Method of making implantable medical devices having controlled surface properties

• US 10,363,125 B2
• Filed: 09/25/2018
• Issued: 07/30/2019
• Est. Priority Date: 11/19/1999
• Status: Expired due to Fees

• Current Assignee: Vactronix Scientific, LLC
• Original Assignee: Vactronix Scientific, LLC
• Inventors: Palmaz, Julio C., Sprague, Eugene A., Banas, Christopher E.
• Primary Examiner(s): Padgett, Marianne L
• Assistant Examiner(s): Bowman, Andrew J
• Application Number:
  US16/140,822
• Publication Number:
  US 20190021844A1
• Time in Patent Office: 308 Days
• CPC Class Codes: A61F 2/0077 Special surfaces of prostheses, e.g. for improving ingrowth A61F2/30767 takes precedence
• 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 2/90 characterised by a net-like or mesh-like structure
• CPC Class Codes: A61F 2/91 made from perforated sheet material or tubes, e.g. perforated by laser cuts or etched holes
• CPC Class Codes: A61F 2/915 with bands having a meander structure, adjacent bands being connected to each other
• CPC Class Codes: A61F 2002/0086 for preferentially controlling or promoting the growth of specific types of cells or tissues of bone tissue onto implantable joints A61F2002/3093
• CPC Class Codes: A61F 2002/072 Encapsulated stents, e.g. wire or whole stent embedded in lining
• CPC Class Codes: A61F 2002/91541 Adjacent bands are arranged out of phase
• CPC Class Codes: A61F 2002/9155 Adjacent bands being connected to each other
• CPC Class Codes: A61F 2220/0041 using additional screws, bolts, dowels or rivets, e.g. connecting screws
• CPC Class Codes: A61F 2220/005 using adhesives
• CPC Class Codes: A61F 2220/0058 soldered or brazed or welded
• CPC Class Codes: A61F 2220/0075 sutured, ligatured or stitched, retained or tied with a rope, string, thread, wire or cable
• CPC Class Codes: A61L 27/04 Metals or alloys
• CPC Class Codes: A61L 27/3679 Hollow organs, e.g. bladder, esophagus, urether, uterus, intestine
• CPC Class Codes: A61L 27/507 for artificial blood vessels apparatus for applying cells on a blood vessel prosthesis A61F2/062
• CPC Class Codes: A61L 31/022 Metals or alloys
• CPC Class Codes: Y10T 29/49936 Surface interlocking

Abstract

An implantable medical device that is fabricated from materials that present a blood or body fluid or tissue contact surface that has controlled heterogeneities in material constitution. An endoluminal stent-graft and web-stent that is made of a monolithic material formed into differentiated regions defining structural members and web regions extending across interstitial spaces between the structural members. The endoluminal stent-graft is characterized by having controlled heterogeneities at the blood flow surface of the stent.

Claims

1. A method for controlling surface properties of an implantable medical device, comprising:

a. vacuum depositing at least one device forming metal selected from one of elemental nickel, elemental titanium, chromium-cobalt alloy, nickel-titanium alloy and nickel-titanium ternary alloy onto a cylindrical substrate maintained at a temperature range between about 300 to 1100 degrees Centigrade, to form a tubular device forming biomaterial on the cylindrical substrate;

b. controlling the formation of heterogeneities at a blood or tissue contacting surface of the tubular device forming biomaterial during the vacuum depositing step, such that controlled heterogeneities are formed at the blood or tissue contacting surface; and

c. removing the formed biomaterial from the substrate.

2. The method according to claim 1, wherein the at least one device forming metal is selected the group of biocompatible metals consisting of elemental nickel, elemental titanium, tantalum, chromium-cobalt alloy, nickel-titanium alloy and nickel-titanium ternary alloy.

3. The method according to claim 1, further comprising forming cell-adhesion domains having inter-domain boundaries less than the surface area of a human endothelial cell and wherein the substrate has a coefficient of thermal expansion different than that of the resultant implantable medical device.

4. The method according to claim 1, further comprising the step of defining cell-adhesion domains having inter-domain boundaries less than the surface area of a human endothelial cell.

5. The method according to claim 1, wherein the controlled heterogeneities are dimensioned to have a blood contact surface area of about less than 6 μ

m2.

6. The method according to claim 1, wherein the controlled heterogeneities are selected from the group consisting of grain size, grain phase and grain composition and luminal surface topography.

7. The method according to claim 1, wherein the controlled heterogeneities have a blood contact surface of diameter less than or equal to about 10 μ

m and an inter-heterogeneity boundary between about 0 and 2 μ

m.

8. The method according to claim 1, wherein the controlled heterogeneities are dimensioned to have a blood contact surface area of about less than 6 μ

m².

9. The method according to claim 1, wherein the cylindrical substrate is maintained at a non-zero bias voltage present between about −

1000 and +1000 volts applied to the generally cylindrical substrate sufficient to impart a hyperthermal energy of energetic species arriving at the surface of the substrate to between about 0.1 eV and about 700 eV.

10. A method for controlling surface properties of an implantable medical device, comprising the steps of:

a. forming a tubular nickel-titanium alloy biomaterial onto a substrate maintained at a temperature range between about 300 to 1100 degrees Centigrade and non-zero bias voltage applied to the generally cylindrical substrate sufficient to impart a hyperthermal energy of energetic species arriving at the surface of the substrate to between about 0.1 eV and about 700 eV, the substrate having a pre-determined pattern of topographical features on an exterior surface thereof, wherein the pattern of topographical features comprises a positive or negative pattern that is imparted to the device forming biomaterial;

b. controlling the formation of heterogeneities at a blood or tissue contacting surface of the biomaterial by fabricating the bulk material of the medical device to have a defined grain sizes that yield sites along the surface of the medical device having protein binding capability, wherein the controlled heterogeneities have a blood contact surface of diameter less than or equal to about 10 μ

m and an inter-heterogeneity boundary between about 0 and 2 μ

m; and

c. removing the medical device from the substrate.

11. The method according to claim 10, wherein the nickel-titanium alloy is a binary or ternary alloy.

12. The method according to claim 10, wherein the step of controlling the formation of heterogeneities further comprises etching.

13. The method according to claim 10 further comprising forming cell-adhesion domains having inter-domain boundaries less than the surface area of a human endothelial cell and wherein the substrate has a coefficient of thermal expansion different than that of the resultant medical device.

14. The method according to claim 10, wherein the controlled heterogeneities are dimensioned to have a blood contact surface area of about less than 6 μ

m2.

15. The method according to claim 10, wherein the controlled heterogeneities further include a grain phase and a grain composition.

16. The method according to claim 10, wherein the implantable medical device is a tubular device and the controlled heterogeneities are on the luminal surface topography.

17. A method for controlling surface properties of an implantable medical device, comprising:

a. vacuum depositing a generally tubular nickel-titanium alloy device onto a substrate, the substrate having a pre-determined pattern of recesses and the substrate is maintained at a non-zero bias voltage present between about −

1000 and +1000 volts applied to the generally cylindrical substrate sufficient to impart a hyperthermal energy of energetic species arriving at the surface of the substrate to between about 0.1 eV and about 700 eV;

b. controlling the formation of heterogeneities at a blood or tissue contacting surface of the biomaterial during fabrication of the medical device, such that controlled heterogeneities are formed and have a substantially homogeneous surface energy and electrostatic charge across a blood contact surface of the metal film, wherein the controlled heterogeneities have a blood contact surface of diameter less than or equal to about 10 μ

m and an inter-heterogeneity boundary between about 0 and 2 μ

m; and

c. removing the medical device from the substrate.

18. The method according to claim 17, wherein the controlled heterogeneities are selected from the group consisting of grain size, grain phase and grain composition and luminal surface topography.

19. The method according to claim 17, wherein the step of controlling the formation of heterogeneities further comprises etching.

20. The method according to claim 17, wherein the controlled heterogeneities are material compositions.

21. The method according to claim 17, wherein the substrate has a coefficient of thermal expansion different than that of the resultant medical device.

22. The method according to claim 17, wherein the substrate is maintained at a temperature range between about 300 to 1100 degrees Centigrade.

23. The method according to claim 17, wherein the controlled heterogeneities are on the luminal surface.