Small Volume In Vitro Analyte Sensor
3 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
158 Claims
-
1-132. -132. (canceled)
-
133. A method for determining a concentration of glucose in a sample, comprising the steps of:
-
lancing a region of forearm skin of a subject to provide a sample; contacting the sample with an electrochemical sensor comprising; (i) an electrode pair comprising a working electrode and a counter electrode, wherein the working electrode and counter electrode are separated by a closest distance in a range of 200 to 1000 μ
m;(ii) a measurement zone positioned adjacent to the working electrode and the counter electrode, wherein the measurement zone is sized to contain a volume of no more than about 1 μ
L of the sample; and(iii) an analyte-responsive enzyme and a redox mediator disposed in the measurement zone; generating a sensor signal at the working electrode within a measurement period of no greater than about 5 minutes, wherein a background signal that is generated by the redox mediator is no more than five times a signal generated by oxidation or reduction of 5 mM of glucose; and determining the concentration of the glucose using the sensor signal. - View Dependent Claims (134, 135, 136, 137, 138, 139, 140, 141, 142, 143, 144, 145)
-
-
146. A method for determining a concentration of glucose in a sample, comprising the steps of:
-
lancing a region of forearm skin of a subject to provide a sample; contacting the sample with an electrochemical sensor comprising; (i) a working electrode and a counter electrode, wherein the working electrode and counter electrode are separated by a closest distance no greater than 1000 μ
m;(ii) a measurement zone positioned adjacent to the working electrode and the counter electrode, wherein the measurement zone is sized to contain a volume of no more than about 1 μ
L of the sample; and(iii) an analyte-responsive enzyme and a redox mediator disposed in the measurement zone; generating a sensor signal at the working electrode within a measurement period, wherein a background signal that is generated by the redox mediator is no more than five times a signal generated by oxidation or reduction of an average normal physiological amount of analyte; and determining the concentration of the glucose by amperometry using the sensor signal. - View Dependent Claims (147, 148, 149)
-
-
150. A method for determining a concentration of an analyte in a sample, comprising the steps of:
-
lancing a region of forearm skin of a subject to provide a sample; contacting the sample with an electrochemical sensor comprising; (i) an electrode pair comprising a working electrode and a counter electrode, wherein the working electrode and counter electrode are separated by a closest distance in a range of 200 to 1000 μ
m;(ii) a measurement zone positioned adjacent to the working electrode and the counter electrode, wherein the measurement zone is sized to contain a volume of no more than about 1 μ
L of the sample; and(iii) an analyte-responsive enzyme and a redox mediator disposed in the measurement zone; generating a sensor signal at the working electrode within a measurement period, wherein a background signal that is generated by the redox mediator is no more than five times a signal generated by oxidation or reduction of an average normal physiological amount of analyte; and determining the concentration of the analyte using the sensor signal. - View Dependent Claims (151, 152, 153, 154, 155, 156, 157, 158)
-
Specification