Abstract: Methods and devices useful for determining the analyte concentration of a sample using output currents obtained from an input potential in the kinetic potential region of a redox mediator are disclosed. Preferably, the input potential used to generate the output currents from the kinetic potential region of the redox mediator is continually increasing with time after initiating the analysis. A method of selecting an initial input potential within the kinetic potential region of a redox mediator based on the sensitivity of an individual or batch of subcutaneously insertable test sensors also is described. A method of selecting an analysis input potential within the kinetic potential region of redox mediator based on the sensitivity of an individual subcutaneously inserted test sensor also is described where the analysis input potential is increased with insertion time.

Abstract: By combining analyte concentration monitoring electrodes and infusion functions into a single subcutaneous element, the described sensing cannulae having a rectangular cross-section avoids the need for two separate devices for insulin delivery and glucose concentration determination. The substantially flat, thus planar, surface of the sensing cannula provides a substrate for deposition of one or more sensing electrodes, preferably through a lithographic-type process. The inner lumen of the sensing cannula serves as a conduit for drug delivery and is formed in a manner that is compatible with lithographic-type electrode formation. The rectangular cross-section of the sensing cannula also allows face and side ports establishing fluid communication between the inner lumen and tissue that preferably reduces the incidence of occlusion of the inner lumen of the sensing cannula.

Abstract: This disclosure teaches the concept, and method of creating, a dual use device intended for persons who take insulin. In one embodiment, the novel device is an insulin delivery cannula, the outer wall of which contains electrodes, chemical compounds and electrical interconnects that allow continuous glucose sensing and delivery of data to a remote device. Heretofore, the main problem in attempting to sense glucose at the site of insulin delivery has been the high current resulting from oxidation by the sensor of the preservatives in the insulin formulations. One means of eliminating these interferences is to poise the indicating electrode(s) of the sensor at a bias sufficiently low to avoid the signal from oxidation of the preservatives. One way of obtaining a glucose signal at a low bias is to use an osmium-ligand-polymer complex instead of conventional hydrogen peroxide sensing.

Abstract: This disclosure teaches the concept, and method of creating, a dual use device intended for persons who take insulin. In one embodiment, the novel device is an insulin delivery cannula, the outer wall of which contains electrodes, chemical compounds and electrical interconnects that allow continuous glucose sensing and delivery of data to a remote device. Heretofore, the main problem in attempting to sense glucose at the site of insulin delivery has been the high current resulting from oxidation by the sensor of the preservatives in the insulin formulations. One means of eliminating these interferences is to poise the indicating electrode(s) of the sensor at a bias sufficiently low to avoid the signal from oxidation of the preservatives. One way of obtaining a glucose signal at a low bias is to use an osmium-ligand-polymer complex instead of conventional hydrogen peroxide sensing.

Abstract: A durable device is disclosed. This device allows concurrent measurement of an analyte such as glucose, and delivery of a glucose-active drug such as insulin. In order to carry out both functions, only one tubular structure is necessary. In one embodiment of the invention, wires or rings of platinum, gold, or carbon which serve as indicating electrodes are circumferentially disposed around a tubular reference electrode. In an embodiment, the reference electrode is made up of a hollow silver or silver-coated tube. The hollow characteristic is necessary in order to allow concurrent delivery of insulin or other drug through the lumen. In order to optimize sensor accuracy, there are multiple individually-addressable indicating electrodes circumferentially disposed around the shaft.

Abstract: A sensing assembly (10), including a body (12) and one or more first indicating electrodes disposed on the body (26). The first indicating electrodes include an electrochemically active layer (32) and a layer (38) of an active functioning enzyme of a first enzyme type on top of the electrochemically active layer. Also, one or more second indicating electrodes (24) are disposed on the body and include an electrochemically active layer (32) and a layer (36) of an inactivated enzyme of the first enzyme type on top of the electrochemically active layer. A reference electrode (22) is also disposed on the body. Finally, an electrical and data processing system (18) is adapted to bias the electrodes and measure electrical signals from the electrodes, and uses said signals to determine an analyte concentration and communicates the analyte concentration to a location apart from the first and second indicating electrodes.