Small volume in vitro analyte sensor
First Claim
1. A method for determining a concentration of an analyte in a body fluid of a patient, comprising the steps of:
- piercing a location of skin on a patient to provide a body fluid sample of less than 1 μ
L, wherein the location comprises a lower nerve end density as compared to a fingertip;
transporting at least a portion of the body fluid into an analyte sensor comprising;
at least two plates, wherein said plates form a boundary area wherein a biological fluid is analyzed, wherein said boundary area receives a volume of biological fluid no greater than 500 nl;
a working electrode and a reference electrode and/or counter electrode;
a reagent layer including an enzyme-based composition, wherein said reagent layer is associated with said working electrode; and
a tapered tip fill region associated with said boundary area for the transport of a biological fluid;
holding the sample within said boundary area of the analyte sensor in a non-flow-through manner; and
determining by coulometry the concentration of the analyte in the body fluid from the portion of the body fluid transported into the analyte sensor.
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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.
461 Citations
16 Claims
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1. A method for determining a concentration of an analyte in a body fluid of a patient, comprising the steps of:
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piercing a location of skin on a patient to provide a body fluid sample of less than 1 μ
L, wherein the location comprises a lower nerve end density as compared to a fingertip;transporting at least a portion of the body fluid into an analyte sensor comprising; at least two plates, wherein said plates form a boundary area wherein a biological fluid is analyzed, wherein said boundary area receives a volume of biological fluid no greater than 500 nl; a working electrode and a reference electrode and/or counter electrode; a reagent layer including an enzyme-based composition, wherein said reagent layer is associated with said working electrode; and a tapered tip fill region associated with said boundary area for the transport of a biological fluid; holding the sample within said boundary area of the analyte sensor in a non-flow-through manner; and determining by coulometry the concentration of the analyte in the body fluid from the portion of the body fluid transported into the analyte sensor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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Specification