Immuno-gold lateral flow assay

Abstract

A chromatographic lateral-flow assay system for rapid, high sensitivity method of detecting low levels of ligands in body fluids, with few false positives and few false negatives. The lateral-flow assay may have a membrane strip in ribbon form, which increases detection on the order of 2 to 10 fold over the conventional chromatographic specific binding assay techniques by placing a dried or lyophilized conjugate in colloidal spheres opposite side of the lateral flow membrane strip. A chromatographic specific binding assay strip device, comprising: a laminate strip having a first side and an second side; a conjugate pad or membrane disposed on said first side of said laminate; a hinge region connecting sample receiving pad or membrane strip and reservoir pad or membrane disposed on said second side of said laminate; wherein said laminating material isolates the conjugate pad from the sample pad such as to slow the fluid path into the fibrous sample pad, and a detection pad or membrane strip disposed between the sample pad or membrane and the reservoir pad or membrane on said first side of said laminate. The more complete mixing permitted by this temporary obstruction provides an important feature of the invention that gives this 2-step test its superior performance. The assay system comprises a housing device, such as a test tube or cassettes to facilitate the mixing of a sample solution with the dried or lyophilized conjugate, and kits.

Description

[0001] This application is a continuation-in-part (CIP) of Ser. No. 11 / 248,214, filed on Oct. 13, 2005, pending, and claims benefit of this earlier filing date under 35 U.S.C. §120, the contents of which are herein incorporated by reference to the extent allowed by law.FIELD OF INVENTION [0002] The present invention generally relates to an assay system and apparatus involving specific binding of analytes and / or ligands, and specifically relates to chromatographic flow binding assays with a colored conjugate, and a novel lateral-flow-platform that includes a dried or lyophilized colloidal sphere conjugate, such as gold, to the back of the lateral flow test. BACKGROUND OF THE INVENTION [0003] It is increasingly desirable to provide a rapid high sensitivity system to detect low levels of ligands in body fluids, plant extracts, environmental samples, tissue samples and enrichment broths. Ideally, such systems should have a minimal number of procedural steps and yield reliable results, e...

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Benefits of technology

[0019] The present invention generally relates to a rapid high sensitivity system apparatus and method for detecting low

Problems solved by technology

To a significant extent, many known tests presently available for detecting ligands are either time consuming, labor intensive, or in need of instrumental assistance to read results.

Most known tests also lack an acceptable degree of sensitivity or specificity.

False positives may be troublesome, particularly with agglutination and other rapid detection methods such as dipstick and color change tests.

Nevertheless, these techniques have not solved all problems related to sensitivity, neither have they been reliable in obtaining results with a minimal number of method steps encountered in these rapid detection methods.

Unfortunately, while these devices are somewhat useful, they suffer from limitations in capture efficiency and sensitivity because most of the analyte i

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