Scaffold system for tissue repair

Abstract

A device for treating a damaged tissue includes an expandable scaffold positionable in a portion of a luminal tissue structure of a mammal; and maintained via stent technology, wherein the scaffold is comprised of electrospun fibers composed of a biodegradable compound. The scaffold serves as a temporary template that allows the tissue to be rebuilt.

What is claimed is: 
     
         1 . A method of manufacturing an electrospun expandable graft comprising the steps of:
 a. providing an electrospinning apparatus including a syringe, a needle coupled to the syringe, a power supply, a fiber collection component, a control pump, and a polymer solution;   b. positioning the syringe and the fiber collection component at a desired tip to collector distance from each other;   c. activating the power supply at a power parameter configured to initiate emission of a polymer fiber from the needle and directed toward the fiber collection component;   d. adjusting at least one electrospinning apparatus control parameter to create polymer fibers having a substantially looped fiber morphology;   e. electrospinning polymer fibers having a substantially looped fiber morphology onto the fiber collection component; and   f. adjusting at least one of the control pump or the power parameter to emit polymer fibers having a substantially linear morphology, the adjusting step further comprising creating a continuous transition gradient from the substantially looped polymer fiber morphology to a substantially linear polymer fiber morphology.   
     
     
         2 . The method of  claim 1 , wherein the fiber collection component is one of a flat collection plate or a cylindrical mandrel. 
     
     
         3 . The method of  claim 2 , wherein the at least one electrospinning apparatus control parameter is selected from cylindrical mandrel rotation speed, the tip to collector distance, polymer solution concentration, polymer solution emission rate, temperature, humidity, volatility of the polymer solution, polymer solution composition, polymer solution viscosity, voltage, or any combination thereof. 
     
     
         4 . The method of  claim 2 , wherein the expandable graft of polymer fibers are electrospun onto the cylindrical mandrel to produce a tubular graft structure. 
     
     
         5 . The method of  claim 4 , wherein the tubular graft structure has a convex exterior surface and a concave interior surface. 
     
     
         6 . The method of  claim 5 , wherein the convex exterior surface has fibers with the substantially linear morphology and the concave interior surface has fibers with the substantially curvilinear morphology. 
     
     
         7 . The method of  claim 6 , wherein the convex exterior surface has a lower concentration of fibers than the concave interior surface. 
     
     
         8 . The method of  claim 1 , wherein the designated polymer solution material is selected from poly(α-hydroxy esters), polyglycolic acid (PGA), poly (D,L-lactide-co-glycolide) (PLGA), polydioxanone (PDO), polycaprolactone (PCL) or polylactic acid (PLA). 
     
     
         9 . The method of  claim 1 , where the designated polymer solution is selected from elastin, collagen, DNA, RNA, glucosaminoglycans, or mixtures thereof. 
     
     
         10 . The method of  claim 1 , wherein repairing the luminal tissue include repairing a void or semi-void space. 
     
     
         11 . The method of  claim 1 , wherein the electrospun fibers of the expandable graft have a diameter between 200 nm to about 10 μm. 
     
     
         12 . The method of  claim 1 , wherein the expandable graft of electrospun fibers has a first porosity state that is substantially permeable and a second porosity state, after the expandable graft has been implanted, where the expandable graft becomes substantially impermeable. 
     
     
         13 . The method of  claim 1 , wherein the expandable graft of electrospun fibers is arranged to have porosities between 70% to 85%. 
     
     
         14 . The method of  claim 1 , further comprising the step of treating the expandable graft of electrospun fibers with cellular growth treatments selected from gas plasma, Platelet Derived Growth Facor (PDGF), Vascular Endothelial Growth Factor (VEGF), Angiotensin II (Ang II), Collagen VIII, Collagen I or Collagen V. 
     
     
         15 . The method of  claim 1 , wherein repairing the luminal tissue includes repairing an aneurysm. 
     
     
         16 . The method of  claim 1 , wherein the tip to collector distance is approximately 10 cm. 
     
     
         17 . The method of  claim 1  further comprising the step of removing the expandable graft from the fiber collection component. 
     
     
         18 . A method of using the expandable graft manufactured in  claim 1 , further comprising the steps of:
 a. obtaining the expandable graft of electrospun fibers and coupling the expandable graft to a delivery catheter;   b. percutaneously inserting the catheter into a blood vessel and delivering the expandable graft to a vascular situs in need thereof;   c. expanding the expandable graft of electrospun fibers such that an external surface of the expandable graft is in apposition to a luminal surface of the vascular situs, thereby securing the expandable graft within the vascular situs; and   d. withdrawing the delivery catheter.   
     
     
         19 . The method of  claim 18 , wherein the expandable graft is made of a material is selected from poly(α-hydroxy esters), polyglycolic acid (PGA), poly (D,L-lactide-co-glycolide) (PLGA), polydioxanone (PDO), polycaprolactone (PCL) or polylactic acid (PLA). 
     
     
         20 . The method of  claim 18 , wherein the expandable graft of electrospun nanofibers promote the growth of endothelial cells on an interior surface and smooth muscle cells on an exterior surface.