Small volume in vitro sensor and methods of making
First Claim
1. A sensor for determining the concentration of an analyte in a sample fluid, the sensor comprising:
- a working electrode and a counter electrode, wherein the working electrode and counter electrode are separated by an effective distance in a range of 25 to 1000 μ
m;
a sample chamber for holding the sample fluid, the sample chamber comprising the working electrode and the counter electrode, wherein the sample chamber is sized to contain a volume of no more than about 1 μ
L of the sample;
two indicator electrodes disposed in the sensor, wherein a first indicator electrode indicates when the sample chamber is beginning to fill with sample and a second indicator electrode indicates when the sample chamber is substantially filled with sample, and wherein the working electrode is disposed between the first and second indicator electrodes; and
an analyte-responsive enzyme and a redox mediator disposed in the sample chamber.
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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.
466 Citations
28 Claims
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1. A sensor for determining the concentration of an analyte in a sample fluid, the sensor comprising:
-
a working electrode and a counter electrode, wherein the working electrode and counter electrode are separated by an effective distance in a range of 25 to 1000 μ
m;a sample chamber for holding the sample fluid, the sample chamber comprising the working electrode and the counter electrode, wherein the sample chamber is sized to contain a volume of no more than about 1 μ
L of the sample;two indicator electrodes disposed in the sensor, wherein a first indicator electrode indicates when the sample chamber is beginning to fill with sample and a second indicator electrode indicates when the sample chamber is substantially filled with sample, and wherein the working electrode is disposed between the first and second indicator electrodes; and an analyte-responsive enzyme and a redox mediator disposed in the sample chamber. - 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, 27, 28)
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Specification