Core-sheath fibers and methods of making and using same

Abstract

According to one aspect of the invention, multicomponent fiber are provided, which comprise (a) a polymeric core that comprises a core-forming polymer and (b) a polymeric sheath that comprises a sheath-forming polymer that is different than the core-forming polymer. Examples of core-forming polymers include, for instance, crosslinked polysiloxanes and thermoplastic polymers, among others. Examples of sheath-forming polymers include, for instance, solvent-soluble polymers, degradable polymers and hydrogel-forming polymers, among others. Other aspects of the present invention pertain to methods of forming such multicomponent fibers. For example, in certain preferred embodiments, the multicomponent fibers are formed using coaxial electrospinning techniques. Still other aspects of the present invention pertain to meshes and other articles that are formed using the multicomponent fibers.

1 . A multicomponent fiber comprising (a) a polymeric core that comprises a core-forming polymer and (b) a polymeric sheath that comprises a hydrophilic polymer, wherein said core-forming fiber is more hydrophobic than said hydrophilic polymer. 
     
     
         2 . The multicomponent fiber of  claim 1 , wherein said multicomponent fiber is formed by a core-sheath electrospinning process. 
     
     
         3 . The multicomponent fiber of  claim 1 , wherein the multicomponent fiber ranges from 0.1 to 20 microns in diameter. 
     
     
         4 . The multicomponent fiber of  claim 1 , wherein the ratio of sheath volume to core volume in the multicomponent fiber ranges from 100:1 to 1:1. 
     
     
         5 . The multicomponent fiber of  claim 1 , wherein the hydrophilic polymer is covalently crosslinked. 
     
     
         6 . The multicomponent fiber of  claim 1 , wherein the hydrophilic polymer is selected from polyvinylpyrrolidone, poly(acrylic acid), poly(vinyl alcohol), poly(ethylene glycol), poly(propylene glycol), poly(acrylamide), poly(methacrylates), polysaccharides, celluloses, chitosans, alginates, carrageenan, hyaluronan, gelatin and collagen. 
     
     
         7 . The multicomponent fiber of  claim 1 , wherein the hydrophilic polymer is a hydrophilic polyurethane. 
     
     
         8 . The multicomponent fiber of  claim 7 , wherein the hydrophilic polyurethane is an aliphatic, polyether-based polyurethane. 
     
     
         9 . The multicomponent fiber of  claim 1 , wherein the core-forming polymer is a thermoplastic polymer. 
     
     
         10 . The multicomponent fiber of  claim 1 , wherein the core-forming polymer is an aliphatic polyether-based thermoplastic polyurethane. 
     
     
         11 . The multicomponent fiber of  claim 1 , wherein the core-forming polymer is a crosslinked polysiloxane. 
     
     
         12 . The multicomponent fiber of  claim 1 , wherein the polysiloxane is polydimethylsiloxane. 
     
     
         13 . A nonwoven mesh formed by the multicomponent fiber of  claim 1 . 
     
     
         14 . The mesh of  claim 13 , wherein the mesh ranges from 10 to 5000 microns in thickness and the multicomponent fiber ranges from 0.1 to 20 microns in diameter. 
     
     
         15 . The mesh of  claim 13 , wherein the mesh has a modulus wet tensile strength of at least 0.005 MPa. 
     
     
         16 . The mesh of  claim 13 , wherein upon immersion in aqueous medium at 25° C. for one hour, the mesh has an absorbency of at least 10%. 
     
     
         17 . The mesh of  claim 13 , wherein the porosity of the mesh is less than 99%. 
     
     
         18 . A medical article comprising the mesh of  claim 13 . 
     
     
         19 . A method for forming the multicomponent fiber of  claim 1 , comprising electrospinning said multicomponent fiber from a first solution comprising said hydrophilic polymer and a second solution comprising said core-forming polymer. 
     
     
         20 . A multicomponent fiber comprising (a) a polymeric core that comprises a crosslinked polysiloxane and (b) a polymeric sheath that comprises a removable sheath-forming polymer. 
     
     
         21 . The multicomponent fiber of  claim 20 , wherein the multicomponent fiber ranges from 0.1 to 20 microns in diameter. 
     
     
         22 . The multicomponent fiber of  claim 20 , wherein the polysiloxane is polydimethylsiloxane. 
     
     
         23 . The multicomponent fiber of  claim 20 , wherein the sheath-forming polymer is a dissolvable or degradable polymer. 
     
     
         24 . A mesh formed by the multicomponent fiber of  claim 20 . 
     
     
         25 . The mesh of  claim 24 , wherein the mesh ranges from 10 to 5000 microns in thickness and the multicomponent fiber ranges from 0.1 to 20 microns in diameter. 
     
     
         26 . A medical article comprising the mesh of  claim 24 . 
     
     
         27 . A method for forming the multicomponent fiber of  claim 20 , comprising electrospinning said multicomponent fiber from a first solution comprising said removable sheath-forming polymer and a second solution comprising a polysiloxane pre-polymer and a crosslinking agent. 
     
     
         28 . A method of forming a silicone fiber, comprising: (a) forming a composite fiber comprising a silicone core and a removable polymer sheath and (b) removing the polymer sheath. 
     
     
         29 . The method of  claim 28 , wherein the removable polymer is a dissolvable or degradable polymer. 
     
     
         30 . The method of  claim 28 , wherein the fiber is electrospun into the form of a mesh prior to removing the polymer sheath.