Small volume in vitro analyte sensor and methods of making
First Claim
1. A system for determining the concentration of an analyte in a sample fluid, the system comprising:
- (a) a sensor comprising;
a first substrate having a proximal end and a distal end, the distal end being configured and arranged for insertion into a sensor reader;
a second substrate disposed over the first substrate;
a spacer disposed between the first and second substrates and defining a first aperture along the first side edge of the sensor, a second aperture along the second side edge of the sensor, and a sample chamber extending from the first aperture to the second aperture, wherein the sample chamber is sized to contain a volume of no more than about 1 μ
L of the sample;
a working electrode and a counter electrode disposed in the sample chamber, wherein the working electrode and the counter electrode are separated by a closest distance in a range of from 200 to 1000 μ
m; and
an analyte-responsive enzyme and a redox mediator disposed in the sample chamber;
(b) a sensor reader configured to;
apply a first potential and a second potential to determine fill of the sample chamber;
apply a third potential to electrolyze the analyte, thereby generating an analyte signal; and
determine the concentration of the analyte using the analyte signal.
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Accused Products
Abstract
A sensor utilizing a non-leachable or diffusible redox mediator is described. The sensor includes a sample chamber to hold a sample in electrolytic contact with a working electrode, and in at least some instances, the sensor also contains a non-leachable or a diffusible second electron transfer agent. The sensor and/or the methods used produce a sensor signal in response to the analyte that can be distinguished from a background signal caused by the mediator. 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, using techniques such as coulometry, amperometry, and potentiometry. An enzyme capable of catalyzing the electrooxidation or electroreduction of the biomolecule is typically provided as a second electron transfer agent.
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Citations
36 Claims
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1. A system for determining the concentration of an analyte in a sample fluid, the system comprising:
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(a) a sensor comprising; a first substrate having a proximal end and a distal end, the distal end being configured and arranged for insertion into a sensor reader; a second substrate disposed over the first substrate; a spacer disposed between the first and second substrates and defining a first aperture along the first side edge of the sensor, a second aperture along the second side edge of the sensor, and a sample chamber extending from the first aperture to the second aperture, wherein the sample chamber is sized to contain a volume of no more than about 1 μ
L of the sample;a working electrode and a counter electrode disposed in the sample chamber, wherein the working electrode and the counter electrode are separated by a closest distance in a range of from 200 to 1000 μ
m; andan analyte-responsive enzyme and a redox mediator disposed in the sample chamber; (b) a sensor reader configured to; apply a first potential and a second potential to determine fill of the sample chamber; apply a third potential to electrolyze the analyte, thereby generating an analyte signal; and determine the concentration of the analyte using the analyte signal. - 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)
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25. A method for determining a concentration of an analyte in a sample, comprising the steps of:
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(a) contacting a sample with a sensor, wherein the sensor comprises; a first substrate having a proximal end and a distal end, the distal end being configured and arranged for insertion into a sensor reader; a second substrate disposed over the first substrate; a spacer disposed between the first and second substrates and defining a first aperture along the first side edge of the sensor, a second aperture along the second side edge of the sensor, and a sample chamber extending from the first aperture to the second aperture, wherein the sample chamber is sized to contain a volume of no more than about 1 μ
L of the sample;a working electrode and a counter electrode disposed in the sample chamber, wherein the working electrode and the counter electrode are separated by a closest distance in a range of from 200 to 1000 μ
m; andan analyte-responsive enzyme and a redox mediator disposed in the sample chamber; (b) applying a first potential and a second potential to determine fill of the sample chamber with sample; (c) applying a third potential to electrolyze the analyte, thereby generating an analyte signal; and (d) determining the concentration of the analyte using the analyte signal. - View Dependent Claims (26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36)
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Specification