Test device and method for quantitative measurement of an analyte in a liquid
First Claim
1. A device of substantially flat construction for application to the skin of a patient, collection of a test sample of sweat, and quantitative determination of the chloride concentration in the test sample of sweat, comprising:
- a top transparent liquid-impermeable layer;
a bottom liquid-impermeable layer for contacting the skin comprising a centrally located inlet and a plurality of channels extending radially from the inlet for collecting the sweat and directing the sweat toward the inlet; and
a middle layer between the top and bottom layers comprising an absorbent material having substantially uniformly dispersed throughout at least a portion thereof (i) a liquid-detecting agent capable of detectably delimiting the liquid front formed as the liquid portion of the test sample migrates radially outwardly from the inlet through the substantially flat absorbent material, and (ii) a partitioning agent comprising a species capable of complexing with chloride ions present in the test sample to form a detectable precipitate disposed radially inwardly of said liquid front.
1 Assignment
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Accused Products
Abstract
A device and method for determining the concentration of an analyte, particularly a chloride ion, in a liquid sample are particularly useful to screen for cystic fibrosis in an individual. In a preferred embodiment, the device takes the form of a patch comprising an absorbent material sandwiched between two liquid-impermeable layers. Chloride ions in the liquid sample complex with a chloride-detecting agent dispersed throughout the absorbent material to form a visible precipitate, preferably silver chloride. A pH indicator is also dispersed throughout the absorbent material, allowing the position of the water front to be monitored thereby permitting calculation of chloride concentration from a partially filled patch.
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Citations
35 Claims
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1. A device of substantially flat construction for application to the skin of a patient, collection of a test sample of sweat, and quantitative determination of the chloride concentration in the test sample of sweat, comprising:
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a top transparent liquid-impermeable layer; a bottom liquid-impermeable layer for contacting the skin comprising a centrally located inlet and a plurality of channels extending radially from the inlet for collecting the sweat and directing the sweat toward the inlet; and a middle layer between the top and bottom layers comprising an absorbent material having substantially uniformly dispersed throughout at least a portion thereof (i) a liquid-detecting agent capable of detectably delimiting the liquid front formed as the liquid portion of the test sample migrates radially outwardly from the inlet through the substantially flat absorbent material, and (ii) a partitioning agent comprising a species capable of complexing with chloride ions present in the test sample to form a detectable precipitate disposed radially inwardly of said liquid front. - View Dependent Claims (2, 3, 4, 5, 6, 16, 27, 28, 29, 30, 31, 32)
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7. A device for quantitatively determining the concentration of a chloride ion containing analyte in a liquid sample comprising:
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a first liquid-impermeable layer; a second liquid-impermeable layer comprising an inlet for the introduction of the liquid sample; and a third layer between the first and second liquid-impermeable layers comprising an absorbent material comprising (i) a liquid-detecting agent capable of detectably delimiting the liquid front formed as the liquid migrates radially outwardly from the inlet through the absorbent material, and (ii) a partitioning agent capable of detectably removing the chloride ions in the analyte from the liquid sample through complexing with chloride ions present in the liquid of said sample. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14, 15)
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17. A device for quantitatively determining the concentration of chloride ion present in an analyte in a liquid sample comprising:
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a first liquid-impermeable layer; a second liquid-impermeable layer comprising an inlet for the introduction of the liquid sample; and a third layer between the first and second liquid-impermeable layers comprising an absorbent material comprising (i) a measurable fill area delimited by a detectable water front formed by a liquid sample introduced into the device through the inlet for radial outward migration therefrom; and
(ii) a measurable detection area comprising a component capable of species specific complexing with chloride ions for forming an immobilized or insoluble detectable complex comprising the analyte. - View Dependent Claims (21)
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18. A method for preparing a device for quantitatively determining the concentration of chloride ions present in an analyte in a liquid sample comprising:
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(a) distributing throughout at least a portion of an absorbent material each of; (i) a liquid-detecting agent, and (ii) a partitioning agent capable of detectably removing chloride present in the analyte from the liquid sample; and (b) positioning the absorbent material between a first liquid-impermeable layer and a second liquid-impermeable layer comprising an inlet for introduction of the liquid sample, wherein the liquid-detecting substance is capable of detectably delimiting the liquid front formed as the liquid containing chloride ion migrates from the inlet through the absorbent material. - View Dependent Claims (19, 20)
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22. A method for determining the concentration of an analyte in a liquid sample comprising:
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providing a device comprising a first liquid-impermeable layer, a second liquid-impermeable layer comprising an inlet, and a third layer between the first and second liquid-impermeable layers, said third layer comprising an absorbent material comprising each of a liquid-detecting agent and a partitioning agent; introducing an amount of the liquid sample into the inlet of the device such that the liquid diffuses through the absorbent material so as to contact both the liquid-detecting agent and the partitioning agent, wherein contact of the liquid with the liquid-detecting agent allows detection of a water front delimiting a fill area of the absorbent material, and wherein contact of the liquid with the partitioning agent causes formation of a detectable complex comprising the analyte thereby effecting removal of the analyte from the liquid, the area of formation of said detectable complex constituting a detection area of the absorbent material; obtaining a measurement of the fill area; obtaining a measurement of the detection area; and evaluating the fill area measurement and the detection area measurement to determine the concentration of the analyte in the liquid sample. - View Dependent Claims (23, 24, 25, 26)
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33. A device of substantially flat construction for application to the skin of a patient, collection of a test sample of sweat, and determination of the chloride concentration in the test sample of sweat, comprising:
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a top transparent liquid-impermeable layer; a bottom liquid-impermeable layer for contacting the skin comprising a centrally located inlet and a plurality of channels extending radially from the inlet for collecting the sweat and directing the sweat toward the inlet; a middle layer between the top and bottom layers comprising an absorbent material having substantially uniformly dispersed throughout at least a portion thereof (i) a liquid-detecting agent capable of detectably delimiting the liquid front formed as the test sample migrates from the inlet through the substantially flat absorbent material, and (ii) a partitioning agent comprising a species capable of complexing with chloride ions to form a detectable precipitate; and wherein said inlet comprises an alkaline substance capable of ensuring that the pH of the sweat entering the device is at least about pH 7.0.
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34. A device for determining the concentration of an analyte in a liquid sample comprising:
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a first liquid-impermeable layer; a second liquid-impermeable layer comprising an inlet for the introduction of the liquid sample; a third layer between the first and second liquid-impermeable layers comprising an absorbent material comprising (i) a liquid-detecting agent capable of detectably delimiting the liquid front formed as the liquid migrates from the inlet through the absorbent material, and (ii) a partitioning agent capable of detectably removing the analyte from the liquid sample; and the liquid-detecting agent comprises a pH indicator.
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35. A method for preparing a device for determining the concentration of an analyte in a liquid sample comprising:
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(a) distributing throughout at least a portion of an absorbent material each of (i) a liquid-detecting agent, and (ii) a partitioning agent capable of detectably removing the analyte from the liquid sample; (b) positioning the absorbent material between a first liquid-impermeable layer and a second liquid-impermeable layer comprising an inlet for introduction of the liquid sample, wherein the liquid-detecting substance is capable of detectably delimiting the liquid front formed as the liquid migrates from the inlet through the absorbent material; and (c) the liquid-detecting substance comprises a pH indicator.
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Specification