System and method for selective pressure-controlled therapeutic delivery

Abstract

A method is provided for manufacturing a polymer-coated elastic braid including forming a plurality of elastic filaments into a braid. The braid is mounted within a tubular mandrel. The mandrel-mounted braid is dip-coating in a polymer solution containing a polymer and at least one solvent. The dip-coated braid is then heated to release the at least one solvent. Then, the dip-coated mandrel-mounted braid is cooled to solidify the polymer on the braid. The braid is then removed from the mandrel. The braid can be attached to a catheter for use as a microvalve in a vessel.

What is claimed is: 
     
         1 . A method for manufacturing a polymer-coated elastic braid, comprising:
 a) forming a plurality of elastic filaments into a braid, the braid having a length;   b) mounting the braid within a tubular mandrel such that the braid is in contact with an inside of the mandrel along the length of the braid;   c) dip-coating the mandrel-mounted braid in a polymer solution containing a polymer and at least one solvent;   d) releasing the at least one solvent;   e) solidifying the polymer on the braid; and   f) removing the dip-coated braid from the mandrel.   
     
     
         2 . The method of  claim 1 , wherein at least a plurality of the elastic filaments comprises nickel-titanium alloy. 
     
     
         3 . The method of  claim 1 , wherein the tubular mandrel is PTFE coated steel. 
     
     
         4 . The method of  claim 1 , wherein the braid has an outer diameter, and the tubular mandrel has an inner diameter, wherein the outer diameter and the inner diameter are the same size within a tolerance of ±0.065 mm. 
     
     
         5 . The method of  claim 1 , wherein the polymer is an elastomeric thermoplastic polymer. 
     
     
         6 . The method of  claim 1 , wherein the polymer is pellethane. 
     
     
         7 . The method of  claim 1 , wherein the polymer includes an aliphatic polyether-based thermoplastic. 
     
     
         8 . The method of  claim 1 , wherein the polymer includes a styrene-isoprene-butadiene-styrene polymer. 
     
     
         9 . The method of  claim 1 , wherein the at least one solvent has a vapor point ranging from 30-200° C. 
     
     
         10 . The method of  claim 1 , wherein the at least one solvent includes dimethylacetamide and tetrahydrofuran. 
     
     
         11 . The method of  claim 1 , wherein the dip-coating is performed at a controlled steady state. 
     
     
         12 . The method of  claim 11 , wherein the controlled steady state is at 1-100 mm/sec. 
     
     
         13 . The method of  claim 1 , wherein dip-coating consists of dipping once in the polymer solution. 
     
     
         14 . The method of  claim 1 , wherein the releasing is performed by heating the solvent. 
     
     
         15 . The method of  claim 14 , wherein solidifying includes cooling the polymer. 
     
     
         16 . A method for manufacturing a vessel occluder, comprising:
 a) forming a plurality of elastic filaments into a braid, the braid having a length and an outer surface;   b) providing a tubular mandrel having an inner surface;   c) mounting the braid within a tubular mandrel such that the outer surface of the braid is in contact with the inner surface of the mandrel along the length of the braid;   d) dip-coating the mandrel-mounted braid in a polymer solution containing a polymer and at least one solvent;   e) heating the dip-coated mandrel-mounted braid to release the at least one solvent;   f) cooling the dip-coated mandrel-mounted braid below a glass transition temperature of the polymer to plasticize the polymer on the braid; and   g) removing the dip-coated braid from the mandrel.   
     
     
         17 . The method of  claim 16 , wherein at least a plurality of the elastic filaments comprises nickel-titanium alloy. 
     
     
         18 . The method of  claim 16 , wherein the inner surface of the tubular mandrel is coated in PTFE. 
     
     
         19 . The method of  claim 16 , wherein the outer surface of the braid defines an outer diameter, and the inner surface of the tubular mandrel defines an inner diameter, and the outer diameter and the inner diameter are the same size within a tolerance of ±0.065 mm. 
     
     
         20 . The method of  claim 16 , wherein the polymer is an elastomeric thermoplastic polymer. 
     
     
         21 . The method of  claim 16 , wherein the polymer is pellethane. 
     
     
         22 . The method of  claim 16 , wherein the polymer includes an aliphatic polyether-based thermoplastic. 
     
     
         23 . The method of  claim 16 , wherein the polymer includes a styrene-isoprene-butadiene-styrene polymer. 
     
     
         24 . The method of  claim 16 , wherein the at least one solvent has a vapor point ranging from 30-200° C. 
     
     
         25 . The method of  claim 16 , wherein the at least one solvent includes dimethylacetamide and tetrahydrofuran. 
     
     
         26 . The method of  claim 16 , wherein the dip-coating is performed at a controlled steady state. 
     
     
         27 . The method of  claim 26 , wherein the controlled steady state is at 1-100 mm/sec. 
     
     
         28 . The method of  claim 16 , wherein dip-coating consists of dipping at most once in the polymer solution. 
     
     
         29 . A polymer-coated elastic braid made by the process of:
 a) forming a plurality of elastic filaments into a braid, the braid having a length;   b) mounting the braid within a tubular mandrel such that the braid is in contact with the mandrel along the length of the braid;   c) dip-coating the mandrel-mounted braid in a polymer solution containing a polymer and at least one solvent;   d) releasing the at least one solvent;   e) solidifying the polymer on the braid; and   f) removing the dip-coated braid from the mandrel.   
     
     
         30 . The braid of  claim 29 , wherein at least a plurality of the elastic filament are comprised of nickel titanium. 
     
     
         31 . A catheter-mounted vessel occluder formed by the process of:
 a) forming a plurality of elastic filaments into a braid, the braid having a first end, a second end, and a length extending between the first and second ends;   b) mounting the braid within a tubular mandrel such that the braid is in contact with the mandrel along the length of the braid;   c) dip-coating the mandrel-mounted braid in a polymer solution containing a polymer and at least one solvent;   d) releasing the at least one solvent;   e) solidifying the polymer on the braid; and   f) removing the dip-coated braid from the mandrel;   g) attaching the first and second ends to at least one catheter.   
     
     
         32 . A catheter-mounted vessel occluder, comprising:
 a catheter having a proximal end and a distal end; and   a braid of elastic filaments permanently attached to the distal end of the catheter, the braid of elastic filament having a coating of a polymer provided thereon, the coating of polymer having a smooth exterior surface.   
     
     
         33 . The vessel occluder of  claim 32 , wherein the braid of elastic filaments has an interior surface that is rougher than the smooth exterior surface. 
     
     
         34 . The vessel occluder of  claim 33 , wherein the elastic filament are nickel titanium. 
     
     
         35 . The vessel occluder of  claim 34 , wherein the polymer is pellethane. 
     
     
         36 . The vessel occluder of  claim 34 , wherein the vessel occluder is made by the process of:
 mounting the braid inside a tubular mandrel;   dip-coating the mandrel-mounted braid in a solution with the polymer and at least one solvent;   releasing the at least one solvent;   solidifying the polymer on the braid; and   removing the dip-coated braid from the mandrel.