Concentrated aqueous silk fibroin solution and use thereof

Abstract

The present invention provides for concentrated aqueous silk fibroin solutions and an all-aqueous mode for preparation of concentrated aqueous fibroin solutions that avoids the use of organic solvents, direct additives, or harsh chemicals. The invention further provides for the use of these solutions in production of materials, e.g., fibers, films, foams, meshes, scaffolds and hydrogels.

1 . A composition comprising a silk fibroin biomaterial essentially free of organic solvent, wherein silk fibroin in the silk fibroin biomaterial comprises a beta-sheet structure. 
     
     
         2 . The composition of  claim 1 , wherein the silk fibroin biomaterial is a regenerated silk fibroin biomaterial. 
     
     
         3 . The composition of  claim 1 , wherein the beta sheet structure comprises those of the beta-sheet crystalline structure (silk II) of native silk fibroin. 
     
     
         4 . The composition of  claim 1 , wherein the silk fibroin biomaterial is in a form selected from the group consisting of a film, a fiber, a foam, a hydrogel, a mesh, a scaffold, and any combinations thereof. 
     
     
         5 . The composition of  claim 1 , wherein the silk fibroin biomaterial further comprises a therapeutic agent. 
     
     
         6 . The composition of  claim 1 , wherein the silk fibroin biomaterial is degradable. 
     
     
         7 . The composition of  claim 1 , wherein the silk fibroin biomaterial is water-stable. 
     
     
         8 . The composition of  claim 1 , wherein the silk fibroin biomaterial is produced from a silk fibroin solution having a concentration of at least about 10% w/w. 
     
     
         9 . The composition of  claim 7 , wherein the concentration of the silk fibroin solution is controlled via osmotic stress. 
     
     
         10 . A method comprising:
 forming a silk fibroin biomaterial essentially free of organic solvent; and contacting the silk fibroin material with water vapor.   
     
     
         11 . The method of  claim 10 , wherein the silk fibroin material is in a form selected from the group consisting of a film, a fiber, a foam, a hydrogel, a mesh, a scaffold, and any combinations thereof. 
     
     
         12 . The method of  claim 10 , wherein the silk fibroin material comprises a silk film. 
     
     
         13 . The method of  claim 10 , wherein the silk fibroin biomaterial is a regenerated silk fibroin biomaterial. 
     
     
         14 . A process for producing a silk film, comprising the steps of:
 (a) casting an aqueous silk fibroin solution comprising silk fibroin in an aqueous salt solution to form a silk film; and   (b) contacting the silk film with water or water vapor.   
     
     
         15 . The process of  claim 14 , further comprising stretching the film mono-axially or biaxially.