Non-irritating antimicrobial coating for medical implants and a process for preparing same

• US 5,945,153 A
• Filed: 07/29/1997
• Issued: 08/31/1999
• Est. Priority Date: 07/11/1994
• Status: Expired due to Term

• Current Assignee: Southwest Research Institute
• Original Assignee: Southwest Research Institute
• Inventors: Dearnaley, Geoffrey
• Primary Examiner(s): PADGETT, MARIANNE L
• Application Number:
  US08/902,488
• Time in Patent Office: 763 Days
• Field of Search: 427/2.1, 427/2.12, 427/2.24, 427/2.26, 427/523, 427/524, 427/525, 427/527, 427/528, 427/530, 427/531, 427/533, 427/566, 427/581, 427/595, 427/249, 427/250, 427/255. 2, 204/192.14, 204/192.15, 204/192.16, 204/192.17
• US Class Current: 427/2.12
• CPC Class Codes: A61F 2310/00574 Coating or prosthesis-covering structure made of carbon, e.g. of pyrocarbon
• CPC Class Codes: A61L 27/303 Carbon
• CPC Class Codes: A61L 27/306 Other specific inorganic materials not covered by A61L27/303 - A61L27/32
• CPC Class Codes: C23C 14/0605 Carbon
• CPC Class Codes: C23C 16/26 Deposition of carbon only
• CPC Class Codes: C23C 16/486 using ion beam radiation

Abstract

The present invention provides a process of forming an antimicrobial coating on a surface of a medical implant, the coating comprising an antimicrobially effective amount of antimicrobial metal atoms incorporated into a coating of amorphous carbonaceous material.

Claims

1. A process of forming an antimicrobial coating on a surface of a biomaterial comprising:

exposing said surface of said biomaterial to a vacuum sufficient to permit a vaporized stream of a carbon-based diffusion pump fluid to condense onto said surface;

depositing onto said surface metal atoms selected from the group consisting of silver, gold, and a combination thereof;

directing onto said surface a vaporized stream of said carbon-based diffusion pump fluid under temperature conditions sufficient to condense said fluid onto said surface, thereby forming a diamond-like carbon precursor film;

bombarding said diamond-like carbon precursor film with an energetic beam of ions under conditions effective to form on said surface an amorphous diamond-like carbon coating comprising a dispersion of said metal atoms;

wherein said dispersion of said metal atoms in said diamond-like carbon coating is effective to provide gradual, controlled release of said metal from said on coating at a rate effective to impart antimicrobial protection, but insufficient to irritate tissue which comes into contact with said surface.

2. The process of claim 1 wherein said process is repeated until said diamond-like carbon coating has a thickness of between about 1-5 microns.

3. The process of claim 1 wherein said energy is about 10 keV.

4. The process of claim 2 wherein said energy is about 10 keV.

5. The process of claim 1 wherein said metal atoms are silver atoms.

6. The process of claim 2 wherein said metal atoms are silver atoms.

7. The process of claim 1 wherein said amount of said metal atoms is about 10 metal atoms for every molecule of said carbon-based diffusion pump fluid.

8. The process of claim 4 wherein said amount of said metal atoms is about 10 metal atoms for every molecule of said carbon-based diffusion pump fluid.

9. The process of claim 1 wherein said depositing said metal atoms comprises sputtering said metal atoms onto said surface.

10. The process of claim 1 wherein said depositing said metal atoms comprises sputtering said metal atoms onto said surface.

11. The process of claim 1 wherein said carbon-based diffusion pump fluid comprises elements selected from the group consisting of oxygen, nitrogen, fluorine, and combinations thereof.

12. The method of claim 1 wherein said vacuum comprises a vacuum chamber evacuated to a pressure of about 10^-5 torr or less.

13. A process of forming an antimicrobial coating on a surface of a medical implant comprising:

exposing said implant to a vacuum sufficient to permit a vaporized stream comprising polyphenyl ether to condense onto said surface of said implant;

depositing metal atoms selected from the group consisting of silver and gold onto said surface;

directing said vaporized stream of polyphenyl ether onto said surface under temperature conditions sufficient to condense said precursor molecules onto said surface, thereby forming a diamond-like carbon precursor film; and

bombarding said diamond-like carbon precursor film with an energetic beam of ions under conditions effective to form on said surface diamond-like carbon coating comprising an amount of said metal atoms sufficient to impart antimicrobial protection to said implant but insufficient to irritate adjacent tissues after implantation.

14. A process of forming an antimicrobial coating on a surface of a biomaterial comprising:

exposing said surface to a vacuum sufficient to permit a vaporized stream of a metallo-organic compound having vaporization properties similar to diffusion pump fluids to condense onto said surface;

directing onto said surface an initial vaporized stream of said metallo-organic compound under temperature conditions sufficient to condense said metallo-organic compound onto said surface, wherein said metallo-organic compound comprises metal atoms selected from the group consisting of atoms of gold, silver, and a combination thereof;

bombarding said surface with an energetic beam of ions under conditions effective to form an amorphous diamond-like carbon coating on said surface comprising a dispersion of said metal atoms;

wherein said dispersion of said metal atoms in said diamond-like carbon coating is effective to provide gradual, controlled release of said metal from said on coating at a rate effective to impart antimicrobial protection, but insufficient to irritate tissue which comes into contact with said surface.

15. The process of claim 14 wherein said metallo-organic compound comprises silver phthalocyanine.

16. The process of claim 14 wherein said process is repeated until said diamond-like carbon coating has a thickness of between about 1-5 microns.

17. The process of claim 15 wherein said process is repeated until said carbonaceous coating has a thickness of between about 1-5 microns.

18. The process of claim 14 wherein said energy is about 10 keV.

19. The method of claim 14 wherein said vacuum comprises a vacuum chamber evacuated to a pressure of about 10^-5 torr or less.

20. A process of forming an antimicrobial coating on a surface of a medical implant comprising:

exposing said surface to a vacuum sufficient to permit a vaporized stream of a carbon-based diffusion pump fluid other than an organosilicon to condense onto said surface of said medical implant;

depositing onto said surface metal atoms selected from the group consisting of silver, gold, and a combination thereof;

directing onto said surface a vaporized stream of said carbon-based diffusion pump fluid under temperature conditions sufficient to condense said fluid onto said surface to form a diamond-like carbon precursor film;

bombarding said diamond-like carbon precursor film with an energetic beam of ions under conditions effective to form on said surface an amorphous diamond-like carbon coating comprising a dispersion of said metal atoms;

wherein said dispersion of said metal atoms in said diamond-like carbon coating is effective to provide gradual, controlled release of said metal from said on coating at a rate effective to impart antimicrobial protection, but insufficient to irritate tissue which comes into contact with said surface.

21. The method of claim 20 wherein said vacuum comprises a vacuum chamber evacuated to a pressure of about 10^-5 torr or less.

22. A process of forming an antimicrobial coating on a surface of a medical implant comprising:

exposing said surface to a vacuum sufficient to permit a vaporized stream of a carbon-based diffusion pump fluid to condense onto a surface of said implant;

subsequently depositing onto said surface metal atoms selected from the group consisting of silver, gold, and a combination thereof;

thereafter directing onto said surface a vaporized stream of said carbon-based diffusion pump fluid under temperature conditions sufficient to condense said fluid onto said surface to form a diamond-like carbon precursor film; and

subsequently bombarding said diamond-like carbon precursor film with an energetic beam of ions under conditions effective to form on said surface an amorphous diamond-like carbon coating comprising a dispersion of said metal atoms;

wherein said dispersion of said metal atoms in said diamond-like carbon coating is effective to provide gradual, controlled release of said metal from said on coating at a rate effective to impart antimicrobial protection, but insufficient to irritate tissue which comes into contact with said surface.

23. The method of claim 22 wherein said vacuum comprises a vacuum chamber evacuated to a pressure of about 10^-5 torr or less.

24. The method of claim 22 wherein said carbon-based diffusion pump fluid comprises a fluid other than an organosilicon.