Covalently immobilized protein gradients in three-dimensional porous scaffolds

Abstract

The invention provides a method for forming an immobilized agent gradient within a 3-dimensional porous scaffold. A 3-dimensional scaffold formed from a biocompatible material is provided. The surface of the scaffold and/or the agent is activated so as to allow binding of the agent to the scaffold. The activated scaffold is contacted with a solution containing the agent. Contact with the solution is maintained for a sufficient period of time to allow diffusion of the solution through a portion of the scaffold, thereby forming a desired gradient of the agent through the 3-dimensional scaffold.

1 . A 3-dimensional porous scaffold comprising at least one agent covalently immobilized within a biocompatible material and forming at least one gradient therein. 
     
     
         2 . The 3-dimensional scaffold of  claim 1 , further comprising cells within the biocompatible material. 
     
     
         3 . The 3-dimensional scaffold of  claim 2 , wherein the cells form a gradient response in the biocompatible material. 
     
     
         4 . The 3-dimensional scaffold of  claim 1 , wherein said at least one gradient is adapted to guide cell development for tissue regeneration and repair. 
     
     
         5 . The 3-dimensional scaffold of  claim 4 , wherein tissue regeneration and repair includes bone and cartilage regeneration, nerve growth, and/or angiogenesis. 
     
     
         6 . The 3-dimensional scaffold of  claim 1 , further comprising a monomer or polymer within the biocompatible material. 
     
     
         7 . The 3-dimensional scaffold of  claim 6 , wherein the monomer or polymer forms a polymer gradient in the biocompatible material. 
     
     
         8 . The 3-dimensional scaffold of  claim 1 , wherein a first agent and a second agent are covalently immobilized within the biocompatible material such that the first agent forms a first concentration gradient in a direction opposite to a second concentration gradient formed by the second agent. 
     
     
         9 . The 3-dimensional scaffold of  claim 1 , wherein the biocompatible material is selected from the group consisting of silk, collagen, keratin, fibronectin, chitosan, hyaluronic acid and alginates. 
     
     
         10 . The 3-dimensional scaffold of  claim 1 , wherein the biocompatible material comprises polylactic acid, polyglycolic acid, or a combination thereof. 
     
     
         11 . The 3-dimensional scaffold of  claim 1 , wherein the biocompatible material comprises silk. 
     
     
         12 . The 3-dimensional scaffold of  claim 1 , wherein said at least one agent comprises a protein or peptide. 
     
     
         13 . The 3-dimensional scaffold of  claim 12 , wherein the protein or peptide comprises an enzyme, a cytokine, a growth factor, a cell binding domain and/or other cell signaling factor. 
     
     
         14 . The 3-dimensional scaffold of  claim 1 , wherein said at least one agent comprises an enzyme. 
     
     
         15 . The 3-dimensional scaffold of  claim 14 , wherein the enzyme is selected for use as a biosensor. 
     
     
         16 . The 3-dimensional scaffold of  claim 1 , wherein said at least one agent comprises a chemotactic agent. 
     
     
         17 . The 3-dimensional scaffold of  claim 1 , wherein said at least one agent comprises a nucleic acid. 
     
     
         18 . The 3-dimensional scaffold of  claim 1 , wherein the biocompatible material has a consistent pore density. 
     
     
         19 . The 3-dimensional scaffold of  claim 18 , wherein the biocompatible material has a porosity of about 90%. 
     
     
         20 . The 3-dimensional scaffold of  claim 1 , wherein surface of the biocompatible material is activated. 
     
     
         21 . The 3-dimensional scaffold of  claim 1 , wherein said at least one agent is activated. 
     
     
         22 . The 3-dimensional scaffold of  claim 20 , wherein the surface of the biocompatible material and/or the agent is activated using 1-Ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC).