Silk-based drug delivery system

Abstract

The present invention provides for novel sustained release silk-based delivery systems. The invention further provides methods for producing such formulations. In general, a silk fibroin solution is combined with a therapeutic agent to form a silk fibroin article. The article is then treated in such a way as to alter its conformation. The change in conformation increases its crystallinity or liquid crystallinity, thus controlling the release of a therapeutic agent from the formulation. This can be accomplished as single material carriers or in a layer-by-layer fashion to load different therapeutic agents or different concentrations of these agents in each layer.

What is claimed is: 
     
         1 . A method comprising:
 providing a silk fibroin composition;   treating the silk fibroin composition with water vapor to induce formation of a beta-sheet structure of silk fibroin in the silk fibroin composition.   
     
     
         2 . The method of  claim 1 , wherein the silk fibroin composition comprises at least one agent. 
     
     
         3 . The method of  claim 2 , wherein the treating step comprises positioning the silk fibroin composition over a solution in at a temperature and a duration sufficient to prevent the loss of activity of the agent. 
     
     
         4 . The method of  claim 2 , wherein said at least one agent comprises a protein or peptide agent. 
     
     
         5 . The method of  claim 2 , wherein said at least one agent is selected from the group consisting of proteins, peptides, small molecules, nucleic acids, anti-infectives, chemotherapeutic agents, anti-rejection agents, analgesics or analgesic combinations, anti-inflammatory agents, hormones, growth factors, anti-angiogenic proteins, genetically engineered proteins, polysaccharides, glycoproteins, lipoproteins, pharmacological materials, vitamins, sedatives, steroids, hypnotics, antibiotics, prostaglandins, radiopharmaceuticals, nucleotides, carbohydrates, simple sugars, cells, genes, anti-thrombotics, anti-metabolics, growth factor inhibitors, growth promoters, anticoagulants, antimitotics, fibrinolytics, anti-inflammatory steroids, monoclonal antibodies, targeting ligands, and any combinations thereof. 
     
     
         6 . The method of  claim 1 , wherein the silk fibroin composition comprises a thread, a fiber, a yarn, a fabric, a film, a foam, a mesh, a hydrogel, a scaffold, a filler, a coating, or a microsphere. 
     
     
         7 . The method of  claim 1 , wherein the silk fibroin composition comprises a micropatterned foam. 
     
     
         8 . The method of  claim 1 , wherein the silk fibroin composition further comprises a biocompatible polymer.