ANALYTE PERMEABLE MEMBRANE SYSTEMS FOR OXIDATIVE AND OPTICAL STABILITY

• US 20140187878A1
• Filed: 12/27/2013
• Published: 07/03/2014
• Est. Priority Date: 12/28/2012
• Status: Active Grant

• Current Assignee: Senseonics, Incorporated (Senseonics Holdings, Inc.)
• Original Assignee: Senseonics, Incorporated (Senseonics Holdings, Inc.)
• Inventors: Emken, Jeremy, Huffstetler, Philip, Whitehurst, Todd
• Granted Patent: US 9,427,182 B2
• Time in Patent Office: Days
• US Class Current: 600/310
• CPC Class Codes: A61B 2562/162 Capsule shaped sensor housings, e.g. for swallowing or implantation
• CPC Class Codes: A61B 5/0031 Implanted circuitry
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/1459 invasive, e.g. introduced into the body by a catheter A61B5/1464 takes precedence

Abstract

A sensor that may be used to detect the presence, amount, and/or concentration of an analyte in a medium within an animal. The sensor may include a sensor housing, an indicator element embedded within and/or covering at least a portion of the sensor housing, and a membrane over the indicator element. The membrane may reduce indicator element deterioration by preventing immune cells, such as white blood cells, from contacting the indicator element, substantially prevent transmission of light of at least a specified wavelength or range of wavelengths through the membrane, and/or permit the analyte to pass through to the indicator element. The membrane may be an opaque diffusion membrane. The sensor may include a foil. The foil may block light and/or reduce indicator element deterioration. The membrane may reduce oxidation of the indicator element.

Claims

1. A sensor for in vivo detection of the presence, amount, and/or concentration of an analyte in a medium within a living animal, the sensor comprising:

a sensor housing;

an indicator element embedded within and/or covering at least a portion of the sensor housing; and

a membrane over at least a portion of the indicator element.

2. The sensor of claim 1, wherein the membrane has pores configured to substantially prevent white blood cells from passing through the membrane but to permit the analyte to pass through the membrane.

3. The sensor of claim 2, wherein the analyte is glucose.

4. The sensor of claim 1, wherein the membrane is opaque.

5. The sensor of claim 1, wherein the membrane catalyzes degradation of reactive oxygen species (ROS), such as hydrogen peroxide, and reduces deterioration of the indicator element.

6. The sensor of claim 1, wherein the membrane comprises nylon, cellulose acetate, polytetrafluoroethylene, polyethylene teraphthlate, polypropylene, polyvinyl alcohol, polybutylene terephthalate, polyether ether ketone, polyanhydride, polyamide, polyvinylchloride, polyethersulfone, polyethylene terephthalate, polyvinylidene difluoride, polytetrafluoroethylene, nitrocellulose, acrylate, poly(methyl methacrylate), polyacrylate homo- or copolymers, polycarbonate, or combinations or derivatives thereof.

7. The sensor of claim 1, wherein the membrane comprises platinum.

8. The sensor of claim 1, further comprising a layer.

9. The sensor of claim 8, wherein the layer comprises platinum.

10. The sensor of claim 8, wherein the layer is configured to block (i) external light from reaching the indicator element and (ii) light from the sensor housing that has passed through the indicator element from reaching bodily tissue of the living animal.

11. The sensor of claim 8, wherein the layer is between the indicator element and the membrane.

12. The sensor of claim 11, wherein the layer is a thin layer sputtered on the outside of the indicator element.

13. The sensor of claim 12, wherein the layer is over the membrane.

14. The sensor of claim 13, wherein the membrane is wrapped around the indicator element and layer.

15. The sensor of claim 1, wherein the membrane is wrapped around the indicator element.

16. The sensor of claim 1, wherein the indicator element is a polymer graft including indicator molecules.

17. The sensor of claim 1, wherein sensor housing includes a light source and a light detector.

18. The sensor of claim 1, wherein the living animal is a human.

19. The sensor of claim 1, wherein the medium is interstitial fluid.

20. The sensor of claim 1, wherein the indicator element comprises a fluorescent indicator element.

21. The sensor of claim 1, wherein the membrane comprises a hydrophilic or hydrophobic membrane material.

22. The sensor of claim 1, wherein the sensor housing comprises an optically transmissive polymer material.

23. The sensor of claim 1, wherein the sensor housing is a shell.

24. The sensor of claim 1, wherein the sensor housing is a capsule.

25. The sensor of claim 1, wherein the membrane comprises a mesh material.

26. The sensor of claim 1, wherein membrane is a porous, opaque diffusion membrane covering at least a portion of the housing and the indicator element, wherein the membrane is configured to substantially prevent white blood cells from passing through the membrane and permit an analyte of interest to pass through the membrane to the indicator element and to substantially prevent transmission of light of at least a specified wavelength or range of wavelengths through the membrane.

27. The sensor of claim 26, wherein the diffusion membrane has pores configured to substantially prevent white blood cells from passing through the membrane but to permit glucose to pass through the membrane.

28. The sensor of claim 27, wherein the diffusion membrane has a porosity of 3-60%.

29. The sensor of claim 27, wherein pores formed through the diffusion membrane have a size of 0.45-6 microns.

30. The sensor of claim 26, wherein the diffusion membrane comprises a layer of hydrophilic material.

31. The sensor of claim 30, wherein the hydrophilic layer has a thickness of 10-200 microns.

32. The sensor of claim 30, wherein the diffusion membrane further comprises a layer of torturous path material disposed over or under the layer of hydrophilic material.

33. The sensor of claim 32, wherein the torturous path material comprises nylon.

34. The sensor of claim 32, wherein the torturous path layer has a thickness of 50-200 microns.

35. The sensor of claim 26, wherein the diffusion membrane comprises a layer of material selected from the group consisting of nylon, cellulose acetate, polytetrafluoroethylene, polyethylene teraphthlate, polypropylene, polyvinyl alcohol, polybutylene terephthalate, polyether ether ketone, polyanhydride, polyamide, polyvinylchloride, polyethersulfone, polyethylene terephthalate, polyvinylidene difluoride, polytetrafluoroethylene, nitrocellulose, acrylate, poly(methyl methacrylate), polyacrylate homo- or copolymers, polycarbonate, derivatives thereof, and combinations thereof.

36. The sensor of claim 26, wherein the diffusion membrane has a thickness of 10-200 microns.

37. The sensor of claim 26, wherein the diffusion membrane comprises an opaque or light absorbing colorant.

38. The sensor of claim 37, wherein the opaque or light absorbing colorant comprises TiO2 or carbon black.

39. The sensor of claim 26, wherein the diffusion membrane comprises an amount of opaque or light absorbing colorant such that light transmission through the diffusion membrane is reduced.