Radio frequency antenna for a wireless intravascular medical device

• US 20070075905A1
• Filed: 10/05/2005
• Published: 04/05/2007
• Est. Priority Date: 10/05/2005
• Status: Active Grant

• Current Assignee: Kenergy, Inc.
• Original Assignee: Kenergy, Inc.
• Inventors: Denker, Stephen, Bulkes, Cherik, Beutler, Arthur
• Granted Patent: US 7,749,265 B2
• Time in Patent Office: Days
• US Class Current: 343/718
• CPC Class Codes: A61N 1/37205 Microstimulators, e.g. implantable through a cannula
• CPC Class Codes: A61N 1/37229 Shape or location of the implanted or external antenna
• CPC Class Codes: A61N 1/3787 from an external energy source
• CPC Class Codes: H01Q 1/273 Adaptation for carrying or wearing by persons or animals
• CPC Class Codes: H01Q 1/40 Radiating elements coated with or embedded in protective material
• CPC Class Codes: H01Q 7/00 Loop antennas with a substantially uniform current distribution around the loop and having a directional radiation pattern in a plane perpendicular to the plane of the loop

Abstract

A radio frequency antenna is provided for use with a medical device for implantation into an animal. The antenna comprises a coil formed by a wire that includes a core formed of a shape-memory material with an electrically conductive first layer applied to an outer surface of the core. A second layer, of an electrically insulating and biologically compatible material, extends around the first layer. If necessary to reduce friction a lubricant is place between the first and second layers. If second layer is formed of porous material or a non-biological compatible material, a biological compatible outer layer surrounds the second layer thereby providing a barrier that is impermeable to body fluids of the animal.

Claims

1. A radio frequency antenna for a medical device that is implanted into an animal, said radio frequency antenna comprising a coil formed by a wire that comprises:

a core formed of a shape-memory material and having an outer surface;

a first layer of electrically conductive material applied to the outer surface of the core; and

a second layer extending around the first layer and formed of an electrically insulating and biologically compatible material.

2. The radio frequency antenna as recited in claim 1 wherein the shape-memory material is a metal alloy.

3. The radio frequency antenna as recited in claim 1 wherein the shape-memory material is an alloy selected from the group consisting of nickel-titanium, titanium-palladium-nickel, gold-cadmium, silver-cadmium, titanium-niobium-aluminum, uranium-niobium, hafnium-titanium-nickel, nickel-titanium, nickel-iron-zinc-aluminum, titanium-niobium, nickel-zirconium-titanium, copper-zinc-aluminum, iron-manganese-silicon, iron-manganese-silicon-chromium-nickel, nickel-titanium-copper, iron-platinum, iron-nickel-carbon, iron-palladium, iron-nickel-tin-cobalt, iron-zinc-copper-aluminum, copper-tin, copper-zinc, copper-aluminum-iron, copper-aluminum-nickel, indium-titanium, nickel-aluminum, manganese-copper, zirconium-copper-zinc, zirconium-aluminum-nickel-copper.

4. The radio frequency antenna as recited in claim 1 wherein the shape-memory material comprises a polymer,

5. The radio frequency antenna as recited in claim 1 wherein the shape-memory material comprises a polymer selected from the group consisting of polynorborene, polyisoprene, styrene butadiene, polyurethane, vinyl acetate,polyester, and an oligo (ε

-caprolactone)diol and crystallisable oligo(ρ

-dioxanone)diol compound.

6. The radio frequency antenna as recited in claim 1 wherein the electrically conductive core is hollow.

7. The radio frequency antenna as recited in claim 1 wherein the electrically conductive material of the first layer is selected from the group consisting of silver, gold, copper, aluminum, steel, and alloys of one or more of those metals.

8. The radio frequency antenna as recited in claim 1 wherein the second layer is formed of expanded polytetrafluoroethylene.

9. The radio frequency antenna as recited in claim 1 wherein the second layer is bonded to the first layer.

10. The radio frequency antenna as recited in claim 1 further comprising an lubricant between the first layer and the second layer.

11. The radio frequency antenna as recited in claim 1 further comprising an outer layer extending around the second layer and providing a barrier that is impermeable to body fluids of the animal.

12. A radio frequency antenna for a medical device that is implanted into an animal, said radio frequency antenna comprising a coil formed by a wire that comprises:

a core formed of a resilient material and having an outer surface;

a first layer of electrically conductive material applied to the outer surface of the core;

a lubricant layer extending around the first layer;

a second layer extending around the lubricant layer and formed of an electrically insulating and biological compatible material; and

an outer layer extending around the second layer and providing a barrier that is impermeable to body fluids of the animal.

13. The radio frequency antenna as recited in claim 12 wherein the resilient material is a shape-memory metal alloy.

14. The radio frequency antenna as recited in claim 13 wherein the shape-memory material selected from the group consisting of a polymer and a ceramic.

15. The radio frequency antenna as recited in claim 12 wherein the electrically conductive material of the first layer is selected from the group consisting of silver, gold, copper, aluminum, and alloys of one or more of those metals.

16. The radio frequency antenna as recited in claim 12 wherein the lubricant layer is formed of polytetrafluoroethylene.

17. The radio frequency antenna as recited in claim 12 wherein the second layer is formed of expanded polytetrafluoroethylene.

18. The radio frequency antenna as recited in claim 12 wherein the outer layer is formed of polytetrafluoroethylene.

19. A radio frequency antenna for a medical device that is implanted into an animal, wherein radio frequency antenna comprises a collapsible coil formed by a wire comprising:

an elongated electrical conductor;

an insulator layer of an electrically insulating and biologically compatible material extending around the elongated electrical conductor; and

a lubricating layer between the elongated electrical conductor and the insulator layer and permitting movement of the elongated electrical conductor and the insulator layer with respect to each other.

20. The radio frequency antenna as recited in claim 19 wherein the elongated electrical conductor comprises a core formed of a material selected from the group consisting of silver, a silver alloy, gold, a gold alloy, copper, aluminum, steel, and a shape-memory material.

21. The radio frequency antenna as recited in claim 19 wherein the elongated electrical conductor comprises a core of a shape-memory material having an outer surface coated with an electrically conductive material.

22. The radio frequency antenna as recited in claim 21 wherein the electrically conductive material is selected from the group consisting of silver, gold, copper, aluminum, and alloys of one or more of those elements.

23. The radio frequency antenna as recited in claim 19 wherein the insulator layer has an exterior surface that is coated with a material that provides a barrier which is impermeable to body fluids of the animal.

24. The radio frequency antenna as recited in claim 19 wherein the elongated electrical conductor comprises a shape-memory material.

25. The radio frequency antenna as recited in claim 24 wherein the shape-memory material is a metal alloy.

26. The radio frequency antenna as recited in claim 24 wherein the shape-memory material is an alloy selected from the group consisting of titanium-palladium-nickel, nickel-titanium, gold-cadmium, silver-cadmium, titanium-niobium-aluminum, uranium-niobium, hafnium-titanium-nickel, nickel-titanium, nickel-iron-zinc-aluminum, titanium-niobium, nickel-zirconium-titanium, copper-zinc-aluminum, iron-manganese-silicon, iron-manganese-silicon-chromium-nickel, nickel-titanium-copper, iron-platinum, iron-nickel-carbon, iron-palladium, iron-nickel-tin-cobalt, iron-zinc-copper-aluminum, copper-tin, copper-zinc, copper-aluminum-iron, copper-aluminum-nickel, indium-titanium, nickel-aluminum, manganese-copper, zirconium-copper-zinc, zirconium-aluminum-nickel-copper.

27. The radio frequency antenna as recited in claim 24 wherein the shape-memory material comprises a polymer selected from the group consisting of polynorborene, polyisoprene, styrene butadiene, polyurethane, vinyl acetate, polyester, and an oligo (ε

-caprolactone)diol and crystallisable oligo(ρ

-dioxanone)diol compound.

28. The radio frequency antenna as recited in claim 19 wherein the elongated electrical conductor is hollow.

29. The radio frequency antenna as recited in claim 19 wherein the lubricating layer is formed of polytetrafluoroethylene.

30. The radio frequency antenna as recited in claim 19 wherein the insulator layer is formed of expanded polytetrafluoroethylene.

31. The radio frequency antenna as recited in claim 19 further comprising an outer layer extending around the insulator layer and providing a barrier that is impermeable to body fluids of the animal.

32. The radio frequency antenna as recited in claim 31 wherein the outer layer is formed of polytetrafluoroethylene.