ELECTROSPUN MATERIAL COVERED MEDICAL APPLIANCES AND METHODS OF MANUFACTURE

• US 20140079758A1
• Filed: 03/14/2013
• Published: 03/20/2014
• Est. Priority Date: 09/19/2012
• Status: Active Grant

• Current Assignee: Merit Medical Systems, Inc.
• Original Assignee: Merit Medical Systems, Inc.
• Inventors: Hall, John William, Dolmatch, Bart, Eller, Zeke, Kellar, Robert S., Simmons, Rachel Lynn, Mower, Wayne L.
• Granted Patent: US 11,541,154 B2
• Time in Patent Office: Days
• US Class Current: 424/443
• CPC Class Codes: A61F 2/07 Stent-grafts
• CPC Class Codes: A61F 2/82 Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents stent-grafts for tubular structures of the body other than blood vessels A61F2/04; stent-grafts for blood vessels A61F2/07; instruments specially adapted for placement or removal of stents or stent-grafts A61F2/95; for closing wounds, or holding wounds closed A61B17/04 - A61B17/115; dilators A61M29/00
• CPC Class Codes: A61F 2002/30003 Material related properties of the prosthesis or of a coating on the prosthesis
• CPC Class Codes: A61F 2002/3006 Properties of materials and coating materials
• CPC Class Codes: A61F 2002/30062 (bio)absorbable, biodegradable, bioerodable, (bio)resorbable, resorptive
• CPC Class Codes: A61F 2002/30067 Coating or prosthesis-covering structure made of thermoplastic material
• CPC Class Codes: A61F 2002/30072 Coating made of plastically deformable or self-moulding material
• CPC Class Codes: A61K 9/70 Web, sheet or filament bases ; Films; Fibres of the matrix type containing drug hollow drug-filled fibres A61K9/0092
• CPC Class Codes: A61L 27/16 obtained by reactions only involving carbon-to-carbon unsaturated bonds
• CPC Class Codes: A61L 27/34 Macromolecular materials
• CPC Class Codes: A61L 27/56 Porous materials, e.g. foams or sponges
• CPC Class Codes: A61L 31/048 obtained by reactions only involving carbon-to-carbon unsaturated bonds A61L31/041 takes precedence
• CPC Class Codes: A61L 31/10 Macromolecular materials
• CPC Class Codes: A61L 31/146 Porous materials, e.g. foams or sponges
• CPC Class Codes: A61L 31/148 Materials at least partially resorbable by the body
• CPC Class Codes: B05D 1/007 using an electrostatic field B05D1/02 - B05D1/16 take precedence
• CPC Class Codes: C08L 27/12 containing fluorine atoms
• CPC Class Codes: C08L 27/18 Homopolymers or copolymers or tetrafluoroethene
• CPC Class Codes: D01D 5/0076 characterised by the collecting device, e.g. drum, wheel, endless belt, plate or grid D01D5/0046 takes precedence
• CPC Class Codes: D01F 6/12 from polymers of fluorinated hydrocarbons
• CPC Class Codes: D04H 1/728 : by electro-spinning electro-spinning methods and apparatus D01D5/0007
• CPC Class Codes: D04H 3/073 : Hollow cylinder shaped

Abstract

A medical appliance or prosthesis may comprise one or more layers of electrospun nanofibers, including electrospun polymers. The electrospun material may comprise layers including layers of polytetrafluoroethylene (PTFE). Electrospun nanofiber mats of certain porosities may permit tissue ingrowth into or attachment to the prosthesis.

Claims

1. A method for promoting endothelial cell growth on an implantable medical appliance, comprising implanting the medical appliance into a patient, the medical appliance coated with at least one electrospun polymer layer having a percent porosity of between about 35% and about 70%, such that endothelial cells grow on or attach to the surface of the at least one electrospun polymer layer.

2. The method of claim 1, wherein the implantable medical appliance comprises a stent.

3. The method of claim 1, wherein the implantable medical appliance comprises a graft.

4. The method of claim 1, wherein the at least one electrospun polymer layer comprises an electrospun PTFE layer.

5. The method of claim 4, wherein the medical appliance is coated with a second polymer layer that inhibits tissue or fluid migration into or through the second polymer layer.

6. The method of claim 5, wherein the second polymer layer comprises an FEP layer.

7. The method of claim 4, wherein the electrospun PTFE comprises a fiber mat of randomized PTFE microfibers or nanofibers.

8. The method of claim 1, wherein the at least one polymer layer of the implanted medical appliance is configured to permit at least 150% in vitro endothelial cell attachment, compared to an expanded PTFE control material.

9. The method of claim 1, wherein the at least one polymer layer of the implanted medical appliance is configured to permit between 30% and 170% in vitro endothelial cell attachment, compared to an expanded PTFE control material.

10. The method of claim 1, wherein the percent porosity of the electrospun polymer layer is between about 40% and about 60%.

11. The method of claim 4, wherein the electrospun PTFE layer has been heated and stretched after sintering.

12. A method for promoting cellular growth into an implantable medical appliance, comprising:

obtaining a medical appliance coated with at least one electrospun polymer layer having a percent porosity of between about 30% and about 80%, and at least one layer that is substantially impervious to cellular growth; and

implanting the medical appliance into a patient such that the electrospun polymer layer of the medical appliance is in direct contact with body fluid or body tissue.

13. The method of claim 12, wherein the at least one electrospun polymer layer comprises electrospun PTFE material.

14. The method of claim 13, wherein the electrospun PTFE material is configured to permit at least 20% cellular penetration, in vivo two weeks after murine implantation.

15. A method for inhibiting a neointimal hyperplasia response to an implantable medical appliance, comprising implanting the medical appliance into a patient, the medical appliance coated with a first electospun PTFE layer comprising a porous mat and a second polymer layer that inhibits tissue ingrowth into or through the second polymer layer.

16. The method of claim 15, wherein the first electrospun polymer layer permits endothelial cell growth or attachment on the surface of the first electrospun polymer layer.

17. The method of claim 15, wherein the second polymer layer comprises an FEP layer.

18. The method of claim 17, wherein the medical appliance is coated with a third polymer layer comprising an electrospun PTFE layer, such that the FEP layer is disposed between the first and third polymer layers.

19. A method for inhibiting an inflammatory response to an implantable medical appliance, comprising implanting the medical appliance into a patient, the medical appliance coated with a first electrospun polymer layer comprising a porous PTFE mat and a second polymer layer comprising FEP that inhibits tissue ingrowth into or through the second polymer layer.

20. The method of claim 19, wherein the first electrospun polymer layer, when placed in vivo, has an H-score of less than 150 two weeks after murine implantation.