METHODS AND MATERIALS FOR CONTROLLING THE ELECTROCHEMISTRY OF ANALYTE SENSORS

• US 20100175992A1
• Filed: 03/25/2010
• Published: 07/15/2010
• Est. Priority Date: 10/18/2002
• Status: Active Grant

• Current Assignee: Medtronic Minimed Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Minimed Incorporated (Medtronic Plc)
• Inventors: Shah, Rajiv, Hoss, Udo, Soundararajan, Gopikrishnan, Gottlieb, Rebecca K., Holker, James D.
• Granted Patent: US 9,541,519 B2
• Time in Patent Office: Days
• US Class Current: 204/403.140
• CPC Class Codes: A61B 5/1486 using enzyme electrodes, e.g. with immobilised oxidase
• CPC Class Codes: C25D 1/10 Moulds; Masks; Masterforms
• CPC Class Codes: C25D 5/10 Electroplating with more than one layer of the same or of different metals for bearings C25D7/10
• CPC Class Codes: C25D 5/605 Surface topography of the layers, e.g. rough, dendritic or nodular layers
• CPC Class Codes: C25D 5/611 Smooth layers
• CPC Class Codes: C25D 5/623 Porosity of the layers
• CPC Class Codes: G01N 27/307 Disposable laminated or multilayered electrodes G01N27/3272 takes precedence
• CPC Class Codes: G01N 27/327 Biochemical electrodes , e.g. electrical or mechanical details for in vitro measurements
• CPC Class Codes: Y10T 428/12389 having variation in thickness
• CPC Class Codes: Y10T 428/12479 Porous [e.g., foamed, spongy, cracked, etc.]
• CPC Class Codes: Y10T 428/12493 Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
• CPC Class Codes: Y10T 428/12875 Platinum group metal-base component
• CPC Class Codes: Y10T 428/12889 Au-base component

Abstract

Embodiments of the invention provide electrochemical analyte sensors having elements designed to modulate their electrochemical reactions as well as methods for making and using such sensors.

Claims

1. An electrode comprising a plurality of electrodeposited metal layers comprising:

(a) a first metal layer having a first surface area and a first adhesion strength;

(b) a second metal layer deposited on the first metal layer, the second metal layer having a second surface area and a second adhesion strength with the first layer on which the second layer is electrodeposited, wherein the second surface area is greater than the first surface area and the second adhesion strength is greater than the first adhesion strength.

2. The electrode of claim 1, further including:

(c) a third metal layer deposited on the second metal layer, the third metal layer having a greater density than the density of the second metal layer.

3. The electrode of claim 1, wherein the substrate comprises a geometric feature selected to increase the surface area of the electrodeposited metal composition.

4. The electrode of claim 1, further comprising:

an analyte sensing layer disposed on the electrode, wherein the analyte sensing layer comprises a material that can detectably alter the electrical current at the electrode in the presence of an analyte;

an adhesion promoting layer disposed on the analyte sensing layer, wherein the adhesion promoting layer promotes the adhesion between the analyte sensing layer and an analyte modulating layer disposed on the analyte sensing layer; and

an analyte modulating layer disposed on the analyte sensing layer, wherein the analyte modulating layer modulates the diffusion of the analyte therethrough; and

a cover layer disposed on at least a portion of the analyte modulating layer;

wherein the cover layer further includes an aperture over at least a portion of the analyte modulating layer, and

the electrode, the analyte sensing layer, the adhesion promoting layer, the analyte modulating layer and the cover layer are configured to form an implantable electrochemical analyte sensor.

5. The electrode of claim 4, wherein the electrode comprises a third metal layer deposited on the second metal layer, wherein the third metal layer has a greater density than the density of the second metal layer.

6. The electrode of claim 4, wherein the enzyme layer comprises glucose oxidase or lactate oxidase.

7. The electrode of claim 4, wherein the electrode, the analyte sensing layer, the adhesion promoting layer, the analyte modulating layer and the cover layer are configured to form a glucose biosensor.

8. The electrode of claim 1, wherein the electrode is made using cycles of differing electroplating conditions by a method comprising:

(a) electroplating a metal composition onto a substrate under a first set of conditions selected to produce a first metal layer having a first surface area and a first adhesion strength between the substrate and the first metal layer; and

(b) electroplating a metal composition onto the first metal layer under a second set of conditions selected to produce a second metal layer having a second surface area and a second adhesion strength between the first metal layer and the second metal layer, wherein;

(i) the second set of conditions produces a second metal layer having a second surface area that is greater than the first surface area of the first metal layer produced by the first set of conditions; and

(ii) the second set of conditions produces a second metal layer having an adhesion with the first metal layer that is greater than the adhesion between the first metal layer and the substrate produced by the first set of conditions;

so that the metallic electrode is made using cycles of differing electroplating conditions.

9. The electrode of claim 8, wherein the electrode is made by a step further comprising:

(c) electroplating a metal composition onto the second layer under a third set of conditions selected to produce a third metal layer having a third surface area.

10. The electrode of claim 9, wherein the third set of conditions produces a third metal layer having a greater density than the density of the second metal layer.

11. The electrode of claim 9, wherein the third set of conditions produces a third metal layer having a third surface area that is less than the second surface area of the second metal layer produced by the second set of conditions.

12. The electrode of claim 8, wherein the substrate does not comprise platinum.

13. The electrode of claim 8, wherein the substrate comprises gold.

14. The electrode of claim 8, wherein the electroplated metal composition comprises platinum black.

15. The electrode of claim 8, wherein the substrate comprises a geometric feature selected to increase the surface area of the electroplated metal composition.

16. The electrode of claim 8, wherein a metal composition is electroplated on to a porous substrate.

17. The electrode of claim 8, wherein the substrate comprises a planar surface and an edge or lip at the boundary of the planar surface and the cycles of differing electroplating conditions further inhibit an uneven deposition of the metal layer electrodeposited onto the planar surface and the edge or lip at the boundary of the planar surface.

18. The electrode of claim 17, wherein the uneven deposition of the metal layer that is inhibited is a greater deposition of metal on the edge or lip at the boundary of the planar surface relative to the deposition of metal on the planar surface.

19. The electrode of claim 8, wherein the first metal layer electroplated under a first set of conditions exhibits a resistance to abrasion from the substrate that is greater than the resistance to abrasion exhibited by a metal layer electroplated to the substrate under the second set of conditions.

20. The electrode of claim 9, wherein surface area of the third layer is at least 160, 170 or 180 times the geometric area of the third layer.

21. The electrode of claim 8, wherein surface area of the third layer is 230 to 260 times the geometric area of the third layer.