Method for derivitizing electrodes and assay methods using such derivitized electrodes

• US 6,132,955 A
• Filed: 09/03/1997
• Issued: 10/17/2000
• Est. Priority Date: 05/18/1995
• Status: Expired due to Fees

• Current Assignee: BioVeris Corporation (Roche Holding AG)
• Original Assignee: IGEN International, Inc. (Roche Holding AG)
• Inventors: Talley, David, Leland, Jonathan K., Blackburn, Gary F.
• Primary Examiner(s): Huff, Sheela
• Application Number:
  US08/922,761
• Time in Patent Office: 1,140 Days
• Field of Search: 204/400, 204/403, 435/4-6, 435/7.1, 435/7.7, 435/817, 436/526, 436/578
• US Class Current: 435/4
• CPC Class Codes: C12Q 1/001 Enzyme electrodes
• CPC Class Codes: G01N 33/5438 Electrodes
• CPC Class Codes: Y10S 435/817 Enzyme or microbe electrode

Abstract

An electrode can be derivitized by contacting it with a derivitizing solution to make it more sensitive to a desired analyte signal as opposed to interfering signals in an assay. Particularly, in an electrochemiluminescence (ECL) immunoassay the working electrode can be derivitized to be more sensitive to desired analyte signals, as opposed to interfering non-bound conjugate or serum matrix signals.

Claims

1. A method for determining the presence or absence of an analyte, said method comprising:

a) contacting a working electrode with a derivitizing solution consisting essentially of a derivitizing agent, said derivitizing agent being a fatty acid or a salt thereof, a short-chain aminated thiol, or a surfactant, a derivitizing-effective voltage being imposed across the electrode so that the derivitizing agent binds to the electrode;

b) contacting with said derivatized electrode an assay solution comprising the sample, an electrochemiluminescent label capable of binding with said analyte of interest, and non-analyte interfering compounds, wherein the electrochemiluminescent label is a metal chelate;

c) imposing an electrochemical voltage upon the derivatized working electrode causing the electrochemiluminescent label to emit electrochemiluminescence; and

d) detecting or measuring emitted luminescence as an indication of whether or in what amount said analyte is present in the sample.

2. The method according to claims 1, wherein the working electrode is caused to be in contact with said derivitizing solution prior to imposition of said derivitizing-effective voltage.

3. The method according to claim 1, wherein said derivitizing-effective voltage is imposed prior to contacting said electrode with said derivitizing solution.

4. The method according to claim 1, wherein the derivitizing solution consists essentially of linolenic acid, linoleic acid, oleic acid, eicosatrienoic acid, undecylenic acid, stearic acid, or capric acid or salts thereof or cystamine hydrochloride.

5. The method according to claim 1, wherein the derivitizing agent is contained in a derivitizing solution in an amount of 0.01 to 0.2 percent.

6. The method according to claim 1, wherein a voltage of 0 to 565 mV is applied to the electrode while it is in contact with the derivitizing solution.

7. The method according to claim 1, wherein the derivitizing solution consists essentially of an amine-terminated thiol containing 1 to 6 carbon atoms.

8. The method according to claim 1, wherein the derivitizing solution consists essentially of 4-lauryl ether, dodecyl maltoside or tetramethyl-5-decyn-4,7-diol.

9. The method according to claim 1, wherein the derivitizing solution consists essentially of cystamine dihydrochloride.

10. The method according to claim 1, wherein the metal in the metal chelate is osmium or ruthenium.

11. The method according to claim 1, wherein the metal chelate is bis[4,4'"'"'-carbomethoxy)-2,2'"'"'-bipyridine] 2-[3-(4-methyl-2,2'"'"'-bipyridine-4-yl)propyl]-1,3-dioxolane ruthenium (II);

bis (2,2'"'"'-bypyridine) [4-(butan-1-al)-4'"'"'-methyl-2,2'"'"'-bipyridine] ruthenium (II);

bis(2,2'"'"'-bipyridine) [4-(4'"'"'-methyl-2,2'"'"'-bipyridine-4'"'"'-yl)-butyric acid] ruthenium(II)i tris (2,2'"'"'-bipyridine) ruthenium (II);

(2,2'"'"'-bipyridine)[bis-bis(1,2-diphenylphosphino)ethylene] 2-[3-(4-methyl-2,2'"'"'-bipyridine-4'"'"'-yl)propyl]-1,3-dioxolane osmium (II);

bis(2,2'"'"'-bipyridine) [4-(4'"'"'-methyl-2,2'"'"'-bipyridine)-butylamine] ruthenium (II);

bis(2,2'"'"'-bipyridine) [1-bromo-4(4'"'"'-methyl-2,2'"'"'-bipyridine-4-yl)butane] ruthenium II;

or bis (2,2'"'"'-bipyridine)maleimidohexanoic acid, 4-methyl-2,2'"'"'-bipyridine-4'"'"'-butylamide ruthenium (II).

12. The method according to claim 1 wherein the non-analyte interfering compounds are serum matrix components, unbound electrochemiluminescent labels not connected to analyte, or mixtures thereof.

13. The method according to claim 12, wherein the non-analyte interfering compounds are unbound electrochemiluminescent labels.

14. The method according to claim 12, wherein the non-analyte interfering compounds are serum matrix components.

15. The method according to claim 1, wherein magnetic microparticles are bound to the electrochemiluminescent label and the analyte is magnetically localized at the derivatized working electrode prior to imposing electrochemical voltage on the working electrode to cause the electrochemiluminescent label to emit electrochemiluminescence.

16. The method according to claim 15, wherein the derivitizing solution flows across the working electrode while constant voltage is applied to the working electrode.

17. The method according to claim 15, wherein the derivitizing agent is sodium oleate;

the flow rate of the derivitizing solution is 21/2 milliliters per minute, and a constant voltage of 565 millivolts is applied to the working electrode for 10 seconds.

18. The method according to claim 15, wherein the derivitizing agent is cystamine dihydrochloride;

the flow rate of the derivitizing solution is 2 1/2 milliliters per minute; and

a constant voltage of 565 millivolts is applied to the working electrode for 10 seconds.

19. The method according to claim 15, wherein the derivitizing agent is linolenic acid;

the flow rate of the derivitizing solution is 21/2 milliliters per minute; and

a constant voltage of 565 millivolts is applied to the working electrode for 10 seconds.

20. The method according to claim 1 wherein the electrode is Pt or Ag.

21. The method according to claim 1, wherein said electrochemiluminescent label is capable of directly binding with said analyte of interest.

22. The method according to claim 1, wherein said electrochemiluminescent label is capable of indirectly binding with said analyte of interest.