Fabrication of neural interfaces using 3D projection micro-stereolithography

1. A method of fabricating a neural interface, comprising: coating a photo-curable polymer resin on a substrate,

displaying an image comprising regular pores onto the polymer resin-coated substrate using projection micro-stereolithography, thereby cross-linking the resin, and

developing the imaged polymer-resin coated substrate in the presence of a first solvent system, thereby revealing an array of pores formed within a porous polymer mat, wherein the first solvent system determines a feature size of the pores, and

wherein the developing step provides a reduction in the feature size of pores within the porous polymer mat, as compared to a feature size of the regular pores provided in the image.

2. The method of claim 1 , wherein the polymer resin further comprises a conductive particle or a precursor thereof, and wherein the porous polymer mat comprises a polymer composite.

3. The method of claim 2 , wherein the conductive particle comprises a metal nanoparticle, a metal microparticle, carbon black, graphene, or a carbon nanotube; or wherein the conductive particle precursor comprises a photoreducible graphene oxide or a metal salt.

4. The method of claim 2 , wherein the mass loading of the conductive particle or precursor thereof is from about 0.5% to about 70% by volume.

5. The method of claim 2 , wherein the polymer composite comprises an electrically conductive region and an insulating region between adjacent pores.

6. The method of claim 5 , wherein the electrically conductive region comprises the conductive particle-loaded or conductive particle precursor-loaded polymer proximate each pore.

7. The method of claim 2 , wherein the conductive particles are elongated.

8. The method of claim 7 , wherein the elongated conductive particles have a long characteristic dimension that is at least ten times greater than a short characteristic dimension.

9. The method of claim 1 , wherein the porous polymer mat has a Young's modulus of between about 10 and about 1000 kPa.

10. The method of claim 1 , wherein the array of pores has a pore size of from about 10 μm to about 900 μm.

11. The method of claim 1 , wherein the porous polymer mat has a thickness of less than about 300 μm.

12. The method of claim 1 , wherein the polymer resin comprises a silicone, a polyolefin, a polyester, a polyurethane, a polyimide, a polyethylene glycol, or a ring opening metathesis polymerization formed polymer, or a copolymer thereof.

13. The method of claim 12 , wherein the polymer resin is the polyester comprising polybutylene fumarate.

14. The method of claim 12 , wherein the polymer resin is the silicone comprising silanol-terminated polydimethylsiloxane.

15. The method of claim 12 , wherein the polymer resin is the silicone comprising at least one photo-crosslinkable reactive group.

16. The method of claim 15 , wherein the at least one photo-crosslinkable reactive group comprises an acrylate, methacrylate, maleimide, allyl, or vinyl group.

17. The method of claim 16 , wherein the silicone comprises methacryloxypropyl-terminated polydimethylsiloxane.

18. The method of claim 12 , wherein the polymer resin further comprises a photoinitiator.

19. The method of claim 18 , wherein the photoinitiator is a bisacyl phosphine oxide or a monoacylphosphine oxide.

20. The method of claim 18 , wherein the polymer resin further comprises at least one photo-crosslinkable reactive group.

21. The method of claim 1 , wherein the porous polymer mat further comprises one or more therapeutic agents.

22. The method of claim 21 , wherein the therapeutic agent is selected from the group consisting of a neurotrophin, a growth factor, a cytokine, a chemokine, a lymphokine, a cell, a protein, a peptide, a drug, an axonal guidance protein, an extracellular matrix (ECM) molecule, and a morphogen.

23. The method of claim 22 , wherein the porous polymer mat further comprises one or more neurotrophins and one or more ECM molecules.

24. The method of claim 21 , wherein the one or more therapeutic agents are encapsulated in one or more particles or fibers.

25. The method of claim 1 , wherein the photo-curable polymer resin comprises one or more therapeutic agents.

26. The method of claim 1 , further comprising adsorbing one or more therapeutic agents on the surface of the porous polymer mat and/or within one or more pores.

27. The method of claim 1 , further comprising incorporating a delivery vehicle on the surface, or a portion thereof, of the porous polymer mat and/or within one or more pores of the porous polymer mat, wherein the delivery vehicle comprises one or more therapeutic agents.

28. The method of claim 27 , wherein the delivery vehicle comprises a degradable polymer.

29. The method of claim 27 , wherein the incorporating step comprises electrospinning, coating, casting, spreading, dipping, spraying and/or using projection micro-stereolithography.

30. The method of claim 1 , wherein the first solvent system comprises dichloroethane, hexane, toluene, water, or combinations thereof.

31. The method of claim 1 , wherein the developing step comprises developing the imaged polymer-resin coated substrate in the presence of the first solvent system to provide a resultant substrate and then further developing the resultant substrate in the presence of a second solvent system, and wherein the first and second solvent systems are different.

32. The method of claim 1 , wherein the displaying step comprises use of a light source.