Analyte sensors and sensing methods featuring dual detection of glucose and ketones

An analyte sensor for detecting glucose and ketones in vivo, the sensor comprising:

• a first working electrode, a second working electrode, a counter electrode, and a reference electrode;
• a ketones-responsive active area disposed directly upon a surface of the first working electrode, the ketones-responsive active area comprising a first polymer and an enzyme system comprising nicotinamide adenine dinucleotide (NAD) and at least two enzymes that facilitate detection of ketones;
• a glucose-responsive active area disposed upon a surface of the second working electrode, the glucose-responsive active area comprising a second polymer and a glucose-responsive enzyme;
• a first membrane suitable for permitting sufficient inward diffusion of ketones and limiting outward diffusion of NAD, the first membrane disposed directly upon the ketones-responsive active area;
• and
• a second membrane suitable for permitting sufficient inward diffusion of glucose and ketones, the second membrane disposed upon the first membrane and upon the glucose-responsive active area,
• wherein the ketones-responsive active area is disposed closer to a distal end of the sensor than the glucose-responsive active area such that the first membrane is selectively disposed over the ketones-responsive active area relative to the glucose-responsive active area, and
• wherein the sensor is configured to be partially inserted into a user's skin such that a distal portion of the sensor is in contact with an interstitial fluid to detect glucose and ketones in vivo.