Modified silk films containing glycerol

Abstract

The present invention provides for compositions and methods for preparing aqueous insoluble, ductile, flexible silk fibroin films. The silk films comprise silk fibroin and about 10% to about 50% (w/w) glycerol, and are prepared by entirely aqueous processes. The ductile silk film may be further treated by extracting the glycerol from and re-drying the silk film. Active agents may be embedded in or deposited on the glycerol modified silk film for a variety of medical applications. The films may be into 3-dimentional structures, or placed on support surfaces as labels or coatings. The glycerol modified silk films of the present invention are useful in variety of applications such as tissue engineering, medical devices or implants, drug delivery, and edible pharmaceutical or food labels.

1 . A silk film comprising silk fibroin and about 10% (w/w) to about 50% (w/w) glycerol. 
     
     
         2 . The silk film of  claim 1 , wherein the glycerol content of the silk film is about 20% (w/w) to about 40% (w/w) 
     
     
         3 . The silk film of  claim 1 , wherein the glycerol content of the silk film is about 30% (w/w). 
     
     
         4 . The silk film of  claim 1 , further comprising at least one active agent. 
     
     
         5 . The silk film of  claim 1 , further comprising silk microspheres or silk nanospheres embedded in the silk film. 
     
     
         6 . The silk film of  claim 1 , wherein said film is layered or folded into a sponge or a block. 
     
     
         7 . The silk film of  claim 4 , wherein the at least one active agent is selected from the group consisting of cells, proteins, peptides, nucleic acid analogues, nucleotides or oligonucleotides, peptide nucleic acids, aptamers, antibodies or fragments or portions thereof, hormones, hormone antagonists, growth factors or recombinant growth factors and fragments and variants thereof, cytokines, enzymes, antibiotics or antimicrobial compounds, viruses, antivirals, toxins, prodrugs, chemotherapeutic agents, small molecules, drugs, and combinations thereof. 
     
     
         8 . (canceled) 
     
     
         9 . (canceled) 
     
     
         10 . (canceled) 
     
     
         11 . (canceled) 
     
     
         12 . The silk film of  claim 1 , further comprising an optical pattern on the silk film. 
     
     
         13 . The silk film of  claim 12 , wherein the optical pattern is a holographic image. 
     
     
         14 . A method for preparing a silk film, comprising:
 blending a silk fibroin solution with glycerol, wherein the concentration of glycerol in the silk fibroin/glycerol blend solution is about 10% to about 50% (w/w);   casting the silk fibroin/glycerol blend solution onto a film-supporting surface; and   drying the silk film.   
     
     
         15 . The method of  claim 14 , further comprising the steps of immersing the silk film in a liquid in which glycerol dissolves for a period of time to deplete glycerol from the silk film; and drying the glycerol-depleted film. 
     
     
         16 . The method of  claim 14 , further comprising annealing said film. 
     
     
         17 . A method for covering a surface of a substrate with a silk composition comprising:
 providing a film-support substrate; and   covering the film-support substrate with a silk fibroin/glycerol blend film comprising about 10% to 50% glycerol (w/w).   
     
     
         18 . The method of  claim 17 , wherein the silk fibroin/glycerol blend film further comprises at least one biopolymer. 
     
     
         19 . The method of  claim 18 , wherein the biopolymer is PVA or PEO. 
     
     
         20 . The method of  claim 19 , wherein the silk fibroin/glycerol blend film further comprises at least one active agent. 
     
     
         21 . (canceled) 
     
     
         22 . (canceled) 
     
     
         23 . (canceled) 
     
     
         24 . A method of embedding at least one active agent in a silk film, comprising:
 blending a silk fibroin solution with at least one active agent and glycerol, wherein the concentration of glycerol in the silk blend solution is about 10% to 50% (w/w);   casting the silk blend solution onto a film-supporting surface; and   drying the film.   
     
     
         25 . The method of  claim 24 , wherein the at least one active agent is selected from the group consisting of cells, proteins, peptides, nucleic acid analogues, nucleotides or oligonucleotides, peptide nucleic acids, aptamers, antibodies or fragments or portions thereof, hormones, hormone antagonists, growth factors or recombinant growth factors and fragments and variants thereof, cytokines, enzymes, antibiotics or antimicrobial compounds, viruses, antivirals, toxins, prodrugs, chemotherapeutic agents, small molecules, drugs, and combinations thereof. 
     
     
         26 . The method of  claim 24 , further comprising the steps of immersing the silk film in a liquid in which glycerol dissolves for a period of time to deplete glycerol from the silk film; and drying the glycerol-depleted film. 
     
     
         27 . The method of  claim 24 , further comprising annealing said film.