Porous polymer scaffolds for neural tissue engineering and methods of producing the same
The present invention relates to scaffolds that can physically guide cells, e.g. neurons, while best matching the material properties of native tissue. The present invention also relates to methods of generating such scaffolds, and for the use of such scaffolds, e.g. in spinal cord and peripheral nerve injury repair. The methods of the present invention include a uniquely controlled freeze casting process to generate highly porous, linearly oriented scaffolds. The scaffolds of the present invention not only comprise a highly aligned porosity, but also contain secondary guidance structures in the form of ridges running parallel to the pores to create a series of microstructured and highly aligned channels. This hierarchy of structural guidance aligns and guides neurite outgrowth down the channels created by the ridges, and keep neurites from branching perpendicular to the inter-ridge grooves.
1. A scaffold for supporting cell growth, the scaffold comprising regions of aligned pores, wherein at least some walls of the pores include ridges that protrude from the walls and run parallel to a long axis of the pores.
2. The scaffold of claim 1 , wherein the scaffold comprises a polymer.
3. The scaffold of claim 2 , wherein the polymer comprises at least one selected from the group consisting of: chitosan, chitin, cellulose, alginate, agar, gelatin, soy protein, hyaluronic acid, collagen, elastin, and silk, and any combination thereof.
4. The scaffold of claim 2 , wherein the modulus of the scaffold is controlled in the kPa to GPa range.
5. The scaffold of claim 2 , wherein the strength of the scaffold is controlled in the kPa to GPa range.
6. The scaffold of claim 2 , wherein the toughness and fracture toughness of the scaffold and scaffold forming material is controlled in the J/m 3 to MJ/m 3 , and in the kPa·m 1/2 to MPa·m 1/2 range, respectively.
7. The scaffold of claim 1 , wherein substantially parallel grooves are formed between adjacent ridges.
8. The scaffold of claim 7 , wherein the width of each groove is controlled in a micrometer to nanometer length scale.
9. The scaffold of claim 1 , wherein the formation of the height and width of each ridge is controlled in a micrometer to nanometer length scale.
10. The scaffold of claim 1 , wherein the ridges have substantially rectangular profiles.
11. The scaffold of claim 1 , wherein adjacent ridges are separated by between about 1 μm and about 50 μm.
12. The scaffold of claim 1 , wherein the ridges have a height between about 6 μm and about 11 μm.