Electrochemical Cell and Method of Making an Electrochemical Cell

• US 20050258035A1
• Filed: 05/20/2005
• Published: 11/24/2005
• Est. Priority Date: 05/21/2004
• Status: Active Grant

• Current Assignee: Agamatrix Incorporated (AgaMatrix Holdings LLC d/b/a WaveForm Diabetes)
• Original Assignee: Agamatrix Incorporated (AgaMatrix Holdings LLC d/b/a WaveForm Diabetes)
• Inventors: Harding, Ian, Oppedahl, Carl, Larson, Marina T., Iyengar, Sridhar G.
• Granted Patent: US 8,268,145 B2
• Time in Patent Office: Days
• US Class Current: 204/403.10
• CPC Class Codes: C12Q 1/004 mediator-assisted
• CPC Class Codes: G01N 27/30 Electrodes, e.g. test electrodes; Half-cells G01N27/414 takes precedence
• 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 27/403 Cells and electrode assemblies
• CPC Class Codes: Y10T 156/1052 with cutting, punching, tearing or severing
• CPC Class Codes: Y10T 156/1062 Prior to assembly
• CPC Class Codes: Y10T 156/1074 Separate cutting of separate sheets or webs
• CPC Class Codes: Y10T 29/49002 Electrical device making
• CPC Class Codes: Y10T 29/49114 including adhesively bonding
• CPC Class Codes: Y10T 29/49117 Conductor or circuit manufacturing

Abstract

Electrochemical test cells are made with precision and accuracy by adhering an electrically resistive sheet having a bound opening to a first electrically conductive sheet. A notching opening is then punched through the electrically resistive sheet and the first electrically conductive sheet. The notching opening intersects the first bound opening in the electrically resistive sheet, and transforms the first bound opening into a notch in the electrically resistive sheet. A second electrically conductive sheet is punched to have a notching opening corresponding to that of first electrically conductive sheet, and this is adhered to the other side of the electrically resistive sheet such that the notching openings are aligned. This structure is cleaved from surrounding material to form an electrochemical cell that has a sample space for receiving a sample defined by the first and second conductive sheets and the notch in the electrically resistive sheet.

Claims

1. A method of manufacturing an electrochemical cell, wherein the electrochemical cell comprises opposing first and second electrodes separated by an electrically resistive sheet, wherein the method comprises the steps of:

(a) forming a first bound opening in an electrically resistive sheet thereby forming a punched electrically resistive sheet;

(b) adhering the punched electrically resistive sheet to a first electrically conductive sheet thereby forming a combined sheet, wherein a first portion of a conductive surface of the first electrically conductive sheet is exposed through the first bound opening, and a second portion of the conductive surface of the electrically conductive sheet is exposed either through a second bound opening in the electrically resistive sheet or as an extension beyond an edge of the electrically resistive sheet;

(c) punching a notching opening through the electrically resistive sheet and the first electrically conductive sheet of the combined sheet, wherein the notching opening intersects the first bound opening in the electrically resistive sheet thereby transforming the first bound opening into a notch in the electrically resistive sheet, and punching a first contact area punch through the second exposed portion of the electrically conductive sheet visible to form a first electrical contact, thereby forming a punched combined sheet;

(d) punching a second electrically conductive sheet with a punch or punches to form an electrically conductive sheet having a notching opening corresponding to that of the punched combined sheet and a second contact area in the second electrically conductive sheet, thereby forming an opposite electrode sheet;

(e) adhering the opposite electrode sheet to the electrically resistive sheet portion of the punched combined sheet with an electrically conductive surface facing the electrically resistive sheet, said opposite electrode sheet being adhered such that the notching opening corresponding to the notching opening in the combined sheet is aligned with the notching opening in the combined sheet, and the second contact area is aligned with the second bound opening, thereby forming an electrochemical sheet, and

(f) cleaving the electrochemical sheet thereby forming a spent electrochemical sheet and a free electrochemical cell having a sample space for receiving a sample defined by the first and second conductive sheets and the notch in the electrically resistive sheet, and first and second contact areas in electrically-conductive contact with electrode portions of the first and second conductive sheets exposed in the sample space for connection of said first and second electrode portions with a meter.

2. The method of claim 1, further comprising as part of forming the opposite electrode, the step of punching a vent opening through the second electrically conductive sheet of the combined sheet, wherein the vent opening is aligned in the assembled cell with the notch in the electrically resistive sheet to form a passageway to the interior of the space for receiving a sample.

3. The method of claim 1, further comprising, as part of forming the punched combined sheet, the step of punching a vent opening through the electrically resistive sheet and the first electrically conductive sheet of the combined sheet, wherein the vent opening is aligned with the notch in the electrically resistive sheet to form a passageway to the interior of the space for receiving a sample.

4. The method of claim 3, further comprising as part of forming the opposite electrode, the step of punching a vent opening through the second electrically conductive sheet of the combined sheet, wherein the vent opening is aligned in the assembled cell with the notch in the electrically resistive sheet to form a passageway to the interior of the space for receiving a sample.

5. The method of claim 1, wherein the vent opening intersects with an end of the first major open area and together with the notching opening defines the length of the sample space.

6. The method of claim 1, further comprising the step of adding a reagent to the space for receiving a sample.

7. The method of claim 6, wherein the reagent is added to the notch in the punched combined sheet prior to formation of the electrochemical sheet.

8. The method of claim 7, wherein the reagent comprises an enzyme and a redox mediator.

9. The method of claim 8, wherein the enzyme is glucose oxidase.

10. The method of claim 1, wherein the first and second electrically conductive sheets comprise gold.

11. The method of claim 1, wherein the bound openings in the electrically resistive sheet are of rectilinear cross-section.

12. The method of claim 1, wherein the electrically resistive sheet and the first and second electrically conductive sheets are each provided with aligned registration holes for manufacturing alignment, said registration holes being located in the portion of the sheets that is cleaved off as the spent electrochemical sheet, such that they do not become part of the final device.

13. The method of claim 1, wherein the electrically resistive sheet has a thickness, and the notch has dimensions such that the space for receiving a sample has volume of less than 1 μ

l, preferably less than 0.5 μ

l.

14. The method of claim 1, wherein two bound openings are formed in the resistive sheet.

15. The method of claim 1, wherein the opposite electrode has two opposing conductive surfaces, and wherein both sides of the opposite electrode are adhered to a combined punched sheet to form a device with two stacked sample receiving spaces.

16. The method of claim 1, wherein a plurality of bound openings are formed in the electrically resistive sheet, whereby a plurality of coplanar sample receiving spaces are formed.

17. An electrochemical device made by the method of claim 1.

18. An electrochemical device having a sample-receiving end and a connector end comprising, in sequence:

(a) a first substrate, having an unpatterned layer of conductive material applied to a first surface thereof;

(b) an electrically-resistive middle layer, and

(c) a second substrate, having an unpatterned layer of conductive material applied to a first surface thereof;

wherein the first surface of the first substrate and the first surface of the second substrate are adhered to the electrically resistive middle layer;

wherein the device has a hole disposed near the sample receiving end, but spaced away from the free edge of the device, said hole passing through the first substrate, the electrically resistive middle layer, and the second substrate,

wherein the device has a first sample space, said first sample space passing through electrically resistive middle layer and being bounded on opposing sides by the unpatterned conductive materials of the first substrate and the unpatterned conductive material of the second substrate and said sample space extending from the free edge of the device to the hole and being open at both ends.

19. The device of claim 18, further comprising a reagent disposed within the sample space.

20. The device of claim 19, wherein the reagent comprises an enzyme and a redox mediator.

21. The device of claim 20, wherein the enzyme is glucose oxidase.

22. The device of claim 18, wherein the conductive material on the first substrate comprises gold.

23. The device of claim 22, wherein the conductive material on the second substrate comprises gold.

24. The device of claim 18, wherein the middle layer has a thickness of 50 to 500 μ

m.

25. The device of claim 18, wherein the sample space has a volume of less than 1 μ

l, preferably less than 500 nl, and more preferably of 100 to 300 nl.

26. The device of claim 18, further comprising a second sample space formed in a stacked configuration relative to the first sample space.

27. The device of claim 18, further comprising an additional sample space formed in a coplanar location relative to the first sample space.