Immunoassay utilizing trapping conjugate
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Publication Number
US-10976315-B2
Publication Date
2021-04-13
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.
Core Innovation
The invention relates to a test device for determining the presence of a first ligand in a liquid sample using a dual-path lateral flow immunoassay test cell architecture with first and second sorbent strips that touch at a test site location. A marker conjugate moves along a first migration path and binds to the first ligand at an immobilized first ligand binding mechanism.
The depletion conjugate is located on or in a second migration path, spaced from the test site, so that sample applied at a second location requires time to migrate to the test site and does not immediately wet the test site. The depletion conjugate comprises depletion molecules bound to particles, where the depletion molecules include ligand-binding elements adapted to specifically bind to second ligands that are different from but related to the first ligand by being cross-reactive therewith.
The depletion molecules are adapted not to substantially bind to the first ligand, thereby reducing binding at the immobilized first ligand binding mechanism. This cross-reactive depletion mechanism is designed to increase selectivity for the first ligand while suppressing signal contributions associated with related ligands. In additional configurations, the device is arranged to determine a second ligand as well, including an IgM ligand, using an additional set of sorbent strips, marker conjugates, depletion conjugates, and a second test site with an immobilized ligand-binding mechanism.
Claims Coverage
The independent claims cover a depletion-enhanced lateral flow test device using two distinct sorbent-strip migration paths with a depletion conjugate placed on a spaced second migration path, and an expanded multi-strip configuration for detecting an additional ligand with corresponding test sites. Across the independent claims, the main inventive coverage includes 2 migration paths, a spaced depletion conjugate with cross-reactive ligand-binding elements that do not substantially bind the first ligand, and an architecture that delays wetting of the test site; the second independent claim additionally adds parallel detection of a second ligand using additional strips and a second test site.
Depletion-enhanced dual-path sorbent strip test architecture
A test device having a first sorbent strip with a first location defining a first migration path, and a second sorbent strip distinct from the first sorbent strip having a second location defining a second migration path, wherein the first and second sorbent strips touch each other at a test site location.
Marker conjugate binding at an immobilized test site
A marker conjugate adapted to move along the first migration path and bind to the first ligand, wherein the test site has an immobilized first ligand binding mechanism for the first ligand.
Spaced depletion conjugate on a second migration path with cross-reactive non-substantially binding ligand-binding elements
A depletion conjugate located on or in the second migration path and spaced from the test site, where depletion molecules include ligand-binding elements adapted to specifically bind to second ligands different from but related to the first ligand by being cross-reactive therewith, and to which the depletion molecules will not substantially bind.
Delayed wetting by removing the sample application location from the test site
A configuration where the second location is removed from the test site such that sample applied to the second location requires time to migrate to the test site and does not immediately wet the test site.
Two-ligand detection using additional strips and a second test site
The test device is also for determining the presence of a second ligand in the liquid sample, where the second ligand is an IgM ligand and the device includes a third sorbent strip with a third migration path, a second marker conjugate adapted to move along the third migration path, additional depletion conjugate molecules on a fourth migration path, and a second test site with an immobilized second ligand binding mechanism, with third and fourth sorbent strips touching each other at the second test site location.
Overall, the independent claim set focuses on a lateral flow device that pairs a marker-driven immobilized test site with a depletion conjugate on a separate, spaced migration path, using cross-reactive ligand-binding elements that do not substantially bind the first ligand. The second independent claim further expands this concept into a multi-strip, two-test-site configuration to determine a second ligand in addition to the first ligand.
Stated Advantages
Increase selectivity for the first ligand while suppressing signal contributions associated with related ligands.
Documented Applications
No documented applications found
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