Composite material for implantable device

• US 20050181012A1
• Filed: 01/11/2005
• Published: 08/18/2005
• Est. Priority Date: 01/12/2004
• Status: Active Grant

• Current Assignee: DexCom Incorporated
• Original Assignee: DexCom Incorporated
• Inventors: Brister, Mark, Saint, Sean
• Granted Patent: US 7,637,868 B2
• Time in Patent Office: Days
• US Class Current: 424/423
• 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 5/14865 invasive, e.g. introduced into the body by a catheter or needle or using implanted sensors
• CPC Class Codes: A61N 1/37512 Pacemakers
• CPC Class Codes: Y10T 29/49002 Electrical device making
• CPC Class Codes: Y10T 29/49018 with other electrical component

Abstract

Devices suitable for implantation in a body of a host and systems and methods for their manufacture are provided. The implantable devices include a composite material formed at least from a matrix material and hollow gas-filled beads. In preferred embodiments, the composite material includes a polymeric matrix mixed with hollow air-filled glass beads, which are mixed and cured to form at least a portion of the body of the implantable device. Implantable devices including this composite material have decreased weight and/or overall density as compared to implantable devices without the beads incorporated therein, which is believed to improve the acceptance and function of the implantable device in vivo. Additionally, implantable devices concerned with transmitting and receiving via RF are believed to achieve improved RF performance due to a reduced dielectric constant provided by the incorporation of beads within the composite material.

Claims

1. A device suitable for implantation in a body of a host, the device comprising a composite material comprising a matrix material and a plurality of hollow gas-filled beads.

2. The device of claim 1, wherein the beads are glass beads.

3. The device of claim 1, wherein the matrix material comprises a polymeric material.

4. The device of claim 3, wherein the polymeric material comprises an epoxy.

5. The device of claim 1, wherein the device comprises a body that is at least partially formed by mixing the matrix material and the hollow gas-filled beads to form a mixture, and curing the mixture.

6. The device of claim 1, wherein a diameter of at least a portion of the beads is from about 0.001 mm to about 3 mm.

7. The device of claim 1, wherein a diameter of at least a portion of the beads is about 1 mm or less.

8. The device of claim 1, further comprising an antenna for radiating or receiving an RF transmission.

9. The device of claim 8, wherein the composite material is proximal to the antenna or adjacent to the antenna.

10. The device of claim 1, wherein a dielectric constant of the composite material is less than a dielectric constant of the matrix material.

11. A method for forming a composite material suitable for implantation in a host, the method comprising:

providing a matrix material having a first dielectric constant;

providing a plurality of hollow gas-filled beads having a second dielectric constant, wherein the second dielectric constant is lower than the first dielectric constant;

mixing the hollow gas-filled beads and the matrix material to obtain a mixture; and

curing the mixture, whereby a composite material with a third dielectric constant is formed, wherein the third dielectric constant is lower than the first dielectric constant and higher than the second dielectric constant.

12. The method of claim 11, wherein the gas-filled beads are air-filled beads.

13. The method of claim 12, wherein the implantable device comprises electronics and an antenna for radiating or receiving a RF transmission, and wherein the step of curing comprises curing the mixture proximal to the antenna.

14. The method of claim 13, wherein the step of curing comprises at least partially encapsulating the electronics and the antenna with the composite material.

15. The method of claim 11, wherein the implantable device comprises a glucose sensor.

16. A device suitable for implantation in a host, the device comprising a body and electronics, wherein the overall density of the device is about 1 g/cm³.

17. The device of claim 16, wherein the body is formed from a composite material comprising a matrix material and a plurality of hollow gas-filled beads.

18. The device of claim 17, wherein the composite material has an overall density of less than about 1 g/cm³.

19. The device of claim 16, wherein the device is configured to measure glucose.

20. The device of claim 20, wherein the device is a wholly implantable glucose sensor configured for implantation in a subcutaneous tissue of a host.