Reference electrodes having an extended lifetime for use in long term amperometric sensors

• US 9,042,955 B2
• Filed: 08/27/2012
• Issued: 05/26/2015
• Est. Priority Date: 06/02/2008
• Status: Active Grant

• Current Assignee: Abbott Diabetes Care Incorporated (Abbott Laboratories Incorporated)
• Original Assignee: Abbott Diabetes Care Incorporated (Abbott Laboratories Incorporated)
• Inventors: Liu, Zenghe, Feldman, Benjamin J., Cho, Brian, Hoss, Udo
• Primary Examiner(s): BROWN, MELANIE YU
• Application Number:
  US13/595,789
• Publication Number:
  US 20130053667A1
• Time in Patent Office: 1,002 Days
• US Class Current: 600/345
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/1486 using enzyme electrodes, e.g. with immobilised oxidase
• CPC Class Codes: C12Q 1/006 for glucose
• CPC Class Codes: G01N 27/301 Reference electrodes
• CPC Class Codes: G01N 27/3272 Test elements therefor, i.e. disposable laminated substrates with electrodes, reagent and channels optical biosensors G01N33/52

Abstract

The present application provides Ag/AgCl based reference electrodes having an extended lifetime that are suitable for use in long term amperometric sensors. Electrochemical sensors equipped with reference electrodes described herein demonstrate considerable stability and extended lifetime in a variety of conditions.

Claims

1. A method for monitoring a level of an analyte, the method comprising:

inserting an electrochemical sensor into skin of a patient, wherein the electrochemical sensor comprises;

a working electrode comprising a sensing layer disposed thereon; and

a reference electrode comprising a layer of Ag/AgCl having a width that is equal to the width of the working electrode and a layer of dielectric material having a width that is at least equal to the width of the layer of Ag/AgCl and a length that is at least equal to the length of the layer of Ag/AgCl disposed on top of the layer of Ag/AgCl;

collecting data regarding a level of an analyte from signals generated by the sensor;

transmitting the collected data to a display unit; and

displaying an indication of the level of the analyte on the display of the display unit.

2. The method of claim 1, wherein the analyte is glucose.

3. The method of claim 1, wherein collecting data comprises generating signals from the sensor and processing the signals into data.

4. The method of claim 1, wherein the data comprises the signals from the sensor.

5. The method of claim 1, further comprising activating an alarm if the data indicates an alarm condition.

6. The method of claim 1, further comprising administering a drug in response to the data.

7. The method of claim 6, wherein the drug is insulin.

8. The method of claim 7, further comprising obtaining a calibration value from a calibration device to calibrate the data.

9. The method of claim 8, wherein the calibration device is coupled to the display unit.

10. The method of claim 9, further comprising transmitting the calibration value from a transmitter in the display unit to a receiver in the sensor control unit.

11. The method of claim 1, wherein the sensing layer of the working electrode comprises a glucose-responsive enzyme.

12. The method of claim 1, wherein the sensing layer of the working electrode comprises a redox mediator.

13. The method of claim 12, wherein the redox mediator comprises a complex selected from the group consisting of a ruthenium-containing complex and an osmium-containing complex.

14. The method of claim 12, wherein the redox mediator is non-leachable with respect to the working electrode.

15. The method of claim 12, wherein the redox mediator is immobilized on the working electrode.

16. The method of claim 1, further comprising a flux limiting membrane disposed over the sensing layer on the working electrode.

17. The method of claim 1, further comprising a second dielectric layer disposed on at least a portion of the working electrode.

18. The method of claim 17, wherein the reference electrode is disposed over the second dielectric layer.

19. The method of claim 18, further comprising a counter electrode disposed on top of the first dielectric layer and a third dielectric layer disposed on top of the counter electrode.