Small volume in vitro sensor and methods of making

• US 8,226,815 B2
• Filed: 09/29/2009
• Issued: 07/24/2012
• Est. Priority Date: 10/08/1998
• Status: Expired due to Fees

• Current Assignee: Abbott Diabetes Care Incorporated (Abbott Laboratories Incorporated)
• Original Assignee: Abbott Diabetes Care Incorporated (Abbott Laboratories Incorporated)
• Inventors: Feldman, Benjamin J., Heller, Adam, Heller, Ephraim, Mao, Fei, Vivolo, Joseph A., Funderburk, Jeffery V., Colman, Fredric C., Krishnan, Rajesh
• Primary Examiner(s): Noguerola, Alex
• Application Number:
  US12/569,159
• Publication Number:
  US 20100018877A1
• Time in Patent Office: 1,029 Days
• Field of Search: 20440301-40315, 205/777.5, 205/778, 205/792, 205/775
• US Class Current: 205/792
• CPC Class Codes: C12Q 1/001 Enzyme electrodes
• CPC Class Codes: C12Q 1/006 for glucose
• CPC Class Codes: C12Q 1/32 involving dehydrogenase
• CPC Class Codes: G01N 27/3271 Amperometric enzyme electrodes for analytes in body fluids, e.g. glucose in blood amperometry per se G01N27/49; aspects concerning the enzyme reagent C12Q1/001
• CPC Class Codes: G01N 27/3272 Test elements therefor, i.e. disposable laminated substrates with electrodes, reagent and channels optical biosensors G01N33/52
• CPC Class Codes: G01N 27/3274 Corrective measures, e.g. error detection, compensation for temperature or hematocrit, calibration coding of calibration information G01N33/48771
• CPC Class Codes: Y10T 156/1052 with cutting, punching, tearing or severing
• CPC Class Codes: Y10T 29/49002 Electrical device making
• CPC Class Codes: Y10T 29/49004 including measuring or testing of device or component part
• CPC Class Codes: Y10T 29/49007 Indicating transducer
• CPC Class Codes: Y10T 29/49126 Assembling bases
• CPC Class Codes: Y10T 29/49128 Assembling formed circuit to base
• CPC Class Codes: Y10T 29/4913 Assembling to base an electrical component, e.g., capacitor, etc.
• CPC Class Codes: Y10T 29/49147 Assembling terminal to base
• CPC Class Codes: Y10T 29/49155 Manufacturing circuit on or in base
• CPC Class Codes: Y10T 29/49204 Contact or terminal manufacturing
• CPC Class Codes: Y10T 29/49208 by assembling plural parts
• CPC Class Codes: Y10T 29/4921 with bonding
• CPC Class Codes: Y10T 29/49794 Dividing on common outline

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.

Claims

1. A method of determining a concentration of an analyte in a sample using an electrochemical sensor, the method comprising:

contacting a sample with an electrochemical sensor;

drawing at least a portion of the sample through one of a first and a second aperture and into a sample chamber;

observing a signal from a first indicator electrode to signify that the sample chamber is beginning to fill with sample;

observing a signal from a second indicator electrode to signify that the sample chamber is sufficiently full for determining the concentration of the analyte using the sensor; and

generating a analyte-responsive signal from the sensor in response to electrolysis of the analyte in the sample to determine the concentration of the analyte in the sample.

2. The method of claim 1, wherein generating a analyte-responsive signal comprises generating the ketone-responsive signal using the working electrode, the counter electrode, and at least one of the first and second indicator electrodes.

3. The method of claim 1, wherein the step of generating a analyte-responsive signal occurs simultaneously with and continues after the step of observing the second indicator electrode.

4. The method of claim 1, wherein the step of generating a analyte-responsive signal occurs after the step of observing the second indicator electrode.

5. The method of claim 1, wherein the concentration of the analyte is determined using coulometry.

6. The method of claim 1, wherein the concentration of the analyte is determined using amperometry.

7. The method of claim 1, wherein the concentration of the analyte is determined using potentiometry.

8. The method of claim 1, wherein the analyte is glucose or a ketone.

9. The method of claim 8, wherein the analyte is glucose.

10. The method of claim 9, wherein the sensor comprises a glucose-responsive enzyme selected from glucose dehydrogenase and glucose oxidase.

11. The method of claim 1, further comprising obtaining the sample from a finger of a subject.

12. The method of claim 1, further comprising obtaining the sample from a region of a subject having a lower nerve end density as compared to a fingertip.

13. The method of claim 12, wherein the region of a subject having a lower nerve end density as compared to a fingertip is selected from the group consisting of:

a forearm region, and a thigh region.