Scaffolds for tissue engineered hair

• US 20040054410A1
• Filed: 07/14/2003
• Published: 03/18/2004
• Est. Priority Date: 08/08/2000
• Status: Active Grant

• Current Assignee: Aderans Research Institute Incorporated
• Original Assignee: Aderans Research Institute Incorporated
• Inventors: Barrows, Thomas H
• Granted Patent: US 7,198,641 B2
• Time in Patent Office: Days
• US Class Current: 623/15.11
• CPC Class Codes: A61F 2/10 Hair or skin implants
• CPC Class Codes: A61K 35/12 Materials from mammals; Compositions comprising non-specified tissues or cells; Compositions comprising non-embryonic stem cells; Genetically modified cells vaccines or medicinal preparations containing antigens or antibodies A61K39/00
• CPC Class Codes: A61L 2430/18 for hair reconstruction
• CPC Class Codes: A61L 27/18 obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
• CPC Class Codes: A61L 27/26 Mixtures of macromolecular compounds
• CPC Class Codes: A61L 27/3804 characterised by specific cells or progenitors thereof, e.g. fibroblasts, connective tissue cells, kidney cells
• CPC Class Codes: A61L 27/3813 Epithelial cells, e.g. keratinocytes, urothelial cells
• CPC Class Codes: A61L 27/3869 Epithelial tissues other than skin
• CPC Class Codes: A61L 27/56 Porous materials, e.g. foams or sponges
• CPC Class Codes: A61P 25/10 for petit-mal
• CPC Class Codes: B33Y 80/00 Products made by additive manufacturing
• CPC Class Codes: C08L 67/04 Polyesters derived from hydroxycarboxylic acids, e.g. lactones C08L67/06 takes precedence
• CPC Class Codes: C12N 2533/40 Polyhydroxyacids, e.g. polymers of glycolic or lactic acid (PGA, PLA, PLGA); Bioresorbable polymers
• CPC Class Codes: C12N 5/0068 General culture methods using substrates for specific animal cell type C12N5/06
• CPC Class Codes: C12N 5/0627 Hair cells

Abstract

Porous, bioabsorbable scaffolds for tissue engineering of human hair follicles, methods for their manufacture and methods of their use in creating new hair.

Claims

1. A porous, bioabsorbable scaffold for tissue engineering of human hair follicles.

2. A scaffold of claim 1 in which said bioabsorbable material is comprised of a polymer synthesized from one or more of the following monomers:

L-lactide, d,l-lactide, glycolide, trimethylene carbonate, caprolactone, andpara-dioxanone.

3. A bioabsorbable material of claim 2 in which said polymer is a copolymer of d,l-lactide and glycolide.

4. A scaffold of claim 1 in which said bioabsorbable material is collagen.

5. A scaffold of claim 1 in which said porosity is due to interconnected pores in the size range of 0.1 to 1,000 microns.

6. A scaffold of claim 5 in which said pores are in the size range of 1 to 500 microns.

7. A scaffold of claim 1 in which said porosity is due to a scaffold with a fibrous structure.

8. A scaffold of claim 7 in which said fibrous structure is comprised of fibers that are bonded together.

9. A scaffold of claim 8 in which said fibers are comprised of a core and sheath structure, said sheath being lower melting than said core, and are bonded together by means of inter-fiber welds in the sheaths at points of contact.

10. A method of making a scaffold of claim 1 comprising the steps of,

a. Provide a bioabsorbable polymer that is soluble in a solvent (solvent A).

b. Provide a form in the shape of the desired scaffold made of a material that is soluble in a different solvent (solvent B) and that is substantially insoluble in solvent A.

c. Coat the form with particles of a substance (the pore-forming substance) that is also soluble in solvent B or in a third solvent (solvent C).

d. Dissolve the bioabsorbable polymer in solvent A and apply the resultant solution to the particle-covered form.

e. Remove solvent A by evaporation or other suitable means.

f. Use solvent B to dissolve said form and said particles.

g. Remove solvent B from the finished porous scaffold.

h. If required, use solvent C additionally to remove said particles.

11. A method of making a scaffold of claim 1 comprising the steps of,

a. Providing a bioabsorbable polymer that is soluble in a first solvent and substantially insoluble in a second solvent.

b. Providing a form in the shape of the desired scaffold made of a material that is soluble in the second solvent and substantially insoluble in the first solvent.

c. Providing a pore-forming substance that is soluble in both first and second solvents.

d. Coating the form with a solution of bioabsorbable polymer and poreforming substance dissolved in the first solvent.

e. Removing the first solvent and causing the pore forming substance to phase separate from the bioabsorbable polymer.

f. Using the second solvent to dissolve said form and said pore forming substance.

g. Removing the second solvent from the finished porous scaffold.

12. A method of making a scaffold of claim 11 in which said bioabsorbable polymer is a copolymer of d,l-lactide and glycolide, said pore forming substance is poly(ethylene glycol), said form is made of sugar the first solvent is dichloromethane and the second solvent is water.

13. A method of making a scaffold of claim 1 comprising the steps of,

a. Providing a thin, non-woven web of bioabsorbable fibers.

b. Placing said web in a two-part mold that has cavities in one part and mating forms in the other part, said cavities and forms providing the desired shape and dimensions of the desired scaffolds.

c. Closing the mold and applying sufficient heat and pressure to form the web into the desired porous structure.

d. Removing the web from the mold and die-cut the molded scaffolds from the web.

14. A method of creating new hair comprising the steps of,

a. Providing scaffolds of claim 1.

b. Seeding hair follicle progenitor cells on said scaffolds.

c. Implanting scaffolds of step 2 into skin where the growth of new hair is desired.

15. The method of creating new hair of claim 14 in which said progenitor cells used in step 2 are obtained from substructures within normal hair follicles that are known to contain such cells including the dermal papilla, the dermal sheath and the bulge area.

16. The method of creating new hair of claim 15 in which said progenitor cells are multiplied in culture prior to seeding on the scaffolds of claim 1.

17. The method of creating new hair of claim 14 in which the method of implantation of said scaffolds in step 3 is substantially equivalent to the procedure currently used by hair transplant surgeons to implant single hair grafts into the scalp.