Devices and Methods for Tissue Engineering

• US 20110106272A1
• Filed: 07/08/2010
• Published: 05/05/2011
• Est. Priority Date: 07/10/2009
• Status: Active Grant

• Current Assignee: Novum Medical Incorporated
• Original Assignee: Bio2 Technologies, Inc.
• Inventors: LIU, JAMES JENG
• Granted Patent: US 8,652,368 B2
• Time in Patent Office: Days
• US Class Current: 623/23.61
• CPC Class Codes: A61F 2/02 Prostheses implantable into the body closure means for urethra or rectum or for artificial body openings therefor A61F2/0004
• CPC Class Codes: A61F 2/28 Bones joints A61F2/30
• CPC Class Codes: A61F 2/30734 Modular inserts, sleeves or augments, e.g. placed on proximal part of stem for fixation purposes or wedges for bridging a bone defect
• CPC Class Codes: A61F 2/3094 Designing or manufacturing processes
• CPC Class Codes: A61F 2/44 for the spine, e.g. vertebrae, spinal discs
• CPC Class Codes: A61F 2/4465 having a circular or kidney shaped cross-section substantially perpendicular to the axis of the spine
• CPC Class Codes: A61F 2002/30062 (bio)absorbable, biodegradable, bioerodable, (bio)resorbable, resorptive
• CPC Class Codes: A61F 2002/3092 having an open-celled or open-pored structure
• CPC Class Codes: A61F 2002/30968 Sintering
• CPC Class Codes: A61F 2002/4495 having a fabric structure, e.g. made from wires or fibres
• CPC Class Codes: A61F 2210/0004 bioabsorbable
• CPC Class Codes: A61F 2310/00329 Glasses, e.g. bioglass
• CPC Class Codes: A61L 2400/18 Modification of implant surfaces in order to improve biocompatibility, cell growth, fixation of biomolecules, e.g. plasma treatment
• CPC Class Codes: A61L 2430/02 for reconstruction of bones; weight-bearing implants
• CPC Class Codes: A61L 2430/38 for reconstruction of the spine, vertebrae or intervertebral discs
• CPC Class Codes: A61L 27/10 Ceramics or glasses
• CPC Class Codes: A61L 27/54 Biologically active materials, e.g. therapeutic substances A61L27/227 takes precedence
• 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: C03C 10/0009 containing silica as main constituent
• CPC Class Codes: C03C 11/00 : Multi-cellular glass ; Porous or hollow glass or glass particles
• CPC Class Codes: C03C 13/006 : Glass-ceramics fibres
• CPC Class Codes: C03C 2204/00 : Glasses, glazes or enamels with special properties
• CPC Class Codes: C03C 2213/02 : Biodegradable glass fibres
• CPC Class Codes: C03C 4/0014 : Biodegradable glass
• CPC Class Codes: Y10T 428/249928 : Fiber embedded in a ceramic, glass, or carbon matrix

Abstract

A resorbable tissue scaffold fabricated from bioactive glass fiber forms a rigid three-dimensional porous matrix having a bioactive composition. Porosity in the form of interconnected pore space is provided by the space between the bioactive glass fiber in the porous matrix. Strength of the bioresorbable matrix is provided by bioactive glass that fuses and bonds the bioactive glass fiber into the rigid three-dimensional matrix. The resorbable tissue scaffold supports tissue in-growth to provide osteoconductivity as a resorbable tissue scaffold, used for the repair of damaged and/or diseased bone tissue.

Claims

1. A method of fabricating a synthetic bone prosthesis comprising:

mixing a bioactive fiber with a pore former and a liquid to provide a plastically formable batch;

kneading the formable batch to distribute the bioactive fiber with the pore former, to provide a formable batch of a homogeneous mass of intertangled and overlapping bioactive fiber;

forming the formable batch into a desired shape to provide a shaped form;

drying the shaped form to remove the liquid; and

heating the shaped form to a bond formation temperature using an exothermic reaction of the pore former to form bonds between the intertangled and overlapping bioactive glass fiber.

2. The method according to claim 1 wherein the bioactive fiber has a devitrification temperature and wherein the exothermic reaction of the pore former initiates when the shaped form is below the devitrification temperature and the exothermic reaction of the pore former is completed before the shaped form reaches the devitrification temperature.

3. The method according to claim 1 wherein the bioactive fiber has a devitrification temperature and wherein the exothermic reaction of the pore former initiates when the shaped form is below the devitrification temperature and the exothermic reaction of the pore former is completed after the shaped form exceeds the devitrification temperature.

4. The method according to claim 1 wherein the step of heating the shaped form to a bond formation temperature is performed in an air-purged kiln.

5. The method according to claim 1 wherein the pore former is selected from a list consisting of activated carbon, graphite flakes, HPMC, PMMA, wood flour, and corn starch.

6. The method according to claim 1 wherein the mixing step further comprises a binder.

7. The method according to claim 6 wherein the mixing step further comprises a bonding agent.

8. The method according to claim 1 wherein the mixing step further comprises a bonding agent.

9. The method according to claim 1 further comprising annealing the synthetic bone prosthesis after the heating step.

10. A synthetic bone prosthesis comprising:

intertangled bioactive glass fibers;

bonds between the intertangled bioactive glass fibers to form a rigid three-dimensional tissue scaffold;

pore space within the rigid three-dimensional tissue scaffold predetermined by volatile components interspersed within the intertangled bioactive fibers and removed during the formation of the bonds; and

the bonds formed using an exothermic reaction of the volatile components.

11. The synthetic bone prosthesis according to claim 10 wherein the volatile components comprises a pore former.

12. The synthetic bone prosthesis according to claim 10 wherein the pore space creates a porosity between about 40% and about 85% in the synthetic bone prosthesis.

13. The synthetic bone prosthesis according to claim 10 wherein the pore space has a pore size between about 10 μ

m and about 500 μ

m.

14. The synthetic bone prosthesis according to claim 10 wherein the pore size has a bi-modal size distribution.

15. The synthetic bone prosthesis according to claim 10 wherein the intertangled bioactive glass fibers have a composition comprising sodium carbonate, calcium carbonate, phosphorus pentoxide, about 45 mol % to about 60 mol % silica, and an about 2 to an about 10 molar ratio of calcium to phosphate.

16. The synthetic bone prosthesis according to claim 10 wherein the intertangled bioactive glass fibers comprise 13-93 glass fiber.

17. The synthetic bone prosthesis according to claim 10 wherein the intertangled bioactive glass fiber comprises a mixture of bioactive glass fiber having different compositions.

18. The synthetic bone prosthesis according to claim 10 wherein the intertangled bioactive glass fibers have a diameter ranging from about 1 μ

m to about 200 μ

m.