Abstract: An improved homogeneous enzyme immunoassay process for quantitatively analyzing an antigen by determining the change in the enzymatic activity caused by a reaction between the antigen and an enzyme-labeled antibody. The antigen is reacted with an enzyme-labeled antibody, followed by the reaction with a second antibody capable of recognizing and binding to a different epitope and then with a third antibody capable of recognizing and binding to the second antibody. The enzymatic activity of the labeling enzyme is determined by a water-insoluble substrate. Using the water-insoluble substrate, steric hindrance is enhanced. A highly-sensitive analysis can be carried out by a simple operation even when the antigen has a molecular weight falling within an intermediate range, for example, a range of M.W. 10,000 to 70,000.

Abstract: The present invention relates to a method of carrying out an immunoassay in a multiphase system. A sample containing an analyte is brought into contact with a receptor A and a tracer. The analyte can either form a complex with the tracer, or counteract the formation of a complex of receptor A and tracer by competing with the tracer for binding to receptor A, or counteract the formation of a complex of receptor A and tracer by competing with receptor A. Receptor B is added and the signal is determined. In this method, receptor A and receptor B are suitably immobilized, ensuring that the tracer either cannot enter into any binding involving the simultaneous participation of receptors A and B or can enter into such a binding to only such a slight extent that it is nevertheless possible to detect and differentiate differing analyte concentrations.

Abstract: Lateral flow device and method are provided for performing semi-quantitative visual or instrument-based detection in a test sample of a large molecule analyte that contains two binding domains, &agr; and &bgr;. The device contains two reagents, a contrast reagent and an indicator reagent, and an analyte test zone (ATZ) that contains a fixed number of immobilized &agr;-domain-specific binding sites. The contrast and indicator reagents each contain signal generators such that the two reagents contrast each other in different regions of a visual, spectrophotometric, calorimetric or fluorometric spectrum. The contrast reagent is prebound to an &agr;-region-fragment of the analyte of interest and, therefore, does not react with the analyte of interest in the test sample. The indicator reagent is attached to a binding ligand specific for the &bgr;-domain of the analyte of interest.

Abstract: The invention relates to novel methods and compositions for the detection of analytes using the nuclear reorganization energy, &lgr;, of an electron transfer process.

Abstract: An assay for the presence of an analyte or determining a biological or medical parameter comprising the steps of adding an assay component to a pH-sensitive material charged with magnetic particles, wherein the assay component causes a pH change which is a function of the analyte or parameter to be measured; subjecting the magnetic particles to an oscillating magnetic field; and measuring the effect of the magnetic field on the magnetic particles. The assay is an enzyme immunoassay. A kit for practicing the enzyme immunoassay is also described.

Abstract: An analytical system for rapid detection and identification of different analytes directly from a test sample by mixing test material with a germinogenic source and enzyme-free spores, allowing the mixture to stand for a time to allow analyte-induced spore germination and subsequent de novo synthesis of an enzyme capable of producing a germinant in the presence of the germinogenic source and detecting the presence of a germination-derived product. The germinant which is formed promotes further spore germination with concomitant additional de novo enzyme synthesis which results in a propagating cascade of analyte-independent germination after which a germination-derived product can be easily detected. The technique is particularly efficient to conduct thousands of parallel assays in an array of microscopic wells.

Abstract: A direct assay for chloramphenicol acetyl transferase (CAT) has been presented wherein the assay reagent comprises chloramphenicol, an acyl CoA compound, and a tetrazolium salt, and wherein the reagent does not have any added coupling redox enzymes. In one embodiment, the reagent is mixed with the test sample and the presence of CAT is detected by an optical response. In a second embodiment, the reagent is mixed with a test sample containing CAT and the optical response is quantitated by comparison with standards to measure CAT activity in the test sample. In another embodiment, an exogenous electron carrier such as phenazines may be used to enhance the detection of CAT. The assay for the presence or activity of CAT can be used in a high-throughput screening assay or to detect CAT as a reporter gene for measuring the expression of a gene of interest. Kits containing the reagents are also provided.

Abstract: A separation method, a method for detection, a sensor, and a test-kit find application in immunological detection. The separation method provides for separation of a primary species which separation method is suitable for use in an immunoassay method for the detection of an analyte species and includes the use of a first auxiliary species capable of being formed into a second auxiliary species which second auxiliary species is capable of interacting with a third species to facilitate separation.

Abstract: An enzyme-labeled immunoassay is performed by the steps of allowing a test sample to react with an enzyme-labeled reagent, allowing a substrate to react with the enzyme to form a signal, and immobilising the enzyme-labeled reagent, with the prevention of a further signal formation from a predetermined time on after the immobilisation of the enzyme-labeled reagent, using an enzyme inhibitor.

Abstract: The present invention has its objects to provide a compound not only which is easy to handle, thermally stable, and high in emission efficiency, but also which can show high emission efficiency without coexisting enhancer in the system even in a protic solvent. The present invention is related to a 1,2-dioxetane derivative of general formula (I). [wherein R1, R2, R3, R4 and R5 each independently represents hydrogen, alkyl or aryl; a pair of R2 and R3 and a pair of R4 and R5 may respectively be joined to each other to form a cycloalkyl group.

Abstract: The subject invention relates generally to immunoassays for detection of antibodies by use chemiluminescent compounds. More particularly, the subject invention relates to chemiluminescent immunoassays to detect antibodies wherein a precomplex mixture is created and a two-step assay is performed resulting in a greater signal.

Abstract: Disclosed is a diagnostic device for the colorimetric detection of an analyte in a test fluid. The device is a dry reagent layer which is overcoated with a transparent, fluid permeable membrane. The membrane is made up of a combination of a water dispersible and a water soluble polymer. The membrane may contain a surfactant and a thickener.

Abstract: A method and compositions for the detection and/or quantification of an analyte through the use of a plurality of labeled probes, with two or more said probes targeted to different regions of said analyte. In specific embodiments, the labels are separately distinguishable, and/or are present at different specific activities on the labels.

Abstract: This invention concerns PAPP-A, its immunodetection and the clinical benefits of such immunodetection. Specifically, the invention includes monoclonal antibodies against PAPP-A and the use of these antibodies to detect PAPP-A at a very early stage of pregnancy. The invention also covers the use of the monoclonal antibodies for the detection of specific types of cancer and Down's Syndrome pregnancies.