Porous membranes for medical implants and methods of manufacture

Abstract

The present invention involves porous polymer membranes, suitable for use in medical implants, having controlled pore sizes, pore densities and mechanical properties. Methods of manufacturing such porous membranes are described in which a continuous fiber of polymer is extruded through a reciprocating extrusion head and deposited onto a substrate in a predetermined pattern. When cured, the polymeric material forms a stable, porous membrane suitable for a variety of applications, including reducing emboli release during and after stent delivery, and providing a source for release of bioactive substances to a vessel or organ and surrounding tissue.

1 . A single-layer porous membrane for use in medical implants comprising:
 an elongated fiber having a width of 5 to 500 micrometers, the elongated fiber forming a plurality of non-crossing traces extending adjacently from a first end to a second end of the membrane, each trace contacting its adjacent traces in an alternating manner, adjacent traces being bonded together at points of contact, the traces defining a plurality of pores of predetermined sizes.   
     
     
         2 . The single-layer porous membrane of  claim 1 , wherein the plurality of pores have essentially the same size. 
     
     
         3 . The single-layer porous membrane of  claim 1 , wherein the membrane has a thickness substantially equal to the thickness of the elongated fiber. 
     
     
         4 . The single-layer porous membrane of  claim 1 , wherein the elongated fiber comprises a bio-compatible material. 
     
     
         5 . The single-layer porous membrane of  claim 1 , wherein the elongated fiber is continuous. 
     
     
         6 . The single-layer porous membrane of  claim 1 , wherein at least one of the plurality of pores has an essentially square shape. 
     
     
         7 . The single-layer porous membrane of  claim 1 , wherein at least one of the plurality of pores has an essentially diamond shape. 
     
     
         8 . The single-layer porous membrane of  claim 1 , wherein at least one of the plurality of pores has an essentially rectangular shape. 
     
     
         9 . The single-layer porous membrane of  claim 1 , wherein adjacent traces have an inter-trace distance of between 0 and 200 micrometers. 
     
     
         10 . The single-layer porous membrane of  claim 1 , wherein the elongated fiber comprises a multi-component fiber. 
     
     
         11 . The single-layer porous membrane of  claim 10 , wherein the multi-component fiber comprises a core filament comprising a first material, the core filament being disposed within a second material. 
     
     
         12 . The single-layer porous membrane of  claim 11 , wherein the second material includes one or more biologically active substances. 
     
     
         13 . The single-layer porous membrane of  claim 12 , wherein the second material is configured to deliver the one or more biologically active substances. 
     
     
         14 . The single-layer porous membrane of  claim 13 , wherein the one or more biologically active substances are configured to be eluted from the second material. 
     
     
         15 . The single-layer porous membrane of  claim 11 , wherein the first material is selected from the group consisting of polyamide, polyethylene, PET, PEEK, ETFE, CTFE, PTFE, metal, and fiberglass. 
     
     
         16 . The single-layer porous membrane of  claim 11 , wherein the second material is selected from the group consisting of polyurethane and copolymers thereof, silicone polyurethane, polypropylene and copolymers thereof, polyamide, polyethylene, PET, PEEK, ETFE, CTFE, and PTFE. 
     
     
         17 . A single-layer porous membrane for use with medical implants comprising:
 a continuous elongated fiber having a width of 5 to 500 micrometers forming a predetermined pattern of non-crossing traces, the traces extending adjacently from a first end to a second end of the membrane, each trace being bonded at contact portions to its adjacent traces, the contact portions being spaced apart, the traces defining a plurality of pores of predetermined sizes, the membrane having a thickness approximately equal to the thickness of the fiber.   
     
     
         18 . The single-layer porous membrane of  claim 17 , wherein the plurality of pores have a dimension between 1 and 500 micrometers. 
     
     
         19 . The single-layer porous membrane of  claim 17 , wherein the elongated fiber comprises a polymeric sheath surrounding a solid core filament. 
     
     
         20 . The single-layer porous membrane of  claim 19 , wherein the solid core filament is co-axially positioned within the polymeric sheath. 
     
     
         21 . An implantable medical device comprising:
 a medical implant;   a single-layer porous membrane coupled to the medical implant, the single-layer porous membrane comprising:
 an elongated fiber of bio-compatible material having a width of 5 to 500 micrometers, the elongated fiber forming a plurality of non-crossing traces extending adjacently from a first end to a second end of the membrane, each trace contacting its adjacent traces in an alternating manner, adjacent traces being bonded together at points of contact, the traces defining a plurality of pores of predetermined sizes. 
   
     
     
         22 . The implantable medical device of  claim 21 , wherein the medical implant is a vascular implant. 
     
     
         23 . The implantable medical device of  claim 22 , wherein the vascular implant is a stent. 
     
     
         24 . The implantable medical device of  claim 22 , wherein the vascular implant is a filter. 
     
     
         25 . The implantable medical device of  claim 22 , wherein the membrane is thermally bonded to the medical implant. 
     
     
         26 . The implantable medical device of  claim 22 , wherein the membrane is bonded to the medical implant with an adhesive.