MEDIATOR STABILIZED REAGENT COMPOSITIONS AND METHODS FOR THEIR USE IN ELECTROCHEMICAL ANALYTE DETECTION ASSAYS
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Abstract
Mediator stabilized reagent compositions and methods for their use in electrochemical analyte determination assays are provided. The subject reagent compositions include an enzyme, a redox mediator and a mediator-stabilizing buffer. Optionally, the reagent compositions may further include one or more of a wetting agent, detergent, enzyme cofactor and combinations thereof. Also provided are electrochemical test strips that include the subject reagent compositions, systems and kits that include the same as well as methods for using the same in analyte detection assays. The subject invention finds use in a variety of different applications, including glucose concentration determination applications.
35 Citations
61 Claims
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1-38. -38. (canceled)
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39. A dry reagent composition comprising:
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an enzyme;
a redox mediator;
an enzyme cofactor; and
a mediator-stabilizing buffer comprising a polycarboxylic acid having at least two carboxylic acid groups, present in an amount in the range of 0.01% wt/wt to 40% wt/wt sufficient to stabilize said redox mediator during storage of the dry reagent composition, wherein said mediator-stabilizing buffer has a low binding affinity for divalent metal ions, said low binding affinity for divalent metal ions being at least 2-fold less than a divalent metal ion binding affinity of an enzyme/cofactor complex formed from the enzyme and the cofactor of the dry reagent mixture. - View Dependent Claims (40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55)
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56. An electrochemical cell comprising a dry reagent composition that includes:
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an enzyme;
a redox mediator;
an enzyme cofactor; and
a mediator-stabilizing buffer comprising a polycarboxylic acid having at least two carboxylic acid groups, present in an amount in the range of 0.01% wt/wt to 40% wt/wt sufficient to stabilize said redox mediator during storage of the dry reagent composition, wherein said mediator-stabilizing buffer has a low binding affinity for divalent metal ions, said low binding affinity for divalent metal ions being at least 2-fold less than a divalent metal ion binding affinity of an enzyme/cofactor complex formed from the enzyme and the cofactor of the dry reagent mixture. - View Dependent Claims (57)
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58. A method for making an electrochemical test strip, the method comprising:
making an electrochemical strip that includes;
a dry reagent composition with;
an enzyme;
a redox mediator;
an enzyme cofactor; and
a mediator-stabilizing buffer comprising a polycarboxylic acid having at least two carboxylic acid groups, present in an amount in the range of 0.01% wt/wt to 40% wt/wt sufficient to stabilize said redox mediator during storage of the dry reagent composition, wherein said mediator-stabilizing buffer has a low binding affinity for divalent metal ions, said low binding affinity for divalent metal ions being at least 2-fold less than a divalent metal ion binding affinity of an enzyme/cofactor complex formed from the enzyme and the cofactor of the dry reagent mixture.
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59. A method for determining the concentration of an analyte in a sample, said method comprising:
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(a) applying said sample to an electrochemical cell comprising a dry reagent composition that includes;
an enzyme;
a redox mediator;
an enzyme cofactor; and
a mediator-stabilizing buffer comprising a polycarboxylic acid having at least two carboxylic acid groups, present in an amount in the range of 0.01% wt/wt to 40% wt/wt sufficient to stabilize said redox mediator during storage of the dry reagent composition, wherein said mediator-stabilizing buffer has a low binding affinity for divalent metal ions, said low binding affinity for divalent metal ions being at least 2-fold less than a divalent metal ion binding affinity of an enzyme/cofactor complex formed from the enzyme and the cofactor of the dry reagent mixture;
(b) detecting an electrical signal produced by said cell; and
(c) relating said detected electrical signal to the concentration of said analyte in said sample. - View Dependent Claims (60, 61)
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Specification