Method of forming a tubular membrane on a structural frame

• US 8,663,541 B2
• Filed: 08/21/2007
• Issued: 03/04/2014
• Est. Priority Date: 05/10/2002
• Status: Active Grant

• Current Assignee: Cordis Corporation (Cardinal Health, Inc.)
• Original Assignee: Cordis Corporation (Cardinal Health, Inc.)
• Inventors: Chun, Iksoo, Roller, Mark B., Majercak, David Christopher
• Primary Examiner(s): Tentoni, Leo B
• Application Number:
  US11/842,804
• Publication Number:
  US 20080036113A1
• Time in Patent Office: 2,387 Days
• Field of Search: 264/129, 264/171.12, 264/171.13, 264/171.14, 264/171.15, 264/171.17, 264/171.26, 264/171.27, 264/171.28, 264/171.29, 264/313, 264/316, 264/338, 264/465, 427/2.24, 427/2.25
• US Class Current: 264/465
• CPC Class Codes: A61F 2/2412 with soft flexible valve members, e.g. tissue valves shaped like natural valves check valves with flexible valve members in general F16K15/14
• CPC Class Codes: A61F 2/2415 Manufacturing methods
• CPC Class Codes: A61F 2/2418 Scaffolds therefor, e.g. support stents
• CPC Class Codes: A61F 2/2475 Venous valves
• CPC Class Codes: A61F 2/915 with bands having a meander structure, adjacent bands being connected to each other
• CPC Class Codes: A61F 2002/825 having longitudinal struts
• CPC Class Codes: A61F 2002/91533 characterised by the phase between adjacent bands
• CPC Class Codes: A61F 2002/91558 connected peak to peak
• CPC Class Codes: A61F 2002/91575 connected peak to trough
• CPC Class Codes: A61F 2002/91583 by a bridge, whereby at least one of its ends is connected along the length of a strut between two consecutive apices within a band
• CPC Class Codes: A61F 2220/0058 soldered or brazed or welded
• CPC Class Codes: A61F 2230/0054 V-shaped
• CPC Class Codes: A61L 2300/00 Biologically active materials used in bandages, wound dressings, absorbent pads or medical devices
• CPC Class Codes: A61L 27/18 obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
• CPC Class Codes: A61L 27/34 Macromolecular materials
• CPC Class Codes: A61L 27/54 Biologically active materials, e.g. therapeutic substances A61L27/227 takes precedence
• CPC Class Codes: C08L 67/04 Polyesters derived from hydroxycarboxylic acids, e.g. lactones C08L67/06 takes precedence
• CPC Class Codes: D01D 5/0084 Coating by electro-spinning, i.e. the electro-spun fibres are not removed from the collecting device but remain integral with it, e.g. coating of prostheses
• CPC Class Codes: D01F 6/32 comprising halogenated hydrocarbons as the major constituent
• CPC Class Codes: D01F 6/84 from copolyesters
• CPC Class Codes: D04H 3/07 : otherwise than in a plane, e.g. in a tubular way

Abstract

The present invention relates to a medical device and method of forming the medical device. In particular, the present invention relates to a medical device having a tubular membrane structure over a radially expandable structural frame, and to a method of forming the tubular membrane on the radially expandable structural frame. In one aspect, a structural frame is placed over a spinning mandrel and a fiber is electro-statically spun over at least a portion of the structural frame forming a membrane. A transfer sheath may be used between the mandrel and structural frame to prevent the electro-statically spun fiber from adhering to the mandrel. In another aspect, a first membrane is spun over the mandrel before the structural frame is placed over the mandrel. In this aspect, at least a portion of the structural frame is sandwiched between the membranes. The membrane or membranes and structural frame form a fiber spun frame assembly. The fiber spun frame assembly may be coated with an elastic polymer. In addition, the membrane or membranes may go through some post processing to achieve desired characteristics or configurations.

Claims

1. A method of forming a tubular membrane on a radially expandable structural frame, the method comprising the steps of:

placing a transfer sheath over a spinning mandrel;

placing the radially expandable structural frame directly onto the transfer sheath;

electro-statically spinning a fiber directly onto at least a portion of the structural frame to form a tubular membrane, the structural frame and tubular membrane forming a fiber spun frame assembly;

forming valve cusps in the tubular membrane, and thinning the tubular membrane to form valve flaps;

and removing the fiber spun frame assembly from the spinning mandrel.

2. The method of claim 1 wherein the step of electro-statically spinning a fiber directly onto the structural frame comprises the steps of:

creating an electrical potential between a fiber forming liquid and a downstream component, whereby the fiber forming liquid is caused to produce a charged fiber;

hardening the fiber by introducing a chemical hardener into the fiber forming liquid;

and collecting the hardened fiber on the structural frame.

3. The method of claim 2 wherein the fiber forming liquid is a polymer.

4. The method of claim 3 wherein the polymer is a fluoropolymer.

5. The method of claim 4 wherein the fluoropolymer is vinylidene fluoride/hexafluoropropylene having a weight to weight ratio of between 75%/25% and 100%/0%.

6. The method of claim 3 wherein the polymer is a bioabsorbable polymer.

7. The method of claim 6 wherein the bioabsorbable polymer is a polylactic acid/polycaprolactone having a weight to weight ratio of between 50%/50% and 70%/30%.

8. The method of claim 6 wherein the bioabsorbable polymer is a polyglycolic acid/polycaprolactone having a weight to weight ratio of between 50%/50% and 70%/30%.

9. The method of claim 3 wherein the polymer comprises a bioabsorbable polymer from the group consisting of homopolymers and copolymers.

10. The method of claim 2 further comprising adding a therapeutic agent to the fiber forming liquid before electrostatically spinning the fiber.

11. The method of claim 2 further comprising adding a pharmaceutic agent to the fiber forming liquid before electrostatically spinning the fiber.

12. The method of claim 2 wherein the step of collecting the hardened fiber on the structural frame comprises:

electrically attracting the fiber forming liquid to a downstream component; and

rotating the structural frame about its longitudinal axis by spinning the spinning mandrel.

13. The method of claim 1 further comprising coating the fiber spun frame assembly with a polymer solution.

14. The method of claim 13 wherein the polymer solution is a fluoropolymer.

15. The method of claim 14 wherein the fluoropolymer is a vinylidene fluoride/hexofluoropropylene having a weight to weight radio of between 50%/50% to 70%/30%.

16. The method of claim 13 wherein the polymer solution is non-siliconized polyurethane.

17. The method of claim 13 wherein the polymer solution comprises a therapeutic agent.

18. The method of claim 13 wherein the polymer solution comprises a pharmaceutic agent.

19. The method of claim 1 further comprising reshaping at least a portion of the tubular membrane after the fiber is spun to provide a thickened, rigid region.

20. A method of forming a tubular membrane on a radially expandable structural frame, the method comprising the steps of:

placing the radially expandable structural frame directly onto a spinning mandrel;

electro-statically spinning a first fiber directly onto at least a portion of the structural frame to form a tubular membrane, the structural frame and tubular membrane forming a fiber spun frame assembly;

forming valve cusps in the tubular membrane and thinning the tubular membrane in the area of the valve cusps to form valve flaps; and

removing the fiber spun frame assembly from the spinning mandrel.