Immunoassay utilizing trapping conjugate
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Publication Number
US-10598657-B2
Publication Date
2020-03-24
Expiration Date
Abstract
Test devices are provided for determining the presence of a first ligand in a sample. In some embodiments depletion conjugates are used to deplete the ligands different from but related to the first ligands from the sample. In some embodiments, interim binding agents are used to enhance the test signal.
Core Innovation
The disclosed subject matter relates to dual-path lateral-flow immunoassay test devices for determining the presence of a first ligand in a liquid sample. The device includes first and second sorbent strips defining first and second migration paths, with a marker conjugate adapted to bind the first ligand on or in the first migration path and a test site on or in at least one of the first and second sorbent strips including an immobilized first ligand binding mechanism.
A depletion zone is provided on or in the second migration path, where depletion molecules include ligand-binding elements that specifically bind second ligands that are different from but related to the first ligand by being cross-reactive, while the depletion molecules do not substantially bind the first ligand. The depletion molecules located on or in the second migration path are sprayed on the second migration path and are not immobilized.
The first and second sorbent strips touch at the test site location, and the second location for receiving the liquid sample is removed from the test site so that sample applied to the second location requires time to migrate to the test site and does not immediately wet the test site. The method content further refers to testing a sample for the presence of a first flavivirus ligand using a test device with a sprayed and non-immobilized depletion zone including antigens specific to at least one of a second flavivirus antibody and an alphavirus antibody.
Claims Coverage
The partial content provides two independent claims: a test device claim and a method claim. Across them, the coverage focuses on four inventive features: dual sorbent strips and migration paths, a sprayed and non-immobilized depletion zone using cross-reactive depletion molecules, delayed wetting by locating the sample application point away from the test site, and inspection of the test site for an indication of presence or lack of the first ligand.
Dual-path lateral-flow test device with sprayed non-immobilized depletion zone
A test device for determining the presence of a first ligand in a liquid sample, comprising first and second sorbent strips defining first and second migration paths, a marker conjugate on or in the first migration path adapted to bind the first ligand, and depletion molecules on or in the second migration path that include ligand-binding elements specifically binding second ligands that are different from but related to the first ligand by cross-reactivity and not substantially binding the first ligand, wherein the depletion molecules are sprayed on the second migration path and are not immobilized.
Delayed wetting test site in a dual-sorbent configuration
A test site located on or in at least one of the first sorbent strip and the second sorbent strip having an immobilized first ligand binding mechanism for the first ligand, where the first and second sorbent strips touch at the test site location, and where the second location is removed from the test site so that sample applied to the second location requires time to migrate to the test site and does not immediately wet the test site.
Lateral-flow method with delayed sample migration and test-site inspection
A method for testing a sample for the presence of a first flavivirus ligand using a test device having a first sorbent strip with a marker conjugate adapted to bind the first ligand, a second sorbent strip with a sprayed and non-immobilized depletion zone including antigens specific to at least one of a second flavivirus antibody and an alphavirus antibody that specifically bind related second ligands different from the first flavivirus ligand and not substantially bind the first flavivirus ligand, and a test site with an immobilized ligand-binding mechanism for the first flavivirus ligand, where the strips touch at the test site location and the sample is applied at a second location removed from the test site requiring time to migrate; applying the sample to the second location, applying a solution to the first location to cause marker conjugate migration, and inspecting the test site to determine an indication of presence or lack of the first flavivirus ligand in the sample.
Across the independent claims, the inventive coverage centers on a dual-sorbent lateral-flow format with a marker binding a first ligand at an immobilized test site, combined with a sprayed, non-immobilized depletion zone on the second migration path containing cross-reactive ligand-binding elements that do not substantially bind the first ligand, together with a delayed-wetting design achieved by positioning the sample-application location away from the test site.
Stated Advantages
Not explicitly described in patent.
Documented Applications
Not explicitly described in patent.
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