Biosensor with peroxidase enzyme
First Claim
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1. A disposable electrode strip for measuring an analyte in a fluid sample said strip comprising:
- a laminated strip having a first strip end, a second strip and and a vent opening spaced from said first strip and, said laminated strip comprising a base layer with at least two electrodes delineated thereon, a reagent holding layer carried on said base layer, said reagent holding layer having at least two cutouts, a channel forming layer carried on said reagent holding layer, and a cover;
an enclosed channel between said first strip end and said vent opening, said enclosed channel containing said at least two cutouts;
a first reagent disposed in a first cutout of said at least two cutouts forming a reference electrode, said first reagent comprising a reference electrode material selected from the group consisting of silver chloride when said reference electrode is silver and a mixture made by combining at least a redox mediator and at least one binder when said reference electrode is selected from the group consisting of gold, gold/tin oxide, palladium, platinum and carbon composition;
a second reagent disposed in a second cutout of said at least two cutouts forming a first working electrode, said second reagent comprising a redox mediator, at least one binder, at least one enzyme that is a substrate of said analyte and a peroxidase capable of catalyzing a reaction involving said redox mediator wherein said redox mediator is oxidized wherein said second reagent is water soluble; and
conductive contacts at said second strip end and insulated from said enclosed channel.
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Abstract
An improved biosensor having at least a first working electrode and a first electrode material disposed on the first working electrode. The first electrode material is a mixture made by combining at least one enzyme where the at least one enzyme is a capable of reacting with the analyte to be measured, a redox mediator capable of reacting with a product of an enzymatic reaction or a series of enzymatic reactions involving the at least one enzyme, a peroxidase capable of catalyzing a reaction involving the redox mediator where the redox mediator is oxidized, a binder and a surfactant.
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Citations
32 Claims
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1. A disposable electrode strip for measuring an analyte in a fluid sample said strip comprising:
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a laminated strip having a first strip end, a second strip and and a vent opening spaced from said first strip and, said laminated strip comprising a base layer with at least two electrodes delineated thereon, a reagent holding layer carried on said base layer, said reagent holding layer having at least two cutouts, a channel forming layer carried on said reagent holding layer, and a cover;
an enclosed channel between said first strip end and said vent opening, said enclosed channel containing said at least two cutouts;
a first reagent disposed in a first cutout of said at least two cutouts forming a reference electrode, said first reagent comprising a reference electrode material selected from the group consisting of silver chloride when said reference electrode is silver and a mixture made by combining at least a redox mediator and at least one binder when said reference electrode is selected from the group consisting of gold, gold/tin oxide, palladium, platinum and carbon composition;
a second reagent disposed in a second cutout of said at least two cutouts forming a first working electrode, said second reagent comprising a redox mediator, at least one binder, at least one enzyme that is a substrate of said analyte and a peroxidase capable of catalyzing a reaction involving said redox mediator wherein said redox mediator is oxidized wherein said second reagent is water soluble; and
conductive contacts at said second strip end and insulated from said enclosed channel.
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2. The electrode strip of claim 1 further comprising a third cutout and a third reagent disposed in said third cutout forming a second working electrode wherein said third reagent comprises said redox mediator and said at least one binder wherein said third reagent is water soluble.
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3. The electrode strip of claim 2 wherein said third reagent further includes said at least one enzyme, a substrate of said at least one enzyme and a peroxidase.
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4. The electrode strip of claim 2 wherein said first reagent, said second reagent and said third reagent are made from a mixture having starting components comprising about 1 wt % to about 6.5 wt % of said redox mediator, about 1 wt % of binder, and about 0.02 wt % of said surfactant in water.
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5. The electrode strip of claim 4 wherein said first reagent, said second reagent and said third reagent further includes about 0.05 wt % to about 0.1 wt % of an antioxidant.
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6. The electrode strip of claim 4 wherein said second reagent is made from a mixture having starting components in water comprising about 2 wt % of potassium ferrocyanide, about 1 wt % of methyl cellulose, about 0.02 wt % of said t-octylphenoxypolyethoxyethanol, about 0.5 wt % of glucose oxidase, and about 0.5 wt % of soybean peroxidase.
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7. The electrode strip of claim 4 wherein said second reagent is made from a mixture having starting components in water comprising about 5 wt % of potassium ferrocyanide, about 1 wt % of methyl cellulose, about 0.02 wt % of t-octylphenoxypolyethoxyethanol, about 2 wt % of cholesterol oxidase, about 1 wt % of cholesterol esterase, and about 0.5 wt % of soybean peroxidase.
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8. The electrode strip of claim 4 wherein said second reagent is made from a mixture having starting components in water comprising about 2 wt % of potassium ferrocyanide, about 1 wt % of methyl cellulose, about 0.02 of t-octylphenoxypolyethoxyethanol, about 2 wt % of creatine amidinohydrolase, about 0.5 wt % of sarcosine oxidase, and about 0.5 of soybean peroxidase, and wherein said third reagent is made from a mixture having starting components in water comprising about 2 wt % of said potassium ferrocyanide, about 1 wt % of said methyl cellulose, about 0.02 wt % of said t-octylphenoxypolethoxyethanol, about 2 wt % of said creatine amidinohydrolase, about 0.4 wt % of creatinine amidohydrolase, about 0.5 wt % of said sarcosine oxidase, and about 0.5 wt % of said soybean peroxidase.
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9. The electrode strip of claim 8 wherein said first reagent and said second reagent further includes about 0.05 wt % of an antioxidant.
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10. The electrode strip of claim 2 wherein the surface area of said first working electrode is substantially the same size as the surface area of said second working electrode.
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11. The electrode strip of claim 1 wherein said peroxidase is at least one of soybean peroxidase and horseradish root peroxidase.
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12. The electrode strip of claim 1 wherein said at least one enzyme is one of creatine amidinohydrolase, glucose oxidase and cholesterol oxidase.
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13. The electrode strip of claim 12 wherein said second reagent further includes a second enzyme when said at least one enzyme is one of creatine amidinohydrolase and cholesterol oxidase.
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14. The electrode strip of claim 13 wherein said second enzyme is sarcosine oxidase when said at least one enzyme is creatine amidinohydrolase.
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15. The electrode strip of claim 13 wherein said second enzyme is cholesterol esterase when said at least one enzyme is cholesterol oxidase.
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16. The electrode strip of claim 1 wherein said redox mediator is an inorganic or organic redox species.
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17. The electrode strip of claim 16 wherein said redox species is at least one of Fe(CN)63−
- , Fe(CN)64−
, Fe(0,10-phenanthroline)32 , Fe(2,2′
-bipyridine)32 , Co(NH3)62 , Co(1,10-phenanthroline)32 , Co(2,2′
-bipyridine)32 , Os(2,2′
-bipyridine)2Cl , Os(1,10-phenanthroline)2Cl , Ru(2,2′
-bipyridine)22 , Rh(2,2′
-bipyridine)22 , cobalt phthalocyanine, ferrocenes, methylene blue, methylene green, 7,7,8,8-tetracyanoquinodimethane, tetrathiafulvalene, toluidine blue, meldola blue, N-methylphenazine methosulfate, phenyldiamines, 3,3′
,5,5′
-tetramethylbenzidine, pyrogallol, and benzoquinone.
- , Fe(CN)64−
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18. The electrode strip of claim 17 wherein said redox mediator is potassium ferrocyanide.
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19. The electrode strip of claim 1 wherein said enclosed channel is hydrophilic.
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20. The electrode strip of claim 1 wherein said enclosed channel has a volume of about 1.5 microliters.
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21. The electrode strip of claim 1 wherein said cover has a hydrophilic coating on at least one side.
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22. The electrode strip of claim 1 wherein said first reagent and said second reagent are made from a mixture having starting components in water comprising about 2 wt % of potassium ferrocyanide, about 1 wt % of methyl cellulose, about 0.02 wt % of said 1-octylphenoxypolyethoxyethanol, about 0.5 wt % of glucose oxidase, and about 0.5 wt % of soybean peroxidase.
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23. The electrode strip of claim 22 wherein said first reagent and said second reagent further includes about 0.1 wt % of an antioxidant.
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24. The electrode strip of claim 1 wherein said first reagent and said second reagent are made from a mixture having starting components in water comprising about 5 wt % of potassium ferrocyanide, about 1 wt % of methyl cellulose, about 0.02 wt % of t-octylphenoxypolyethoxyethanol, about 2 wt % of cholesterol oxidase, about 1 wt % of cholesterol esterase, and about 0.5 wt % of soybean peroxidase.
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25. The electrode strip of claim 24 wherein said first reagent and said second reagent further includes about 0.1 wt % of an antioxidant.
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26. A device for measuring creatinine comprising:
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a creatine measuring electrode having a creatine reagent comprising two enzymes capable of catalyzing a reaction involving a substrate for the enzyme creatine, a redox mediator and a peroxidase enzyme capable of catalyzing a reaction involving said redox mediator wherein said creatine reagent is water soluble;
a creatinine measuring electrode having a creatinine reagent comprising three enzymes capable of catalyzing a reaction involving a substrate for the enzyme creatinine, a redox mediator and a peroxidase enzyme capable of catalyzing a reaction involving said redox mediator wherein said creatinine reagent is water soluble; and
a reference electrode.
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27. The device of claim 26 wherein said two enzymes are creatine amidinohydrolase and sarcosine oxidase.
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28. The device of claim 26 wherein said three enzymes are creatinine amidohydrolase, creatine amidinohydrolase and sarcosine oxidase.
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29. The device of claim 26 further comprising a sample chamber containing said creatine measuring electrode, said creatinine measuring electrode and said reference electrode.
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30. A creatinine sensor comprising:
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a laminated body having a fluid sampling end and an electrical contact end;
a sampling end aperture at said fluid sampling end;
a sample fluid channel in communication between said fluid sample inlet and a vent opening, said sample fluid channel being adapted to collect a fluid sample through said sampling end aperture;
a creatine measuring electrode having a creatine reagent comprising two enzymes capable of catalyzing a reaction involving a substrate for the enzyme creatine, a redox mediator and a peroxidase enzyme capable of catalyzing a reaction involving said redox mediator wherein said creatine reagent is water-soluble;
a creatine-creatinine measuring electrode having a creatinine reagent comprising three enzymes capable of catalyzing a reaction involving a substrate for the enzyme creatinine, a redox mediator and a peroxidase enzyme capable of catalyzing a reaction involving said redox mediator wherein said creatinine reagent is water-soluble; and
a reference electrode wherein said creatine measuring electrode, said creatine-creatinine measuring electrode and said reference electrode are disposed within said sample fluid channel.
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31. The creatinine sensor of claim 30 wherein said two enzymes are creatine amidinohydrolase and sarcosine oxidase.
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32. The creatinine sensor of claim 30 wherein said three enzymes are creatinine amidohydrolase, creatine amidinohydrolase and sarcosine oxidase.
Specification