Reagent including an osmium-containing redox mediator

• US 5,846,702 A
• Filed: 12/20/1996
• Issued: 12/08/1998
• Est. Priority Date: 12/30/1993
• Status: Expired due to Term

• Current Assignee: Roche Diabetes Care Inc. (Roche Holding AG)
• Original Assignee: Boehringer Mannheim Corporation (Roche Holding AG)
• Inventors: Jernigan, Walter W., Sigler, Gerald F., Wilsey, Christopher D., Surridge, Nigel A., Deng, Zhi David, McEnroe, Robert J., Muddiman, Rebecca W.
• Primary Examiner(s): LEARY, LOUISE N
• Application Number:
  US08/770,975
• Time in Patent Office: 718 Days
• Field of Search: 435/4, 435/14, 435/25, 435/817, 420/461, 356/39, 356/344, 204/193, 204/450
• US Class Current: 435/4
• CPC Class Codes: C07F 15/0026 without a metal-carbon linkage
• CPC Class Codes: C12Q 1/004 mediator-assisted
• CPC Class Codes: Y10S 435/817 Enzyme or microbe electrode

Abstract

A new group of Os(II) and Os(III) compounds useful as redox mediators in electrochemical biosensors. These compounds have 1) low oxidation potential, 2) fast reaction kinetics between the electroactive center of an enzyme and the compound, 3) slow oxidation of osmium by oxygen, and 4) excellent solubility in aqueous medium. These mediators are particularly useful as a component of a reagent used in an electrochemical biosensor, wherein the biosensor is useful for measuring analytes from a biological fluid, such as blood.

Claims

1. A reagent for an electrochemical device that measures an analyte from a fluid sample, comprising:

a redox mediator and an enzyme, the redox mediator having the formula ##STR5## wherein R and R'"'"' are the same or different and are 2,2'"'"'-bipyridyl, 4,4'"'"'-disubstituted-2,2'"'"'-bipyridyl, 5,5'"'"'-disubstituted-2,2'"'"'-bipyridyl, 1,10-phenanthrolinyl, 4,7-disubstituted-1,10-phenanthrolinyl, or 5,6-disubstituted-1,10-phenanthrolinyl, wherein the disubstitution is a methyl, ethyl, or phenyl group,

R and R'"'"' are coordinated to Os at their nitrogen atoms,

R" is hydrogen, methyl or ethyl,

Z is chloro or bromo,

m is +2,

X is an anion and is chloride, bromide, iodide, fluoride, tetrafluoroborate, perchlorate, nitrate, sulfate, carbonate, or sulfite,

Y is an anion and is chloride, bromide, iodide, fluoride, tetrafluoroborate, perchlorate or nitrate, and

n is 1 or zero,

but when X is sulfate, carbonate, or sulfite, n is zero,

wherein the aqueous solubility of the redox mediator is greater than about 1 millimolar, and

wherein the redox mediator is reduced by a reaction involving the enzyme, the analyte, and the redox mediator, and the redox mediator is in sufficient amount such that oxidation of the reduced form of the redox mediator produces a current that correlates to the concentration of the analyte in the fluid sample, and

the enzyme is in sufficient amount to catalyze the reaction involving the enzyme, the analyte, and the redox mediator.

2. The reagent of claim 1, wherein R and R'"'"' are the same or different and are 2,2'"'"'-bipyridyl, 4,4'"'"'-disubstituted-2,2'"'"'-bipyridyl, or 5,5'"'"'-disubstituted 2,2'"'"'-bipyridyl, wherein the disubstitution is a methyl, ethyl, or phenyl group.

3. The reagent of claim 1, wherein R and R'"'"' are 2,2'"'"'-bipyridyl and R" is hydrogen or methyl.

4. The reagent of claim 1, wherein the redox mediator has the formula ##STR6## wherein R and R'"'"' are the same or different and are 2,2'"'"'-bipyridyl, 4,4'"'"'-dimethyl-2,2'"'"'-bipyridyl, 4,4'"'"'-diphenyl-2,2'"'"'-bipyridyl, 1,10-phenanthrolinyl, 4,7-dimethyl- 1,10-phenanthrolinyl, 4,7-diphenyl-1,10-phenanthrolinyl, or 5,6-dimethyl-1,10-phenanthrolinyl,

R and R'"'"'are coordinated to Os at their nitrogen atoms,

R" is hydrogen, methyl or ethyl,

Z is chloro or bromo,

m is +2,

X is an anion and is chloride, bromide, iodide, fluoride, tetrafluoroborate, perchlorate, nitrate, sulfate, carbonate, or sulfite,

Y is an anion and is chloride, bromide, iodide, fluoride, tetrafluoroborate, perchlorate or nitrate, and

n is 1 or zero,

but when X is sulfate, carbonate, or sulfite, n is zero,

wherein the aqueous solubility of the redox mediator is greater than about 1 millimolar.

5. The reagent of claim 1, wherein the reagent further comprises at least one additional enzyme and an additional redox mediator.

6. The reagent of claim 1, wherein the reagent further comprises a buffer, the buffer having a higher oxidation potential than the reduced form of the redox mediator and being in sufficient amount to provide and maintain a pH at which the enzyme catalyzes the reaction involving enzyme, analyte, and the redox mediator.

7. The reagent of claim 2, wherein the reagent further comprises a buffer, the buffer having a higher oxidation potential than the reduced form of the redox mediator and being in sufficient amount to provide and maintain a pH at which the enzyme catalyzes the reaction involving enzyme, analyte, and the redox mediator.

8. The reagent of claim 7, wherein R and R'"'"' are 2,2'"'"'-bipyridyl and R" is hydrogen or methyl.

9. The reagent of claim 6, wherein the redox mediator has the formula of claim 4.

10. The reagent of claim 6, wherein the reagent further comprises at least one additional enzyme and an additional redox mediator.

14. A reagent for use in an electrochemical device that measures glucose from a fluid sample, comprising:

about 160 millimolar of a redox mediator having the formula of claim 1;

about 150 millimolar 3-sulfobenzoic acid at pH about 5.5;

about 0.06% (by weight) Triton X-100 surfactant; and

about 3,000 units of glucose oxidase per milliliter of reagent.

15. The reagent of claim 14, wherein the redox mediator has the formula of claim 2.

16. The reagent of claim 14, wherein the redox mediator has the formula of claim 3.

17. The reagent of claim 14, wherein the redox mediator has the formula of claim 4.

18. The reagent of claim 14, excluding 3-sulfobenzoic acid at pH about 5.5 and including phosphate buffer at a concentration of about 100 millimolar and a pH of about 6.8.

19. The reagent of claim 18, wherein the redox mediator has the formula of claim 4.

11. A reagent for an electrochemical device that measures an analyte from a fluid sample, comprising:

an enzyme, a buffer, and a redox mediator having the formula ##STR7## wherein R and R'"'"' are the same or different and are 2,2'"'"'-bipyridyl, 4,4'"'"'-disubstituted-2,2'"'"'-bipyridyl, 5,5'"'"'-disubstituted-2,2'"'"'-bipyridyl, 1,10-phenanthrolinyl, 4,7-disubstituted-1,10-phenanthrolinyl, or 5,6-disubstituted-1,10-phenanthrolinyl, wherein the disubstitution is a methyl, ethyl, or phenyl group,

R and R'"'"'are coordinated to Os at their nitrogen atoms,

R" is hydrogen, methyl or ethyl,

Z is chloro or bromo,

m is +1,

X is an anion and is chloride, bromide, iodide, fluoride, tetrafluoroborate, perchlorate, or nitrate,

wherein the aqueous solubility of the redox mediator is greater than about 1 millimolar,

wherein the redox mediator is oxidized by a reaction involving enzyme, analyte, and the redox mediator, and the redox mediator is in sufficient amount such that reduction of the oxidized form of the redox mediator produces a current that correlates to the concentration of the analyte in the fluid sample,

the enzyme is in sufficient amount to catalyze the reaction involving enzyme, analyte, and the redox mediator, and

the buffer has a lower reduction potential than the oxidized form of the redox mediator and is in sufficient amount to provide and maintain a pH at which the enzyme catalyzes the reaction involving enzyme, analyte, and the redox mediator.

12. The reagent of claim 11, wherein R and R'"'"' are 2,2'"'"'-bipyridyl and R" is hydrogen or methyl.

13. The reagent of claim 11, wherein the redox mediator has the formula ##STR8## wherein R and R'"'"' are the same or different and are 2,2'"'"'-bipyridyl, 4,4'"'"'-dimethyl-2,2'"'"'-bipyridyl, 4,4'"'"'-diphenyl-2,2'"'"'-bipyridyl, 1,10-phenanthrolinyl, 4,7-dimethyl- 1,10-phenanthrolinyl, 4,7-diphenyl-1,10-phenanthrolinyl, or 5,6-dimethyl- 1,10-phenanthrolinyl,

R and R'"'"' are coordinated to Os at their nitrogen atoms,

R" is hydrogen, methyl or ethyl,

Z is chloro or bromo,

m is+1

X is an anion and is chloride, bromide, iodide, fluoride, tetrafluoroborate, perchlorate, or nitrate,

wherein the aqueous solubility of the redox mediator is greater than about 1 millimolar.

20. A reagent for use in an electrochemical device that measures glucose from a fluid sample, which before drying comprises:

a mixture of a polymer matrix, glucose oxidase, and a redox mediator having the formula of claim 11 in the ratio of about 1 milliliter of polymer matrix to about 7 micromoles of the redox mediator, to about 6,000 units glucose oxidase,

the polymer matrix comprising about 100 millimolar 2-(N-morpholino) ethanesulfonic acid, about 0.02% (by weight) Triton X-100 surfactant, and about 1% (by weight) polyvinyl alcohol, wherein the polymer matrix is at a pH of about 6.55.

21. The reagent of claim 20, wherein the redox mediator has the formula ##STR9## wherein R and R'"'"' are the same or different and are 2,2'"'"'-bipyridyl, 4,4'"'"'-disubstituted2,2'"'"'-bipyridyl, or 5,5'"'"'-disubstituted-2,2'"'"'-bipyridyl,

wherein the disubstitution is a methyl, ethyl, or phenyl group,

R and R'"'"' are coordinated to Os at their nitrogen atoms,

R" is hydrogen, methyl or ethyl,

Z is chloro or bromo,

m is+1,

X is an anion and is chloride, bromide, iodide, fluoride, tetrafluoroborate, perchlorate, or nitrate,

wherein the aqueous solubility of the redox mediator is greater than about 1 millimolar.

22. The reagent of claim 20, wherein R and R'"'"' are 2,2'"'"'-bipyridyl and R" is hydrogen or methyl.

23. The reagent of claim 20, wherein the redox mediator has the formula ##STR10## wherein R and R'"'"' are the same or different and are 2,2'"'"'-bipyridyl, 4,4'"'"'-dimethyl-2,2'"'"'-bipyridyl, 4,4'"'"'-diphenyl-2,2'"'"'-bipyridyl, 1,10-phenanthrolinyl, 4,7-dimethyl- 1,10-phenanthrolinyl, 4,7-diphenyl-1,10-phenanthrolinyl, or 5,6-dimethyl-1,10-phenanthrolinyl,

R and R'"'"' are coordinated to Os at their nitrogen atoms,

R" is hydrogen, methyl or ethyl,

Z is chloro or bromo,

m is +1

X is an anion and is chloride, bromide, iodide, fluoride, tetrafluoroborate, perchlorate, or nitrate,

wherein the aqueous solubility of the redox mediator is greater than about 1 millimolar.

24. A reagent for use in an electrochemical device that measures glycerol from a fluid sample, which before drying comprises:

a mixture of a buffer polymer matrix, glycerol-3-phosphate oxidase, glycerol kinase and a redox mediator in the ratio of about 1 milliliter buffer polymer matrix to about 1,333 units of glycerol-3-phosphate oxidase, to about 3,333 units of glycerol kinase, to about 4.7 micromoles redox mediator,

the redox mediator having the formula ##STR11## wherein R and R'"'"' are the same or different and are 2,2'"'"'-bipyridyl, 4,4'"'"'-disubstituted-2,2'"'"'-bipyridyl, 5,5'"'"'-disubstituted-2,2'"'"'-bipyridyl, 1,10-phenanthrolinyl, 4,7-disubstituted-1,10-phenanthrolinyl, or 5,6-disubstituted- 1,10-phenanthrolinyl, wherein the disubstitution is a methyl, ethyl, or phenyl group,

R and R'"'"' are coordinated to Os at their nitrogen atoms,

R" is hydrogen, methyl or ethyl,

Z is choro or bromo,

m is +1,

X is an anion and is chloride, bromide, iodide, fluoride, tetrafluoroborate, perchiorate, or nitrate,

wherein the aqueous solubility of the redox mediator is greater than about 1 millimolar,

the buffer polymer matrix comprising about 150 millimolar N-2-hydroxyethylpiperazine-N'"'"'-2-ethanesulfonic acid, about 20 millimolar magnesium sulfate, about 1% (by weight) polyvinyl alcohol, and about 15 millimolar adenosine triphosphate, wherein the buffer polymer matrix is at a pH of about 8.

25. The reagent of claim 24, wherein the redox mediator has the formula ##STR12## wherein R and R'"'"' are 2,2'"'"'- bipyridyl, R and R'"'"' are coordinated to Os at their nitrogen atoms,

R" is hydrogen or methyl,

Z is chloro or bromo,

m is +1,

X is an anion and is chloride, bromide, iodide, fluoride, tetrafluoroborate, perchlotsyr, or nitrate,

wherein the aqueous solubility of the redox mediator is greater than about 1 millimolar.