Capillary immunoassay and device therefor comprising mobilizable particulate labelled reagents
DCFirst Claim
1. An analytical test device for detecting an analyte suspected of being present in a liquid biological sample, said device comprising:
- a) a hollow casing having a liquid biological sample application aperture and means permitting observation of a test result;
b) a test strip comprising a dry porous carrier contained within said hollow casing, said carrier communicating directly or indirectly with the exterior of said hollow casing through said liquid biological sample application aperture to receive applied liquid biological sample, said carrier having a test result zone observable via said means permitting observation, said test strip, in the dry unused state, containing a labelled reagent capable of specifically binding with said analyte to form a first complex of said labelled reagent and said analyte, said label being a particulate direct label, wherein said labelled reagent is dry on said test strip prior to use and is released into mobile form by said applied liquid biological sample,wherein mobility of said labelled reagent within said test strip is facilitated by at least one of
1) coating at least a portion of said test strip upstream from said test result zone with, or
2) drying said labelled reagent onto a portion of said test strip upstream from said test result zone in the presence of, a material comprising a sugar, in an amount effective to reduce interaction between said test strip and said labelled reagent;
said carrier containing in said test result zone a means for binding said first complex, said means for binding comprising specific binding means and being immobilized in said test result zone;
migration of said applied liquid biological sample through said dry porous carrier conveying by capillarity said first complex to said test result zone of said dry porous carrier whereat said binding means binds said first complex thereby to form a second complex;
said second complex being observable via said means permitting observation, thereby to indicate the presence of said analyte in said liquid biological sample.
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Abstract
An analytical test device useful for example in pregnancy testing, includes a hollow casing (500) constructed of moisture-impervious solid material, such as plastics materials, containing a dry porous carrier (510) which communicates indirectly with the exterior of the casing via a bibulous sample receiving member (506) which protrudes from the casing such that a liquid test sample can be applied to the receiving member and permeate therefrom to the porous carrier, the carrier containing in a first zone a labelled specific binding reagent is freely mobile within the porous carrier when in the moist state, and in a second zone spatially distinct from the first zone unlabelled specific binding reagent for the same analyte which unlabelled reagent is permanently immobilised on the carrier material and is therefore not mobile in the moist state, the two zones being arranged such that liquid sample applied to the porous carrier can permeate via the first zone into the second zone, and the device incorporating an aperture (508) in the casing, enabling the extent (if any) to which the labelled reagent becomes bound in the second zone to be observed. Preferably the device includes a removable cap for the protruding bibulous member.
612 Citations
36 Claims
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1. An analytical test device for detecting an analyte suspected of being present in a liquid biological sample, said device comprising:
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a) a hollow casing having a liquid biological sample application aperture and means permitting observation of a test result; b) a test strip comprising a dry porous carrier contained within said hollow casing, said carrier communicating directly or indirectly with the exterior of said hollow casing through said liquid biological sample application aperture to receive applied liquid biological sample, said carrier having a test result zone observable via said means permitting observation, said test strip, in the dry unused state, containing a labelled reagent capable of specifically binding with said analyte to form a first complex of said labelled reagent and said analyte, said label being a particulate direct label, wherein said labelled reagent is dry on said test strip prior to use and is released into mobile form by said applied liquid biological sample, wherein mobility of said labelled reagent within said test strip is facilitated by at least one of
1) coating at least a portion of said test strip upstream from said test result zone with, or
2) drying said labelled reagent onto a portion of said test strip upstream from said test result zone in the presence of, a material comprising a sugar, in an amount effective to reduce interaction between said test strip and said labelled reagent;said carrier containing in said test result zone a means for binding said first complex, said means for binding comprising specific binding means and being immobilized in said test result zone; migration of said applied liquid biological sample through said dry porous carrier conveying by capillarity said first complex to said test result zone of said dry porous carrier whereat said binding means binds said first complex thereby to form a second complex; said second complex being observable via said means permitting observation, thereby to indicate the presence of said analyte in said liquid biological sample. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. An analytical method comprising:
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contacting an analytical test device for detecting an analyte suspected of being present in a liquid biological sample, said device including; a) a hollow casing having a liquid biological sample application aperture and means permitting observation of a test result; b) a test strip comprising a dry porous carrier contained within said hollow casing, said carrier communicating directly or indirectly with the exterior of said hollow casing through said liquid biological sample application aperture to receive applied liquid biological sample, said carrier having a test result zone observable via said means permitting observation, said test strip, in the dry unused state, containing a labelled reagent capable of specifically binding with said analyte to form a first complex of said labelled reagent and said analyte, said label being a particulate direct label, wherein said labelled reagent is dry on said test strip prior to use and is released into mobile form by said applied liquid biological sample, wherein mobility of said labelled reagent within said test strip is facilitated by at least one of
1) coating at least a portion of said test strip upstream from said test result zone with, or
2) drying said labelled reagent onto a portion of said test strip upstream from said test result zone in the presence of, a material comprising a sugar, in an amount effective to reduce interaction between said test strip and said labelled reagent;said carrier containing in said test result zone a means for binding said first complex, said means for binding comprising specific binding means and being immobilized in said test result zone; migration of said applied liquid biological sample through said dry porous carrier conveying by capillarity said first complex to said test result zone of said dry porous carrier whereat said binding means binds said first complex thereby to form a second complex; said second complex being observable via said means permitting observation, thereby to indicate the presence of said analyte in said liquid biological sample, with said liquid biological sample suspected of containing said analyte; allowing said liquid biological sample to convey by capillary action through said dry porous carrier into said test result zone and said labelled reagent is conveyed therewith; and detecting the presence of said analyte in said liquid biological sample by observing the presence of any labelled reagent-analyte complex bound in said test result zone. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27, 28)
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29. An analytical test device for detecting an analyte suspected of being present in a liquid biological sample, said device comprising:
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a) a hollow casing having a liquid biological sample aperture, a test result observation aperture, and a control zone observation aperture; b) a test strip comprising a dry porous carrier contained within said hollow casing, said carrier communicating directly or indirectly with the exterior of said hollow casing through said liquid biological sample aperture to receive applied liquid biological sample, said carrier having a test result zone observable through said test result observation aperture and a control zone observable through said control zone observation aperture, said test strip, in the dry unused state, containing a labelled reagent capable of specifically binding with said analyte to form a first complex of said labelled reagent and said analyte, said label being a particulate direct label, wherein said labelled reagent is dry on said test strip prior to use and is released into mobile form by said applied liquid biological sample; c) an absorbent sink at a distal end of said dry porous carrier, said sink having sufficient absorptive capacity to allow any labelled reagent not bound to said analyte to wash out of said test zone; said carrier containing in said test result zone a means for binding said first complex, said means for binding said first complex comprising specific binding means and being immobilized in said test result zone, said carrier containing in said control zone a means for binding said labelled reagent, said means for binding said labelled reagent being immobilized in said control zone, wherein mobility of said labelled reagent within said test strip is facilitated by at least one of
1) coating at least a portion of said test strip upstream from said test result zone with, or
2) drying said labelled reagent onto a portion of said test strip upstream from said test result zone in the presence of, a material comprising a sugar, in an amount effective to reduce interaction between said test strip and said labelled reagent;migration of said applied liquid biological sample through said dry porous carrier conveying by capillarity said first complex to said test result zone of said dry porous carrier whereat said means for binding said first complex binds said first complex, thereby to form a second complex; said second complex being observable through said test result observation aperture, thereby to indicate the presence of said analyte in said liquid biological sample. - View Dependent Claims (30, 31, 32, 33, 34, 35, 36)
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Specification