Syntex (u.s.a.) Inc.

Abbott Laboratories Corporation

Behringwerke Aktiengesellschaft

Litai Weng

Edwin F Ullman

Nurith Kurn

Pyare L Khanna

Vartan E Ghazarossian

David Calderhead

Ian Gibbons

Hrair Kirakossian

John S Pease

Iam Gibbons

A method and device for determining the presence of an analyte in a sample suspected of containing the analyte is disclosed. The method involves contacting a test solution containing the sample and a first member of a specific binding pair with an end portion of a strip of bibulous material capable of being traversed by the test solution through capillary action. The first member of a specific binding pair is capable of binding the analyte. The strip contains a second member of a specific binding pair integral therewith for concentrating and non-diffusively binding the first sbp member at a small situs on the strip separated from the end portion of the strip. The detectible signal is produced in relation to the presence of the analyte in the test solution. The test solution passes through the situs as the test solution traverses the bibulous material. After the test solution has been allowed to traverse at least a portion of the strip, the strip is contacted with a developer solution containing members of a signal producing system in a manner that provides contact of the developer solution with the small situs following its contact with the test solution. The strip is then contacted with any remaining members of the signal producing system. The detectible signal produced at the situs is then compared with the signal detectible at a portion of the strip other than the situs to determine the analyte in the sample. In one embodiment of the invention the signal produced at the small situs has a sharp-edged distinctive pattern that provides a sharp contrast to the signal produced at adjacent sites on the strip when analyte is present in the test solution.

Concentrating immunochemical test device and method

A method is disclosed for separating a substance from a liquid medium. The method comprises combining the liquid medium containing the substance with magnetic particles under conditions for non-specific chemical binding of the magnetic particles. Thereafter, the medium is subjected to a magnetic field gradient to separate the particles from the medium. The preferred non-specific binding is achieved as the result of charge interactions between the particles usually by means of a polyionic reagent. The method of the invention has particular application to the separation of cells and microorganisms from aqueous suspensions and also to the determination of an analyte in a sample suspected of containing the analyte. The analyte is a member of a specific binding pair (sbp). The sample is combined in an assay medium with magnetic particles and a sbp member complementary to the analyte. Magnetic or non-magnetic particles capable of specific binding to the analyte or its complementary sbp member must be included in the assay medium. The combination is made under conditions for non-specifically aggregating the magnetic particles or coaggregating the magnetic and non-magnetic particles when non-magnetic particles are present. The assay medium is subjected to a magnetic field gradient to separate the aggregated particles from the medium. Then, the medium or the particles are examined for the presence or amount of the analyte or an sbp member, the binding of which is affected by the presence of the analyte.

Particle separation method

Magnetic composition for particle separation

Assay methods are provided for determining an analyte in a sample suspected of containing the analyte. The method is carried out using a composition that includes a conjugate of a first sbp member with a particle. A luminescer is reversibly associated with a nonaqueous phase of the particle. Where the first sbp member is not complementary to the analyte, a second sbp member that is capable of binding to the first sbp member is employed. Unbound conjugate is separated from conjugate that is bound to the analyte or to the second sbp member. A reagent for enhancing the detectability of the luminescer is added and the light emission of the luminescer acted on by the reagent is measured.

Particle with luminescer for assays

Concentrating immunochemical test strip

A method and device for determining the presence of an analyte in a sample suspected of containing the analyte is disclosed. The method involves contacting a test solution containing the sample and a first member of a specific binding pair with an end portion of a strip of bibulous material capable of being traversed by the test solution through capillary action. The first member of a specific binding pair is capable of binding the analyte. The strip contains a second member of a specific binding pair integral therewith for concentrating and non-diffusively binding the first sbp member at a small situs on the strip separated from the end portion of the strip. The detectible signal is produced in relation to the presence of the analyte in the test solution. The test solution passes through the situs as the test solution traverses the bibulous material. After the test solution has been allowed to traverse at least a portion of the strip, the strip is contacted with a developer solution containing members of a signal producing system in a manner that provides contact of the developer solution with the small situs following its contact with the test solution. The strip is then contacted with any remaining members of the signal producing system. The detectible signal produced at the situs is then compared with the signal detectible at a portion of the strip other than the situs to determine the analyte in the sample.

A method for assaying for a ligand analyte which is a member of a specific binding pair ('sbp member') consisting of ligand and its complementary receptor is disclosed. The ligand analyte has a binding site in common with an interfering substance present in a sample suspected of containing the analyte. The interfering substance has at least two binding sites. The method comprises combining in an assay medium without intervening separation (1) the sample, (2) a blocking receptor which does not bind to the ligand and does bind to the interfering substance, thereby blocking the binding of a common receptor to the interfering substance, and (3) a common receptor which binds to the common binding site. Any additional members of a signal producing system capable of producing a detectable signal in relation to the amount of analyte in the sample are added to the assay medium. Next, the assay medium is examined for the presence of a detectable signal. The method has application to both heterogeneous and homogeneous assays.

Reducing interference in ligand-receptor binding assays

Enzyme channeling assay is provided employing a solid non-porous surface to which is bound a member of a specific binding pair and an enzyme. A complementary member of a specific binding pair is conjugated to second enzyme, so that the amount of second enzyme which becomes bound to said solid non-porous surface by the binding of a specific binding pair(s) is related to the amount of analyte in the liquid assay medium with which the solid surface is in contact. The first and second enzymes are related by the product of one being the substrate of the other. The turnover of the substrate formed by one of the enzymes results in a detectable product, which can be related to the amount of analyte in the medium.

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Mt. View, CA, United States of America

Litai Weng