Patent ID: 8233953

Claim:
An implantable electro-optical sensing device for detecting the presence of an analyte in a medium, said sensing device comprising: a. a radiation source that emits radiation; b. a first and a second photosensitive elements configured to receive radiation and output an electrical signal in response thereto; c. a first and a second indicator elements positioned to receive radiation from the radiation source and to transmit radiation to said first and second photosensitive elements, said first and second indicator elements each containing indicator molecules with an optical characteristic responsive to the presence of an analyte; and wherein said first indicator element is exposed to an exterior of the device and is responsive to a presence of an analyte in a medium external to the device, and wherein said second indicator element is exposed to the exterior of the device and is configured such that an optical response thereof is insensitive to the presence of the analyte in the medium external to the device, and wherein said sensing device is configured to be implantable in an animal.