Small volume in vitro analyte sensor
First Claim
1. A method for determining a concentration of an analyte in a body fluid of a patient, comprising the steps of:
- piercing a portion of the skin of a patient to create a flow of a body fluid;
transporting 500 nl or less of the body fluid into an analyte sensor comprising two pairs of electrodes and a redox mediator, each pair of electrodes comprising a working electrode and a reference or counter electrode, wherein the sensor is configured and arranged for determining the concentration of the analyte from 500 nL or less of body fluid;
holding the sample within the analyte sensor in a non-flow through manner such that the sample is in electrolytic contact with the pairs of electrodes; and
determining by coulomtery the concentration of the analyte in the body fluid from the 500 nl or less of body fluid transported into the analyte sensor.
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Accused Products
Abstract
A sensor designed to determine the amount and concentration of analyte in a sample having a volume of less than about 1 μL. The sensor has a working electrode coated with a non-leachable redox mediator. The redox mediator acts as an electron transfer agent between the analyte and the electrode. In addition, a second electron transfer agent, such as art enzyme, can be added to facilitate the electrooxidation or etectroreduction of the analyte. The redox mediator is typically a redox compound bound to a polymer. The preferred redox mediators are air-oxidizable. The amount of analyte can be determined by coulometry. One particular coulometric technique includes the measurement of the current between the working electrode and a counter or reference electrode at two or more times. The charge passed by this current to or from the analyte is correlated with the amount of analyte in the sample. Other electrochemical detection methods, such as arnperometric, voltammetric and potentiometric techniques, can also be used. The invention can be used to determine the concentration of a biomolecute, such as glucose or lactate, in a biological fluid, such as blood or serum. An enzyme capable of catalyzing the electrooxidation or electroreduction of the biomolecute is provided as a second electron transfer agent.
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Citations
57 Claims
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1. A method for determining a concentration of an analyte in a body fluid of a patient, comprising the steps of:
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piercing a portion of the skin of a patient to create a flow of a body fluid; transporting 500 nl or less of the body fluid into an analyte sensor comprising two pairs of electrodes and a redox mediator, each pair of electrodes comprising a working electrode and a reference or counter electrode, wherein the sensor is configured and arranged for determining the concentration of the analyte from 500 nL or less of body fluid; holding the sample within the analyte sensor in a non-flow through manner such that the sample is in electrolytic contact with the pairs of electrodes; and determining by coulomtery the concentration of the analyte in the body fluid from the 500 nl or less of body fluid transported into the analyte sensor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
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27. A method for determining a concentration of an analyte in a body fluid of a patient, comprising the steps of:
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piercing a portion of the skin of a patient to create a flow of a body fluid; transporting 500 nl or less of the body fluid into an analyte sensor comprising three pairs of electrodes and a redox mediator, each pair of electrodes comprising a working electrode and a reference or counter electrode, wherein the sensor is configured and arranged for determining the concentration of the analyte from 500 nL or less of body fluid; holding the sample within the analyte sensor in a non-flow through manner such that the sample is in electrolytic contact with the pairs of electrodes; and determining by coulometry the concentration of the analyte in the 500 nl or less of body fluid transported into the analyte sensor. - View Dependent Claims (28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39)
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40. A method for determining a concentration of an analyte in a body fluid of a patient, comprising the steps of:
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piercing a portion of the skin of a patient to create a flow of a body fluid; transporting 500 nl or less of the body fluid into an analyte sensor comprising one pair of electrodes and a redox mediator, the pair of electrodes comprising a working electrode and a reference or counter electrode, wherein the sensor is configured and arranged for determining the concentration of the analyte from 500 nL or less of body fluid; holding the sample within the analyte sensor in a non-flow through manner such that the sample is in electrolytic contact with the pair of electrodes; and determining by coulometry the concentration of the analyte in the 500 nl or less of body fluid transported into the analyte sensor. - View Dependent Claims (41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57)
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Specification