Oxygen enhancing membrane systems for implantable devices

• US 8,255,032 B2
• Filed: 01/15/2010
• Issued: 08/28/2012
• Est. Priority Date: 07/25/2003
• Status: Expired due to Term

• Current Assignee: DexCom Incorporated
• Original Assignee: DexCom Incorporated
• Inventors: Petisce, James R., Tapsak, Mark A., Simpson, Peter C., Carr-Brendel, Victoria E., Brauker, James H.
• Primary Examiner(s): Natnithithadha, Navin
• Application Number:
  US12/688,763
• Publication Number:
  US 20100145172A1
• Time in Patent Office: 956 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 implantable device comprising:

a sensing region operatively connected to electronic circuitry configured to generate a signal associated with a concentration of an analyte in a host; and

a membrane located over the sensing region, wherein the membrane comprises a first domain comprising an enzyme configured to react with the analyte and a second domain configured to control a flux of the analyte and oxygen therethrough to the underlying first domain, wherein the first domain comprises a first silicone-containing polymer and the second domain comprises a second silicone-containing polymer, and wherein the second domain comprises a blend that comprises the second silicone-containing polymer and a hydrophilic polymer.

2. The implantable device of claim 1, wherein a silicone composition of the first domain is different from a silicone composition of the second domain.

3. The implantable device of claim 1, wherein the first silicone-containing polymer is different from the second silicone-containing polymer.

4. The implantable device of claim 1, wherein the first silicone-containing polymer is the same as the second silicone-containing polymer.

5. The implantable device of claim 1, wherein the first domain is positioned between the second domain and the sensing region.

6. The implantable device of claim 1, wherein the membrane has a thickness of from about 11 microns to about 65 microns.

7. The implantable device of claim 1, wherein the second domain is configured to protect the implantable device from a biological environment.

8. The implantable device of claim 1, wherein at least a portion of the second silicone-containing polymer is cross-linked.

9. The implantable device of claim 1, wherein the hydrophilic polymer is selected from the group consisting of polyvinylpyrrolidone, polyhydroxyethyl methacrylate, polyvinylalcohol, polyacrylic acid, polyethers, and copolymers thereof.

10. The implantable device of claim 1, wherein the second domain comprises polyurethane.

11. The implantable device of claim 1, wherein the implantable device is configured to measure a glucose concentration.

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

a sensing region operatively connected to electronic circuitry configured to generate a signal associated with a concentration of an analyte in a host; and

a membrane located over the sensing region, wherein the membrane comprises a first domain comprising an enzyme configured to react with the analyte and a second domain configured to control a flux of the analyte and oxygen therethrough, wherein the first domain comprises a first silicone-containing polymer and the second domain comprises a second silicone-containing polymer, wherein the second domain comprises a blend that comprises the second silicone-containing polymer and a hydrophilic polymer, wherein a silicone composition of the first domain is different from a silicone composition of the second domain, wherein the membrane further comprises a third domain, wherein the third domain comprises a third silicone-containing polymer, and wherein a silicone composition of the third domain is different from the silicone composition of the first domain and is different from the silicone composition of the second domain.

13. The implantable device of claim 12, wherein the third domain is configured to reduce a passage of interfering species therethrough.

14. The implantable device of claim 12, wherein the membrane further comprises a fourth domain, wherein the fourth domain comprises a fourth silicone-containing polymer, and wherein a silicone composition of the fourth domain is different from the silicone composition of the first domain, and is different from the silicone composition of the second domain, and is different from the silicone composition of the third domain.

15. The implantable device of claim 14, wherein the fourth domain is configured to protect the implantable device from a biological environment.