Medical implants including iridium oxide

• US 8,231,980 B2
• Filed: 12/03/2009
• Issued: 07/31/2012
• Est. Priority Date: 12/03/2008
• Status: Active Grant

• Current Assignee: Boston Scientific Scimed, Inc. (Boston Scientific Corporation)
• Original Assignee: Boston Scientific Scimed, Inc. (Boston Scientific Corporation)
• Inventors: Atanasoska, Liliana, Gupta, Pankaj, Deng, Charles
• Primary Examiner(s): Speer, Timothy
• Application Number:
  US12/630,250
• Publication Number:
  US 20100137978A1
• Time in Patent Office: 971 Days
• Field of Search: 428/315.9, 428/469, 623/1.46, 623/1.15
• US Class Current: 428/469
• CPC Class Codes: A61F 2/82 Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents stent-grafts for tubular structures of the body other than blood vessels A61F2/04; stent-grafts for blood vessels A61F2/07; instruments specially adapted for placement or removal of stents or stent-grafts A61F2/95; for closing wounds, or holding wounds closed A61B17/04 - A61B17/115; dilators A61M29/00
• CPC Class Codes: A61L 31/028 Other inorganic materials not covered by A61L31/022 - A61L31/026
• CPC Class Codes: A61L 31/088 Other specific inorganic materials not covered by A61L31/084 or A61L31/086
• CPC Class Codes: B32B 9/00 Layered products comprising a layer of a particular substance not covered by groups B32B11/00 - B32B29/00
• CPC Class Codes: C23C 14/08 Oxides C23C14/10 takes precedence

Abstract

A medical implant includes iridium oxide. The iridium oxide has a plurality of Ir—O σ bonds and a plurality of Ir═O π bonds. The iridium oxide has a ratio of the Ir—O σ bonds to the Ir═O π bonds that is greater than 1.3.

Claims

1. A medical implant comprising iridium oxide, the iridium oxide having a plurality of Ir—

O σ

bonds and a plurality of Ir═

O π

bonds, the iridium oxide having a ratio of the Ir—

O σ

bonds to the Ir═

O π

bonds that is between 1.6 and 2.1.

2. The medical implant of claim 1, wherein the iridium oxide has a plurality of Ir atoms having a mean valance state of less than 3.4+.

3. The medical implant of claim 1, wherein the iridium oxide comprises a morphology of defined grains with an aspect ratio of about 5:

1 or more.

4. The medical implant of claim 1, wherein the iridium oxide exhibits a charge of at least 0.0060 Coul/cm² in a cyclic voltammetry potentiodynamic electrochemical measurement having a sweep rate no more than 50 mV/s.

5. The medical implant of claim 1, wherein the iridium oxide defines an outer surface of the medical implant.

6. The medical implant of claim 1, further comprising a base metal, the iridium oxide coating the base metal.

7. The medical implant of claim 6, wherein the base metal is selected from the group consisting of stainless steels, stainless steels enhanced with radiopaque elements, nickel-titanium alloys, cobalt alloys, titanium and titanium alloys, platinum and platinum alloys, niobium and niobium alloys, tantalum and tantalum alloys, and combinations thereof.

8. The medical implant of claim 1, wherein the medical implant comprises an electrode, the electrode comprising the iridium oxide.

9. The medical implant of claim 1, wherein the medical implant is an endoprosthesis.

10. The medical implant of claim 9, wherein the endoprosthesis is a stent.

11. The medical implant of claim 1, wherein the Ir atoms having a mean valance state of between 3.20+ and 3.35+.

12. The medical implant of claim 1, wherein the iridium oxide is deposited on to

a medical implant or precursor thereof in a physical vapor deposition processing chamber

using a power of at least 750 watts, and a total pressure of between 3 mTorr and 7 mTorr.

13. A medical implant comprising iridium oxide, the iridium oxide having a plurality of Ir atoms having a mean valance state of between 3.20+ and 3.35+.

14. The medical implant of claim 13, wherein the iridium oxide has a plurality of Ir—

O σ

bonds and a plurality of Ir═

O π

bonds, the iridium oxide having a ratio of the Ir—

O σ

bonds to the Ir═

O π

bonds that is between 1.45 and 3.0.

15. The medical implant of claim 14, wherein the ratio is between 1.6 and 2.1.

16. The medical implant of claim 13, further comprising a base metal, the iridium oxide coating the base metal and defining an outer surface of the medical implant, the base metal being selected from the group consisting of stainless steels, stainless steels enhanced with radiopaque elements, nickel-titanium alloys, cobalt alloys, titanium and titanium alloys, platinum and platinum alloys, niobium and niobium alloys, tantalum and tantalum alloys, and combinations thereof.

17. The medical implant of claim 13, wherein the medical implant comprises an electrode, the electrode comprising the iridium oxide.

18. The medical implant of claim 13, wherein the medical implant is an endoprosthesis.

19. The medical implant of claim 13, wherein the iridium oxide is deposited on to a medical implant or precursor thereof in a physical vapor deposition processing chamber using a power of at least 750 watts, and a total pressure of between 3 mTorr and 7 mTorr.

20. An endoprosthesis comprising:

a tublular member defined by a plurality of bands and a plurality of connectors that extend between and connect adjacent bands, the tubular member comprising a base metal; and

a coating on the tubular member, the coating comprising iridium oxide, the iridium oxide having a plurality of Ir—

O σ

bonds and a plurality of Ir═

O π

bonds, the iridium oxide having a ratio of the Ir—

O σ

bonds to the Ir═

O π

bonds that is between 1.6 and 2.1, the iridium oxide having a plurality of Ir atoms having a mean valance state of between 3.20+ and 3.35+.