Wake-up batteries for invasive biosensors

A method comprising:

• providing first and second electrodes, the first electrode having a distal end for insertion into a subcutaneous layer beneath a patient's skin, the second electrode coupled to the first electrode, a portion of the second electrode for insertion into the subcutaneous layer;
• applying an anode material to a portion of the distal end of the first electrode;
• coupling a wake-up circuit to the first and second electrodes to receive an electrical signal from a first battery in response to immersion of the first battery in an electrolytic fluid, the anode material and the portion of the second electrode forming a portion of a first battery, wherein the anode material is configured to deplete over time while the first battery is active;
• and
• coupling a second battery to the wake-up circuit, the wake-up circuit to electrically couple the second battery to the first and second electrodes in response to the signal from the first battery.

A method comprising:

• inserting a distal end of a first electrode and a portion of a second electrode into a patient's skin and into the patient's interstitial fluid, the first and second electrodes forming a portion of a biosensor of a device, the first electrode coupled to the second electrode, wherein an anode material is coupled to a portion of a distal end of the first electrode, the anode material and the second electrode forming a portion of a first battery;
• the device further comprising a second battery comprising two terminals to apply a voltage across the first and second electrodes, at least one of the two terminals electrically decoupled from the first and second electrodes,
• generating an electrical signal by the first battery in response to the anode material and the portion of the second electrode being immersed in the patient's interstitial fluid, wherein the anode material depletes over time while the first battery is active;
• and
• electrically coupling the second battery to the first and second electrodes by a wake-up circuit of a device in response to receiving the electrical signal from the first battery, the device comprising the biosensor.