Biocompatible material and method of manufacture and use thereof

• US 5,998,024 A
• Filed: 09/26/1995
• Issued: 12/07/1999
• Est. Priority Date: 02/02/1995
• Status: Expired due to Fees

• Current Assignee: Brehm H. Peter, Lothar Sellin, Rainer H. Frey
• Original Assignee: Brehm H. Peter, Lothar Sellin, Rainer H. Frey
• Inventors: Sellin, Lothar, Frey, Rainer H.
• Primary Examiner(s): Krynski, William
• Assistant Examiner(s): GRAY, JILL M
• Application Number:
  US08/533,963
• Time in Patent Office: 1,533 Days
• Field of Search: 428/364, 428/375, 428/408, 428/367, 428/378, 428/400, 428/394, 427/244, 427/412.3
• US Class Current: 428/367
• 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 31/084 Carbon; Graphite
• CPC Class Codes: A61L 33/025 Carbon; Graphite
• CPC Class Codes: B01D 2323/10 Specific pressure applied
• CPC Class Codes: B01D 2323/38 Graft polymerization
• CPC Class Codes: B01D 2323/385 involving radiation
• CPC Class Codes: B01D 67/0093 Chemical modification
• CPC Class Codes: B01D 67/00933 by addition of a layer chemically bonded to the membrane
• CPC Class Codes: B01D 71/021 Carbon
• CPC Class Codes: B05D 1/60 Deposition of organic layers from vapour phase vapour phase deposition in general C23C14/00, C23C16/00
• CPC Class Codes: C08F 2/46 Polymerisation initiated by wave energy or particle radiation
• CPC Class Codes: C08J 2323/06 Polyethene
• CPC Class Codes: C08J 2427/08 Homopolymers or copolymers of vinylidene chloride
• CPC Class Codes: C08J 7/0427 with only one layer of a composition containing a polymer binder with more layers C08J7/042
• CPC Class Codes: C08J 7/18 using wave energy or particle radiation
• CPC Class Codes: D06M 14/28 of macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
• CPC Class Codes: Y10T 428/2913 Rod, strand, filament or fiber
• CPC Class Codes: Y10T 428/2918 including free carbon or carbide or therewith [not as steel]
• CPC Class Codes: Y10T 428/2933 Coated or with bond, impregnation or core
• CPC Class Codes: Y10T 428/2938 : Coating on discrete and individual rods, strands or filaments
• CPC Class Codes: Y10T 428/2967 : Synthetic resin or polymer
• CPC Class Codes: Y10T 428/30 : Self-sustaining carbon mass or layer with impregnant or other layer

Abstract

A biocompatible material comprising a substrate made of a polyolefin material, and having a coating of biocompatible carbon material, wherein the coating is obtained by a process comprising the following steps:

introducing a preformed substrate into an atmosphere of gaseous monomer vinylidene chloride (1,1 di-chloro ethylene);

inducing a graft-polymerization reaction and grafting a uniform layer of polyvinylidene chloride on the substrate; and

substantially eliminating and removing hydrogen chloride (dehydrochlorination reaction) from the polyvinylidene chloride in order to convert the polyvinylidene chloride layer into a coating of biocompatible carbon material.

Claims

1. A biocompatible material

comprising a substrate made of a polyolefin material, and having a coating of biocompatible carbon material chemically bound to said substrate wherein said coating is obtained by a process comprising the following steps:

introducing a preformed substrate into an atmosphere of gaseous monomer vinylidene chloride;

inducing a graft-polymerization reaction and grafting a uniform layer of polyvinylidene chloride on said substrate; and

substantially eliminating and removing hydrogen chloride from said polyvinylidene chloride in order to convert said polyvinylidene chloride layer into a chemically bound coating of biocompatible carbon material.

2. A biocompatible material according to claim 1 wherein said coating of biocompatible carbon material has a residual chlorine content of less than 6% based on the chlorine content of the original layer of polyvinylidene chloride.

3. A biocompatible material according to claim 1, wherein said graft polymerization reaction is a gas phase graft polymerization induced by ionizing radiation.

4. A biocompatible material according to claim 3, wherein said graft polymerization reaction is induced by ionizing radiation having an average dose rate of from about 0.1 to about 1.5 watt per kg radiated material.

5. A biocompatible material according to claim 4, wherein said graft polymerization reaction continues for a duration of at least 20 hours.

6. A biocompatible material according to claim 3, wherein said ionizing radiation is gamma radiation.

7. A biocompatible material according to claim 1, wherein 0.1 to 1.2 parts per weight of polyvinvlidene chloride have been grafted on 1 part per weight of said substrate.

8. A biocompatible material according to claim 1, wherein 0.7 to 1.0 parts per weight of polyvinlidene chloride have been grafted on 1 part per weight of said substrate and wherein said substrate is a fiber.

9. A biocompatible material according to claim 1, wherein said dehydrochlorination reaction comprises treatment with a hot concentrated aqueous ammonia solution.

10. A biocompatible material according to claim 9, wherein said dehydrochlorination reaction continues for a duration of at least 20 hours.

11. A biocompatible material according to claim 1, wherein said dehydrochlorination reaction provides a residual chlorine content of less than 3%, based on the chlorine content of the original layer of polyvinylidene chloride.

12. A biocompatible material according to claim 1, wherein the coating has a thickness of more than 5 microns.

13. A biocompatible material according to claim 1, wherein the substrate is a member selected from the group consisting of a fiber, a filament, a thread and a yarn and said polyolefin is a polypropylene material.

14. A biocompatible material according to claim 13, wherein the polypropylene material has been oriented by a drawing step.

15. A biocompatible material according to claim 13, wherein the substrate comprises an oriented fiber or a multifilament yarn of oriented filaments, each consisting of a polypropylene material;

wherein the coating comprises a carbon material having a density of approximately 1.8 g/cm³ ; and

wherein the amount of said carbon material is about 10 to 20% per weight based on the total weight of the coating and fiber or yarn.

16. A biocompatible material according to claim 13, wherein the amount of said carbon material is about 10 to 20% per weight based on the total weight of the coating and fiber or yarn.

17. A biocompatible material according to claim 1, wherein said biocompatible carbon material is flexible and bound inseparably to said substrate.

18. A biocompatible material according to claim 1, wherein said coating of biocompatible carbon material is covalently bonded to said substrate by C--C bonds to the carbon chain of the substrate.

19. A biocompatible material according to claim 1, wherein said layer of polyvinylidene chloride is an epitaxial layer.

20. A biocompatible material according to claim 19, wherein said coating consists essentially of pure carbon with a residual chlorine content of less than 3% based on the chlorine content of the original layer of polyvinylidene chloride.

21. The biocompatible material of claim 1, wherein said dehydrochlorination reaction comprises treating with a hot aqueous ammonia solution comprising an ammonia concentration of 20 to 35% by weight.

22. The biocompatible material of claim 1, wherein said dehydrochlorination reaction is carried out at a temperature from 80°

C. to 100°

C.

23. The biocompatible material of claim 1, which further comprises after said dehydrochlorination reaction, rinsing said substrate with hot water.

24. The biocompatible material of claim 23, which further comprises after said rinsing, heating said substrate under reduced pressure.

25. The biocompatible material of claim 1 wherein said polyolefin is a copolymer of propylene with another α

-olefin.