Oxygen enhancing membrane systems for implantable devices

• US 8,255,030 B2
• Filed: 04/25/2006
• Issued: 08/28/2012
• Est. Priority Date: 07/25/2003
• Status: Active Grant

• Current Assignee: DexCom Incorporated
• Original Assignee: DexCom Incorporated
• Inventors: Petisce, James, Tapsak, Mark A., Simpson, Peter C., Carr-Brendel, Victoria, Brauker, James H.
• Primary Examiner(s): Natnithithadha, Navin
• Application Number:
  US11/410,555
• Publication Number:
  US 20060189856A1
• Time in Patent Office: 2,317 Days
• Field of Search: 600/309, 600345-366
• US Class Current: 600/345
• CPC Class Codes: A61B 5/145 Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissuemeasuring of blood pressure or blood flow A61B5/02; non-radiation detecting or locating of foreign bodies in blood A61B5/06
• CPC Class Codes: A61B 5/14503 invasive, e.g. introduced into the body by a catheter or needle or using implanted sensors A61B5/1459, A61B5/1464, A61B5/1473, A61B5/1482, A61B5/14865 take precedence
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/14546 for measuring analytes not otherwise provided for, e.g. ions, cytochromes
• CPC Class Codes: A61B 5/1468 using chemical or electrochemical methods, e.g. by polarographic means A61B5/1486 takes precedence
• CPC Class Codes: A61B 5/1473 invasive, e.g. introduced into the body by a catheter A61B5/1482 takes precedence
• CPC Class Codes: A61B 5/14735 comprising an immobilised reagent
• CPC Class Codes: A61B 5/14865 invasive, e.g. introduced into the body by a catheter or needle or using implanted sensors
• CPC Class Codes: C12Q 1/002 Electrode membranes
• CPC Class Codes: C12Q 1/006 for glucose

Abstract

The present invention relates generally to systems and methods for increasing oxygen availability to implantable devices. The preferred embodiments provide a membrane system configured to provide protection of the device from the biological environment and/or a catalyst for enabling an enzymatic reaction, wherein the membrane system includes a polymer formed from a high oxygen soluble material. The high oxygen soluble polymer material is disposed adjacent to an oxygen-utilizing source on the implantable device so as to dynamically retain high oxygen availability to the oxygen-utilizing source during oxygen deficits. Membrane systems of the preferred embodiments are useful for implantable devices with oxygen-utilizing sources and/or that function in low oxygen environments, such as enzyme-based electrochemical sensors and cell transplantation devices.

Claims

1. An implantable device for continuous in vivo measurement of an analyte concentration in a host, the device comprising:

a sensor configured for implantation in a host, the sensor configured to operatively connect with electronic circuitry configured to generate a signal associated with a concentration of an analyte in a host; and

a membrane located over the sensor and configured to control a flux of oxygen and the analyte therethrough, wherein the membrane comprises a material having an oxygen permeability of from about 5 Barrers to about 1000 Barrers.

2. The device of claim 1, wherein the material comprises a copolymer comprising a fluorocarbon segment.

3. The device of claim 2, wherein the fluorocarbon segment is perfluorinated.

4. The device of claim 2, wherein the copolymer further comprises a polycarbonate segment.

5. The device of claim 2, wherein the copolymer has an oxygen solubility of about 50-volume %.

6. The device of claim 2, wherein the membrane comprises a blend, wherein the blend comprises the copolymer and a hydrophilic polymer.

7. The device of claim 6, wherein the hydrophilic polymer is selected from the group consisting of polyvinylpyrrolidone, polyhydroxyethyl methacrylate, polyvinylalcohol, polyacrylic acid, polyethers, and copolymers thereof.

8. The device of claim 1, wherein the membrane has a thickness of from about 3 microns to about 65 microns.

9. The device of claim 1, wherein the membrane comprises an enzyme domain, wherein the enzyme domain comprises an enzyme configured to react with the analyte.

10. The device of claim 1, wherein the membrane is configured to limit or block passage of interfering species therethrough.

11. The device of claim 1, wherein the membrane is configured to provide protection to the sensor from a biological environment.

12. The device of claim 1, wherein the material has an oxygen permeability of at least about 10 Barrers.

13. The device of claim 1, wherein the material has an oxygen permeability of at least about 100 Barrers.

14. The device of claim 1, wherein the material has an oxygen permeability of at least about 500 Barrers.

15. The device of claim 1, wherein the material has an oxygen permeability of at least about 800 Barrers.

16. The device of claim 1, wherein the analyte is glucose.

17. The device of claim 1, wherein the membrane has an oxygen permeability from about 30 Barrers to about 1000 Barrers.

18. The device of claim 1, wherein the membrane comprises a domain that has an oxygen permeability from about 30 Barrers to about 1000 Barrers.

19. The device of claim 1, wherein the material has an oxygen solubility that is from about three times to about ten times greater than an oxygen solubility of aqueous media.

20. An implantable device for continuous in vivo measurement of a glucose concentration in a host, the device comprising:

a sensor operatively connected to electronic circuitry configured to generate a signal associated with a concentration of glucose in a host; and

a membrane located over the sensor and configured to control a flux of oxygen and glucose therethrough, wherein the membrane comprises a material having an oxygen permeability of from about 5 Barrers to about 1000 Barrers, wherein the material comprises a copolymer comprising a fluorocarbon segment and a polycarbonate segment, wherein the membrane has a thickness of from about 3 microns to about 65 microns, and wherein the membrane comprises an enzyme domain comprising an enzyme configured to react with glucose.

21. The device of claim 20, wherein the material has an oxygen solubility that is from about three times to about ten times greater than an oxygen solubility of aqueous media.