Composite filar for implantable medical device

Patent metadata

Field	Value
Publication number	US-2016111178-A1
Application number	US-201514695724-A
Country	US
Kind code	A1
Filing date	Apr 24, 2015
Priority date	Oct 21, 2014
Publication date	Apr 21, 2016
Grant date	—

Abstract

A composite filar has a conductive core, an outer fatigue-resistant metallic layer and a diffusion barrier between the core and the fatigue-resistant layer to prevent intermetallic diffusion between the core and the fatigue-resistant layer.

First claim

1 . A composite filar for use in an implantable medical device, the filar comprising:
a metallic core having a resistivity of less than 25 micro-ohm-cm; a metallic diffusion barrier disposed about and in contact with the core; and a fatigue-resistant metallic layer disposed about and in contact with the diffusion barrier, wherein the diffusion barrier prevents intermetallic diffusion between the core and the fatigue-resistant layer.

2 . A composite filar according to claim 1 , wherein fatigue performance of the filar is at least three times greater than a similar filar that does not include the fatigue-resistant metallic layer disposed about the diffusion barrier when fatigue performance is determined by ASTM E2948-14, Standard Test Method for Conducting Rotating Bending Fatigue Tests of Solid Round Fine Wire.

3 . A composite filar according to claim 1 , wherein the fatigue performance of the filar is at least five times greater than a similar filar that does not include the fatigue-resistant metallic layer disposed about the diffusion barrier when fatigue performance is determined by ASTM E2948-14, Standard Test Method for Conducting Rotating Bending Fatigue Tests of Solid Round Fine Wire.

4 . A composite filar according to claim 1 , wherein the fatigue-resistant metallic layer has an elastic modulus of less than 150 GigaPascals (GPa).

5 . A composite filar according to claim 1 , wherein the fatigue-resistant metallic layer has an elastic modulus ranging from 30 GPa to 90 GPa.

6 . A composite filar according to claim 1 , wherein the fatigue-resistant metallic layer comprises a titanium alloy comprising one or more of molybdenum, niobium, tantalum, zirconium, chromium, iron and tin.

7 . A composite filar according to claim 1 , wherein the metallic layer comprises a titanium-molybdenum alloy.

8 . A composite filar according to claim 1 , wherein the metallic core comprises one or more metal selected from the group consisting of: silver; tantalum, a tantalum alloy comprising one or more of Mo, Nb, Zr, W and Pd; niobium, a niobium alloy comprising one or more of Ta, Mo, Zr, W, Pt, and Pt); platinum; a platinum alloy; palladium; a palladium alloy comprising one or both of Re and Rh; and gold.

9 . A composite filar according to claim 1 , wherein the metallic core comprises silver.

10 . A composite filar according to claim 1 , wherein metallic core consists essentially of silver.

11 . A composite filar according to claim 1 , wherein the diffusion barrier comprises a radiopaque material.

12 . A composite filar according to claim 1 , wherein the diffusion barrier comprises a nickel-cobalt-molybdenum-chromium alloy.

13 . A composite filar according to claim 1 , wherein the diffusion barrier comprises an alloy comprising 33% to 37% by weight nickel, 31.5% to 39% by weight cobalt, 9% to 10.5% by weight molybdenum, and 19% to 21% by weight chromium.

14 . A composite filar according to claim 1 , wherein the core, the diffusion barrier, and the metallic layer are capable of being cold-drawn.

15 . A composite filar according to claim 1 , further comprising an insulating layer disposed about the metallic layer.

16 . A conductive cable comprising two or more filers according to claim 1 .

17 . A conductive cable according to claim 16 , wherein at least two of the two or more filars are twisted about each other.

18 . An implantable medical lead comprising a filar according to claim 1 .

19 . An implantable medical lead according to claim 19 , wherein the filar is coiled about a longitudinal axis of the lead.

20 . A composite filar for use in an implantable medical device, the filar comprising:
a core comprising silver; a diffusion barrier disposed about and in contact with the core, the diffusion barrier comprising an alloy comprising 33% to 37% by weight nickel, 31.5% to 39% by weight cobalt, 9% to 10.5% by weight molybdenum, and 19% to 21% by weight chromium; and a metallic layer comprising a titanium-molybdenum alloy disposed about and in contact with the diffusion barrier.

Assignees

• Medtronic Inc

Inventors

• Mcintyre Peter B
• Popp Jacob L

Classifications

• A61N1/0531

  Brain cortex electrodes · CPC title

• A61N1/0509

  Stomach and intestinal electrodes · CPC title

• A61L2420/08

  Coatings comprising two or more layers · CPC title

• A61L31/088

  Other specific inorganic materials not covered by A61L31/084 or A61L31/086 · CPC title

• A61L31/022

  Metals or alloys · CPC title