Thermally and Dimensionally Stabilized Electrospun Compositions and Methods of Making Same

Abstract

Thermally stable absorbable fiber populations, i.e. fiber populations that do not undergo thermally induced crystallization, can be intermixed with thermally unstable fibers to yield a stabilizing effect without altering morphological properties of a fiber system. Via this, one may minimize thermally induced shrinkage and maintain physical properties of electrospun materials in the as-formed state.

What is claimed is: 
     
         1 . A thermally stable electrospun material comprising:
 at least two independent fiber populations;   a major fiber component comprising at least one thermally unstable species;   a minor fiber component comprising at least one thermally stable species; and   wherein the major and minor fiber components are co-mingled and distributed throughout the electrospun material; and   wherein the material exhibits limited macroscopic changes in physical and mechanical properties when exposed to thermal or mechanical stress.   
     
     
         2 . The thermally stable electrospun material of  claim 1 , wherein the thermally stable species comprises a bioabsorbable polyether-ester. 
     
     
         3 . The thermally stable electrospun material of  claim 2 , wherein the bioabsorbable polyether-ester comprises poly (para-dioxanone). 
     
     
         4 . The thermally stable electrospun material of  claim 1 , wherein the thermally stable species comprises at least  30  percent of the thermally stable electrospun material. 
     
     
         5 . The thermally stable electrospun material of  claim 1 , wherein the thermally unstable species comprises a bioabsorbable polyester. 
     
     
         6 . The thermally stable electrospun material of  claim 5 , wherein the bioabsorbable polyester is a copolymer derived from cyclic monomers selected from the group consisting of glycolide, L-lactide, ε-caprolactone, para-dioxanone, trimethylene carbonate or mixtures thereof. 
     
     
         7 . The thermally stable electrospun material of  claim 6 , wherein the bioabsorbable polyester is a copolymer of glycolide and L-lactide. 
     
     
         8 . The thermally stable electrospun material of  claim 7 , wherein the copolymer of glycolide and lactide has a monomer ratio of glycolide from 80 to 95 and lactide from 20 to 5. 
     
     
         9 . A multiple fiber population electrospun fabric comprising:
 at least two fiber populations;   wherein at least one fiber population is a thermally stable polyether-ester;   wherein at least one fiber population is a thermally unstable bioabsorbable polyester;   the at least two fiber populations dispersed throughout the three-dimensional structure of the multiple fiber electrospun fabric; and   wherein the multiple fiber electrospun fabric mimics the fibrous topography of the extracellular matrix.   
     
     
         10 . The multiple fiber population electrospun fabric of  claim 9 , wherein the thermally stable polyether-ester comprises at least 30 percent of the thermally stable electrospun material. 
     
     
         11 . The multiple fiber population electrospun fabric of  claim 10 , wherein the thermally stable polyether-ester comprises at least 33 percent of the thermally stable electrospun material. 
     
     
         12 . The multiple fiber population electrospun fabric of  claim 9 , wherein the thermally stable polyether-ester comprises poly (para-dioxanone). 
     
     
         13 . The multiple fiber population electrospun fabric of  claim 9 , wherein the thermally unstable bioabsorbable polyester comprises a poly (L-lactide-coglycolide) copolymer. 
     
     
         14 . The multiple fiber population electrospun fabric of  claim 9 , wherein pore size of the multiple fiber population electrospun fabric is maintained after exposure of temperatures of up to 50° C. 
     
     
         15 . The multiple fiber population electrospun fabric of  claim 9 , wherein the thermally unstable bioabsorbable polyester is a copolymer derived from cyclic monomers selected from the group consisting of glycolide, L-lactide, ε-caprolactone, para-dioxanone, trimethylene carbonate or mixtures. 
     
     
         16 . A method of forming a fiber mesh comprising:
 dissolving a bioabsorbable polyester in a solvent;   dissolving a polyether-ester in the solvent;   dispensing the solutions in an intermixed fashion onto a substrate to form a fiber mesh; and   forming the fiber mesh with a three-dimensional structure wherein the bioabsorbable polyester and polyether-ester are dispersed throughout the three-dimensional structure of the fiber mesh.   
     
     
         17 . The method of  claim 16 , wherein the bioabsorbable polyester is a copolymer derived from cyclic monomers selected from the group consisting of glycolide, L-lactide, ε-caprolactone, para-dioxanone, trimethylene carbonate or mixtures thereof. 
     
     
         18 . The method of  claim 17  wherein the bioabsorbable polyester comprises a poly (L-lactide-co-glycolide) copolymer. 
     
     
         19 . The method of  claim 16  wherein the polyether-ester comprises poly (para-dioxanone). 
     
     
         20 . The method of  claim 16  wherein the bioabsorbable polyester and polyether ester solutions are dispersed in such a fashion wherein the polyether ester comprises at least 30% of the fiber mesh. 
     
     
         21 . The method of  claim 20 , wherein the polyether ester comprises at least 33% of the fiber mesh.