Implantable continuous glucose monitor device

A continuous glucose monitor (CGM) system comprising:

• a first device comprising a continuous glucose monitor (CGM) device, wherein at least a portion of the first device is configured to be inserted into a subject's body,
• wherein the CGM device comprises:
• electrodes comprising a first electrode and a second electrode that are configured to contact interstitial fluid of the subject when the first device is inserted into the subject's body, wherein the first electrode comprises a nanoporous layer configured to cause oxidation of glucose therein and comprising metal nanoparticles, wherein the nanoporous layer's sensitivity for glucose oxidation changes over time while the first electrode is in contact with the interstitial fluid;
• at least one battery;
• at least one wireless communication circuit configured for wirelessly sending data to an external device;
• and
• circuitry comprising at least one DC voltage circuit, at least one non-DC voltage input circuit, and an electrochemical impedance spectrometry (EIS) circuit,
• wherein the at least one DC voltage circuit is configured to apply a DC voltage input between the first electrode and second electrode,
• wherein the at least one non-DC voltage circuit comprises an AC voltage circuit configured to apply an AC voltage input between the first electrode and second electrode,
• wherein in response to the AC voltage applied between the first electrode and second electrode, the EIS circuit is configured to measure an impedance indicative of an effective surface area of metal nanoparticles of the nanoporous layer;
• a second device configured to be in wireless communication with the first device and to receive the data sent from the at least one wireless communication circuit of the first device,
• wherein the CGM system is configured to determine information indicative of real time sensitivity of the nanoporous layer for glucose oxidation using the impedance and a predetermined correlation between impedance and sensitivity of the nanoporous layer.