Drug delivery stent

• US 20050203613A1
• Filed: 03/11/2004
• Published: 09/15/2005
• Est. Priority Date: 03/11/2004
• Status: Active Grant

• Current Assignee: WSOU Investments, LLC (WSOU Holdings, LLC)
• Original Assignee: Alcatel-Lucent SA (Nokia Corporation)
• Inventors: Weiss, Donald, Kroupenkine, Timofei Nikita, Arney, Susanne
• Granted Patent: US 8,915,957 B2
• Time in Patent Office: Days
• US Class Current: 623/1.420
• CPC Class Codes: A61F 2/92 Stents in the form of a rolled-up sheet expanding after insertion into the vessel , e.g. with a spiral shape in cross-section
• CPC Class Codes: A61F 2210/0076 multilayered, e.g. laminated structures
• CPC Class Codes: A61F 2250/0002 for data transfer
• CPC Class Codes: A61F 2250/001 for adjusting a diameter
• CPC Class Codes: A61F 2250/0035 differing in release or diffusion time
• CPC Class Codes: A61F 2250/0039 differing in diameter
• CPC Class Codes: A61F 2250/0056 differing in wettability, e.g. in hydrophilic or hydrophobic behaviours
• CPC Class Codes: A61F 2250/0067 Means for introducing or releasing pharmaceutical products into the body
• CPC Class Codes: A61F 2250/0068 the pharmaceutical product being in a reservoir
• CPC Class Codes: A61L 31/14 Materials characterised by their function or physical properties , e.g. injectable or lubricating compositions, shape-memory materials, surface modified materials

Abstract

An implantable stent comprises a tubular member having an interior surface and an exterior surface, with a region of at least one of the surfaces being hydrophobic. The region is provided with an array of microstructures or nanostructures that covers first portions of the surface but leaves second portions exposed in the interstices of the array. These structures cause the region to have a dynamically controllable hydrophobicity. In one embodiment, a control device, which is affixed to the tubular member, varies the hydrophobicity of the region. In another embodiment, which is particularly applicable to the delivery of a medicinal substance to fluids in body vessels, the stent also includes such a medicinal substance that adheres to the exposed portions until the control device alters the hydrophobicity of the region and causes the substance to be released into a body fluid in contact with the stent. Various ways to load the stent are described. In yet another embodiment, the tubular member is provided with a mechanism that enables the shape of the stent (e.g., its diameter) in vivo to be controlled dynamically, again by means of external wireless communication. In one more embodiment, sensors are affixed to the tubular member to enable fluid parameters (e.g., pressure, flow rate) to be monitored remotely.

Claims

1. An implantable stent comprising:

a tubular member having an interior surface and an exterior surface, characterized in that

at least one of said surfaces is hydrophobic, and

a region of said at least one surface includes an array of microstructures or nanostructures that covers first portions of said surface, said array causing the region to have a dynamically controllable hydrophobicity.

2. The stent of claim 1, further including a control device affixed to said tubular member for varying said hydrophobicity.

3. The stent of claim 2, wherein said control device comprises an electronic device or an optical device.

4. The stent of claim 3, wherein said control device is remotely actuatable from an external source.

5. The stent of claim 1, wherein said array leaves second portions of said surface exposed, and further including a chemically active substance adhered to at least one of said exposed second portions.

6. The stent of claim 5, wherein said substance comprises a pharmacological agent or a drug.

7. The stent of claim 6, further including a control device affixed to said tubular member, said device being capable of releasing said agent or drug from said at least one second portion.

8. The stent of claim 7, further including

an electrically conductive substrate that is configured to be electrically isolated from body fluid in contact with said array of microstructures or nanostructures, and

wherein said control device is capable of applying a voltage between said array and said substrate to vary the penetration of the interstices of said array by said fluid, thereby causing release of said agent or drug into said fluid.

9. The stent of claim 1, wherein said array leaves second portions of said surface exposed, and further including

means for electrically isolating said array into separate spatial zones,

at least two of said zones containing chemically active substances adhered to the exposed second portions thereof, and

wherein said control device is capable of causing the release of said substances of the separate zones at different times.

10. The stent of claim 9, wherein said substances are the same chemically active substances of the same or a different dose.

11. The stent of claim 9, wherein said substances are different chemically active substances.

12. The stent of claim 1, further including means for altering the shape of said stent in vivo.

13. The stent of claim 12, wherein said altering means is capable of changing the diameter of said tubular member.

14. The stent of claim 1, wherein said tubular member has an elongated slot that is coextensive with its length, thereby forming a pair of elongated edges that are movable relative to one another, and the stent further comprising a plurality of electrically controllable structures thereon, the structures capable of moving said edges and releasably latching said edges.

15. The stent of claim 1, wherein said tubular member comprises a semiconductor substrate and said array of microstructures or nanostructures is disposed on said substrate.

16. The stent of claim 15, wherein said tubular member further comprises a layer disposed on said substrate, said substrate and said layer having different thermal expansion coefficients.

17. The stent of claim 16, wherein said microstructures or nanostructures have at least one dimension that is in the range of 4 μ

m to 20 nm.

18. An implantable stent comprising

a tubular member including a conducting substrate, said member having an interior surface and an exterior surface, characterized in that

at least one of said surfaces is hydrophobic to a body fluid, and

a region of said at least one surface includes an array of microstructures or nanostructures that covers first portions of said surface, said array rendering the region to have a dynamically controllable hydrophobicity,

a medicinal substance adhered to an exposed second portion of said surface, and

a control device affixed to said tubular member for applying a voltage between said fluid and said substrate to vary said hydrophobicity and release said substance into said body fluid, said device being actuatable from an ex vivo source.

19. The stent of claim 18, wherein

said exposed second portion is electrically isolated into first and second spatial zones, each zone containing a medicinal substance adhered thereto, and

said control device is capable of causing the separate release of said substances from the first and second zones.

20. The stent of claim 19, wherein said substances adhered to said first and second zones are the same substance of the same or a different dose.

21. The stent of claim 19, wherein said substances adhered to said first and second zones are different substances.

22. A method of making an implantable stent comprising the steps of:

forming a stack that includes a planar conductive substrate of a first material and a layer of a second material disposed on said substrate, said materials having different thermal expansion coefficients,

forming on a surface region of said stack an array of microstructures or nanostructures,

forming a control device affixed to said stack for dynamically controlling a hydrophobicity of said surface region, and

heating said stack for a predetermined time at a predetermined temperature such that said stack rolls into a tubular member.

23. The method of claim 22, wherein said substrate comprises single crystal Si.

24. The method of claim 23, wherein said layer comprises a shaped memory material.

25. The method of claim 22, further including, before the heating step, the additional steps of:

providing actuatable means for heating said stack, and

implanting said stack into a body, and

actuating the heating means to cause the stack to roll up and form a tubular member.

26. An implantable stent comprising

a tubular member having an elongated slot that is coextensive with its length, thereby forming a pair of elongated edges that are movable relative to one another, and

means for changing the diameter of said member by moving said edges relative to one another.

27. The stent of claim 26, further including means for releasably latching said edges after they have been moved.

28. The stent of claim 26, wherein said changing means includes a scratch drive actuator coupled to said edges.