Viscoelastic ink for direct writing of hydrogel structures

Patent metadata

Field	Value
Publication number	US-9045657-B2
Application number	US-201113636542-A
Country	US
Kind code	B2
Filing date	Mar 22, 2011
Priority date	Mar 24, 2010
Publication date	Jun 2, 2015
Grant date	Jun 2, 2015

Abstract

A viscoelastic ink for direct writing of hydrogel structures includes a long chain polymer and a photopolymerizable moiety, which may be a photopolymerizable monomer or a photopolymerizable group attached to the long chain polymer. The ink may also include a crosslinking agent, a photoinitiator, and water. The long chain polymer is present at a concentration greater than a critical overlap concentration c* of the long chain polymer in the ink.

First claim

The invention claimed is:

1. A viscoelastic ink for direct writing of hydrogel structures, the ink comprising:
a polymer;
a photopolymerizable moiety;
a photoinitiator; and
water,
wherein the polymer comprises poly(hyaluronic acid) (pHA), methacrylated hyaluronic acid or a blend of the two and is present at a concentration of about 5 wt. % or greater in the ink.

2. The ink of claim 1 , wherein the photopolymerizable moiety is selected from the group consisting of: a photopolymerizable monomer; and a photopolymerizable group attached to the polymer.

3. A method for forming a hydrogel scaffold, the method comprising:
forming an ink comprising a polymer and a photopolymerizable moiety, the polymer comprising poly(hyaluronic acid) (pHA), methacrylated hyaluronic acid or a blend of the two and being present at a concentration of about 5 wt. % or greater in the ink;
extruding the ink through a micronozzle to form an extruded filament;
photopolymerizing the extruded filament; and
depositing the extruded filament in a pattern on a substrate to form a hydrogel scaffold,
wherein the ink comprises a first viscosity at a low shear rate of about 0.1 s −1 and a second viscosity during the extrusion, the second viscosity being at least about an order of magnitude lower than the first viscosity.

4. The method of claim 3 , wherein the second viscosity is about 20 Pa·s or less.

5. The method of claim 3 , wherein the photopolymerization of the extruded filament occurs prior to depositing the extruded filament on the substrate.

6. The method of claim 3 , wherein the photopolymerization of the extruded filament occurs after depositing the extruded filament on the substrate.

7. The method of claim 3 , further comprising, after the photopolymerization, chemically treating the hydrogel scaffold to render the scaffold compliant for tissue growth.

8. The method of claim 7 , wherein chemically treating the scaffold comprises immersing the scaffold in a polylysine solution.

9. The method of claim 3 , wherein the concentration of the polymer is between about 10 wt. % and about 50 wt. %.

10. The method of claim 3 , wherein the photopolymerizable moiety comprises a photopolymerizable monomer present at a concentration of between about 25 wt. % and 55 wt. %.

11. The method of claim 3 , wherein the photopolymerizable moiety comprises a photopolymerizable group attached to the polymer.

12. The method of claim 3 , wherein, after photopolymerization, the extruded filament comprises a physically entangled polymer network and a chemically crosslinked polymer network.

13. The method of claim 3 , wherein, after photopolymerization, the extruded filament comprises a chemically crosslinked polymer network with no physically entangled polymer chains.

14. The ink of claim 1 , wherein the ink further comprises polyethylene glycol diacrylate (PEGDA).

15. The ink of claim 14 , wherein the PEGDA is present at a concentration in the ink of up to about 10 wt. %.

16. The ink of claim 15 , wherein the concentration of the pHA, the methacrylated hyaluronic acid, or said blend of the two is 10 wt. % and the concentration of the PEGDA is 8 wt. %.

17. The method of claim 3 , wherein the ink further comprises polyethylene glycol diacrylate (PEGDA).

18. The method of claim 16 , wherein the PEGDA is present at a concentration in the ink of up to about 10 wt. %.

19. The method of claim 18 , wherein the concentration of the pHA, the methacrylated hyaluronic acid, or said blend of the two is 10 wt. % and the concentration of the PEGDA is 8 wt. %.

Assignees

• Lewis Jennifer A
• Shepherd Robert F
• Barry Iii Robert A
• Parker Sara T
• Shepherd Jennifer N H
• Wiltzius Pierre
• Nuzzo Ralph G
• Univ Illinois

Inventors

• Lewis Jennifer A
• Shepherd Robert F
• Barry Iii Robert A
• Parker Sara T
• Shepherd Jennifer N H
• Wiltzius Pierre
• Nuzzo Ralph G

Classifications

• A61L27/16 Primary

  obtained by reactions only involving carbon-to-carbon unsaturated bonds · CPC title

• C09D11/101

  Inks specially adapted for printing processes involving curing by wave energy or particle radiation, e.g. with UV-curing following the printing · CPC title

• C08L5/08

  Chitin; Chondroitin sulfate; Hyaluronic acid; Derivatives thereof · CPC title

• A61L27/56

  Porous materials, {e.g. foams or sponges} · CPC title

• C09D11/16 Primary

  Writing inks · CPC title