Electrochemical analyte detection apparatus and method
First Claim
1. A method for determining the amount of enzyme present at one electrode independent of the amount of enzyme present at a second electrode, comprising the steps of:
- (a) introducing a sample to a test cell comprising first and second electrodes, a mobile test reagent comprising a redox enzyme portion, and reagents that interact with the mobile test reagent and/or the analyte, such that the mobile test reagent has a first distribution relative to the electrodes when analyte is present in the sample and a second distribution relative to the electrodes when analyte is not present sample, one of said first and second distributions being asymmetric with respect to a line between the electrodes, and the other of the first and second distributions being symmetric or less asymmetric with respect to the line between the electrodes,(b) supplying a redox substrate for the redox enzyme in the test cell, said redox substrate being acted upon by the redox enzyme to produce a chemical potential gradient between the first and second electrodes, wherein the magnitude of the chemical potential gradient is determined by the distribution of the mobile test reagent and thus on the presence of analyte,(c) detecting the chemical potential gradient, I0, between the first and second electrodes to determine the ratio of enzyme activity present at the two electrodes, wherein the formation and detection of the chemical potential gradient are performed without application of an external potential or current,(d) applying a potential and measuring the resulting current, I300, between the first and second electrodes, and(e) calculating an amount of enzyme, E1, present at one electrode.
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Accused Products
Abstract
A method and apparatus for electrochemical detection of analyte in a sample makes use of a binding interaction and relies on the discovery that asymmetric distribution of a redox enzyme between two electrodes that occurs when a redox enzyme-containing reagent is immobilized at the surface of one electrode can be detected as a chemical potential gradient arising from an asymmetry in the distribution of oxidized or reduced redox substrate. This chemical potential gradient can be detected potentiometrically by observing the potential difference between the electrodes in an open circuit, or amperometrically by observing the current flow between the electrodes when the circuit is closed. In both cases, the observation of asymmetry can be done without the application of an external potential or current to the electrodes.
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Citations
15 Claims
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1. A method for determining the amount of enzyme present at one electrode independent of the amount of enzyme present at a second electrode, comprising the steps of:
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(a) introducing a sample to a test cell comprising first and second electrodes, a mobile test reagent comprising a redox enzyme portion, and reagents that interact with the mobile test reagent and/or the analyte, such that the mobile test reagent has a first distribution relative to the electrodes when analyte is present in the sample and a second distribution relative to the electrodes when analyte is not present sample, one of said first and second distributions being asymmetric with respect to a line between the electrodes, and the other of the first and second distributions being symmetric or less asymmetric with respect to the line between the electrodes, (b) supplying a redox substrate for the redox enzyme in the test cell, said redox substrate being acted upon by the redox enzyme to produce a chemical potential gradient between the first and second electrodes, wherein the magnitude of the chemical potential gradient is determined by the distribution of the mobile test reagent and thus on the presence of analyte, (c) detecting the chemical potential gradient, I0, between the first and second electrodes to determine the ratio of enzyme activity present at the two electrodes, wherein the formation and detection of the chemical potential gradient are performed without application of an external potential or current, (d) applying a potential and measuring the resulting current, I300, between the first and second electrodes, and (e) calculating an amount of enzyme, E1, present at one electrode. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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Specification