Method of using a small volume in vitro analyte sensor
First Claim
1. A method of determining a concentration of an analyte in a sample, the method comprising steps of:
- contacting the sample with an electrochemical sensor comprising a working electrode, a counter electrode, and a measurement zone bounded on at least two sides by the working electrode and counter electrode, wherein the measurement zone is sized to contain less than about 1 μ
L of sample;
holding the sample within the measurement zone in a non-flowing manner;
applying a potential between the working and counter electrodes to electrolyze a portion of the analyte in the sample in the measurement zone;
measuring current generated by the electrochemical sensor at a plurality of times while portion of the analyte is being electrolyzed; and
determining, by coulometry, a concentration of the analyte in the sample using the measured currents.
4 Assignments
0 Petitions
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 an enzyme, can be added to facilitate the electrooxidation or electroreduction 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 amperometric, voltammetric, and potentiometric techniques, can also be used.
The invention can be used to determine the concentration of a biomolecule, 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 biomolecule is provided as a second electron transfer agent.
-
Citations
115 Claims
-
1. A method of determining a concentration of an analyte in a sample, the method comprising steps of:
-
contacting the sample with an electrochemical sensor comprising a working electrode, a counter electrode, and a measurement zone bounded on at least two sides by the working electrode and counter electrode, wherein the measurement zone is sized to contain less than about 1 μ
L of sample;holding the sample within the measurement zone in a non-flowing manner; applying a potential between the working and counter electrodes to electrolyze a portion of the analyte in the sample in the measurement zone; measuring current generated by the electrochemical sensor at a plurality of times while portion of the analyte is being electrolyzed; and determining, by coulometry, a concentration of the analyte in the sample using the measured currents. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
-
-
15. A method of determining a concentration of an analyte in a sample, the method comprising steps of:
-
contacting the sample with an electrochemical sensor comprising a working electrode, a counter electrode, and a sample chamber for holding the sample in electrolytic contact with the working electrode and counter electrode, wherein the sample chamber is sized to contain less than about 1 μ
L of sample;holding the sample within the sample chamber in a non-flowing manner; applying a potential between the working and counter electrodes to electrolyze a portion of the analyte in the sample within the sample chamber; measuring current generated by the working electrode at a plurality of times while the portion of the analyte is being electrolyzed; and determining, by coulometry, a concentration of the analyte in the sample using the measured currents. - View Dependent Claims (16, 17, 18, 19)
-
-
20. A method of determining a concentration of an analyte in a sample, the method comprising steps of:
-
contacting the sample with an electrochemical sensor comprising a working electrode, a counter electrode, and a sample chamber for holding the sample in electrolytic contact with the working electrode and counter electrode; holding the sample within the sample chamber in a non-flowing manner; applying a potential between the working and counter electrodes to electrolyze the analyte in a portion of the sample within the sample chamber, wherein the portion of the sample in which the analyte is electrolyzed has a volume of less than 1 μ
L;measuring current generated by the electrochemical sensor at a plurality of times while the analyte in the portion of the sample is being electrolyzed; and determining, by coulometry, a concentration of the analyte in the sample using the measured currents. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31)
-
-
32. A method for determining a concentration of an analyte in a sample, comprising the steps of:
contacting a sample with an electrochemical sensor comprising; a facing electrode pair comprising a working electrode and a counter electrode; and a sample chamber for holding the sample in electrolytic contact with the working electrode, the sample chamber comprising a measurement zone positioned between the working and counter electrodes, wherein the measurement zone is sized to contain a volume of less than about 1 μ
L of sample;holding the sample stationary in the sample chamber; and determining the concentration of the analyte in the sample by coulometry. - View Dependent Claims (33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77)
-
78. A method of determining the concentration of an analyte in a sample, comprising the steps of:
-
contacting a sample with an electrochemical sensor, wherein the sensor comprises a working electrode, a non-leachable redox mediator on the working electrode, and a sample chamber sized to contain a volume of less than about 1 μ
L of sample in electrolytic contact with the working electrode;holding the sample stationary in the sample chamber; and determining the concentration of the analyte in the sample by coulometry. - View Dependent Claims (79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95)
-
-
96. A method for determining the concentration of an analyte in a sample, comprising the steps of:
contacting the sample with an electrochemical sensor;
the sensor comprising;an electrode pair comprising a working electrode and a counter electrode; a sample chamber for holding the sample in electrolytic contact with the working electrode; and a sorbent disposed within the sample chamber; wherein the sample chamber is sized to hold less than about 1 μ
L of sample;holding the sample stationary in the sample chamber; and determining the concentration of the analyte by coulometry. - View Dependent Claims (97, 98)
-
99. A method for measuring analyte in a patient sample, the method comprising:
-
contacting the patient with an analyte measuring device, the device comprising; sample acquisition means for producing a patient sample; and an electrochemical sensor for measuring analyte in the sample;
wherein the electrochemical sensor comprises;a facing electrode pair, comprising a working electrode and a counter electrode; and a measurement zone positioned between the working electrode and counter electrode, wherein the measurement zone is sized to contain a volume of less than about 1 μ
L of sample;acquiring a sample using the sample acquisition means; transporting a portion of the sample to the measurement zone of the electrochemical sensor; holding the sample stationary in the sample chamber; and determining the concentration of the analyte in the sample by coulometry. - View Dependent Claims (100, 101, 102, 103, 104, 105, 106, 107, 108)
-
-
109. A method for measuring analyte in a patient sample, the method comprising:
-
contacting the patient with an analyte measuring device, the device comprising; sample acquisition means for producing a patient sample; and an electrochemical sensor for measuring analyte in the sample, wherein the electrochemical sensor comprises; a working electrode; non-leachable redox mediator on the working electrode; and a sample chamber for holding the sample in electrolytic contact with the working electrode, wherein the sample chamber is sized to contain a volume of less than about 1 μ
L of sample;acquiring a sample using the sample acquisition means; transporting a portion of the sample to the sample chamber of the electrochemical sensor; holding the sample within the sample chamber in a non-flowing manner; and determining the concentration of the analyte in the sample by coulometry.
-
-
110. A method for determination of a concentration of an analyte in a sample, the method comprising the steps of:
-
contacting a sample with an electrochemical sensor comprising; first and second electrode pairs, each pair comprising a working electrode, and a sample chamber for holding the sample in electrolytic contact with the working electrode, the sample chamber sized to contain a volume of less about 1 μ
L of sample;
wherein said first electrode pair includes a non-leachable redox mediator and a non-leachable enzyme on the working electrode; and
wherein said second electrode pair includes non-leachable redox mediator on the working electrode in the absence of enzyme;holding the sample stationary in the sample chamber; measuring substantially simultaneously, and at two or more times, a first current generated at the first electrode pair and a second current generated at the second electrode pair; and integrating the measured first currents over time to obtain a first charge; integrating the measured second currents over time to obtain a second charge; subtracting the second charge from the first charge to obtain a noise-reduced charge; and correlating the concentration of the analyte to the noise-reduced charge. - View Dependent Claims (111)
-
-
112. A method for determining a concentration of an analyte in a sample, the method comprising the steps of:
-
providing an electrochemical sensor, the sensor having one or more facing electrode pairs, each electrode pair comprising a working electrode, a counter electrode, and a measurement zone between the working electrode and the counter electrode, the measurement zone having a volume of less than about 1 μ
L, wherein the measurement zones of the one or more electrode pairs have approximately equal volumes, and wherein at least one of the electrode pairs further comprises redox mediator on its working electrode;measuring a capacitance of at least one of the electrode pairs; calculating the volume of the measurement zone from the capacitance measurement; contacting the sample with the sensor; and determining the concentration of the analyte in the sample by coulometry. - View Dependent Claims (113)
-
-
114. A method for determining a concentration of an analyte in a sample comprising the steps of:
-
contacting the sample with an electrochemical sensor, the sensor comprising a working electrode and a non-leachable redox mediator on the working electrode, wherein the molar amount of redox mediator in a reduced form prior to introduction of the sample is less than, on a stoichiometric basis, 5% of the expected molar amount of the analyte to be electrolyzed; holding the sample stationary in the sample chamber; electrolyzing less than about 1 μ
L of sample; anddetermining the concentration of the analyte in the sample by coulometry.
-
-
115. A method of determining a concentration of an analyte in a sample comprising the steps of:
-
contacting the sample with an electrochemical sensor comprising a working electrode, a counter electrode, and a measurement zone bounded on at least two sides by the working and the counter electrodes, wherein the measurement zone is sized to contain less than about 1 μ
L of sample;holding the sample stationary in the sample chamber; and determining the concentration of the analyte in the sample by coulometry.
-
Specification