Structurally optimized hollow fiber membranes

• US 7,354,392 B2
• Filed: 02/25/2004
• Issued: 04/08/2008
• Est. Priority Date: 02/25/2004
• Status: Expired due to Fees

• Current Assignee: Transvivo, Inc.
• Original Assignee: Transvivo, Inc.
• Inventors: Handley, Harold H. Jr., Peters, Harold W., Gorsuch, Reynolds G.
• Primary Examiner(s): Zalukaeva; Tatyana
• Assistant Examiner(s): Craig; Paula L
• Application Number:
  US10/786,339
• Publication Number:
  US 20050187508A1
• Time in Patent Office: 1,504 Days
• Field of Search: 604/6.04, 604/6.09, 604/6.16, 604/4.01, 210/321.88, 210/483
• US Class Current: 604/6.04
• CPC Class Codes: A61M 1/1678 intracorporal peritoneal dialysis A61M1/28
• CPC Class Codes: B01D 69/08 Hollow fibre membranes manufacture of hollow fibres D01D5/24, D01F1/08
• CPC Class Codes: D01D 5/247 Discontinuous hollow structure or microporous structure

Abstract

An elongated hollow microporous fiber comprises an inner wall surface defining an interior fiber lumen, an outer wall surface, and a microporous fiber wall therebetween, the fiber wall having one or more continuous, cohesive, elongated filaments embedded in the fiber and extending lengthwise of the elongated fiber along substantially the full length of the fiber.

Claims

1. A filter device for being implanted in a blood vessel for carrying out in-vivo plasma separation comprising:

a plurality of elongated hollow tubes comprising one or more first and one or more second elongated hollow tubes, and a plurality of elongated fibers each fiber having a microporous membrane fiber wall with an outer wall surface and an inner wall surface defining an interior lumen extending along the length thereof wherein the fiber wall morphology of each of the elongated fibers is asymmetrical between the inner wall surface and the outer wall surface, said fiber wall having a higher mass density zone adjacent to the outer wall surface and a lower mass density zone adjacent to the inner wall surface, said higher mass density zone having a smaller average nominal pore size than the average nominal pore size in the lower mass density zone, each fiber having a first end secured to a first said elongated hollow tube and a second end secured to a second said elongated hollow tube, wherein the interior of the said plurality of elongated hollow tubes communicates with the interior lumen of each of the fibers, said fibers including one or more continuous filaments embedded in the microporous fiber wall between the first and second ends of the fiber.

2. A filter device of claim 1 comprising two of said elongated hollow tubes, each of said tubes having a plurality of holes spaced apart along a substantial portion of the length thereof, each hole receiving a first or a second end of an elongated microporous fiber.

3. A filter device of claim 1 wherein said one or more filaments extend along said fiber wall substantially uniformly between said inner wall surface and said outer wall surface.

4. A filter device of claim 1 wherein said one or more filaments extend along said fiber wall substantially equidistant between said inner wall surface and said outer wall surface.

5. A filter device of claim 1 wherein the one or more filaments have a substantially uniform tensile strength along the length thereof.

6. A filter device of claim 1 wherein said one or more filaments occupy less than about 15% of the fiber wall cross-sectional area of said fiber.

7. A filter device of claim 1 wherein said one or more filaments occupy less than about 10% of the fiber wall cross-sectional area of said fiber.

8. A filter device of claim 1 wherein each of said one or more filaments has a cross-sectional area occupying between about 0.1% and about 2% of the cross-sectional area of said fiber.

9. A filter device of claim 1 wherein each of said one or more filaments has a cross-sectional area occupying between about 0.2 and about 2% of the cross-sectional area of said fiber.

10. A filter device of claim 1 comprising a plurality of said filaments and wherein each filament has a cross-sectional area occupying between about 0.2% and about 2% of the cross-sectional area of said fiber.

11. A filter device of claim 1 wherein said one or more filaments have a tensile strength of at least about 5,000 psi.

12. A filter device of claim 1 wherein said one or more filaments comprise fiberglass, polypropylene, silk, polysulfone, polyethersulfone, polyimide, polyamide or aramid.

13. A filter device of claim 1 comprising two of said filaments.

14. A filter device of claim 13 wherein said one or more filaments comprise fiberglass, polypropylene, silk, polysulfone, polyethersulfone, polyimide, polyamide or aramid.

15. A filter device of claim 14 wherein each of said one or more filaments has a cross-sectional area occupying between about 0.2% and about 2% of the cross-sectional area of said fiber.

16. A filter device of claim 14 comprising a plurality of said filaments occupying between about 0.5% and about 5% of the cross-sectional area of said fiber.

17. A filter device of claim 16 wherein said higher mass density zone is characterized by a nominal average pore diameter of between about 0.005 μ

m and about 0.05 μ

m.

18. A filter device of claim 1 wherein the fiber wall structure comprises a continuous change in mass density from the outer wall surface to the inner wall surface.

19. A filter device of claim 18 wherein the fiber wall structure comprises a continuum of voids bounded by solid frames.

20. A filter device of claim 1 wherein said membrane fiber wall has three mass density zones and wherein each of said zones is characterized by a different average nominal pore size.

21. A filter device of claim 1 wherein said membrane fiber wall has four or more mass density zones and wherein each of said zones is characterized by a different average nominal pore size.

22. A filter device of claim 1, 20, or 21 wherein said lower mass density zone is characterized by a nominal average pore diameter of between about 1 μ

m and about 60 μ

m.

23. A filter device of claim 22 wherein said higher mass density zone is characterized by a nominal average pore diameter of between about 0.3 μ

m and about 1 μ

m.

24. A filter device of claim 1, 20, or 21 wherein said higher mass density zone is characterized by a nominal average pore diameter of between about 0.3 μ

m and about 1 μ

m.

25. A filter device of claim 1 wherein said lower mass density zone is characterized by a nominal average pore diameter of between about 2 μ

m and about 6 μ

m.

26. A filter device of claim 25 wherein said higher mass density zone is characterized by a nominal average pore diameter of between about 0.4 μ

m and about 0.8 μ

m.

27. A filter device of claim 26 having one or more intermediate mass density zones having a nominal average pore diameter of between about 0.8 μ

m and about 2 μ

m.

28. A filter device of claim 27 having two intermediate mass density zones, a first intermediate zone having a nominal average pore diameter of between about 0.8 μ

m and about 1.2 μ

m and a second intermediate zone having a nominal average pore diameter of between about 1.2 μ

m and about 2 μ

m.

29. A filter device of claim 1 wherein said higher mass density zone is characterized by a nominal average pore diameter of between about 0.4 μ

m and about 0.8 μ

m.