Chemical apparatus and process disinfecting – deodorizing – preser – Analyzer – structured indicator – or manipulative laboratory... – Means for analyzing liquid or solid sample
Reexamination Certificate
1999-03-05
2003-12-16
Le, Long V. (Department: 1641)
Chemical apparatus and process disinfecting, deodorizing, preser
Analyzer, structured indicator, or manipulative laboratory...
Means for analyzing liquid or solid sample
C422S051000, C422S068100, C422S051000, C422S105000, C422S105000, C422S110000, C436S165000, C436S178000, C436S518000, C435S286500, C435S287100
Reexamination Certificate
active
06663833
ABSTRACT:
FIELD OF THE INVENTION
This relates to the fields of analytical chemistry and immunology and more specifically relates to an integrated assay device for determining the presence or amount of an analyte in a sample.
BACKGROUND OF THE INVENTION
Assay technology involves methods or instrumentation for the detection or quantitation of one or more antigens or analytes in a sample. Immunoassays are based on the highly specific binding reaction between an antibody, or analyte receptor, and an antigen recognized by the antibody or antigen receptor. Antibodies are binding proteins produced by the immune system of vertebrates in response to substances identified by the immune system as foreign. Immunoassays are commonly used by the medical community to determine the presence, amount or identity of analyte in a biological sample for purposes such as diagnosis and for monitoring therapy. Immunoassays are also used for the detection of environmental contaminants. More recently, immunoassays have been used by non-technical persons in the home for private determinations of medical conditions such as pregnancy and ovulation.
Various approaches for performing homogeneous or heterogeneous immunoassays in both competitive and noncompetitive formats have been described in the literature. Homogeneous immunoassays are performed by combining labeled reagent with a sample and detecting labeled analyte without a separation step. Although homogeneous immunoassays are easy to perform, they are subject to matrix interference. In homogeneous assays it is difficult to ascertain the proportion of bound and free label in the reaction mixture, and thus sophisticated instrumentation is often required to detect and analyze the results. Heterogeneous immunoassay methods contain a separation step in which bound label is separated from free label.
The original enzyme linked immunosorbent assay (ELISA) methods were “competitive” heterogeneous assays in which an enzyme-labeled antigen or antibody competed with an antigen or antibody to be detected for a reaction site on a bead, pad or surface to which one member of an immunologically-coupling pair was attached. Subsequently, the “sandwich” assay, a non-competitive assay, was developed. Non-competitive assays generally utilize antibodies in substantial excess over the concentration of analyte to be determined in the assay. In the sandwich assay, the antibody or antigen to be determined is “sandwiched” by an immunochemical reaction between a solid surface treated with an immunological species reactive with the species to be determined and the same or a different reactive immunological species which had been coupled to a signal-generating label.
Competitive assays generally include a sample suspected of containing analyte, an analyte analog-assay conjugate, and the competition between these components for a limited number of binding sites on the antibody. Due to competition between unbound analyte and analyte analog-assay conjugate for analyte-receptor binding sites, as the analyte concentration increases, the amount of unbound analyte analog-enzyme conjugate increases, thereby decreasing the observed signal associated with the solid phase. The product of the enzyme reaction may then be measured using an instrument such as a spectrophotometer.
Exemplary analytes detected by immunoassays include haptens, hormones, peptides, proteins, deoxyribonucleic. acid (DNA), ribonucleic acids (RNA), metabolites of these materials and other substances of either natural or synthetic origin, which may be of diagnostic interest. Binding assays are generally useful for the in vitro determination of the presence and concentration of analyte in body fluids, food products, animal fluids, and environmental samples, such as the determination of specific hormones, peptides, proteins, therapeutic drugs, forensics, paternity and toxic drugs in human or animal blood or urine.
Numerous detection systems have been developed to detect or measure antibody-analyte complexes including enzyme-catalyzed chromogenic reactions, radionuclides, chemiluminescence, bioluminescence, fluorescence, fluorescence polarization and a variety of potentiometric and optical biosensor techniques.
One disadvantage to the presently available immunoassay methods is that multiple manipulations are often required by the individual performing the assay as reagents are added, mixed, incubated, separated and detected, thereby introducing the potential for error. Another disadvantage is that conventional immunoassays require a substantial amount of sample, which could be unavailable, difficult or painful to obtain. In addition, the accuracy of many immunoassays depends on precise sample and reagent measurements and the standardization of conditions such as incubation time and temperature.
Although some simplified immunoassays are available for use by non-technical personnel, these assays lack precision and provide the user with only a “positive” or “negative” response, no quantifiable results are produced. Furthermore, these presently available devices are composed entirely of membranes or absorbent fibrous materials that vary from lot to lot and contain imprecise volumes of sample and the reagents employed.
There is a continuing need for simple, rapid assays for the qualitative, semi-quantitative, and quantitative determination of analytes in a sample. In many situations, such assays need to be simple enough to be performed and interpreted by non-technical users outside of a laboratory.
Thus, simple assay methods are needed that will provide reliable, accurate and rapid results within and outside of conventional laboratory facilities in places such as hospitals, medical offices, homes, on the streets and in the field. There is also a great need for simple, inexpensive and easy-to-use assay devices, particularly immunoassay devices, that are easily manufactured and can be used by technical and non-technical personnel, such as emergency medical technicians, police, firefighters, corrections facilities, and military personnel.
SUMMARY OF THE INVENTION
Assay devices for the detection of analyte in a sample and methods for performing an assay using the devices are provided herein. Also provided are methods of manufacturing the assay devices. The devices can be used for nucleic acid-based assays, chemical assays, and immunoassays, including heterogeneous immunoassays for both competitive and sandwich immunoassay formats. Also provided are simple immunochromatographic strip detection membrane formats having increased precision and accuracy over existing formats.
The device includes self-contained, integrated components for conducting an assay for analyte with minimal manipulation by the individual performing the assay. Upon adding the sample to be analyzed and introducing a force to initiate the assay, no further interaction is required for assay completion. Therefore, by using the device, the assay can be performed by technical and non-technical personnel within and outside of a conventional laboratory environment. The components are miniaturized and compacted into a conveniently-sized, self-contained housing, thereby utilizing a minimal amount of space to facilitate transport and use.
The device is a continuous liquid flow channel having a proximal and a distal end, wherein the sample is introduced to the channel via a sample delivery means so that the sample travels toward the distal end of the channel to a detection membrane in fluid communication with the distal end of the channel. Continuous with the liquid flow channel, are a sample delivery means, one or more reservoirs containing one or more buffers and reagents necessary for conducting the assay, and, optionally, mixing or incubation reservoirs for combining the sample and reagents. The locations of the sample valve and reservoirs, and liquid volume capacities of the flow channel, sample delivery means and reservoirs can be modified and rearranged as needed to optimize the conditions for a wide variety of assay formats and analytes to be detected.
One or more liquid flow ch
Kroll Werner
Stave James W.
Teaney, III George B.
Counts Gary
Kilpatrick & Stockton LLP
Le Long V.
Strategic Diagnostics Inc.
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