Nonseparation assay methods
Assay methods are disclosed involving specific binding reactions which are simplified compared to known methods. A compound capable of producing chemiluminescence is immobilized on a solid support as is a member of a specific binding pair for capturing an analyte from a sample. An activator compound that activates the chemiluminescent compound and is conjugated to a specific binding pair member is added in excess along with the sample to the solid support. Addition of a trigger solution causes a chemiluminescent reaction at the sites where the activator conjugate has been specifically bound. The assay methods are termed non-separation assays because they do not require removal or separation of excess detection label (activator conjugate) prior to the detection step. The methods are applicable to various types of assays including immunoassays, receptor-ligand assays and nucleic acid hybridization assays.
1. A method for detecting an analyte in a sample in an assay procedure comprising:
a) providing a sample containing or suspected to contain the analyte and a solid support having immobilized thereon
1) a chemiluminescent compound, and
2) a first specific binding partner for the analyte;
b) contacting the sample and the solid support to permit analyte to bind to the immobilized specific binding partner for the analyte;
c) providing an excess of an activator compound conjugate comprising an activator compound conjugated to either a second specific binding partner for the analyte or to the analyte;
d) permitting the activator compound conjugate to undergo a specific binding pair reaction thereby bringing a first portion of the activator compound conjugate into proximity to the immobilized chemiluminescent compound, wherein a second portion of the activator compound conjugate does not undergo a specific binding pair reaction and is not brought into proximity to the immobilized chemiluminescent compound, and wherein the portion of the activator compound conjugate in proximity to the immobilized chemiluminescent compound activates a portion of the immobilized chemiluminescent compound;
e) providing a trigger solution to produce chemiluminescence from the activated portion of the chemiluminescent compound;
f) detecting the chemiluminescence produced; and
g) relating the chemiluminescence produced to the presence, location, or amount of the analyte in the sample.
2. The method of claim 1 wherein the second portion of the activator compound conjugate that is not brought into proximity to the immobilized chemiluminescent compound is not removed before adding the trigger solution to produce chemiluminescence.
3. The method of claim 1 wherein the second portion of the activator compound conjugate that is not brought into proximity to the immobilized chemiluminescent compound is removed before adding the trigger solution to produce chemiluminescence.
4. The method of claim 1 wherein the activator compound is selected from at least one of transition metal salts and complexes, peroxidase enzymes, and transition metal-containing enzymes, wherein the transition metal is selected from at least one of iron, copper, cobalt, zinc, manganese, and chromium.
5. The method of claim 4 wherein the trigger solution is an aqueous solution comprising a peroxide compound.
6. The method of claim 1 wherein the solid support is selected from microwell plates, test tubes, sample cups, plastic spheres, cellulose test strips, paper test strips, plastic test strips, latex particles, polymer particles, silica particles, and magnetic particles.
7. The method of claim 1 wherein the chemiluminescent compound is capable of being oxidized to produce chemiluminescence in the presence of the activator and a trigger solution and comprises a chemiluminescent moiety and a linking moiety that links the chemiluminescent moiety to the solid support, wherein the chemiluminescent moiety is selected from luminol, isoluminol, aminobutylethylisoluminol, aminohexylethylisoluminol, 7-dimethylaminonaphthalene-1,2-dicarboxylic acid hydrazide, anthracene-2,3-dicarboxylic acid hydrazide, phenathrene-1,2-dicarboxylic acid hydrazide, pyrenedicarboxylic acid hydrazide, 5-hydroxyphthalhydrazide, 6-hydroxyphthalhydrazide, acridan esters, acridan thioesters, acridan sulfonamides, and groups of formula I
wherein R 1 , R 2 and R 3 are organic groups containing from 1 to 50 non-hydrogen atoms, and each of R 4 - R 11 is hydrogen or a noninterfering substituent, wherein at least one of the groups R 1 - R 11 comprises the linking moiety.
8. The method of claim 1 wherein the chemiluminescent compound is covalently attached to the solid support.
9. The method of claim 1 wherein the chemiluminescent compound is covalently attached to an auxiliary substance that is immobilized on the solid support.
10. The method of claim 1 wherein the chemiluminescent compound is covalently attached to a specific binding pair member that is immobilized on the solid support.
11. The method of claim 1 wherein the assay is an immunoassay.
12. The method of claim 11 wherein the immunoassay is a sandwich immunoassay.
13. The method of claim 1 wherein the assay is nucleic acid hybridization assay wherein the analyte is a target nucleic acid and wherein the first specific binding partner is a nucleic acid complementary to a first region of the target and wherein the activator compound conjugate is an activator compound conjugated to a nucleic acid that is complementary to a second region of the target.