Stabilizing agents and capture ligands for use in assays measuring analyte concentrations

• US 20080182341A1
• Filed: 07/20/2007
• Published: 07/31/2008
• Est. Priority Date: 07/28/2006
• Status: Active Grant

• Current Assignee: Beckman Coulter Incorporated (Danaher Corporation)
• Original Assignee: Beckman Coulter Incorporated (Danaher Corporation)
• Inventors: Lu, Wenyuan, Leith, Katherine M., Walton, Courtney E., Chan, Stephen P.
• Granted Patent: US 7,897,352 B2
• Time in Patent Office: Days
• US Class Current: 436/526
• CPC Class Codes: C07K 16/00 Immunoglobulins [IGs], e.g. monoclonal or polyclonal antibodies antibodies with enzymatic activity, e.g. abzymes C12N9/0002
• CPC Class Codes: G01N 33/53 Immunoassay; Biospecific binding assay; Materials therefor
• CPC Class Codes: G01N 33/5306 Improving reaction conditions, e.g. reduction of non-specific binding, promotion of specific binding
• CPC Class Codes: G01N 33/543 with an insoluble carrier for immobilising immunochemicals
• CPC Class Codes: G01N 33/54393 Improving reaction conditions or stability, e.g. by coating or irradiation of surface, by reduction of non-specific binding, by promotion of specific binding

Abstract

The present invention is related to compositions useful for the measurement of free or unbound analyte concentrations in a fluid. The present invention includes the use of capture ligands and stabilizing agents to improve the accuracy of analyte concentration assays. Methods and tools for using the present invention are also disclosed.

Claims

1. A method for measuring a concentration of a free analyte, the method comprising:

(a) adding a capture ligand for the free analyte to a vessel;

(b) adding a stabilizing agent, or salt thereof, to the vessel, wherein the stabilizing agent comprises the general formula RX,

wherein R is a saturated or unsaturated alkyl, aryl, or silicon-based polymer, any of which is optionally derivatized with one or more moiety containing oxygen, nitrogen, halogen, or combination thereof, and wherein X is an oxoanion or oxide of sulfur or phosphorus, an oxoanion or carbonyl derivative of nitrogen, a carboxylate, a borate, a silicate, or a halogen, with the proviso that the stabilizing agent does not comprise an alkyl amine fluoro-surfactant.

(c) adding a sample comprising the analyte to the vessel;

(d) adding a detection system to the vessel; and

(e) measuring the concentration of the analyte in the sample using the detection system.

2. The method of claim 1, wherein the stabilizing agent comprises the general formula RX, wherein R is C_6-18 alkyl and X is sulfate, sulfonic acid, or sulfonate.

3. The method of claim 1, wherein the stabilizing agent is 2-ethyl-hexyl sulfate, or salt thereof.

4. The method of claim 1, wherein the analyte is a thyroid hormone.

5. The method of claim 1, wherein the capture ligand is analyte-specific and selected from the group consisting of antibody, antibody fragment, antibody mimic, analyte-specific binding protein, and combinations thereof.

6. The method of claim 5, wherein the analyte-specific binding protein is intrinsic factor or folate-binding protein.

7. The method of claim 1, wherein the detection system comprises a solid phase coated with a capture ligand-specific binding molecule, a detectable label, or combination thereof.

8. The method of claim 7, wherein the solid phase is a paramagnetic particle.

9. The method of claim 7, wherein the capture ligand-specific binding molecule is hapten-specific, and wherein the capture ligand is haptenated.

10. The method of claim 9, wherein the hapten is biotin.

11. The method of claim 7, wherein the capture ligand-specific binding molecule is selected from the group consisting of streptavidin, avidin, biotin-specific antibody, biotin-specific antibody fragment, and biotin-specific antibody mimic.

12. The method of claim 1, wherein the capture ligand is immobilized on a solid phase.

13. A composition for use in an assay measuring a concentration of a free analyte, the composition comprising:

(i) a capture ligand for the free analyte; and

(ii) a stabilizing agent, wherein the stabilizing agent comprises the general formula RX, or salt thereof,

wherein R is a saturated or unsaturated alkyl, aryl, or silicon-based polymer, any of which is optionally derivatized with one or more moiety containing oxygen, nitrogen, halogen, or combination thereof, and wherein X is an oxoanion or oxide of sulfur or phosphorus, an oxoanion or carbonyl derivative of nitrogen, a carboxylate, a borate, a silicate, or a halogen, with the proviso that the stabilizing agent does not comprise an alkyl amine fluoro-surfactant.

14. The composition of claim 13, wherein R is selected from the group consisting of straight or branched silicone, straight or branched siloxane, straight or branched carbosilane, straight or branched alkyl, cycloalkyl, heterocyclyl, arylalkyl, heteroaryl, and combinations thereof.

15. The composition of claim 13, wherein R is an alkyl, aryl, or silicon-based polymer optionally substituted with one or more hydroxy, keto, carbonyl, carboxy, or combinations thereof.

16. The composition of claim 13, wherein R is an ether, an ester, or combination thereof.

17. The composition of claim 16, wherein the R comprises polyoxypropylene or polyoxyethylene.

18. The composition of claim 13, wherein R is alkyl, alkylene, or alkyne.

19. The composition of claim 13, wherein R is an alkyl, aryl, or silicon-based polymer optionally substituted with one or more nitrogen-containing moiety comprising amine, amino, imine, imino, amide, ammonium, or combination thereof.

20. The composition of claim 13, wherein R is selected from the group consisting of alkoxyalkyl, alkoxyalkoxyalkyl, alkylaminoalkyl, alkylaminooxyalkyl, alkoxyaminoalkyl, phosphonoalkyl, carboxyalkyl, carboxyalkoxyalkyl, carboxyalkylaminoalkyl, carboxyalkylamidoalkyl, cycloalkylalkyl, hetercycloalkylalkyl, heteroarylalkyl, and combinations thereof.

21. The composition of claim 13, wherein R is alkyl, and alkyl is selected from the group consisting of ethyl, propyl, isopropyl, butyl, isobutyl, pentyl, hexyl, heptyl, octyl, 2-methyl butyl, 2-ethyl butyl, 2-propyl butyl, 3-methyl butyl, 3-ethyl butyl, 3-propyl pentyl, 2-methyl pentyl, 2-ethyl pentyl, 2-propyl pentyl, 3-methyl pentyl, 3-ethyl pentyl, 3-propyl pentyl, 4-methyl pentyl, 4-ethyl pentyl, 4-propyl pentyl, 2-methyl hexyl, 2-ethyl hexyl, 2-propyl hexyl, 3-methyl hexyl, 3-ethyl hexyl, 3-propyl hexyl, 4-methyl hexyl, 4-ethyl hexyl, 4-propyl hexyl, 5-methyl hexyl, 5-ethyl hexyl, 5-propyl hexyl, 2-methyl heptyl, 2-ethyl heptyl, 2-propyl heptyl, 3-methyl heptyl, 3-ethyl heptyl, 3-propyl heptyl, 4-methyl heptyl, 4-ethyl heptyl, 4-propyl heptyl, 5-methyl heptyl, 5-ethyl heptyl, 5-propyl heptyl, 6-methyl heptyl, 6-ethyl heptyl, 6-propyl heptyl, 2-methyl octyl, 2-ethyl octyl, 2-propyl octyl, 3-methyl octyl, 3-ethyl octyl, 3-propyl octyl, 4-methyl octyl, 4-ethyl octyl, 4-propyl octyl, 5-methyl octyl, 5-ethyl octyl, 5-propyl octyl, 6-methyl octyl, 6-ethyl octyl, and 6-propyl octyl, any of which is optionally substituted with one or more hydroxy, carbonyl, halogen, phosphate, acetyl, ammonium, and combinations thererof.

22. The composition of claim 13, wherein X is selected from the group consisting of sulfate, sulfonic acid, sulfonate, sulfite, sulfoxide, taurate, sulfosuccinate, sulfobetaine, sulfatobetaine, sulfonamide, phosphate, nitrate, carboxylate, borate, silicate, bromate, and combinations thereof.

23. The composition of claim 13, wherein X is sulfate, sulfonic acid, sulfonate, sulfosuccinate, or taurate.

24. The composition of claim 13, comprising a salt of the stabilizing agent.

25. The composition of claim 13, wherein R is C_6-18 alkyl and X is sulfate, sulfonic acid, or sulfonate.

26. The composition of claim 13, wherein the stabilizing agent is selected from the group consisting of 2-ethyl-hexyl sulfate;

1-hexane sulfonic acid, or salt thereof;

1-heptane sulfonic acid, or salt thereof;

1-octane sulfonic acid, or salt thereof;

1-decane sulfonic acid, or salt thereof;

sodium C_14-16 olefin sulfonate;

sodium dodecyl sulfate;

sodium dioctyl sulfosuccinate;

sodium N-oleyl-N-methyltaurate;

sodium polyoxyethylene lauryl sulfate;

amine alkylbenzyl sulfonate;

sodium ethyl-hexyl sulfate; and

combinations thereof.

27. The composition of claim 13, wherein the stabilizing agent is 2-ethyl-hexyl sulfate, or salt thereof.

28. The composition of claim 13, wherein a concentration of the stabilizing agent is about 5 micromolar to about 750 micromolar.

29. The composition of claim 26, wherein a concentration of the 2-ethyl-hexyl sulfate is about 75 micromolar to about 650 micromolar.

30. The composition of claim 13, wherein the capture ligand is an analyte-specific binding protein.

31. The composition of claim 13, wherein the capture ligand is an antibody, antibody fragment, or antibody mimic.

32. A kit for use in estimating a concentration of a free analyte, the kit comprising:

(a) a capture ligand for the free analyte;

(b) a stabilizing agent, or salt thereof, wherein the stabilizing agent comprises the general formula RX,

wherein R is a saturated or unsaturated alkyl, aryl, or silicon-based polymer, any of which is optionally derivatized with one or more moiety containing oxygen, nitrogen, halogen, or combination thereof, and wherein X is an oxoanion or oxide of sulfur or phosphorus, an oxoanion or carbonyl derivative of nitrogen, a carboxylate, a borate, a silicate, or a halogen, with the proviso that the stabilizing agent does not comprise an alkyl amine fluoro-surfactant.

(c) a detection system.