Abstract: A method is disclosed for conducting an assay for an analyte. The method comprises causing a specific binding pair member in a first aqueous medium to become bound to a first bibulous member by contacting a portion of the first bibulous member with the medium. The first bibulous member is in liquid receiving relationship with an absorbent member. The contacting is carried out under conditions wherein the first medium traverses the first bibulous member and at least a portion of the absorbent member by capillary action. The method further comprises causing the first bibulous member to come into liquid receiving relationship with a second bibulous member. A reagent in a second aqueous medium is absorbed by and preferably becomes a non-diffusively bound to the second bibulous member in relation to the presence of analyte in the first medium.

Abstract: A method is disclosed for producing multiple copies of a primary polynucleotide sequence located at the 3' terminus of a polynucleotide. The method comprises (a) forming in the presence of nucleoside triphosphates and template-dependent polynucleotide polymerase an extension of a primary polynucleotide sequence hybridized with a template sequence of a single stranded pattern polynucleotide comprising two or more template sequences each containing one or more site specific cleavage sequences, (b) cleaving into fragments said extension at cleavable polynucleotide sequences in the presence of means for specifically cleaving said cleavable polynucleotide sequences when said extension is hybridized with said site specific cleavage sequences, (c) dissociating said fragments, (d) hybridizing said fragments with single stranded pattern polynucleotide, and repeating steps (a)-(d). Steps (a)-(d) may be conducted simultaneously or wholly or partially sequentially.

Abstract: A device is disclosed for conducting an assay. The device comprises a housing, means enclosed in the housing for capturing a first member of a specific binding pair (sbp) in a zone and for allowing liquid to be transported by capillary action away from the zone, first means in the housing for introducing the sample into the device, and second means in the housing other than the first means for introducing a liquid reagent other than the sample into the device. The device of the invention finds use in assay methods for the determination of an analyte in a sample suspected of containing the analyte. Kits for conducting an assay are also disclosed.

Abstract: 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.

Abstract: 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.

Abstract: A device and a method for producing the device for use in a chromatographic system wherein a component of a mixture is partitioned is comprised of a chromatographic material. In the chromatographic system the component traverses at least a portion of the chromatographic material. The device generally has at least one longitudinal edge substantially corresponding to the direction of traverse of the component. The longitudinal edge is modified to control the shape of the fron t of the traversing component by introducing along the edge either a plurality of indentations or a chemical substance.

Abstract: 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.

Abstract: A method for determining the presence of a polynucleotide analyte in a sample suspected of containing the analyte is disclosed. The method comprises combining in an assay medium the sample and first and second polynucleotide reagents complementary to the analyte. Each of the first and second reagents hybridize with a different region of the analyte. The first reagent contains means for rendering the first reagent non-covalently polymerizable. The second reagent contains means for rendering the second reagent detectable. The sample and the first and second reagents are combined in the assay medium under conditions for polymerizing the first reagent wherein the second reagent becomes bound to the polymerized first reagent only when the analyte is present in the sample. A determination is then made as to whether the second reagent has become bound to the polymerized first reagent.

Abstract: Novel fluorogenic peroxidase substrates are provided employing novel water soluble activated capped aromatic fluorescent compounds for use as peroxidase substrates. The novel compounds can be used in a wide variety of ways for determination of peroxides, peroxidase, and in assays for analytes employing peroxidase as a label on a member of a specific binding pair.

Abstract: A device is disclosed for conducting an assay method. The device comprises a housing, means enclosed in the housing for capturing a member of a specific binding pair in a zone and for allowing liquid to be transported by capillary action away from the zone, one or more self-contained liquid reagents enclosed in the housing for conducting an assay method for the determination of an analyte in the sample, and means in the housing for introducing the sample into the device. Preferably, the self-contained reagents are liquid reagents which are contained in a breakable container. The device of the invention finds use in assay methods for the determination of an analyte in a sample suspected of containing the analyte. Kits for conducting an assay method are also disclosed.

Abstract: An assay method and compositions are provided for determining the presence of an analyte in a sample. The analyte is a member of an immunological pair (mip) comprising ligand and receptor. By providing a first measurement surface capable of specifically binding a labelled reagent in an amount depending upon the presence of analyte in the sample and a second calibration surface capable of binding a second labeled reagent in a manner unaffected by the presence of analyte in the sample, calibration of individual tests can be accomplished simultaneously with the performance of the test itself. A signal producing system includes an enzyme, a catalyst usually bonded to a mip which defines the first labeled reagent for binding to the measurement surface and the same catalyst conjugated to a ligand capable of binding to the calibration surface. Preferably, both labeled reagents have the same composition and the calibration surface include anti-(first catalyst).

Abstract: An assay method and compositions are provided for determining the presence of an analyte in a sample. The analyte is a member of an immunological pair (mip) comprising ligand and receptor. By providing a first measurement surface capable of specifically binding a labelled reagent in an amount depending upon the presence of analyte in the sample and a second calibration surface capable of binding a second labeled reagent in a manner unaffected by the presence of analyte in the sample, calibration of individual tests can be accomplished simulataneously with the performance of the test itself. A signal producing system includes an enzyme bonded to a mip which defines the first labeled reagent for binding to the measurement surface and the same enzyme conjugated to a ligand capable of binding to the calibration surface. Preferably, both labeled reagents have the same composition and the calibration surface includes anti-(first enzyme).

Abstract: Compounds and methods are disclosed for reversibly aggregating particles suspended in a liquid medium. The method comprises combining the liquid medium containing the particles with a polyionic polymer capable of aggregating the particles under conditions suitable for such aggregation. Thereafter, the particles are contacted with a chemical reagent capable of cleaving the polyionic polymer under conditions sufficient to reverse the aggregation. Optionally, magnetic particles are added to the liquid medium in the present method under conditions for non-specific binding and the medium including the aggregates is subjected to a magnetic field gradient to separate the aggregates from the medium. The compounds of the present invention are polyions. The aggregation of the particles is reversible upon contact with chemical agents which cleave at least some of the bonds within the polyionic polymer.

Abstract: Novel assays for ligands and receptors employing novel compounds that are conjugates of squarates dyes and members of a specific binding pair (sbp) are disclosed. The sbp members are selected from the group consisting of ligand and its complementary receptor. The sbp member is covalently or non-covalently bound to the squarate dye, which usually has an absorption maximum greater than 600 nanometers. The novel conjugates are employed in assays for determining the presence or amount of an sbp member analyte in a sample suspected of containing such analyte. Kits comprising such novel conjugates are also disclosed.

Abstract: A method is disclosed for reducing the oxygen content of a medium in which are present cells, usually anaerobic microorganisms, to extend the time during which the cells remain viable. The method comprises having in fluid contact with the aqueous medium an effective amount of an oxidase and substrate for the oxidase. The oxidase and substrate for the oxidase in an aqueous medium can be in fluid, e.g., air, contact with a separately contained aqueous medium in which the cells are present. Alternatively, the cells can be present in the same aqueous medium as the oxidase and substrate for the oxidase. The aqueous medium containing the oxidase and the substrate for the oxidase can further contain a hydrogen peroxide scavenger in an effective amount.

Abstract: Fluorescent antigen conjugates are provided comprising antigens covalently bonded to at least one 2,7-dialiphatic substituted-9-phenyl-6-hydroxy-3H-xanthen-3-one, wherein the 1- and 8-positions are unsubstituted. Also provided are novel fluorescent compounds absorbing at wavelengths in excess of 500 nm, having active functionalities for linking to the antigen. Finally, methods are provided for analyzing antigens in serum, whereby serum interference is avoided.

Abstract: A device is disclosed for use in a chromatographic system wherein a component of a mixture is paritioned between a liquid phase and an immobile phase. The device is comprised of a chromatographic material. In the chromatographic system the component traverses at least a portion of the chromatographic material. The device generally has at least one longitudinal edge substantially corresponding to the direction of traverse of the component. The longitudinal edge includes means for controlling the shape of the front of the traversing component.

Abstract: A method is provided for determining the presence in a sample of a member of a specific binding pair ("sbp member") consisting of ligand and its homologous receptor. The sample is combined in an aqueous medium with (1) a complementary sbp member wherein at least the sbp member or the complementary sbp member is bound to the surface of a cell and (2) a fuorescent agent capable of being incorporated into the cell. The presence of the sbp member is indicated by a change in fluorescence of the unseparated cell suspension as a result of agglutination of the cells.The present invention has particular application to blood typing, for example, for the determination of the presence of blood group antigens A, B, AB, O, and D (Rh.sub.o) and antibodies to such antigens.

Abstract: 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.

Abstract: Methods are provided for modulating Ligand-Receptor interactions by binding of molecules at two epitopes of a receptor, where the epitopes are in relatively close special relationship. By providing for inhibition of changes in conformation of the receptor, where the inhibition is due to steric interactions or molecular bridging between the two epitopic sites, Ligand-Receptor interactions may be modulated. The modulation of Ligand-Receptor interactions has application to diagnostic assays, modulation of cellular activity, and modulation of the physiological activity of macromolecular compounds.