Prosthetic device including electrostatically spun fibrous layer & method for making the same

Abstract

In accordance with certain embodiments of the present disclosure, a process of forming a prosthetic device is provided. The process includes forming a dispersion of polymeric nanofibers, a fiberizing polymer, and a solvent, the dispersion having a viscosity of at least about 50,000 cPs. A tubular frame is positioned over a tubular polymeric structure. Nanofibers from the dispersion are electrospun onto the tubular frame to form a prosthetic device. The prosthetic device is heated.

1 - 20 . (canceled) 
     
     
         21 . A medical appliance, comprising:
 a first layer of polytetrafluoroethylene (PTFE), having a porosity sufficient to permit tissue ingrowth, the first layer of PTFE disposed such that it defines a first surface of the medical appliance;   a second layer of PTFE, the second layer of PTFE disposed such that it defines a second layer of the medical appliance; and   a tie layer disposed between the first layer of PTFE and the second layer of PTFE, wherein the tie layer is configured to inhibit tissue or fluid migration into or through the tie layer.   
     
     
         22 . The medical appliance of  claim 21 , wherein the first layer of PTFE has an average pore size configured to permit tissue ingrowth on the first surface of the medical appliance. 
     
     
         23 . The medical appliance of  claim 21 , wherein the second layer of PTFE has a porosity sufficient to permit tissue ingrowth. 
     
     
         24 . The medical appliance of  claim 21 , wherein the second layer of PTFE has an average pore size configured to resist tissue ingrowth into or through the second surface of the medical appliance. 
     
     
         25 . The medical appliance of  claim 21 , wherein the tie layer comprises PTFE. 
     
     
         26 . The medical appliance of  claim 21 , wherein the tie layer is fluorinated ethylene propylene (FEP). 
     
     
         27 . The medical appliance of  claim 26 , wherein the FEP partially bonds to fibers of the first and second layers of PTFE. 
     
     
         28 . The medical appliance of  claim 27 , wherein the FEP flows into and coats the fibers of the first and second layers of PTFE while maintaining the porosity of the layers. 
     
     
         29 . The medical appliance of  claim 24 , wherein at least one of the first and second layers of PTFE have been heated and stretched. 
     
     
         30 . The medical appliance of  claim 21 , further comprising a reinforcing layer of PTFE. 
     
     
         31 . The medical appliance of  claim 30 , wherein the medical appliance comprises a tubular construct. 
     
     
         32 . The medical appliance of  claim 31 , wherein the medical appliance has increased resistance to creep in the radial direction as compared to the axial direction. 
     
     
         33 . A stent, comprising:
 a frame configured to resist radial compression when disposed in a lumen of a patient, and   a covering disposed on at least a portion of the scaffolding structure, the covering comprising:   a first layer of polytetrafluoroethylene (PTFE), the first layer having a porosity sufficient to permit tissue ingrowth, the first layer of PTFE defining an inside surface of the stent;   a second layer of PTFE, the second layer of PTFE defining an outside surface of the stent; and   a tie layer disposed between the first layer of PTFE and the second layer of PTFE, wherein   the tie layer is configured to inhibit tissue or fluid migration into or through the tie layer.   
     
     
         34 . The stent of  claim 33 , wherein the first layer of PTFE has an average pore size configured to permit tissue ingrowth on the inside surface of the stent. 
     
     
         35 . The stent of  claim 33 , wherein the second layer of PTFE has a porosity sufficient to permit tissue ingrowth. 
     
     
         36 . The stent of  claim 33 , wherein the second layer of PTFE has an average pore size configured to resist tissue ingrowth into or through the second layer of PTFE. 
     
     
         37 . The stent of  claim 33 , wherein the tie layer is fluorinated ethylene propylene (FEP). 
     
     
         38 . The stent of  claim 37 , wherein the second layer of PTFE material is configured to permit tissue ingrowth into the second layer. 
     
     
         39 . A tubular vascular prosthesis comprising:
 a porous inner layer comprising polytetrafluoroethylene (PTFE),   a porous outer layer comprising PTFE, and   a substantially non-porous tie layer disposed between the inner layer and the outer layer, wherein the tie layer is substantially impervious to tissue or fluid migration into or through the tie layer.   
     
     
         40 . The prosthesis of  claim 39 , wherein the inner and outer layers are configured to permit cellular ingrowth. 
     
     
         41 . The medical appliance of  claim 21 , further comprising a layer of FEP. 
     
     
         42 . The tubular vascular prosthesis of  claim 39 , further comprising a layer of FEP.