Small volume in vitro analyte sensor and methods of making

• US 8,449,758 B2
• Filed: 09/29/2009
• Issued: 05/28/2013
• 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:
  US12/569,351
• Publication Number:
  US 20100018873A1
• Time in Patent Office: 1,337 Days
• Field of Search: 20440301-40315, 205/777.5, 205/778, 205/792
• US Class Current: 205/777.5
• 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 for determining a concentration of glucose in a sample, comprising the steps of:

(a) contacting a sample with an electrochemical sensor comprising;

(i) a proximal end and a distal end, the distal end being configured and arranged for insertion into a sensor reader;

(ii) a first electrode, a second electrode, and a third electrode, wherein the first and second electrodes are separated by a closest distance in a range of 25 to 1000 μ

m;

(iii) a sample chamber comprising the first electrode, the second electrode, and the third electrode, wherein the sample chamber is sized to contain a volume of no more than about 1 μ

L of the sample; and

(iv) a glucose-responsive enzyme and a redox mediator disposed in the sample chamber;

(b) applying a first potential between the first and second electrodes to determine when the sample chamber is beginning to fill with sample;

(c) applying a second potential between the first and third electrodes to determine when the sample chamber is substantially filled with sample;

(d) applying a third potential between the first and second electrodes to electrolyze the glucose, thereby generating a glucose signal; and

(e) determining the concentration of the glucose using the glucose signal.

2. The method of claim 1, wherein the step of contacting a sample with an electrochemical sensor comprises contacting a sample with the electrochemical sensor, wherein the first electrode and the third electrode are separated by a closest distance in a range of 25 to 1000 μ

m.

3. The method of claim 1, wherein the first electrode is disposed on a first substrate and the second electrode is disposed on the first substrate.

4. The method of claim 1, wherein the step of determining the concentration of the glucose using the glucose signal comprises determining the concentration of the glucose by amperometry using the glucose signal.

5. The method of claim 1, wherein the step of determining the concentration of the glucose using the glucose signal comprises determining the concentration of the glucose by coulometry using the glucose signal.

6. The method of claim 1, wherein the step of determining the concentration of the glucose using the glucose signal comprises determining the concentration of the glucose by potentiometry using the glucose signal.

7. The method of claim 1, wherein the step of determining the concentration of the glucose using the glucose signal comprises determining the concentration of the glucose by voltammetry using the glucose signal.

8. The method of claim 1, wherein the sample chamber is sized to contain a volume of no more than about 0.5 μ

L of the sample.

9. The method of claim 1, wherein the sample chamber is sized to contain a volume of no more than about 0.2 μ

L of the sample.

10. The method of claim 1, wherein the sample chamber is sized to contain a volume of no more than about 0.1 μ

L of the sample.

11. The method of claim 1, wherein the sample is a blood sample, and wherein the method further comprises obtaining the sample from a finger of a subject.

12. The method of claim 1, wherein the sample is a blood sample, and wherein the method further comprises 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 1, wherein the proximal end comprises a first extension positioned at a first sample entry port and a second extension positioned at a second sample entry port.