Glass scaffolds with controlled resorption rates and methods for making same

• US 20030198660A1
• Filed: 02/28/2003
• Published: 10/23/2003
• Est. Priority Date: 01/30/2001
• Status: Active Grant

• Current Assignee: Advanced Technologies and Regenerative Medicine, LLC
• Original Assignee: Ethicon Incorporated (Johnson & Johnson)
• Inventors: Tenhuisen, Kevor S., Janas, Victor F.
• Granted Patent: US 7,005,135 B2
• Time in Patent Office: Days
• US Class Current: 424/423
• CPC Class Codes: A61F 2/28 Bones joints A61F2/30
• 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 2002/2835 Bone graft implants for filling a bony defect or an endoprosthesis cavity, e.g. by synthetic material or biological material
• CPC Class Codes: A61F 2002/30032 differing in absorbability or resorbability, i.e. in absorption or resorption time
• CPC Class Codes: A61F 2002/30062 (bio)absorbable, biodegradable, bioerodable, (bio)resorbable, resorptive
• CPC Class Codes: A61F 2002/30535 Special structural features of bone or joint prostheses not otherwise provided for
• CPC Class Codes: A61F 2002/30677 Means for introducing or releasing pharmaceutical products, e.g. antibiotics, into the body
• CPC Class Codes: A61F 2002/30766 Scaffolds for cartilage ingrowth and regeneration
• CPC Class Codes: A61F 2210/0004 bioabsorbable
• CPC Class Codes: A61F 2250/003 differing in adsorbability or resorbability, i.e. in adsorption or resorption time
• CPC Class Codes: A61F 2250/0058 Additional features; Implant or prostheses properties not otherwise provided for
• CPC Class Codes: A61F 2310/00293 containing a phosphorus-containing compound, e.g. apatite
• CPC Class Codes: A61F 2310/00329 Glasses, e.g. bioglass
• CPC Class Codes: A61L 27/10 Ceramics or glasses
• CPC Class Codes: A61L 27/425 of phosphorus containing material, e.g. apatite
• CPC Class Codes: A61L 27/427 of other specific inorganic materials not covered by A61L27/422 or A61L27/425
• CPC Class Codes: A61L 27/58 Materials at least partially resorbable by the body
• CPC Class Codes: C03B 5/0334 Pot furnaces; Core furnaces
• CPC Class Codes: C03C 13/00 Fibre or filament compositions manufacture of fibres or filaments C03B37/00
• CPC Class Codes: C03C 2213/02 Biodegradable glass fibres
• CPC Class Codes: C03C 4/0007 : for biologically-compatible glass

Abstract

The present invention relates to resorbable glass scaffolds for use in biological applications and methods for making same. Specifically, these scaffolds are composed of phosphate glass fibers, where the rate of dissolution into biological fluids is controlled by the length of time the glass is held above its melt temperature prior to spinning the fiber.

Claims

1. A method for making a hard tissue scaffold used in repairing an injury to hard tissue, said method comprising the steps of:

(a) selecting a glass composition;

(b) melting a first amount of the selected glass composition to yield a first glass in a melted state;

(c) maintaining the first glass in a melted state for a first melt hold time to confer a first resorption rate to the first glass, the first resorption rate being matched to a predetermined rate of bone growth into the scaffold;

(d) forming the first glass into a first resorbable fiber having the first resorption rate;

(e) melting a second amount of the selected glass composition to yield a second glass in a melted state;

(f) maintaining the second glass in a melted state for a second melt hold time to confer a second resorption rate to the second glass, the second resorption rate being slower than the first resorption rate;

(g) forming the second glass into a second resorbable fiber having the second resorption rate;

(h) including both the first resorbable fiber and the second resorbable fiber in the hard tissue scaffold, whereby the first resorbable fiber resorbs to promote bone in-growth while the second resorbable fiber persists for a predetermined time in order to maintain structural support for the scaffold.

2. The method of claim 1, further including the step of forming the first and the second fibers into a composite textile structure for inclusion in the hard tissue scaffold.

3. The method of claim 2, wherein the first and second fibers have a diameter in a range of from about 1 μ

m to about 100 μ

m.

4. The method of claim 2, wherein the glass composition is a phosphate glass composition.

5. The method of claim 4, wherein the glass composition includes CaO, Fe₂O₃ and P₂O₅ in a molar ratio of approximately 16.5:

33.5;

50.0.

6. The method of claim 4, wherein the glass composition includes CaO, Fe₂O₃ and P₂O₅ in approximately the following range of molar ratios (CaO) 16.5 to 33.5:

(Fe₂O₃) 16.5 to 33.5;

(P₂O₅) 50.0.

7. The method of claim 1, wherein the first melt hold time and the second melt hold time are each in the range of from about 8 hours to about 72 hours.

8. The method of claim 2, wherein said step of forming the composite textile structure results in a spacial distribution of each of the first and second fibers.

9. The method of claim 2, wherein the first and second fibers have approximately the same diameter.

10. The method of claim 2, further including the steps of preparing a resorbable matrix material to combine with the composite textile structure and combining the resorbable matrix material therewith to form the hard tissue scaffold.

11. The method of claim 10, wherein said matrix material is selected from the group consisting of:

resorbable synthetic polymers, bipolymers, ceramics and photocurable polymers.

12. The method of claim 10, further comprising the step of adding bone growth agents to the matrix material.

13. The method of claim 10, further comprising the step of adding a medicament to the matrix to enable controlled release of the medicament.

14. The method of claim 1, further comprising the steps of:

(i) casting each of the first glass and the second glass into a solid form after the performance of said steps (c) and (f), respectively; and

(j) remelting said solid form prior to the performance of said steps (d) and (g), respectively.

15. A hard tissue replacement scaffold, comprising a plurality of resorbable glass fibers made from the same composition, a first of said plurality having a resorption rate greater than a second of said plurality, said first and second fibers having the resorption rate thereof controlled by the duration that the glass from which said first and second fibers are formed is held in a melted state.

16. The scaffold of claim 15, wherein said resorption rate of said first fiber approximately matches the rate of cellular ingrowth.

17. The scaffold of claim 15, further comprising a bone growth agent incorporated therein.

18. The scaffold of claim 15, further comprising a polymer matrix material disposed about said fibers.

19. The scaffold of claim 18, further including a medicament incorporated therein, the resorption rate of said scaffold determining the controlled rate of release of said medicament.

20. The scaffold of claim 15, wherein said fibers are formed into a textile structure.