Anti-microbial coating for medical device

• US 5,753,251 A
• Filed: 06/02/1995
• Issued: 05/19/1998
• Est. Priority Date: 05/19/1992
• Status: Expired due to Term

• Current Assignee: NUCRYST Pharmaceuticals Corp. (The Westaim Corporation)
• Original Assignee: Westaim Technologies Inc.
• Inventors: Burrell, Robert Edward, Morris, Larry Roy
• Primary Examiner(s): AZPURU, CARLOS A
• Application Number:
  US08/459,474
• Time in Patent Office: 1,082 Days
• Field of Search: 424/423, 424/426, 427/248.1, 427/250, 106/1.05, 106/1.13, 106/1.14, 106/1.15, 106/1.16, 106/1.17, 106/1.18, 106/1.19, 106/1.21, 106/723, 106/733
• US Class Current: 424/426
• CPC Class Codes: A01N 59/16 Heavy metals; Compounds thereof
• CPC Class Codes: A61B 2018/00119 with metal oxide nitride
• CPC Class Codes: A61L 17/145 Coating
• CPC Class Codes: A61L 2300/102 Metals or metal compounds, e.g. salts such as bicarbonates, carbonates, oxides, zeolites, silicates
• CPC Class Codes: A61L 2300/104 Silver, e.g. silver sulfadiazine
• CPC Class Codes: A61L 2300/404 Biocides, antimicrobial agents, antiseptic agents
• CPC Class Codes: A61L 2300/602 Type of release, e.g. controlled, sustained, slow
• CPC Class Codes: A61L 2300/606 Coatings
• CPC Class Codes: A61L 27/306 Other specific inorganic materials not covered by A61L27/303 - A61L27/32
• CPC Class Codes: A61L 27/54 Biologically active materials, e.g. therapeutic substances A61L27/227 takes precedence
• CPC Class Codes: A61L 29/106 Inorganic materials other than carbon
• CPC Class Codes: A61L 29/16 Biologically active materials, e.g. therapeutic substances A61L29/048 takes precedence
• CPC Class Codes: A61L 31/16 Biologically active materials, e.g. therapeutic substances A61L31/047 takes precedence
• CPC Class Codes: C23C 14/0036 Reactive sputtering
• CPC Class Codes: C23C 14/025 Metallic sublayers
• CPC Class Codes: C23C 14/06 characterised by the coating material C23C14/0021 , C23C14/04 take precedence
• CPC Class Codes: C23C 14/0688 Cermets, e.g. mixtures of metal and one or more of carbides, nitrides, oxides or borides
• CPC Class Codes: C23C 14/086 of zinc, germanium, cadmium, indium, tin, thallium or bismuth
• CPC Class Codes: C23C 14/14 Metallic material, boron or silicon
• CPC Class Codes: C23C 14/16 on metallic substrates or on substrates of boron or silicon
• CPC Class Codes: C23C 14/205 : by cathodic sputtering
• CPC Class Codes: C23C 14/225 : Oblique incidence of vaporised material on substrate
• CPC Class Codes: C23C 14/35 : by application of a magnetic field, e.g. magnetron sputtering C23C14/3457 takes precedence
• CPC Class Codes: C23C 14/588 : by mechanical treatment
• CPC Class Codes: H01H 2300/014 : Application surgical instrument
• CPC Class Codes: Y10S 977/781 : Possessing nonosized surface openings that extend partially into or completely through the host material
• CPC Class Codes: Y10S 977/89 : Deposition of materials, e.g. coating, cvd, or ald
• CPC Class Codes: Y10S 977/891 : Vapor phase deposition
• CPC Class Codes: Y10S 977/904 : for medical, immunological, body treatment, or diagnosis
• CPC Class Codes: Y10S 977/931 : Medical device coating

Abstract

Anti-microbial coatings and method of forming same on medical devices are provided. The coatings are formed by depositing a biocompatible metal by vapor deposition techniques to produce atomic disorder in the coating such that a sustained release of metal ions sufficient to produce an anti-microbial effect is achieved. Preferred deposition conditions to achieve atomic disorder include a lower than normal substrate temperature, and one or more of a higher than normal working gas pressure and a lower than normal angle of incidence of coating flux. Anti-microbial powders formed by mechanical working to produce atomic disorder are also provided. The invention extends to other metal coatings and powders similarly formed so as to provide enhanced solubility.

Claims

1. A method of forming an anti-microbial coating on a device intended for use in contact with an alcohol or water based electrolyte, comprising:

depositing a coating containing an anti-microbial metal on the surface of the device by vapour deposition to provide a thin film of the metal having atomic disorder such that the coating, in contact with an alcohol or a water based electrolyte, releases ions, atoms, molecules or clusters of the anti-microbial metal into the alcohol or water based electrolyte at a concentration sufficient to provide a localized anti-microbial effect on a sustainable basis.

2. The method as set forth in claim 1, wherein the deposition is performed by a physical vapour deposition technique selected from vacuum evaporation, sputtering, magnetron sputtering or ion plating, under conditions which limit diffusion during deposition and which limit annealing or recrystallization following deposition.

3. The method as set forth in claim 2, wherein the deposition is performed such that the ratio of the temperature of the surface being coated to the melting point of the metal is maintained at less than about 0.5.

4. The method as set forth in claim 3, wherein the deposition is performed such that the angle of incidence of the coating flux on the device to be coated is less than about 75°

.

5. The method as set forth in claim 3 or 4, wherein the deposition is performed by arc evaporation at an ambient or working gas pressure of greater than about 0.01 mT.

6. The method as set forth in claim 3 or 4, wherein the deposition is performed by gas scattering evaporation at a working gas pressure of greater than about 20 mT.

7. The method as set forth in claim 3 or 4, wherein the deposition is performed by sputtering at a working gas pressure of greater than about 75 mT.

8. The method as set forth in claim 3 or 4, wherein the deposition is performed by magnetron sputtering at a working gas pressure of greater than about 10 mT.

9. The method as set forth in claim 3 or 4, wherein the deposition is performed by ion plating at a working gas pressure of greater than about 200 mT.

10. The method as set forth in claim 3 or 4 wherein the metal is selected from the group consisting of Ag, Au, Pt, Pd, Ir, Sn, Cu, Sb, Bi, and Zn or an alloy or compound containing one or more of these metals.

11. The method as set forth in claim 3 or 4 wherein the metal is Ag, Au or Pd or an alloy or compound containing one or more of these metals.

12. The method as set forth in claim 3 or 4, wherein the anti-microbial metal is silver or an alloy or compound containing silver.

13. The method as claimed in claim 1, wherein the coating is a composite coating formed by co-, sequentially or reactively depositing an anti-microbial metal in a matrix with atoms or molecules of a material different from the anti-microbial metal, such that the atoms or molecules of the different material create atomic disorder in the matrix.

14. The method as claimed in claim 13, wherein the different material is selected from atoms or molecules containing oxygen, nitrogen, hydrogen, boron, sulphur, and halogen absorbed or trapped in the matrix from the atmosphere of the vapour deposition.

15. The method as claimed in claim 13, wherein the anti-microbial metal is silver and wherein the different material is selected from atoms or molecules containing oxygen, nitrogen, hydrogen, boron, sulphur, and halogen.

16. The method as claimed in claim 13, wherein the different material is an oxide, nitride, carbide, boride, sulphide, halide, or hydride of an inert metal selected from the group consisting of Ta, Ti, Nb, V, Hf, Zn, Mo, Si, and Al.

17. The method as claimed in claim 13, wherein the anti-microbial metal is silver or an alloy or compound containing silver and the different material is an oxide of Ta, Ti or Nb.

18. The method as set forth in claim 13, wherein the anti-microbial metal is silver and wherein the different material comprises silver oxide and optionally absorbed or trapped atoms or molecules containing oxygen.

19. The method as set forth in claim 2, wherein the deposition is performed such that the ratio of the temperature of the surface being coated to the melting point of the metal is maintained at less than about 0.3.

20. The method as set forth in claim 3 or 4, wherein the deposition is performed by magnetron sputtering at a working gas pressure of greater than about 30 mT.