Photocatalytic disinfection of implanted catheters

Patent metadata

Field	Value
Publication number	US-9259513-B2
Application number	US-201213528765-A
Country	US
Kind code	B2
Filing date	Jun 20, 2012
Priority date	Jun 20, 2011
Publication date	Feb 16, 2016
Grant date	Feb 16, 2016

Abstract

An implantable catheter is provided that may be disinfected without removal from the body of a patient, using a photocatalytic method to activate a reaction on the catheter surface that generates oxidizing agents in the form of Reactive Oxygen Species (“ROS”) and thus destroy microorganisms in a biofilm that is present or forming. A catheter system includes the implantable catheter, a light source, and a source of power operably connected to the light source. Methods are also provided for disinfecting the implantable catheter in vivo.

First claim

We claim:

1. An implantable catheter that can be photocatalytically disinfected without removal from a patient's body, comprising:
an elongate catheter body of predetermined length having a proximal end, a distal end, at least one lumen extending through the catheter body and adapted to transport fluid from the proximal end to the distal end, an outer surface on the exterior of the catheter body, and an inner surface on the interior of the lumen;
an outer photocatalytic layer on the outer surface that undergoes a photocatalysis reaction upon irradiation with ultraviolet light to generate reactive oxygen species;
an out-coupling means for facilitating out-coupling of ultraviolet light directed into the catheter at the proximal end so that along the length of the catheter a first fraction of the light is refracted toward the catheter surfaces and thus toward the outer photocatalytic layer, thereby activating the photocatalysis reaction;
wherein the out-coupling means has a density gradient that increases axially along the length of the catheter from the proximal end to the distal end for ensuring that the amount of out-coupled ultraviolet light is substantially uniform along the length of the catheter from the proximal end to the distal end.

2. The implantable catheter of claim 1 , wherein the outer photocatalytic layer is comprised of particulate crystalline titanium dioxide selected from anatase, brookite, rutile, and combinations thereof.

3. The implantable catheter of claim 2 , wherein the crystalline titanium dioxide comprises at least 50% anatase.

4. The implantable catheter of claim 3 , wherein the crystalline titanium dioxide comprises has a particle size in the range of about 10 nm to about 300 nm.

5. The implantable catheter of claim 3 , wherein the particle size is in the range of about 100 nm to about 300 nm.

6. The implantable catheter of claim 1 , wherein the outer photocatalytic layer has a thickness in the range of about 20 nm to 1 μm.

7. The implantable catheter of claim 1 , wherein the outer photocatalytic layer has a thickness in the range of about 20 nm to about 200 nm.

8. The implantable catheter of claim 1 , wherein the outer photocatalytic layer is embedded in the outer surface of the catheter and thus integral therewith.

9. The implantable catheter of claim 1 , wherein the catheter body comprises a flexible elastomeric material that is substantially transparent to ultraviolet radiation.

10. The implantable catheter of claim 9 , wherein the flexible elastomeric material comprises a silicone polymer substantially free of unsaturated bonds.

11. The implantable catheter of claim 1 , wherein the out-coupling means comprises scattering particles dispersed in the catheter body along the length thereof.

12. The implantable catheter of claim 1 , wherein the out-coupling means comprises a tubular reinforcing element in the catheter body that extends from the proximal end to the distal end and comprises a material that is substantially transparent to the ultraviolet light.

13. The implantable catheter of claim 12 , wherein the tubular reinforcing element comprises a braid.

14. The implantable catheter of claim 13 , wherein the tubular reinforcing element comprises a helix or weave.

15. The implantable catheter of claim 12 , wherein the tubular reinforcing element also serves as a structural support and increases the tear strength of the catheter body.

16. The implantable catheter of claim 12 , wherein the tubular reinforcing element is comprised of a material selected from fluoropolymers, poly(vinyl chloride), polyethylene, and polypropylene.

17. The implantable catheter of claim 16 , wherein the tubular reinforcing element is comprised of a fluoropolymer.

18. The implantable catheter of claim 17 , wherein the fluoropolymer comprises a fluorinated ethylene propylene (FEP) resin.

19. The implantable catheter of claim 17 , wherein the fluoropolymer comprises a perfluoroalkoxy copolymer (PFA) resin.

20. The implantable catheter of claim 1 , wherein the out-coupling means comprises bubbles in the catheter body along the length thereof extending from the proximal end to the distal end.

21. The implantable catheter of claim 1 , wherein the out-coupling means comprises the texturing of the outer wall of the catheter body along the length thereof in a manner that increases the extent of out-coupling from the proximal end to the distal end.

22. The implantable catheter of claim 11 , wherein the out-coupling means comprises incorporation of the scattering particles in a density gradient that increases axially along the length of the catheter from the proximal end to the distal end.

23. The implantable catheter of claim 22 , wherein the density of scattering particles increases by a factor of about 2 to about 100 from the proximal end to the distal end.

24. The implantable catheter of claim 23 , wherein the density of scattering particles increases by a factor of about 5 to about 15 from the proximal end to the distal end.

25. The implantable catheter of claim 12 , wherein the out-coupling means comprises incorporation of the tubular reinforcing element in a density gradient that increases axially along the length of the catheter from the proximal end to the distal end.

26. The implantable catheter of claim 11 , further including an additional out-coupling means in the form of a tubular reinforcing element in the catheter body that extends from the proximal end to the distal end and comprises a material that is substantially transparent to ultraviolet light.

27. The implantable catheter of claim 1 , further including an inner photocatalytic layer on the inner surface that undergoes a photocatalysis reaction upon irradiation with ultraviolet light to generate reactive oxygen species.

28. The implantable catheter of claim 27 , wherein the outer photocatalytic layer and the inner photocatalytic layer are comprised of the same material.

29. The implantable catheter of claim 28 , wherein the outer photocatalytic layer and the inner photocatalytic layer are comprised of particulate crystalline titanium dioxide selected from anatase, brookite, rutile, and combinations thereof.

30. The implantable catheter of claim 1 , further including a light confinement means for ensuring that a second portion of the light is internally reflected and thereby continues to travel axially through the length of the catheter to the distal end.

31. The implantable catheter of claim 30 , wherein the light confinement means comprises a cladding layer interposed between the outer surface of the catheter body and the photocatalytic layer.

32. The implantable catheter of claim 31 , wherein the cladding layer is comprised of a material having a lower index of refraction than the catheter body.

33. The implantable catheter of claim 32 , wherein the cladding layer has a thickness in the range of about 0.002 mm to about 0.5 mm.

34. The implantable catheter of claim 33 , wherein the cladding layer has a thickness in the range of about 0.05 mm to about 0.2 mm.

35. The implantable catheter of claim 1 , further including a structural reinforcing means for increasing the tear strength of the catheter, the tensile strength of the catheter, the force at break, or any

Assignees

• Bedwell William
• Moro Lorenza
• Arons Eric A
• Garcia Pablo E
• Onugha Osita
• Dutta Sanjeev
• Young Sarah
• Shakespear Karen F
• Haagensen Janus A J
• Stanford Res Inst Int

Inventors

• Bedwell William
• Moro Lorenza
• Arons Eric A
• Garcia Pablo E
• Onugha Osita
• Dutta Sanjeev
• Young Sarah
• Shakespear Karen F
• Haagensen Janus A J

Classifications

• A61L2103/15

  Laboratory, medical or dentistry appliances, e.g. catheters or sharps · CPC title

• A61L2/10

  Ultraviolet [UV] radiation · CPC title

• A61M2025/0056

  provided with an antibacterial agent, e.g. by coating, residing in the polymer matrix or releasing an agent out of a reservoir · CPC title

• A61M25/005

  with embedded materials for reinforcement, e.g. wires, coils, braids · CPC title

• A61M25/0045

  multi-layered, e.g. coated (coating materials A61L29/08) · CPC title