
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Citations
12 Claims
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1. An optical assay method comprising the following steps:
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providing a coated metallic medium, the coating thereof being sensitized for a specific assay species;
generating in the metallic medium a resonant signal at optical frequency, the power of this signal extending into the sensitized coating;providing coupling between said resonant signal and a monitored optical beam;
exposing the coated metallic medium to a fluid assay sample; and
,measuring any changes in the optical beam to detect a response to the presence of the specific assay species in the fluid sample.
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2. An optical assay apparatus comprising:
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a light source; a light detector; a propagating medium arranged relative to the source and detector for directing light from the source onto the detector; a buffer means of optically less dense material than that of the propagating medium adjacent to a surface of the propagating medium; a metallic medium, having the form of a metal film, on the surface of the buffer medium remote from the propagating medium; and a coating, adjacent to the metallic medium, sensitized for a specific assay species.
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3. An optical assay apparatus comprising:
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a light source; a light detector; a propagating medium arranged relative to the source and detector for directing light from the source onto the detector; an optical grating at a surface of the propagating medium; a metallic medium, having the form of a metal film, on a surface of the optical grating; and a coating, adjacent to the metallic medium, sensitized for a specific assay species.
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4. An optical assay apparatus comprising:
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a light source; a light detector; a propagating medium, arranged relative to the source and the detector, for directing light from the source onto the detector; a dispersion of fine metal particles, each coated with a material sensitized for a specific assay species; and said propagating medium and dispersion of fine metal particles being positioned relative to one another to provide optical coupling therebetween.
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5. An optical assay apparatus comprising:
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a light source; a light detector; a light propagating medium having a reflecting surface, said reflecting surface being arranged relative to the source and the detector for directing light from the source onto the detector; a coated metallic medium arranged in close proximity to said reflecting surface, said metallic medium having a coating sensitized for a specific assay species; and said propagating medium and metallic medium being positioned relative to one another to provide optical coupling therebetween. - View Dependent Claims (6)
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7. An optical assay apparatus comprising:
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a light source; a light detector; a light propagating medium having a reflecting surface, said reflecting surface being arranged relative to the source and the detector for directing light from the source onto the detector; a coating metallic medium arranged in close proximity to said reflecting surface, said metallic medium having a coating sensitized for a specific assay species; and said coated metallic medium having the form of a continuous thin metal film spaced from the reflecting surface of the light propagating medium by a buffer layer of material optically less dense than that of the light propagating medium.
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8. An optical assay apparatus comprising:
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a light source; a light detector; a light propagating medium having a reflecting surface, said reflecting surface being arranged relative to the source and the detector for directing light from the source onto the detector; and a coating metallic medium arranged in close proximity to said reflecting surface, said metallic medium having a coating sensitized for a specific assay species; and said metallic medium having the form of a dispersion of metal particles, with a multiplicity of the metal particles lying upon the reflecting surface.
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9. An optical assay method comprising the following steps:
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providing a light propagating medium having a reflecting surface, said reflecting surface arranged to direct light from a source onto a detector; providing a coated metallic medium arranged in close proximity to said reflecting surface, said coated metallic medium having a coating sensitized for a specific assay species; providing optical coupling between the coated metallic medium and the directed light to generate in the coated metallic medium a resonant signal at optical frequency with the power of said signal extending into the coating; exposing the coated metallic medium to a fluid assay sample; and measuring any changes in the directed light to detect a response to the presence of the specific assay species in the fluid assay sample. - View Dependent Claims (10, 11, 12)
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Specification