MANUFACTURING THREE-DIMENSIONAL SCAFFOLDS USING CRYOGENIC PROTOTYPING

• US 20100291176A1
• Filed: 12/05/2007
• Published: 11/18/2010
• Est. Priority Date: 12/05/2006
• Status: Active Grant

• Current Assignee: Nanyang Technological University
• Original Assignee: Nanyang Technological University
• Inventors: Lim, Tze Chiun, Leong, Kah Fai, Chian, Kerm Sin
• Granted Patent: US 8,557,163 B2
• Time in Patent Office: Days
• US Class Current: 424/423
• CPC Class Codes: A61L 27/38 containing added animal cells organs or tissue containing native cells A61L27/36
• CPC Class Codes: A61L 27/56 Porous materials, e.g. foams or sponges
• CPC Class Codes: B33Y 10/00 Processes of additive manufacturing
• CPC Class Codes: B33Y 70/00 Materials specially adapted for additive manufacturing
• CPC Class Codes: B33Y 80/00 Products made by additive manufacturing

Abstract

The present invention refers to a method of fabricating a three dimensional scaffold suitable for tissue-engineering having a controlled micro- and macroporous structure using cryogenic prototyping. The present invention also refers to scaffolds obtained by the method of the present invention and to their use.

Claims

1. A method of fabricating a three dimensional scaffold suitable for tissue-engineering having a controlled microporous and macroporous structure using cryogenic prototyping comprising:

a) dispensing a first polymer solution in one direction into a reaction chamber to form a first lane;

wherein said first polymer solution comprises a first polymer and a first solvent;

wherein said reaction chamber has a first temperature which is at or below the freezing point of said first solvent;

b) dispensing a second polymer solution into said reaction chamber to form a second lane;

wherein said second polymer solution comprises a second polymer and a second solvent;

wherein said second polymer solution is dispensed such that said second lane is arranged next to said first lane in the same orientation as said first lane and being in contact with said first lane on one side;

wherein said reaction chamber has a second temperature, wherein said second temperature is the same or different from said first temperature as long as it is at or below the freezing point of said second solvent; and

c) dispensing further polymer solutions into said reaction chamber by repeating steps a) and b) to form further lanes in a first plane;

d) repeating steps a) to c) to form further lanes in a next plane,

wherein at least some of the lanes in said next plane are in contact with said lanes of said first plane;

e) repeating step d) to form a three-dimensional scaffold comprising different planes of lanes formed by said polymer solutions;

wherein in any of steps c) to d) said polymer solutions are dispensed such that macropores of said controlled macroporous structure are created;

f) removing said solvents from said three-dimensional scaffold so obtained.

3. The method according to claim 1 or 2, wherein the temperature of said reaction chamber can be varied between about 30°

C. to about −

196°

C.

4. The method according to any of the preceding claims, wherein said method further comprises using different time intervals between dispensing of said different planes into said reaction chamber.

5. The method according to claim 4, further comprising dispensing lanes, threads or drops forming a plane into said reaction chamber only after the lanes, threads or drops forming said previous plane are frozen and subsequently dispensing any further lanes, threads or drops for a further plane into said chamber according to the method in claim 4.

6. The method according to claim 4, further comprising dispensing every lanes, threads or drops forming a plane into said reaction chamber only after the lanes, threads or drops forming the previous plane are frozen.

7. The method according to claim 1, wherein said three-dimensional scaffold is formed by a single lane of polymer solution which is dispensed as a continuous lane into said reaction chamber until said three-dimensional scaffold is formed.

8. The method according to any of the previous claims, further comprising decreasing or increasing the pore size of said microporous scaffold structure by increasing and lowering the temperature of said reaction chamber, respectively, as long as the temperature of said reaction chamber is equal or below the freezing point of said solvent or solvents.

9. The method according to any of the previous claims, wherein all polymer solutions used for the fabrication of a three-dimensional scaffold are identical.

10. The method according to any of the previous claims, wherein the bottom of said reaction chamber is made of metal, ceramics, plastics or glass.

11. The method according to any of the preceding claims, further comprising using at least one needle for dispensing said polymer solution having varying diameters for the outlet opening of said at least one needle.

12. The method according to claim 11, wherein the diameter of said outlet opening of said at least one needle is in a range of about 0.1 mm to about 2 mm.

13. The method according to claim 11 or 12, further comprising varying the speed with which the at least one needle for dispensing said polymer solution into said reaction chamber is moved above said reaction chamber.

14. The method according to any of the preceding claims, further comprising changing the pressure with which said polymer solution is dispensed into said reaction chamber.

15. The method according to any of the preceding claims, wherein said solvent is organic or inorganic.

16. The method according to any of claims 1 to 15, wherein said solvent is selected from the group consisting of 1,1,1,3,3,3-hexafluoroisopropanol (HFIP), acetone, molten phenol, naphthalene, N,N-dimethylformamide (DMF), water, formic acid, acetic acid, lactic acid, ethanol, trifluoroethanol, xylene, diethylformamide, hexa-fluoro-2-propanol, dioxane, chloroform, dimethylacetamide, dichloromethane, tetrahydrofuran (THF), trifluoroacetic acid, N,N-dimethyl acetamide (DMAc), isopropyl alcohol (IPA), methylene chloride, methyl ethyl ketone, octane, propyl alcohol, pyridine, tetraline, toluene, heptane, hexane, methanol, ethyl ether, ethyl alcohol, ethyl acetate, dichloroethyl, carbon tetrachloride, cresol, chlorobenzene, cyclohexane, n-butyl alcohol, butyl acetate, benzyl alcohol, benzene, sulphuric acid or hexafluoro isopropanol, HFIP and mixtures thereof.

17. The method according to any of the preceding claims, wherein said polymer is a biocompatible and/or biodegradable polymer.

18. The method according to any of claims 1 to 16, wherein said polymer is selected from the group consisting of α

-tricalcium phosphate, β

-tricalcium phosphate, poly(D,L-lactide) (PLA), poly(urethanes), poly(siloxanes), poly(silicones), poly(ethylene), poly(vinyl pyrrolidone), poly(2-hydroxy ethyl methacrylate), poly(N-vinyl pyrrolidone), poly(methyl methacrylate), poly(vinyl alcohol) (PVA), poly(acrylic acid), poly(vinyl acetate), polyacrylamide, poly(ethylene-co-vinyl acetate), poly(ethylene glycol), poly(methacrylic acid), polyglycolic acids (PGA), poly(lactide-co-glycolides) (PLGA), nylons, polyamides, polyanhydrides, poly(ethylene-co-vinyl alcohol) (EVOH), polycaprolactone, poly(vinyl acetate), polyvinylhydroxide, poly(ethylene oxide) (PEO), polyorthoesters and copolymers or physical blends of these materials.

19. The method according to any of claims 1 to 16, wherein said polymer is selected from the group consisting of chitosan, collagen, cellulose ether, cellulose, cellulosic ester, fluorinated polyethylene, phenolic, poly-4-methylpentene, polyacrylonitrile, polyamide, polyamideimide, polyacrylate, polybenzoxazole, polycarbonate, polycyanoarylether, polyester, polyestercarbonate, polyether, polyetheretherketone, polyetherimide, polyetherketone, polyethersulfone, polyethylene, polyfluoroolefin, polyimide, polyolefin, polyoxadiazole, polyphenylene oxide, polyphenylene sulfide, polypropylene, polystyrene, polysulfide, polysulfone, polytetrafluoroethylene, polythioether, polytriazole, polyurethane, polyvinyl, polyvinylidene fluoride, regenerated cellulose, silicone, urea-formaldehyde, and copolymers or physical blends of these materials.

20. The method according to any of the preceding claims, wherein said polymer solution dispensed into said reaction chamber is supplemented with at least one bioactive substance.

21. The method according to any of the preceding claims, wherein said removing of said solvent is carried out by a method selected from the group consisting of freeze-drying, sublimation, liquid exchange, and critical point drying (CPD).

22. Use of a method according to any of the preceding claims for the manufacture of scaffolds for tissue engineering.

23. The use according to claim 22, wherein said scaffold is used as skin replacement or bone replacement or esophagus replacement.

24. A scaffold obtained by a method according to any of claims 1 to 21.

25. A scaffold according to claim 24, wherein said scaffold is seeded with eucaryotic cells.

2. A method of fabricating a three dimensional scaffold suitable for tissue-engineering having a controlled micro- and macroporous structure using cryogenic prototyping comprising:

a) dispensing multiple threads or drops of a first polymer solution into a reaction chamber to form a first plane;

wherein said first polymer solution comprises a first polymer and a first solvent;

wherein the reaction chamber has a first temperature which is at or below the freezing point of said first solvent;

b) dispensing multiple threads or drops of a second polymer solution into said reaction chamber to form a second plane;

wherein said second polymer solution comprises a second polymer and a second solvent;

wherein said second threads or drops are in contact with said deposited threads or drops of said first plane but are laterally shifted in any direction with respect to said threads or drops forming said first plane when they are dispensed into said reaction chamber;

wherein said reaction chamber has a second temperature, wherein said second temperature is the same or different from said first temperature as long as it is at or below the freezing point of said second solvent;

c) dispensing multiple threads or drops of a third polymer solution into said reaction chamber to form a third plane;

wherein said third polymer solution comprises a third polymer and a third solvent;

wherein said third threads or drops are in contact with said deposited threads or drops of said second plane but are laterally shifted in any direction with respect to said deposited threads or drops of said first plane when they are dispensed into said reaction chamber in the same direction as said first plane;

wherein said reaction chamber has a third temperature, wherein said third temperature is the same or different from said first and/or second temperature as long as it is at or below the freezing point of said third solvent;

d) dispensing further threads or drops of polymer solutions into said reaction chamber to form further planes by repeating steps a) to c) to obtain said three-dimensional scaffold;

wherein the macroporous structure of said scaffold is defined by controlling within one plane the distance of at least some of said multiple threads or drops to each other;

wherein the microporous structure of said scaffold is defined by controlling the temperature of said reaction chamber when dispensing said polymer solutions into said reaction chamber; and

e) removing said solvent of said three-dimensional scaffold.