Small Volume In Vitro Analyte Sensor and Methods of Making

• US 20100086961A1
• Filed: 09/29/2009
• Published: 04/08/2010
• Est. Priority Date: 10/08/1998
• Status: Abandoned Application

• Current Assignee: Abbott Diabetes Care Incorporated (Abbott Laboratories Incorporated)
• Original Assignee: Abbott Diabetes Care Incorporated (Abbott Laboratories Incorporated)
• Inventors: FUNDERBURK, Jeffery V., KRISHNAN, Rajesh, HELLER, Ephraim, COLMAN, Fredrick C., FELDMAN, Benjamin J., HELLER, Adam, VIVOLO, Joseph A., MAO, Fei
• Application Number:
  US12/569,445
• Publication Number:
  US 20100086961A1
• Time in Patent Office: Days
• US Class Current: 435/29
• 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

1-11. -11. (canceled)

12. A method of determining a concentration of a ketone in blood, the method comprising steps of:

stimulating a region of skin having a lower nerve end density as compared to a fingertip by manually rubbing the region of skin;

after stimulating the region of skin, lancing the region of skin to cause a flow of blood from the region of skin;

contacting a sensor strip to the blood and transporting the blood to a sample chamber in the sensor strip; and

determining the concentration of the ketone.

13. The method of claim 12, wherein the period of time is for a period of time adequate to obtain a ketone measurement that is at least 10% nearer a concentration determined from blood obtained from a fingertip measurement than a determination of the concentration of the ketone from blood obtained from the region of skin without stimulating.

14. The method of claim 12, wherein the sensor strip is an electrochemical sensor strip.

15. The method of claim 14, wherein the electrochemical sensor strip comprises a working electrode and a counter electrode, wherein the working electrode and the counter electrode are separated by a closest distance no greater than 1000 μ

m.

16. The method of claim 15, wherein the electrochemical sensor strip comprises a ketone-responsive enzyme and a diffusible redox mediator disposed proximate to the working electrode.

17. The method of claim 12, wherein the sensor strip is an optical sensor strip.

18. The method of claim 12, wherein the step of stimulating the region of skin comprises manually rubbing the skin for a period of at least one second.

19. The method of claim 12, wherein the step of stimulating the region of skin comprises manually rubbing the skin for a period of at least 2 seconds.

20. The method of claim 12, wherein the step of stimulating the region of skin comprises manually rubbing the skin for a period of at least 5 seconds.

21. The method of claim 12, wherein the step of transporting the blood to a sample chamber in the sensor strip comprises transporting no more than about 1 microliter of the blood.

22. The method of claim 21, wherein the step of transporting no more than about 1 microliter of the blood to a sample chamber in the sensor strip comprises transporting no more than about 0.5 microliter of the blood.

23. The method of claim 22, wherein the step of transporting no more than about 0.5 microliter of the blood comprises transporting no more than about 0.25 microliter of the blood.

24. The method of claim 23, wherein the step of transporting no more than about 0.25 microliter of the blood comprises transporting no more than about 0.1 microliter of the blood.

25. The method of claim 12, wherein the sensor strip comprises a tip-fill sensor strip.

26. The method of claim 12, wherein the sensor strip comprises a side-fill sensor strip.

27. The method of claim 12, wherein the step of determining the concentration of ketone comprises determining the concentration of ketone using coulometry.

28. The method of claim 12, wherein the step of determining the concentration of ketone comprises determining the concentration of ketone using amperometry.

29. The method of claim 12, wherein the step of determining the concentration of ketone comprises determining the concentration of ketone using potentiometry.

30. A method of determining a concentration of a ketone in blood, the method comprising steps of:

stimulating a region of skin having a lower nerve end density as compared to a fingertip by manually rubbing the region of skin for at least one second;

after stimulating the region of skin, lancing the region of skin to cause a flow of blood from the region;

contacting an electrochemical sensor strip to the blood and transporting the blood to a sample chamber in the sensor strip, wherein the electrochemical sensor strip comprises;

a working electrode and a counter electrode, wherein the working electrode and the counter electrode are separated by a closest distance no greater than 1000 μ

m, and

ketone-responsive enzyme and a diffusible redox mediator disposed proximate to the working electrode; and

determining the concentration of the ketone using coulometry, amperometry, or potentiometry.

31. The method of claim 31, wherein the period of time is for a period of time adequate to obtain a ketone measurement that is at least 10% nearer a concentration determined from blood obtained from a fingertip measurement than a determination of the concentration of ketone from blood obtained from the region of skin without stimulating.

32. The method of claim 31, wherein the sensor strip comprises a tip-fill sensor strip.

33. The method of claim 31, wherein the sensor strip comprises a side-fill sensor strip.

34. The method of claim 31, wherein the step of transporting the blood to a sample chamber in the sensor strip comprises transporting no more than about 1 microliter of the blood.