Method for modifying a medical implant surface for promoting tissue growth
Disclosed is an occluder for closing an intracardiac defect, such as a patent foramen ovale (PFO), and a method for making the same. The occluder includes a frame and at least one scaffold which are formed from a bioabsorbable polymer, such as poly-4-hydroxybutyrate. The surface of the frame and scaffold are textured to promote cell attachment. Texturing of the surface can be achieved by any number of mechanical or chemical procedures. The device is coated with collagen and heparin which are covalently bound to the surface of the device. The occluder provides improved defect closure compared to other septal occluders known in the art. In particular, the occluder described is specifically designed to improve host cell attachment to and tissue ingrowth over the device when implanted in a patient as compared to the level of host cell attachment and tissue ingrowth achieved with other implantable devices made of bioabsorbable polymers.
1 . An occluder for closing an intracardiac defect, the occluder comprising:
a frame supporting at least one scaffold, said frame and said scaffold being formed from a bioabsorbable polymer, wherein a surface of the scaffold is textured to promote cell attachment, and wherein collagen and heparin are covalently bound to the surface of the scaffold.
2 . The occluder of claim 1 , wherein a surface of the frame is textured to promote cell attachment, and wherein collagen and heparin are covalently bound to the surface of the frame.
3 . The occluder of claim 1 , wherein the surface of the scaffold is plasma treated with O 2 .
4 . The occluder of claim 1 , wherein the surface of the scaffold is plasma treated with N 2 .
5 . The occluder of claim 1 , wherein the surface of the scaffold is plasma treated with amine gas.
6 . The occluder of claim 5 , wherein the surface of the scaffold is also plasma treated with O 2 .
7 . The occluder of claim 1 , where the collagen is Type I collagen.
8 . The occluder of claim 7 , where the collagen is recombinant human Type I collagen.
9 . The occluder of claim 1 , where the collagen is Type III collagen.
10 . The occluder of claim 9 , where the collagen is recombinant human Type III collagen.
11 . The occluder of claim 1 , wherein the bioabsorbable polymer is poly-4-hydroxybutyrate.
12 . A method of manufacturing a septal occluder for closing a septal defect, the method comprising the steps of:
forming a septal occluder from a scaffold and frame comprising a bioabsorbable polymer;
texturing the surface of the scaffold; and
covalently binding collagen and heparin to the surface of the scaffold.
13 . The method of claim 12 , further comprising the steps of texturing the surface of the frame and covalently binding collagen and heparin to the surface of the frame.
14 . The occluder of claim 12 , wherein the surface of the scaffold is textured by mechanical roughening.
15 . The occluder of claim 12 , wherein the surface of the scaffold is textured by extrusion and puncturing.
16 . The occluder of claim 12 , wherein the surface of the scaffold is textured by forming the scaffold in a mold with a roughened surface.
17 . The occluder of claim 12 , wherein the surface of the scaffold is plasma treated with amine gas.
18 . The occluder of claim 17 , wherein the surface of the scaffold is also plasma treated with O 2 gas.
19 . The method of claim 12 , wherein the bioabsorbable polymer is poly-4-hydroxybutyrate.
20 . The method of claim 12 , wherein the step of covalently binding collagen to the surface of the scaffold occurs separately from the step of covalently binding heparin to the surface of the scaffold.
21 . A method of closing an intracardiac defect comprising implanting the occluder of claim 1 in a patient.
22 . The method of claim 21 , where the intracardiac defect is a patent foramen ovale.