Membrane assay using focused sample application
First Claim
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1. An assay method for determining the presence of an analyte in a liquid sample, said method employing:
- a reaction cell including a microporous membrane and an absorbent in liquid receiving relationship with the membrane;
an applicator separate from the reaction cell and having a port with an open area in the range from about 0.5 mm2 to 20 mm2, said area being substantially less than the area of the membrane; and
a reagent system including components capable of interacting with analyte immobilized within the microporous membrane to produce a visual signal;
said method comprising;
applying to the membrane of the reaction cell in a predetermined order (1) a preselected volume of sample, and (2) the components of the reagent system, wherein at least one of the sample and the components is applied using the applicator, the port of the applicator being contacted with the membrane to limit outward diffusion of the analyte within the membrane, whereby a visual signal is produced having the dimensions of the port; and
observing the entire surface of the membrane to determine if the visual signal has been produced.
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Abstract
Methods and kits are described for performing immunoassays. The kit includes a reaction cell having a microporous membrane and an absorbent capable of drawing liquid sample through the membrane. An applicator is provided for applying a small volume of the liquid sample to the membrane by contacting a port of the applicator to the membrane and allowing the sample to flow therethrough by capillary action. Analyte in the sample is immobilized, typically by immunoadsorption, and the immobilized analyte may then be visualized using conventional signal producing systems, such as color, fluorescence, and luminescent systems.
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Citations
47 Claims
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1. An assay method for determining the presence of an analyte in a liquid sample, said method employing:
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a reaction cell including a microporous membrane and an absorbent in liquid receiving relationship with the membrane; an applicator separate from the reaction cell and having a port with an open area in the range from about 0.5 mm2 to 20 mm2, said area being substantially less than the area of the membrane; and a reagent system including components capable of interacting with analyte immobilized within the microporous membrane to produce a visual signal;
said method comprising;applying to the membrane of the reaction cell in a predetermined order (1) a preselected volume of sample, and (2) the components of the reagent system, wherein at least one of the sample and the components is applied using the applicator, the port of the applicator being contacted with the membrane to limit outward diffusion of the analyte within the membrane, whereby a visual signal is produced having the dimensions of the port; and observing the entire surface of the membrane to determine if the visual signal has been produced. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 45)
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20. An assay method for determining the presence of an analyte in a liquid sample, said method comprising:
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passing a predetermined volume of the sample through a limited area in the range from about 0.5 mm2 to 20 mm2 on a microporous membrane capable of immobilizing the analyte, wherein the exposed area of the membrane is sufficiently greater than the limited area to allow visualization of the sample on the limited area in contrast to the remaining area of the membrane; applying to the entire membrane surface in a predetermined order components of a reagent system capable of interacting with analyte immobilized on the microporous membrane to produce a visual signal within said well-defined area only; and observing the membrane to determine if a visual signal has been produced within the limited area. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 46)
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31. An assay kit comprising:
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a reaction cell including a microporous membrane and an absorbent in liquid receiving relationship with the membrane; an applicator separate from the reaction cell and having a port with an open area in the from range from about 0.5 mm2 to 20 mm2, said area being substantially less than the area of the membrane; a reagent system including components capable of interacting with analyte immobilized within the microporous membrane to produce a visual signal; and instructions to apply to the membrane of the reaction cell in a predetermined order (1) a preselected volume of sample, and (2) the components of the reagent system, wherein at least one of the sample and the components is applied using the applicator with the port in contact with the membrane to limit outward diffusion of the sample within the membrane; and
to observe the membrane to determine if a visual signal has been produced. - View Dependent Claims (32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 47)
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Specification