Optimized sensor geometry for an implantable glucose sensor

• US 20060211921A1
• Filed: 05/02/2006
• Published: 09/21/2006
• Est. Priority Date: 04/04/2003
• Status: Active Grant

• Current Assignee: DexCom Incorporated
• Original Assignee: DexCom Incorporated
• Inventors: Brauker, James H., Carr-Brendel, Victoria, Martinson, Laura A., Neale, Paul V.
• Granted Patent: US 7,881,763 B2
• Time in Patent Office: Days
• US Class Current: 600/309
• CPC Class Codes: A61B 2562/187 Strain relief means
• 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 5/14546 for measuring analytes not otherwise provided for, e.g. ions, cytochromes
• CPC Class Codes: A61B 5/1486 using enzyme electrodes, e.g. with immobilised oxidase
• CPC Class Codes: A61B 5/415 the glands, e.g. tonsils, adenoids or thymus
• CPC Class Codes: A61B 5/418 lymph vessels, ducts or nodes
• CPC Class Codes: A61B 5/6882 Anchoring means

Abstract

An implantable sensor for use in measuring a concentration of an analyte such as glucose in a bodily fluid, including a body with a sensing region adapted for transport of analytes between the sensor and the bodily fluid, wherein the sensing region is located on a curved portion of the body such that when a foreign body capsule forms around the sensor, a contractile force is exerted by the foreign body capsule toward the sensing region. The body is partially or entirely curved, partially or entirely covered with an anchoring material for supporting tissue ingrowth, and designed for subcutaneous tissue implantation. The geometric design, including curvature, shape, and other factors minimize chronic inflammatory response at the sensing region and contribute to improved performance of the sensor in vivo.

Claims

1. An implantable sensor for use in measuring a concentration of an analyte in a bodily fluid, the sensor comprising:

a body comprising a sensing region adapted for transport of analytes between the sensor and the bodily fluid, wherein the sensing region is located on a curved portion of the body such that when a foreign body capsule forms around the sensor, a contractile force is exerted by the foreign body capsule toward the sensing region, wherein the body comprises a first surface and a second surface, wherein the sensor region is situated approximately at a center point of said first surface, and wherein the sensor is a subcutaneous sensor suitable for implantation in a soft tissue of a body.

2. The sensor of claim 1, wherein the sensor comprises a plurality of sensor regions.

3. The sensor of claim 1, wherein said second surface is flat.

4. The sensor of claim 1, wherein said second surface comprises a curvature.

5. The sensor of claim 1, wherein said first surface, when viewed from a direction perpendicular to a center of said first surface, has a substantially oval profile.

6. The sensor of claim 1, wherein said first surface, when viewed from a direction perpendicular to a center of said first surface, has a substantially circular profile.

7. The sensor of claim 1, wherein the body is substantially cylindrical defined by a curved lateral surface and two ends.

8. The sensor of claim 1, wherein the body is substantially cylindrical defined by a curved lateral surface and two ends, and wherein at least one of said ends comprises the substantially curved portion on which the sensor region is located.

9. The sensor of claim 1, wherein the second surface comprises anchoring material thereon for supporting tissue ingrowth.

10. The sensor of claim 1, further comprising a mechanical anchoring mechanism formed on the body.

11. The sensor of claim 1, wherein said curved portion comprises a plurality of radii of curvature.

12. The sensor of claim 1, wherein said curved portion comprises a radius of curvature between about 0.5 mm and about 10 cm.

13. The sensor of claim 1, wherein the body comprises a first surface on which said sensing region is located and a second surface, and wherein the first and second surfaces together account for at least about 40% of the surface area of the device.

14. The sensor of claim 1, and wherein edges of the first surface are rounded and transition smoothly away from the first surface.

15. The sensor of claim 1, wherein the body defines a surface area, and wherein between 10% and 100% of the surface area is convexly curved.

16. The sensor of claim 1, wherein the body comprises plastic.

17. The sensor of claim 16, wherein the plastic is selected from the group consisting of thermoplastic and thermoset.

18. The sensor of claim 17, wherein the thermoset is selected from the group consisting of epoxy, silicone, and polyurethane.

19. The sensor of claim 1, wherein the body comprises a material selected from the group consisting of metal, ceramic, and glass.

20. The sensor of claim 1, further comprising a porous biointerface material that covers at least a portion of the sensing region.

21. The sensor of claim 20, wherein the biointerface material comprises interconnected cavities dimensioned and arranged to interfere with formation of occlusive cells.

22. The sensor of claim 1, wherein the sensor is a glucose sensor.

23. A wholly implantable sensor adapted to measure a concentration of an analyte in a bodily fluid, comprising:

a wholly implantable body comprising a sensing region adapted for transport of analytes between the sensor and the bodily fluid, wherein the sensing region is located on a curved portion of a first surface of said body, wherein the body further comprises a second surface, wherein the sensing region is situated approximately at a center point of said first surface, wherein the sensor is a subcutaneous sensor suitable for implantation in a soft tissue of a body, and wherein said first surface comprises a porous material thereon for supporting tissue ingrowth.

24. An implantable sensor adapted to measure a concentration of an analyte in a bodily fluid, comprising:

a body having a first surface and, opposite thereto, a second surface, wherein the first surface is generally planar, slightly convex, and has rounded edges, with a sensor region located on the first surface that is spaced away-from the rounded edges and approximately at a center point of said first surface, wherein the first surface is sufficiently convex that when a foreign body capsule forms around the sensor, contractile forces are exerted thereby generally uniformly towards the sensing region, and wherein the sensor is a subcutaneous sensor suitable for implantation in a soft tissue of a body.