A tissue-implantable sensor for measurement of solutes in fluids and gases, such as oxygen and glucose, is provided. The sensor includes: i) a detector array including at least one detector； ii) a telemetry transmission portal； iii) an electrical power source； and iv) circuitry electrically connected to the detector array including signal processing means for determining an analyte level, such as glucose level, in a body fluid contacting the detectors. The sensor components are disposed in a hermetically sealed housing having a size and shape suitable for comfortable, safe, and unobtrusive subcutaneous implantation allowing for in vivo detection and long term monitoring of tissue glucose concentrations by wireless telemetry.
