Method of making a sensor with layered electrodes

• US 9,179,870 B2
• Filed: 08/27/2014
• Issued: 11/10/2015
• Est. Priority Date: 09/23/2005
• Status: Active Grant

• Current Assignee: Medtronic Minimed Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Minimed Incorporated (Medtronic Plc)
• Inventors: Shah, Rajiv, Gottlieb, Rebecca K.
• Primary Examiner(s): ARBES, CARL J
• Application Number:
  US14/470,167
• Publication Number:
  US 20140367246A1
• Time in Patent Office: 440 Days
• Field of Search: 295/921, 295/95, 298/25, 298/46
• US Class Current: 1/1
• CPC Class Codes: A61B 5/0004 characterised by the type of physiological signal transmitted
• CPC Class Codes: A61B 5/0017 transmitting optical signals transmission by light H04B10/00
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/14865 invasive, e.g. introduced into the body by a catheter or needle or using implanted sensors
• CPC Class Codes: A61B 5/6848 Needles
• CPC Class Codes: A61B 5/6849 in combination with a needle set
• CPC Class Codes: C12Q 1/006 for glucose
• CPC Class Codes: C23C 14/20 on organic substrates
• CPC Class Codes: C23C 14/3414 Metallurgical or chemical aspects of target preparation, e.g. casting, powder metallurgy
• CPC Class Codes: G01N 27/307 Disposable laminated or multilayered electrodes G01N27/3272 takes precedence
• CPC Class Codes: G01N 27/3273 Devices therefor, e.g. test element readers, circuitry details not specific to biochemical electrodes G01N33/4875
• CPC Class Codes: G01N 27/4166 measuring a particular property of an electrolyte
• CPC Class Codes: Y10T 29/49002 Electrical device making
• CPC Class Codes: Y10T 29/49005 Acoustic transducer
• CPC Class Codes: Y10T 29/49007 Indicating transducer
• CPC Class Codes: Y10T 29/49117 Conductor or circuit manufacturing
• CPC Class Codes: Y10T 29/49155 Manufacturing circuit on or in base

Abstract

A thin film sensor, such as a glucose sensor, is provided for transcutaneous placement at a selected site within the body of a patient. The sensor includes several sensor layers that include conductive layers and includes a proximal segment defining conductive contacts adapted for electrical connection to a suitable monitor, and a distal segment with sensor electrodes for transcutaneous placement. The sensor electrode layers are disposed generally above each other, for example with the reference electrode above the working electrode and the working electrode above the counter electrode. The electrode layers are separated by dielectric layer.

Claims

1. A method of making a flexible analyte sensor, the method comprising:

providing a base layer;

forming a first electrode layer on the base layer, wherein the first electrode layer includes a first electrode;

forming a first insulative layer on the first electrode layer;

forming a second electrode layer on the first insulative layer, wherein the second electrode layer includes a second electrode; and

forming a second insulative layer on the second electrode layer, wherein the first and second electrodes are in a staggered configuration.

2. The method of claim 1, wherein the providing a base layer includes spin coating polyimide onto a rigid substrate.

3. The method of claim 1, wherein the forming a first electrode layer includes surface sputtering a chrome-based layer on the base layer.

4. The method of claim 3, wherein the forming a first electrode layer further includes surface sputtering a gold-based layer on the chrome-based layer.

5. The method of claim 1, wherein the forming a first insulative layer includes spin-coating polyimide onto the first electrode layer.

6. The method of claim 1, wherein the maximum height of the sensor is about 25 microns.

7. The method of claim 1, wherein the second electrode layer is laterally offset from the first electrode layer.

8. The method of claim 1, further comprising forming a third electrode layer on the second insulative layer, wherein the third electrode layer includes a third electrode.

9. The method of claim 8, further comprising forming a third insulative layer on the third electrode layer, wherein the first, second and third electrodes are in a staggered configuration.

10. The method of claim 8, further comprising depositing one or more compounds selected from the group consisting of silver and silver chloride on the third electrode.

11. The method of claim 10, further comprising coating at least a portion of the first electrode and the second electrode with an enzyme layer including glucose oxidase.

12. The method of claim 11, further comprising vapor cross-linking the enzyme layer.

13. The method of claim 11, wherein the enzyme layer further includes albumin.

14. The method of claim 11, further comprising forming an adhesion promoter layer above the enzyme layer.

15. The method of claim 11, further comprising forming a glucose limiting membrane over the enzyme layer.

16. The method of claim 15, wherein the glucose limiting membrane comprises at least one of a silane and polyamine.

17. The method of claim 15, further comprising forming a hydrophilic layer over the glucose limiting membrane.

18. The method of claim 1, wherein a first aperture is formed in the first insulative layer to expose at least a portion of the first electrode.

19. The method of claim 18, wherein the first aperture is formed by a photoresist process.

20. The method of claim 1, wherein the forming the first electrode layer further includes forming a first conductive trace leading from the first electrode to a first conductive pad configured to electrically connect to sensor electronics, and the forming the second electrode layer further includes forming a second conductive trace leading from the second electrode to a second conductive pad configured to electrically connect to the sensor electronics.

21. The method of claim 20, wherein the sensor electronics communicate wirelessly with a monitor.

22. The method of claim 21, wherein the wireless communication is selected from the group consisting of radio frequency, infrared, WiFi, ZigBee and Bluetooth.

23. The method of claim 21, wherein the type of wireless communication is one of single frequency communication, spread spectrum communication, adaptive frequency selection, and frequency hopping communication.

24. The method of claim 1, wherein the first insulative layer is disposed directly on the first electrode layer without any intervening layers.

25. The method of claim 1, wherein the second electrode layer is disposed directly on the first insulative layer without any intervening layers.

26. The method of claim 1, wherein the second insulative layer is disposed directly on the second electrode layer without any intervening layers.