Small volume in vitro analyte 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 separated by an effective distance in a range of 25 to 1000 μ
m; and
a sample chamber for holding the sample fluid, the sample chamber comprising the working electrode, the counter electrode, an analyte-responsive enzyme, a diffusible redox mediator, and a barrier disposed only on the counter electrode, which barrier prevents or slows diffusion of the redox mediator to the counter electrode, wherein the sample chamber is sized to contain a volume of no more than about 1 μ
L of the sample.
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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
27 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 separated by an effective distance in a range of 25 to 1000 μ
m; anda sample chamber for holding the sample fluid, the sample chamber comprising the working electrode, the counter electrode, an analyte-responsive enzyme, a diffusible redox mediator, and a barrier disposed only on the counter electrode, which barrier prevents or slows diffusion of the redox mediator to the counter electrode, wherein the sample chamber is sized to contain a volume of no more than about 1 μ
L of the sample. - 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)
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Specification