Silk microspheres for encapsulation and controlled release

Abstract

A method was developed to prepare silk fibroin microspheres using lipid vesicles as templates to efficiently load therapeutic agents in active form for controlled release. The lipids are subsequently removed through the use of a dehydration agent, such as methanol or sodium chloride, resulting in β-sheet structure dominant silk microsphere structures having about 2 μm in diameter. The therapeutic agent can be entrapped in the silk microspheres and used in pharmaceutical formulations for controlled-release treatments.

1 . (canceled) 
     
     
         2 . A composition comprising silk fibroin microspheres distributed in a silk fibroin matrix, wherein the silk fibroin microspheres comprise a therapeutic agent. 
     
     
         3 . The composition of  claim 2 , wherein the silk fibroin matrix is a silk fibroin scaffold. 
     
     
         4 . The composition of  claim 2 , wherein the silk fibroin matrix comprises at least one silk fibroin layer. 
     
     
         5 . The composition of  claim 2 , wherein the silk fibroin matrix is a hydrogel. 
     
     
         6 . The composition of  claim 2 , wherein the therapeutic agent is selected from the group consisting of proteins, peptides, nucleic acids, peptide nucleic acids (PNAs), aptamers, antibodies, growth factors, cytokines, enzymes, small molecules, and any combinations thereof. 
     
     
         7 . The composition of  claim 2 , wherein the therapeutic agent comprises an antibiotic. 
     
     
         8 . The composition of  claim 2 , wherein the therapeutic agent comprises adenosine. 
     
     
         9 . The composition of  claim 2 , wherein the silk fibroin microspheres comprise a multilamellar-structured silk fibroin microsphere. 
     
     
         10 . The composition of  claim 2 , wherein the silk fibroin microspheres comprise a unilamellar-structured silk fibroin microsphere.