Silk fibroin fiber bundles for matrices in tissue engineering

Abstract

The present invention provides a novel silk-fiber-based matrix having a wire-rope geometry for use in producing a ligament or tendon, particularly an anterior cruciate ligament, ex vivo for implantation into a recipient in need thereof. The invention further provides the novel silk-fiber-based matrix which is seeded with pluripotent cells that proliferate and differentiate on the matrix to form a ligament or tendon ex vivo. Also disclosed is a bioengineered ligament comprising the silk-fiber-based matrix seeded with pluripotent cells that proliferate and differentiate on the matrix to form the ligament or tendon. A method for producing a ligament or tendon ex vivo comprising the novel silk-fiber-based matrix is also disclosed.

1 . A fiber construct comprising sericin-extracted silkworm fibroin fibers, wherein the fibers have a diameter of about 20 to about 40 μm and an average ultimate tensile strength of at least about 0.67 N/fiber.  
     
     
         2 . The fiber construct of  claim 1 , wherein the fibers are organized in parallel.  
     
     
         3 . The fiber construct of  claim 1 , wherein the fibers are organized in a helical, wire rope, twisted, braided, mesh-like or cabled geometry.  
     
     
         4 . The fiber construct of  claim 1 , wherein the fibers comprise a coating and/or surface modification that promotes cellular attachment and/or tissue differentiation and proliferation thereon.  
     
     
         5 . The fiber construct of  claim 4 , wherein said coating and/or surface modification comprises an arginine-glycine-aspartate (RGD) peptide.  
     
     
         6 . The fiber construct of  claim 4 , wherein said coating and/or surface modification comprises a growth factor.  
     
     
         7 . The fiber construct of  claim 1 , wherein the construct comprises a group of at least one to about 1300 fibroin fibers.  
     
     
         8 . The fiber construct of  claim 7 , wherein the construct further comprises at least two groups forming a bundle.  
     
     
         9 . The fiber construct of  claim 8 , wherein the construct further comprises at least two bundles forming a strand.  
     
     
         10 . The fiber construct of  claim 9 , wherein the construct further comprises at least two strands forming a cord.  
     
     
         11 . The fiber construct of  claim 7 , wherein the group comprises fibroin fibers organized in a parallel, helical, wire rope, twisted, braided, mesh-like or cabled geometry.  
     
     
         12 . The fiber construct of  claim 8 , wherein the bundle comprises groups organized in a parallel, helical, wire rope, twisted, braided, mesh-like or cabled geometry.  
     
     
         13 . The fiber construct of  claim 9 , wherein the strand comprises bundles organized in a parallel, helical, wire rope, twisted, braided, mesh-like or cabled geometry.  
     
     
         14 . The fiber construct of  claim 10 , wherein the cord comprises strands organized in a parallel, helical, wire rope, twisted, braided, mesh-like or cabled geometry.  
     
     
         15 . The fiber construct of  claim 1 , wherein the construct has an average ultimate tensile strength of at least about 6.67 N.  
     
     
         16 . The fiber construct of  claim 1 , further comprising cells.  
     
     
         17 . The fiber construct of  claim 16 , wherein the cells are selected from the group consisting of stem cells, muscle cells, bone marrow stromal cells, pluripotent cells, or fibroblast cells.  
     
     
         18 . A method for producing a sericin-extracted silk-fibroin fiber construct comprising: contacting at least one silkworm fibroin fiber with an aqueous solution of Na 2 Co 3  and detergent to extract sericin from the fiber.  
     
     
         19 . A method for producing a sericin-extracted silk-fibroin fiber construct comprising: 
 a. arranging at least 2 silkworm fibroin fibers to form a group; and    b. contacting the group with an aqueous solution of Na 2 Co 3  and detergent to extract sericin from the fibers.    
     
     
         20 . A method for producing a sericin-extracted silk-fibroin fiber construct comprising: 
 a. arranging at least 2 groups of silkworm fibroin fibers to form a bundle; and    b. contacting the bundle with an aqueous solution of Na2Co3 and detergent to extract sericin from the fibers.    
     
     
         21 . A method for producing a sericin-extracted silk-fibroin fiber construct comprising: 
 a. arranging at least 2 bundles of silkworm fibroin fibers to form a strand; and    b. contacting the strand with an aqueous solution of Na2Co3 and detergent to extract sericin from the fibers.    
     
     
         22 . A method for producing a sericin-extracted silk-fibroin fiber construct comprising: 
 a. arranging at least 2 strands of silkworm fibroin fibers to form a cord; and    b. contacting the cord with an aqueous solution of Na2Co3 and detergent to extract sericin from the fibers.    
     
     
         23 . The method as in one of claims  18 - 22 , wherein the sericin is extracted at a temperature no greater than about 90° C.  
     
     
         24 . The method as in one of claims  18 - 22 , further comprising the step of coating the fibroin fibers with a coating and/or surface modifier that promotes cellular attachment and/or tissue proliferation on the fibers.  
     
     
         25 . The method of  claim 24 , wherein said coating and/or surface modifier comprises an arginine-glycine-aspartate (RGD) peptide.  
     
     
         26 . The method of  claim 24 , wherein said coating and/or surface modifier comprises a growth factor.  
     
     
         27 . The method of  claim 19 , wherein said group comprises up to 1300 fibroin fibers.  
     
     
         28 . The method of  claim 18 , further comprising the step of placing the fiber in a twisted, helical, braided, mesh-like or cabled geometry.  
     
     
         29 . The method of  claim 19 , wherein the fibers are organized in a parallel, helical, wire rope, twisted, braided, mesh-like or cabled geometry.  
     
     
         30 . The method of  claim 20 , wherein the groups are organized in a parallel, helical, wire rope, twisted, braided, mesh-like or cabled geometry forming a bundle.  
     
     
         31 . The method of  claim 21 , wherein the bundles are organized in a parallel, helical, wire rope, twisted, braided, mesh-like or cabled geometry forming a strand.  
     
     
         32 . The method of  claim 22 , wherein the strands are organized in a in parallel, helical, wire rope, twisted, braided, mesh-like or cabled geometry forming a cord.  
     
     
         33 . The method as in any of claims  18 - 22 , further comprising: 
 a. contacting the construct with cells; and    b. culturing the construct under conditions suitable for cell growth and regeneration.    
     
     
         34 . The method of  claim 33 , wherein the cells are stem cells, muscle cells, bone marrow stromal cells, pluripotent cells, or fibroblast cells.