Prosthetic device including electrostatically spun fibrous layer and 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.

What is claimed is: 
     
         1 . A composite structure comprising a tubular frame and comprising a first tubular polymeric layer defining an inner surface of the structure and a second tubular polymeric layer defining an outer surface of the structure, wherein at least one of the first tubular polymeric layer and second tubular polymeric layer comprises a plurality of polytetrafluoroethylene (PTFE) nanofibers. 
     
     
         2 . The composite structure of  claim 1 , wherein the composite structure is a stent and wherein at least one of the first tubular polymeric layer and tubular polymeric layer is configured to enhance cellular ingrowth. 
     
     
         3 . The composite structure of  claim 2 , wherein the plurality of PTFE fibers is a plurality of spun PTFE fibers. 
     
     
         4 . The composite structure of  claim 2 , wherein the plurality of spun PTFE fibers is a plurality of electrospun PTFE fibers. 
     
     
         5 . The composite structure of  claim 2 , further comprising a frame configured to exhibit radial strength and promote recovery during deployment of the stent. 
     
     
         6 . The composite structure of  claim 2 , wherein the plurality of PTFE fibers has a density such that there is a range of distances of about 0.1μ to about 50μ between points of contact of the fibers. 
     
     
         7 . The composite structure of  claim 2 , further comprising a third layer joined to the first layer and the second layer. 
     
     
         8 . The composite structure of  claim 7 , wherein the third layer is configured to inhibit cellular communication. 
     
     
         9 . The composite structure of  claim 8 , wherein both the first tubular polymeric layer and the second tubular polymeric layer are configured to enhance cellular ingrowth. 
     
     
         10 . The composite structure of  claim 2 , wherein one of the first tubular polymeric layer and the second tubular polymeric layer is configured to enhance cellular ingrowth into the respective layer and the other of the first tubular polymeric layer and the second tubular polymeric is configured to inhibit cellular ingrowth into the respective layer. 
     
     
         11 . The composite structure of  claim 2 , wherein the PTFE fibers are electrospun from a mixture comprising PTFE, polyethylene oxide, and water. 
     
     
         12 . A prosthetic device comprising a layer of nanofibers around a central lumen, wherein the nanofibers comprise polytetrafluoroethylene (PTFE). 
     
     
         13 . The prosthetic device of  claim 12 , comprising a tubular frame and a coating disposed on the tubular frame, the coating comprising the layer of PTFE nanofibers. 
     
     
         14 . The prosthetic device of  claim 13 , wherein the prosthetic device is a tubular vascular prosthesis comprising a luminal and abluminal surface, and the first layer of PTFE nanofibers is present on the luminal surface. 
     
     
         15 . The prosthetic device of  claim 13 , wherein the layer of PTFE nanofibers is a first layer of PTFE nanofibers, and the prosthetic device further comprises a second layer of PTFE nanofibers. 
     
     
         16 . The prosthetic device of  claim 15 , wherein the pore structure of one or more of the layers as defined by ASTM F316 is between about 0.05 μm and about 50 μm. 
     
     
         17 . The prosthetic device of  claim 15 , wherein one or more of the layers has a porosity to enhance cellular ingrowth or attachment. 
     
     
         18 . The prosthetic device of  claim 15 , wherein one or more of the layers has a porosity to inhibit cellular ingrowth or attachment. 
     
     
         19 . The prosthetic device of  claim 13 , wherein the layer of PTFE nanofibers has been spun from an aqueous dispersion comprising polytetrafluoroethylene. 
     
     
         20 . The prosthetic device of  claim 13 , wherein the layer of PTFE nanofibers comprises PTFE that has been spun onto a rotating assembly. 
     
     
         21 . The prosthetic device of  claim 12 , wherein the nanofibers comprise spun nanofibers in random orientation around the central lumen. 
     
     
         22 . The prosthetic device of  claim 12 , wherein the spun nanofibers comprise electrospun fibers. 
     
     
         23 . The prosthetic device of  claim 12 , further comprising a tubular frame. 
     
     
         24 . The prosthetic device of  claim 12 , wherein the prosthetic device is a graft. 
     
     
         25 . The prosthetic device of  claim 12 , wherein the layer of PTFE nanofibers is designed to enhance, inhibit, or retard the migration of endothelium. 
     
     
         26 . A method of constructing a prosthetic device, comprising:
 providing a frame; and   applying a layer of polytetrafluoroethylene (PTFE) nanofibers to the frame to form a prosthetic device.   
     
     
         27 . The method of  claim 26 , further comprising applying a fluorinated ethlyene propylene (FEP) layer to the device. 
     
     
         28 . The method of  claim 26 , wherein the applying step comprises spinning PTFE onto a cylindrical frame and, thereafter, sintering the spun PTFE while in place on the frame.