Methods using novel chemiluminescent labels
Methods using chemiluminescent label compounds and chemiluminescent labeled conjugates are provided. The compounds comprise an acridan ring bearing an exocyclic ketene dithioacetal group and further contain a labeling substituent which permits attachment to compounds of interest. The novel chemiluminescent compounds and labeled conjugates are convenient to prepare, are highly stable, and generate chemiluminescence rapidly on demand. The compounds and conjugates are useful in assays of an analyte in a sample and in assays employing labeled specific binding pairs.
1. A method for detecting a labeled compound in a sample, wherein the labeled compound comprises a compound linked to a chemiluminescent label, said labeled compound having the formula:
wherein each of R 1 , R 2 and R 3 is selected from substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted alkynyl, substituted or unsubstituted aryl, substituted or unsubstituted aralkyl groups of 1-20 carbon atoms, wherein R 1 and R 2 can be joined together in a ring, R 4 -R 11 are independently selected from hydrogen and substituents which do not interfere with the generation of chemiluminescence, and at least one of R 1 -R 11 is linked to the compound by means of L-RG, wherein L is a linking group and RG is a reactive group, said method comprising:
a) reacting the labeled compound with a peroxide and a peroxidase for producing chemiluminescence from the chemiluminescent label wherein the ratio of labeled compound to peroxidase ranges from 100:1 to about 1:1000 and the peroxide is added in a concentration in the range of 10 −6 M to 10 −1 M to produce the chemiluminescence as a flash of light lasting not more than about five seconds; and
b) detecting the chemiluminescence as an indication of the presence of said compound in said sample.
2. The method of claim 1 wherein the compound is attached to the chemiluminescent label on R 1 or R 2 .
3. The method of claim 1 wherein each of R 4 -R 11 is a hydrogen atom.
4. The method of claim 1 wherein one of R 4 -R 11 is selected from halogen and alkoxy groups and the other of R 4 -R 11 are hydrogen atoms.
5. The method of claim 3 wherein the compound is attached to the chemiluminescent label on R 1 , wherein R 2 is alkyl substituted with an SO 3 − group, and wherein R 3 is selected from substituted or unsubstituted C 1 -C 4 alkyl groups, phenyl, substituted or unsubstituted benzyl groups.
6. The method of claim 1 wherein the labeled compound comprises a labeled analyte or a labeled specific binding pair member.
7. The method of claim 6 wherein the analyte is selected from drugs, hormones, pesticides, pesticide metabolites, DNA, RNA, oligonucleotides, antibodies, and antigens.
8. The method of claim 6 wherein the specific binding pair member is selected from antigens, antibodies, haptens, oligonucleotides, polynucleotides, avidin, streptavidin, hormones, receptors, lectins, carbohydrates, IgG, protein A, and nucleic acid binding proteins.
9. The method of claim 1 wherein the peroxide can be hydrogen peroxide or a complex of hydrogen peroxide, urea peroxide, perborate or percarbonate.
10. The method of claim 1 further comprising detecting the amount of the chemiluminescence and relating the amount of chemiluminescence to the amount of said labeled compound.
11. The method of claim 1 wherein the compound is covalently attached to the chemiluminescent label.
12. The method of claim 1 wherein the compounds is attached to the chemiluminescent label by physical forces selected from the group consisting of hydrogen bonding, electrostatic attraction, ionic attraction, and hydrophobic attraction.