Surface treated bioerodible metal endoprostheses

• US 8,668,732 B2
• Filed: 03/22/2011
• Issued: 03/11/2014
• Est. Priority Date: 03/23/2010
• Status: Expired due to Fees

• Current Assignee: Boston Scientific Scimed, Inc. (Boston Scientific Corporation)
• Original Assignee: Boston Scientific Scimed, Inc. (Boston Scientific Corporation)
• Inventors: Scheuermann, Torsten, Weber, Jan, Deng, Charles, Stinson, Jonathan S., Larsen, Steven R., Boismier, Dennis A., Edick, Jacob D.
• Primary Examiner(s): GHERBI, SUZETTE JAIME J
• Application Number:
  US13/053,791
• Publication Number:
  US 20110238151A1
• Time in Patent Office: 1,085 Days
• Field of Search: 623 111- 148
• US Class Current: 623/1.38
• CPC Class Codes: A61F 2/91 made from perforated sheet material or tubes, e.g. perforated by laser cuts or etched holes
• CPC Class Codes: A61F 2210/0004 bioabsorbable
• CPC Class Codes: A61L 31/022 Metals or alloys
• CPC Class Codes: A61L 31/088 Other specific inorganic materials not covered by A61L31/084 or A61L31/086
• CPC Class Codes: A61L 31/148 Materials at least partially resorbable by the body

Abstract

An endoprosthesis includes an expandable tubular body defined by a plurality of struts. In some embodiments, the expandable tubular body includes a bioerodible metal that has at least a first surface region and a second surface region. The first and second surface regions can have different surface oxide compositions. In some embodiments, the first portion has a thermally altered microstructure and the second portion has a wrought microstructure. The thermally altered microstructure can be a cast microstructure comprising dendritic grains. The first portion forms at least a portion of an outer surface of the expandable tubular body. In some embodiments, the expandable tubular body includes iron or a bioerodible iron alloy and at least one surface of the expandable tubular body includes a substantially uniform coating of iron(III) oxide.

Claims

1. An endoprosthesis comprising an expandable tubular body defined by a plurality of struts, the expandable tubular body comprising a bioerodible metal having at least a first surface region and a second surface region, the first and second surface regions having different surface oxide compositions, wherein the second surface region comprises a sulfide of the bioerodible metal.

2. The endoprosthesis of claim 1, wherein the bioerodible metal is iron or an alloy thereof.

3. The endoprosthesis of claim 2, the first surface region comprising ferrous oxide (iron(II) oxide) and has a higher percentage of ferrous oxide (iron(II) oxide) as a percentage of total oxides in each region than the second surface region.

4. The endoprosthesis of claim 3, wherein the first surface region comprises a cast microstructure and the second region comprises a wrought microstructure.

5. The endoprosthesis of claim 2, wherein the second surface region comprises ferroso ferric oxide (iron (II, III) oxide).

6. The endoprosthesis of claim 5, wherein the first surface region is essentially free of ferroso ferric oxide.

7. The endoprosthesis of claim 2, wherein the second surface region comprises ferric oxide (iron(III) oxide).

8. The endoprosthesis of claim 7, wherein the first surface region is essentially free of ferric oxide.

10. The endoprosthesis of claim 1, wherein the first region is essentially free of sulfides.

11. The endoprosthesis of claim 1, wherein the bioerodible metal is iron or an alloy thereof and the sulfide is iron (II) sulfide.

12. The endoprosthesis of claim 11, wherein The endoprosthesis is a stent.

9. An endoprosthesis comprising an expandable tubular body defined by a plurality of struts, the expandable tubular body comprising a bioerodible metal having at least a first surface region and a second surface region, the first and second surface regions having different surface oxide compositions, wherein the bioerodible metal is iron or an alloy thereof, wherein the second surface region comprises ferric oxide (iron(III) oxide), wherein the first surface region comprises hematite.

13. An endoprosthesis comprising an expandable tubular body defined by a plurality of struts, the expandable tubular body comprising a bioerodible metal having at least a first portion and a second portion, the first portion having a thermally altered microstructure, the second portion having a wrought microstructure, the first portion forming at least a portion of an outer surface of the expandable tubular body, wherein the tubular body comprises a continuous body of the second portion with a plurality of first portions each having a cast microstructure comprising dendritic grains, wherein each first portion defines at least a portion of the outer surface of the expandable tubular member.

14. The endoprosthesis of claim 13, wherein the bioerodible metal is iron or an alloy thereof.

15. The endoprosthesis of claim 13, the first portion encapsulates the second portion.

16. The endoprosthesis of claim 13, wherein the first portion defines the abluminal surface of the expandable tubular body.

17. The endoprosthesis of claim 13, wherein the plurality of first portions comprise holes or cavities each surrounded by the second portion.

18. The endoprosthesis of claim 13, wherein the first portion and the second portion each include surface regions having different surface oxide compositions.

19. The endoprosthesis of claim 13, further comprising a coating overlying the outer surface of the expandable tubular member.

20. The endoprosthesis of claim 13, wherein the endoprosthesis is a stent.

21. An endoprosthesis comprising an expandable tubular body defined by a plurality of struts, the struts comprising one or more surfaces, the expandable tubular body comprising iron or a bioerodible iron alloy, at least one surface of the expandable tubular body comprising a substantially uniform coating of iron(III) oxide, wherein the coating of ferric oxide encapsulates the expandable tubular body.

22. The endoprosthesis of claim 21, wherein the tubular body comprises a continuous body of the iron or the bioerodible iron alloy.

24. The endoprosthesis of claim 21, wherein the endoprosthesis is a stent.

23. An endoprosthesis comprising an expandable tubular body defined by a plurality of struts, the expandable tubular body comprising iron or a bioerodible iron alloy, at least one surface of the expandable tubular body comprising a substantially uniform coating of iron(III) oxide, wherein the expandable tubular body comprises an alloy consisting essentially of iron and about 2.3 weight percent manganese.