Mass transport limited in vivo analyte sensor

A method of determining the concentration of glucose in a body fluid of a mammal, the method comprising:

• providing an electrochemical sensor comprising a planar body, a top layer permeable to oxygen and impervious to glucose, a base layer impervious to glucose, a working electrode between the top layer and the base layer, and an analyte-responsive sensing layer comprising glucose oxidase and redox polyer proximate the working electrode and between the working electrode and the top layer, the sensing layer exposed for contact with analyte only at a peripheral edge of the sensor;
• implanting at least a portion of the sensor into the body of the mammal such that the edge of the sensor contacts body fluid of the mammal;
• and
• measuring the concentration of the glucose in body fluid of the mammal using the sensor.

An electrochemical sensor for subcutaneous glucose sensing, the sensor comprising:

• a planar body having a top layer permeable to oxygen and impervious to glucose, and a base layer impervious to glucose;
• a working electrode disposed between the top layer and the base layer;
• and
• an analyte-responsive sensing layer comprising glucose oxidase and a redox polymer proximate the working electrode between the top layer and the working electrode,
• wherein the sensor defines a channel having therein an inner peripheral surface extending into the sensor, and wherein the sensing layer is exposed for contact with analyte only at a portion of the inner peripheral surface of the channel.

An electrochemical sensor for subcutaneous glucose sensing, the sensor comprising:

• a planar sensor body having an outer portion impervious to glucose and at least a part of which is permeable to oxygen, and a peripheral edge;
• a working electrode disposed within the sensor body;
• and
• an analyte-responsive sensing layer comprising glucose oxidase and redox polymer disposed at least partially between the outer portion and the working electrode and extending to the peripheral edge of the sensor for contact with glucose only at the edge of the sensor.