MICROARRAY ELECTRODES USEFUL WITH ANALYTE SENSORS AND METHODS FOR MAKING AND USING THEM

• US 20140163346A1
• Filed: 12/06/2012
• Published: 06/12/2014
• Est. Priority Date: 12/06/2012
• Status: Active Grant

• Current Assignee: Medtronic Minimed Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Minimed Incorporated (Medtronic Plc)
• Inventors: Pesantez, Daniel E., Li, Xiaolong, Liang, Bradley Chi
• Granted Patent: US 10,194,840 B2
• Time in Patent Office: Days
• US Class Current: 600/347
• CPC Class Codes: A61B 2562/028 Microscale sensors, e.g. electromechanical sensors [MEMS]
• CPC Class Codes: A61B 2562/046 in a matrix array
• 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: C12Q 1/006 for glucose
• CPC Class Codes: C25D 17/12 Shape or form C25D17/14 takes precedence
• CPC Class Codes: C25D 3/50 of platinum group metals
• CPC Class Codes: C25D 5/02 Electroplating of selected surface areas
• CPC Class Codes: C25D 5/18 Electroplating using modulated, pulsed or reversing current
• CPC Class Codes: C25D 5/611 Smooth layers

Abstract

Embodiments of the invention provide analyte sensors having optimized electrodes and/or configurations of electrode elements as well as methods for making and using such sensors. Typical embodiments of the invention include glucose sensors used in the management of diabetes.

Claims

1. A sensor electrode comprising:

a base layer;

a plurality of electrically conductive members disposed on the base layer in an array, wherein;

the electrically conductive members comprise an electroactive surface adapted to sense fluctuations in electrical current at the electroactive surface; and

the array of electrically conductive members is coupled to an electrical conduit.

2. The sensor electrode of claim 1, wherein the electrically conductive members comprise ellipses having a diameter of at least 1 μ

m.

3. The sensor electrode of claim 1, wherein the electrically conductive members comprise circular discs having a diameter from 1 μ

m to 100 μ

m.

4. The sensor electrode of claim 1, wherein the electrically conductive members comprise a combination of circular discs and ellipses.

5. The sensor electrode of claim 1, wherein the array comprises at least 10 electrically conductive members.

6. The sensor electrode of claim 1, wherein the base comprises a plurality of indentations and the plurality of electrically conductive members are individually positioned within the plurality of indentations.

7. The sensor electrode of claim 1, wherein the electrode is coupled to a piercing member adapted to be implanted in vivo.

8. The sensor electrode of claim 1, wherein the electrical conduit is coupled to a potentiostat.

9. The sensor electrode of claim 1, wherein the electrode is coupled to a processor adapted to convert data obtained from observing fluctuations in electrical current from a first format into a second format.

10. An analyte sensor apparatus comprising:

a base layer;

a working electrode comprising a plurality of electrically conductive members disposed on the base layer in an array, wherein;

the electrically conductive members comprise an electroactive surface adapted to sense fluctuations in electrical current at the electroactive surface; and

the electrically conductive members are coupled to a power source adapted to sense fluctuations in electrical current of the working electrode;

an analyte sensing layer disposed over the array of electrically conductive members, wherein the analyte sensing layer detectably alters the electrical current at the working electrode in the presence of an analyte; and

an analyte modulating layer disposed over the analyte sensing layer, wherein the analyte modulating layer modulates the diffusion of analyte therethrough.

11. The analyte sensor apparatus of claim 10, wherein the apparatus comprises:

a reference electrode; and

a counter electrode comprising a plurality of electrically conductive members disposed on the base layer in an array.

12. The analyte sensor apparatus of claim 11, wherein:

the apparatus comprises a plurality of working electrodes, counter electrodes and reference electrodes clustered together in units consisting essentially of one working electrode, one counter electrode and one reference electrode; and

the clustered units are longitudinally distributed on the base layer in a repeating pattern of units.

13. The analyte sensor apparatus of claim 10, wherein the electrically conductive members are circular and have a diameter between 10 μ

m and 100 μ

m.

14. The analyte sensor apparatus of claim 10, wherein the array comprises at least 20 electrically conductive members.

15. The analyte sensor apparatus of claim 10, wherein the analyte sensing layer comprises glucose oxidase.

16. The analyte sensor apparatus of claim 10, wherein the apparatus comprises an adhesion promoting layer disposed between the analyte sensing layer and the analyte modulating layer.

17. The analyte sensor apparatus of claim 10, wherein the analyte modulating layer comprises a hydrophilic comb-copolymer having a central chain and a plurality of side chains coupled to the central chain, wherein at least one side chain comprises a silicone moiety.

18. The analyte sensor apparatus of claim 16, wherein the analyte modulating layer comprises a blend of:

(1) a polyurethane/polyurea polymer formed from a mixture comprising;

(a) a diisocyanate;

(b) a hydrophilic polymer comprising a hydrophilic diol or hydrophilic diamine; and

(c) a siloxane having an amino, hydroxyl or carboxylic acid functional group at a terminus; and

(2) a branched acrylate polymer formed from a mixture comprising;

(a) a butyl, propyl, ethyl or methyl-acrylate;

(b) an amino-acrylate;

(c) a siloxane-acrylate; and

(d) a poly(ethylene oxide)-acrylate.

19. A method of sensing an analyte within the body of a mammal, the method comprising:

implanting an analyte sensor of claim 10 into the mammal;

sensing an alteration in current at the working electrode in the presence of the analyte; and

correlating the alteration in current with the presence of the analyte, so that the analyte is sensed.

20. A method of making a sensor electrode, the method comprising the steps of:

(a) providing a base layer having an outer surface, the outer surface comprising a plurality of circular indentations;

(b) immersing the base layer in an electroplating electrolyte solution; and

(c) applying an electric field to coat the plurality of circular indentations with an electrically conductive material, thereby forming a plurality of circular discs;

wherein the plurality of circular discs are connected to an electrical conduit and adapted to measure fluctuations in an electrical current.