Composite material for implantable device

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.

1 . 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.   
     
     
         2 . The method of  claim 1 , wherein the gas-filled beads are air-filled beads. 
     
     
         3 . The method of  claim 2 , 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. 
     
     
         4 . The method of  claim 3 , wherein the step of curing comprises at least partially encapsulating the electronics and the antenna with the composite material. 
     
     
         5 . The method of  claim 1 , wherein the implantable device comprises a glucose sensor.