Methods for maintaining low impedance of electrodes

• US 20060004432A1
• Filed: 06/23/2005
• Published: 01/05/2006
• Est. Priority Date: 06/23/2004
• Status: Active Grant

• Current Assignee: Cochlear Limited
• Original Assignee: Cochlear Limited
• Inventors: Parker, John, Milojevic, Dusan
• Granted Patent: US 7,519,435 B2
• Time in Patent Office: Days
• US Class Current: 607/137
• CPC Class Codes: A61L 31/10 Macromolecular materials
• CPC Class Codes: A61N 1/0541 Cochlear electrodes
• CPC Class Codes: A61N 1/36038 Cochlear stimulation
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: C08L 71/02 Polyalkylene oxides

Abstract

An implantable tissue-stimulating device for an implantee. The device comprising an elongate member having at least one electrode. At least a portion of the device is coated with a coating that at least partially inhibits adhesion of organic molecules to the device following implantation

Claims

1. An implantable tissue-stimulating device for an implantee comprising:

an elongate member; and

at least one electrode disposed on said elongate member,

wherein at least a portion of the device is coated with a coating that at least partially inhibits adhesion of organic molecules to said device following implantation.

2. The device of claim 1, wherein the coating is a hydrophilic polymer or derivative thereof.

3. The device of claim 2, wherein the coating is polyethylene glycol (PEG).

4. The device of claim 1, wherein the coating has functional groups that enable functional bonding between the coating and said portion of the device.

5. The device of claim 4, wherein the functional groups enable functional bonding between the coating and an electrically active electrode surface.

6. The device of claim 5, wherein the electrically active electrode surface is gold or platinum.

8. The device of claim 1, wherein said at least one electrode is coated with said coating.

9. The device of claim 1, wherein a portion of the elongate member is coated with the coating.

10. The device of claim 1, wherein each electrode is positioned in a recess formed in the elongate body.

11. The device of claim 10, wherein the coating is applied to each electrode in a liquid form and then solidifies on application, the quantity of coating applied in each recess being such that an outer surface of the solidified coating is below the top of the recess, at or about the top of the recess, or is proud of the top of the recess.

12. The device of claim 1, wherein the coating is soluble and has a limited lifespan following implantation.

13. The device of claim 1, wherein the coating is removable by an electrochemical cleaning process.

14. The device of claim 13, wherein the cleaning process comprises increasing the potential of the electrodes of the device and then reducing the potential.

15. The device of claim 14, wherein the coating is at least partially electrically conductive.

16. The device of claim 1, wherein the coating is a self-assembled monolayer.

17. The device of claim 16, wherein where the elongate member is formed of a silicone, a layer of a suitable metal is applied to the elongate member prior to coating with the monolayer.

18. The device of claim 1, wherein the tissue-stimulating device is a cochlear implant.

19. A method of modifying the surface of at least a portion of a tissue stimulating device, the method comprising:

coating said portion with a material that at least partially inhibits adhesion of organic materials following implantation.

20. An implantable apparatus for delivering electrical stimulation to an implantee, the apparatus comprising:

a stimulator device that generates stimulation signals;

an elongate member having at least one electrode supported thereon that receives the stimulation signals and delivers electrical stimulation in response to said signals; and

wherein the stimulation at least partially inhibits adhesion of organic molecules to said elongate member in a region proximal the at least one electrode.

21. The apparatus of claim 20, wherein the apparatus is able to deliver stimulation to tissue surrounding the elongate member.

22. The apparatus of claim 20, wherein the elongate member is positioned to directly deliver stimulation to the auditory system of the implantee via the at least one electrode.

23. The apparatus of claim 22, wherein the stimulation has a magnitude below the auditory perception threshold of the implantee.

24. The apparatus of claim 23, wherein the apparatus is also able to deliver auditory informative stimuli, having a magnitude that is about at or above the auditory perception threshold of the implantee, to the auditory system of the implantee.

25. The apparatus of claim 24, wherein the elongate member is implantable in the cochlea of the implantee, with the at least one electrode being capable of delivering said stimulation and auditory informative stimuli.

26. The apparatus of claim 25, wherein said apparatus is configured to deliver said stimulation prior to activation of said apparatus to deliver said auditory informative stimuli to the implantee.

27. The apparatus of claim 26, wherein following activation of said apparatus to deliver auditory informative stimuli, the apparatus ceases further delivery of said stimulation that inhibits organic molecular adhesion.

28. The apparatus of claim 27, wherein the apparatus delivers said stimulation at times when the apparatus is not delivering auditory informative stimuli.

29. The apparatus of claim 20, wherein said stimulation comprises an anodic pulse that oxidises the one or more electrodes thereby desorbing organic molecules from the one or more electrodes, and a cathodic pulse that dissolves the oxide back to its metal state.