Patent ID: 9163333
Filing Date: 2015-10-20
Classification: A61F,A61L,B29C,B29K,B29L,B32B,D01D,D04H

Abstract:
1. A method of making a stent-graft with an inner layer and an outer layer where the outer layer is less porous than the inner layer, comprising: applying a first charge to a mandrel; applying a second charge to a first needle; rotating and translating said mandrel and said first needle relative to each other; dispensing a first polymer mixed with a first solvent through said first needle at a first flow rate, a first layer of fibers thereby being electrospun onto said mandrel; disposing a stent onto said first layer; applying a third charge to said mandrel; applying a fourth charge to a second needle; rotating and translating said mandrel and said second needle relative to each other; dispensing a second polymer mixed with a second solvent through said second needle at a second flow rate, a second layer of fibers thereby being electrospun onto said stent; and wherein said second needle has a larger lumen than said first needle and said second flow rate is higher than said first flow rate; wherein said first and second solvents are hygroscopic, a first humidity during said dispensing of said first polymer mixed with said first solvent is about 55% to about 65%, and a second humidity during said dispensing of said second polymer mixed with said second solvent is about 35% to about 42%.