Porous medical device and method for its manufacture

• US 7,964,206 B2
• Filed: 08/20/2004
• Issued: 06/21/2011
• Est. Priority Date: 08/20/2003
• Status: Active Grant

• Current Assignee: Bioretec Oy
• Original Assignee: Bioretec Oy
• Inventors: Ashammakhi, Nureddin, Törmälä, Pertti, Suokas, Esa, Hupa, Mikko, Ylänen, Heimo
• Primary Examiner(s): Wax; Robert A
• Assistant Examiner(s): Al-Awadi; Danah
• Application Number:
  US10/568,890
• Publication Number:
  US 20070141111A1
• Time in Patent Office: 2,496 Days
• Field of Search: None
• US Class Current: 424/422
• CPC Class Codes: A61F 2/28 Bones joints A61F2/30
• CPC Class Codes: A61F 2/3094 Designing or manufacturing processes
• CPC Class Codes: A61F 2/30965 Reinforcing the prosthesis by embedding particles or fibres during moulding or dipping
• CPC Class Codes: A61F 2002/2817 Bone stimulation by chemical reactions or by osteogenic or biological products for enhancing ossification, e.g. by bone morphogenetic or morphogenic proteins [BMP] or by transforming growth factors [TGF]
• CPC Class Codes: A61F 2002/30062 (bio)absorbable, biodegradable, bioerodable, (bio)resorbable, resorptive
• CPC Class Codes: A61F 2002/30065 thermoplastic, i.e. softening or fusing when heated, and hardening and becoming rigid again when cooled
• CPC Class Codes: A61F 2002/30677 Means for introducing or releasing pharmaceutical products, e.g. antibiotics, into the body
• CPC Class Codes: A61F 2002/30914 Details of the mesh structure, e.g. disposition of the woven warp and weft wires
• CPC Class Codes: A61F 2002/30915 made of a stack of bonded perforated sheets, grids or wire meshes
• CPC Class Codes: A61F 2002/30971 Laminates, i.e. layered products
• CPC Class Codes: A61F 2210/0004 bioabsorbable
• CPC Class Codes: A61F 2210/0071 thermoplastic
• CPC Class Codes: A61F 2310/00179 Ceramics or ceramic-like structures
• CPC Class Codes: A61F 2310/00293 containing a phosphorus-containing compound, e.g. apatite
• CPC Class Codes: A61L 27/44 having a macromolecular matrix
• CPC Class Codes: A61L 27/56 Porous materials, e.g. foams or sponges
• CPC Class Codes: A61L 27/58 Materials at least partially resorbable by the body
• CPC Class Codes: B32B 2255/02 on fibrous or filamentary layer
• CPC Class Codes: B32B 2255/26 Polymeric coating
• CPC Class Codes: B32B 2262/105 Ceramic fibres
• CPC Class Codes: B32B 2305/08 : Reinforcements
• CPC Class Codes: B32B 2556/00 : Patches, e.g. medical patches, repair patches
• CPC Class Codes: B32B 5/26 : another layer next to it also being fibrous or filamentary relative arrangement of fibres or filaments of different layers B32B5/12
• CPC Class Codes: D02G 3/448 : Yarns or threads for use in medical applications D02G3/449 takes precedence; surgical suture materials A61L17/00
• CPC Class Codes: D04B 1/14 : Other fabrics or articles characterised primarily by the use of particular thread materials
• CPC Class Codes: D04C 1/06 : Braid or lace serving particular purposes
• CPC Class Codes: D10B 2509/08 : Hernia repair mesh
• CPC Class Codes: Y10T 442/2525 : Coating or impregnation functions biologically [e.g., insect repellent, antiseptic, insecticide, bactericide, etc.]

Abstract

Porous bioabsorbable, bioactive and load-bearing composite medical device structure includes a plurality of regular textile planar layers (1a, 1b . . . ) formed of continuous bioabsorbable polymer matrix and bioceramic fibers acting as reinforcements, both included in continuous fibrous elements (3) forming the textile layers. The layers are placed on top of each other to form a structure having two dimensions (x, y) at right angles to each other according to the two dimensions of the textile layer and a third dimension (z) perpendicular to them and resulting from the piling of the layers. A plurality of passages extend through the layers as a result of the openings (2) defined by portions of the continuous fibrous elements (3) extending substantially in the direction of the plane. The continuous fibrous elements (3) comprise both bioactive ceramic reinforcing fibers which form a reinforcing structure and a bioabsorbable polymer matrix material which forms a matrix which binds the layers together and also binds the portions of continuous fibers defining the openings together, thereby forming the passages and stiffening the structure. This bioactive and bioabsorbable composite structure is suitable to be used as a basic structure in medical devices, especially in osteochondral applications where the load-bearing properties of implant are required.

Claims

1. A porous bioabsorbable, bioactive and load-bearing medical device composite structure having a bioabsorbable matrix and reinforcing structure, said composite structure further comprising:

a plurality of textile planar layers, said layers being formed of continuous fibrous elements and being placed on top of each other to a position with respect to each other to form a structure having two dimensions which are nonparallel to each other and a third dimension originating from piling of said planar layers on top of each other;

a plurality of openings extending through said layers, said openings being defined by portions of said continuous fibrous elements extending substantially in the direction of said plane and existing in the textile planar layers prior to placing them on top of each other;

a plurality of passages extending through said structure, said passages being formed of the openings in different textile planar layers placed on top of each other;

a reinforcing structure formed by reinforcing bioactive ceramic fibers included in said continuous fibrous elements; and

a bioabsorbable matrix formed by bioabsorbable polymer matrix material also included in said continuous fibrous elements;

the position of the layers with respect to each other being fixed when said bioabsorbable polymer matrix binds together said portions of said continuous fibrous elements defining said openings and binds said layers together, simultaneously stiffening said structure;

said bioabsorbable polymer matrix material comprising bioabsorbable thermoplastic polymer material or polymer blend material, and said continuous fibrous elements defining said openings are bound together and the structure is stiffened by said bioabsorbable thermoplastic polymer material or polymer blend material softened or melted in heat treatment and solidified.

2. A structure according to claim 1, wherein said textile planar layers are regular textile planar layers whose openings make the planar layers regular in structure.

3. A structure according to claim 2, wherein the regular planar textile layers are selected from the group consisting of knitted, woven, and braided layers.

4. A structure according to claim 3, wherein said regular textile planar layers comprise knitted layers, said passages being formed by loops in different layers of said knitted layers.

5. A structure according to claim 3, wherein said regular textile planar layers comprise woven layers including weft and warp yarns;

and said passages are formed by openings between said weft and warp yarns.

6. A structure according to claim 2, wherein the structure comprises two or several textile planar layers of different types, selected from the group consisting of knitted, woven or braided layers, or the structure comprises a commingled layered textile structure of reinforcing bioactive ceramic fibers and bioabsorbable polymer matrix.

7. A structure according to claim 1, wherein the reinforcing bioactive ceramic fibers are filaments.

8. A structure according to claim 1, wherein the continuous fibrous elements are hybrid yarns comprising both reinforcing bioactive ceramic fibers and bioabsorbable polymer matrix.

9. A structure according to claim 1, wherein said continuous fibrous elements comprise a continuous bioabsorbable polymer matrix filament and reinforcing bioactive ceramic filament.

10. A structure according to claim 1, wherein said continuous fibrous elements comprise a reinforcing bioactive ceramic filament and a bioabsorbable polymer matrix coating on it.

11. A structure according to claim 8, wherein said continuous fibrous elements comprise reinforcing bioactive ceramic staple fibers and bioabsorbable polymer matrix staple fibers spun together.

12. A structure according to claim 1, wherein said bioactive ceramic fibers are bioactive glass or calcium phosphates.

13. A structure according to claim 1, wherein the bioactive ceramic fiber component is arranged to induce tissue growth and the bioabsorbable polymer matrix component is arranged to simultaneously induce fixation or support strength in an implanted medical device.

14. A method of manufacturing the porous bioabsorbable, bioactive and load-bearing composite medical device of claim 1, the method comprising:

providing a plurality of textile planar layers, said layers being formed of continuous fibrous elements and having each a plurality of openings defined by portions of said continuous fibrous elements, said fibrous elements comprising a bioabsorbable matrix formed by bioabsorbable polymer matrix material and reinforcing ceramic elements;

placing said textile planar layers on top of each other to form a piled structure having two dimensions at right angles to each other and a third dimension perpendicular to them and originating from piling of said textile layers on top of each other, the piled structure having passages extending through said structure and formed of the openings in different textile planar layers.

15. A method according to claim 14 wherein the method further comprises fixing the layers to each other.

16. A method according to claim 15, wherein the layers are fixed by heat.

17. A method according to claim 16, wherein said bioabsorbable polymer matrix material is thermoplastic bioabsorbable polymer matrix material, and the layers are fixed by means of said thermoplastic bioabsorbable polymer matrix material by subjecting it to heat and then cooling.

18. A method of using the structure of claim 1 as a bioabsorbable, bioactive and load-bearing composite medical device or part thereof in desired shape in hard tissue repair, augmentation or regeneration, or in hard tissue generation.

19. A structure according to claim 1, wherein bioactive agents selected from a group consisting of cytokines and pharmaceutical agents, and/or living cells and/or micro-organisms are incorporated in the structure.

20. A structure according to claim 19, wherein genetically modified or non-modified living cells are impregnated or seeded in the pores of the structure.

21. A structure according to claim 19, wherein both bioactive agents selected from a group consisting of cytokines, appropriate growth factors, BMPs, angiogenic factors, pharmaceutical agents, genes, gene vectors, natural and synthetic genetic materials and chromosomes, are carried in the pores of the structure, and genetically modified or non-modified living cells are seeded in the pores of the structure.

22. A structure according to claim 19, wherein the bioactive agents selected from the group consisting of cytokines and pharmaceutical agents are dispersed in the bioabsorbable polymer component of the medical device.

23. A structure according to claim 19, wherein bioactive ceramic particles are dispersed in the bioabsorbable polymer component of the structure.

24. A structure according to claim 23, wherein the bioactive ceramic particles are selected from calcium phosphates.

25. A structure according to claim 19, wherein the bioactive agents or living cells are impregnated into the pores of the structure and the pharmaceutical agents are dispersed in the bioabsorbable polymer component of the structure.

26. A structure according to claim 19, wherein micro-organisms capable of preventing or healing inflammation and/or bioactive agents are impregnated into the pores of the structure.

27. A structure according to claim 23, wherein the bioactive agents or living cells are impregnated into the pores of the structure and the bioactive ceramic particles are dispersed in the bioabsorbable polymer component of the structure.

28. A structure according to claim 23, wherein the bioactive agents are dispersed in the bioabsorbable polymer component of the structure and the bioactive ceramic particles are dispersed in the bioabsorbable polymer component of the structure.