Insulated implantable electrical circuit
(19)AUSTRALIAN PATENT OFFICE (54) Title Insulated implantable electrical circuit (51)6 International Patent Classification(s) A61N 001/05 (21) Application No: 2003268068 (22) Application Date: 2003.08.11 (87) WIPO No: WO04/014479 (30) Priority Data (31) Number (32) Date Not Given 2003 .08.11 (33) Country US 60/402,591 2002 .08.09 us (43) Publication Date : 2004 .02.25 (43) Publication Journal Date : 2004 .04.08 (71) Applicant(s) SECOND SIGHT MEDICAL PRODUCTS, INC (72) Inventor(s) Neysmith, Jordan; Ok, Jerry; Greenberg Robert; Talbot, Neil (-|-|) Application No AU 2003268068 A8(19)AUSTRALIAN PATENT OFFICE (54) Title Insulated implantable electrical circuit (51)6 International Patent Classification(s) A61N 001/05 (21) Application No: 2003268068 (22) Application Date: 2003.08.11 (87) WIPO No: WO04/014479 (30) Priority Data (31) Number (32) Date Not Given 2003 .08.11 (33) Country US 60/402,591 2002 .08.09 us (43) Publication Date : 2004 .02.25 (43) Publication Journal Date : 2004 .04.08 (71) Applicant(s) SECOND SIGHT MEDICAL PRODUCTS, INC (72) Inventor(s) Neysmith, Jordan; Ok, Jerry; Greenberg Robert; Talbot, Neil-1- The invention is directed to an implantable insulated electrical circuit that utilizes polyparaxylylene, preferably as Parylene, a known polymer that has excellent living tissue implant characteristics, to provide for chronic implantation of conductive electrical devices, such as stimulators and sensors. The device is thin, flexible, electrically insulated, and stable after long exposure to living tissue. Layers of Parylene may be combined with layers of a polymer, such as polyimide, to yield greater design flexibility in the circuit. Multiple electrical conduction layers may be stacked in the circuit to increase packing density. CLAIMS What is claimed is: 1. An insulated flexible electrical circuit suitable for implantation comprising: a first polyparaxylylene layer ; a second polyparaxylylene that defines at least one aperture exposing an electrical conductor, and said electrical conductor located between said first polyparaxylylene layer and said second polyparaxylylene layer.
2. The electrical circuit of claim 1, wherein said polyparaxylylene is comprised of Parylene.
3. The electrical circuit of claim 1, further comprising at least one polymer layer between said first polyparaxylylene layer and said second polyparaxylylene layer.
4. The electrical circuit of claim 3, wherein said polymer is comprised of polyimide.
5. The electrical circuit of claim 1, further comprising at least one polymer layer on said first polyparaxylylene layer or said second polyparaxylylene layer that is not located between said layers.
6. The electrical circuit of claim 5, wherein said polymer is comprised of polyimide.
7. The electrical circuit of claim 1, further comprising a layer of a polymer between said first polyparaxylylene. layer and said electrical conductor. <Desc/Clms Page number 10> 8. The electrical circuit of claim 7, wherein said polymer is comprised of polyimide.
9. The electrical circuit of claim 1, wherein said electrical conductor is suitable for stimulating a nerve.
10. The electrical circuit of claim 1, wherein said electrical conductor is suitable for sensing a signal from a nerve.
11. The electrical circuit of claim 1, wherein said second polyparaxylylene that defines at least one aperture further defines an electrode site suitable for detecting or transmitting signals to living tissue.
12. The electrical circuit of claim 1, wherein said electrical conductor is comprised of a biocompatible material.
13. The electrical circuit of claim 12, wherein said biocompatible material is selected from at least one metal from the group of titanium, platinum, gold, or iridium.
14. The electrical circuit of claim 1, wherein said electrical conductor is at least partially coated with a biocompatible material.
15. The electrical circuit of claim 14, wherein said biocompatible material is comprised of titanium nitride. <Desc/Clms Page number 11> 16. A method of forming an insulated flexible electrical circuit suitable for implantation, comprising the steps of: choosing a rigid substrate; cleaning said rigid substrate; depositing a first polyparaxylylene layer on said rigid substrate; depositing an electrical conductor on said first polyparaxylylene layer ; patterning said electrical conductor to form a conductive path thereon; depositing a second polyparaxylylene layer ; defining at least one select portion of said second polyparaxylylene layer ; and removing said at least one select portion of said second polyparaxylylene layer defining at least one aperture therein, thereby forming at least one electrode that is suitable for contacting living tissue.
17. The method of claim 16, wherein said step of choosing a rigid substrate is accomplished by choosing said substrate comprised of glass.
18. The method of claim 16, further comprising the step of enhancing said first polyparaxylylene layer for adhesion after said step of depositing a first polyparaxylylene layer.
19. The method of claim 16, further comprising the step of enhancing said electrical conductor for adhesion after said step of patterning said electrical conductor to form a conductive path.
20. The method of claim 16, further comprising the step of enhancing said first polyparaxylylene layer for adhesion before said step of depositing a second polyparaxylylene layer.
21. The method of claim 16, further comprising the step of applying silane to enhance adhesion. <Desc/Clms Page number 12> 22. The method of claim 16, further comprising the step of modifying by chemical means said first polyparaxylylene layer.
23. The method of claim 16, further comprising the step of roughening the polyparaxylylene surface.
24. The method of claim 16, further comprising the step of compressing thermally said first polyparaxylylene layer and said second polyparaxylylene layer to increase adhesion.
25. The method of claim 16, wherein said step of removing said at least one select portion of said second polyparaxylylene layer is accomplished by etching with reactive ions.