Channeled biomedical foams and method for producing same

• US 20030181978A1
• Filed: 03/25/2002
• Published: 09/25/2003
• Est. Priority Date: 03/25/2002
• Status: Abandoned Application

• Current Assignee: Ethicon Incorporated (Johnson & Johnson)
• Original Assignee: Ethicon Incorporated (Johnson & Johnson)
• Inventors: Melican, Mora C., Chun, Iksoo, Brown, Kelly R.
• Application Number:
  US10/106,007
• Publication Number:
  US 20030181978A1
• Time in Patent Office: Days
• US Class Current: 623/11.11
• CPC Class Codes: A61F 2/0077 Special surfaces of prostheses, e.g. for improving ingrowth A61F2/30767 takes precedence
• CPC Class Codes: A61F 2/28 Bones joints A61F2/30
• CPC Class Codes: A61F 2/30756 Cartilage endoprostheses A61F2/3603 takes precedence
• CPC Class Codes: A61F 2/30767 Special external or bone-contacting surface, e.g. coating for improving bone ingrowth
• CPC Class Codes: A61F 2002/0086 for preferentially controlling or promoting the growth of specific types of cells or tissues of bone tissue onto implantable joints A61F2002/3093
• 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 2002/30199 Three-dimensional shapes
• CPC Class Codes: A61F 2002/30677 Means for introducing or releasing pharmaceutical products, e.g. antibiotics, into the body
• CPC Class Codes: A61F 2002/30762 Means for culturing cartilage
• CPC Class Codes: A61F 2002/30766 Scaffolds for cartilage ingrowth and regeneration
• CPC Class Codes: A61F 2002/30785 parallel
• CPC Class Codes: A61F 2002/30787 inclined obliquely with respect to each other
• CPC Class Codes: A61F 2002/3093 for promoting ingrowth of bone tissue
• CPC Class Codes: A61F 2002/4648 Means for culturing bone graft
• CPC Class Codes: A61F 2210/0004 bioabsorbable
• CPC Class Codes: A61F 2230/0063 Three-dimensional shapes
• CPC Class Codes: A61F 2250/0067 Means for introducing or releasing pharmaceutical products into the body
• CPC Class Codes: A61L 27/18 obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
• CPC Class Codes: A61L 27/56 Porous materials, e.g. foams or sponges
• CPC Class Codes: A61L 31/06 : obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds A61L31/041 takes precedence
• CPC Class Codes: A61L 31/146 : Porous materials, e.g. foams or sponges
• CPC Class Codes: C08L 67/04 : Polyesters derived from hydroxycarboxylic acids, e.g. lactones C08L67/06 takes precedence

Abstract

The present invention provides a biomedical, biocompatible, polymeric foam scaffold suitable for use in the repair and regeneration of tissue and which contains located therein a network of, branched channels that are effective to encourage and facilitate vascularization and tissue growth within the scaffold and to methods for making such biomedical scaffolds.

Claims

1. A biomedical, biocompatible scaffold suitable for use in the repair and regeneration of tissue, comprising a polymeric foam, said foam comprising a network of branched channels effective to encourage and facilitate vascularization and tissue growth in said scaffold.

2. The biomedical scaffold of claim 1 wherein said scaffold is bioabsorbable.

3. The biomedical scaffold of claim 1 wherein said scaffold comprises a bioabsorbable polymer selected from the group consisting of aliphatic polyesters, poly(amino acids), polyalkylenes oxalates, polyamides, tyrosine derived polycarbonates, polyorthoesters, polyoxaesters, and poly(anhydrides).

4. The biomedical scaffold of claim 3 wherein said polymer comprises an aliphatic polyester selected from the group consisting of homopolymers and copolymers of lactide, lactic acid, glycolide, glycolic acid, ε

-caprolactone, p-dioxanone, trimethylene carbonate, alkyl derivatives of trimethylene carbonate, δ

-valerolactone, β

-butyrolactone, γ

-butyrolactone, ε

-decalactone, hydroxybutyrate, hydroxyvalerate, 1,4-dioxepan-2-one, 1,5,8,12-tetraoxacyclotetradecane-7,14-dione, 1,5-dioxepan-2-one, and 6,6-dimethyl-1,4-dioxan-2-one.

5. The biomedical scaffold of claim 4 wherein said aliphatic polyester comprises an elastomer selected from the group consisting of copolymers of lactide and ε

-caprolactone, and lactide and glycolide.

6. The biomedical scaffold of claim 5 wherein said elastomer has an inherent viscosity in the range of about 1 to 2 deciliters per gram as determined at 25°

C. in a 0.1 gram per deciliter solution of polymer in hexafluoroisopropanol.

7. The biomedical scaffold of claim 6 wherein said copolymer of lactide and ε

-caprolactone comprises a mole ratio of lactide to ε

-caprolactone from about 30/70 to about 50/50.

8. The biomedical scaffold of claim 6 wherein said copolymer of lactide and glycolide comprises a mole ratio of lactide to glycolide from about 75/25 to about 95/5.

9. The biomedical scaffold of claim 1 comprising a continuous polymer phase comprising interconnected pores of between about 50 and about 500 microns in diameter.

10. The biomedical scaffold of claim 1 further comprising cells.

11. The biomedical scaffold of claim 1 further comprising a bioactive substance.

12. A process for making biomedical, biocompatible scaffolds suitable for use in the repair and regeneration of tissue, comprising:

preparing a homogenous mixture comprising a synthetic, biocompatible polymer, a solvent in which said polymer is soluble, and a non-solvent in which said polymer is not soluble, wherein said solvent and said non-solvent are miscible, and wherein the freezing point of said non-solvent is higher than the freezing point of said solvent,

placing said homogenous mixture in a mold or other device suitable for preparing foam scaffolds suit-able for use in repair and regeneration of tissue,

cooling said homogenous mixture to a first temperature effective to freeze said non-solvent, maintaining said first temperature for a time effective to allow phase separation of said non-solvent from said homogenous mixture,

cooling said homogenous mixture to a second temperature sufficient to form a solid, and

removing said solvent and said non-solvent from said solid to provide a biocompatible, porous foam scaffold which comprises a network of branched channels.

13. The process of claim 12 wherein said polymer is bioabsorbable.

14. The process of claim 13 wherein said bioabsorbable polymer is selected from the group consisting of aliphatic polyesters, poly(amino acids), polyalkylenes oxalates, polyamides, tyrosine derived polycarbonates, polyorthoesters, polyoxaesters and poly(anhydrides).

15. The process of claim 14 wherein said polymer comprises an aliphatic polyester selected from the group consisting of homopolymers and copolymers of lactide, lactic acid, glycolide, glycolic acid, ε

-caprolactone, p-dioxanone, trimethylene carbonate, alkyl derivatives of trimethylene carbonate, δ

-valerolactone, β

-butyrolactone, δ

-butyrolactone, ε

-decalactone, hydroxybutyrate, hydroxyvalerate, 1,4-dioxepan-2-one, 1,5,8,12-tetraoxacyclotetradecane-7,14-dione, 1,5-dioxepan-2-one, and 6,6-dimethyl-1,4-dioxan-2-one.

16. The process of claim 15 wherein said aliphatic polyester comprises an elastomer selected from the group consisting of copolymers of lactide and ε

-caprolactone, lactide and glycolide, and blends thereof.

17. The process of claim 16 wherein said copolymer of lactide and ε

-caprolactone comprises a mole ratio of lactide to ε

-caprolactone from about 30/70 to about 50/50.

18. The process of claim 16 wherein said copolymer of lactide and glycolide comprises a mole ratio of lactide to glycolide from about 75/25 to about 95/5.

19. The process of claim 14 wherein said solvent is selected from the group consisting of dimethyl carbonate, 1,4-dioxane and diethyl carbonate.

20. The process of claim 19 wherein said non-solvent is selected from the group consisting of t-butanol, tert-amyl alcohol, 3,3 dimethyl-2 butanol, octanol, nonanol, decanol, n-decanol and dodecanol.