Devices and methods for measuring a concentration of a target analyte in a biological fluid in vivo

A device for continuously measuring a concentration of at least one target analyte in a biological fluid in vivo, the device comprising:

• a transcutaneous analyte sensor configured to be inserted into interstitial fluid, the transcutaneous analyte sensor comprising:
• a substrate;
• a working electrode disposed directly on the substrate;
• a solid contact layer disposed on the working electrode, the solid contact layer comprising a conductive polymer;
• an ion-selective membrane comprising an ionophore, the ion-selective membrane disposed directly on the solid contact layer opposite the working electrode and configured to selectively transport the at least one target analyte to or within the working electrode;
• a first membrane disposed directly on the ion-selective membrane, the first membrane configured to limit leaching from at least the ion-selective membrane;
• a reference electrode disposed directly on the substrate;
• and
• a second membrane disposed directly on the reference electrode, the second membrane configured to limit leaching from at least the reference electrode;
• and
• sensor electronics coupled to the transcutaneous analyte sensor, the sensor electronics-comprising at least one processor and memory, wherein the at least one processor executes operations comprising:
• determining an electromotive force at least partially based on a potential difference that is generated between the working electrode and the reference electrode responsive to the ionophore transporting the at least one target analyte to the working electrode and responsive to the biological fluid conducting an electrophysiological signal to the working electrode, wherein a first contribution to the electromotive force from the electrophysiological signal varies rapidly relative to a second contribution to the electromotive force from the concentration of the at least one target analyte in the biological fluid, and wherein determining the electromotive force further comprises identifying the first contribution and the second contribution;
• generating a signal corresponding to the electromotive force;
• and
• determining the concentration of the at least one target analyte based at least on the signal.