An analyte monitor includes a sensor, a sensor control unit, and a display unit. The sensor has, for example, a substrate, a recessed channel formed in the substrate, and conductive material disposed in the recessed channel to form a working electrode. The sensor control unit typically has a housing adapted for placement on skin and is adapted to receive a portion of an electrochemical sensor. The sensor control unit also includes two or more conductive contacts disposed on the housing and configured for coupling to two or more contact pads on the sensor. A transmitter is disposed in the housing and coupled to the plurality of conductive contacts for transmitting data obtained using the sensor. The display unit has a receiver for receiving data transmitted by the transmitter of the sensor control unit and a display coupled to the receiver for displaying an indication of a level of an analyte. The analyte monitor may also be part of a drug delivery system to alter the level of the analyte based on the data obtained using the sensor.

Analyte Monitoring Device And Methods Of Use

A small diameter flexible electrode designed for subcutaneous in vivo amperometric monitoring of glucose is described. The electrode is designed to allow “one-point” in vivo calibration, i.e., to have zero output current at zero glucose concentration, even in the presence of other electroreactive species of serum or blood. The electrode is preferably three or four-layered, with the layers serially deposited within a recess upon the tip of a polyamide insulated gold wire. A first glucose concentration-to-current transducing layer is overcoated with an electrically insulating and glucose flux limiting layer (second layer) on which, optionally, an immobilized interference-eliminating horseradish peroxidase based film is deposited (third layer). An outer (fourth) layer is biocompatible.

Subcutaneous glucose electrode

A sensor designed to determine the amount and concentration of analyte in a sample having a volume of less than about 1 μL. The sensor has a working electrode coated with a non-leachable redox mediator. The redox mediator acts as an electron transfer agent between the analyte and the electrode. In addition, a second electron transfer agent, such as an enzyme, can be added to facilitate the electrooxidation or electroreduction of the analyte. The redox mediator is typically a redox compound bound to a polymer. The preferred redox mediators are air-oxidizable. The amount of analyte can be determined by coulometry. One particular coulometric technique includes the measurement of the current between the working electrode and a counter or reference electrode at two or more times. The charge passed by this current to or from the analyte is correlated with the amount of analyte in the sample. Other electrochemical detection methods, such as amperometric, voltammetric, and potentiometric techniques, can also be used. The invention can be used to determine the concentration of a biomolecule, such as glucose or lactate, in a biological fluid, such as blood or serum. An enzyme capable of catalyzing the electrooxidation or electroreduction of the biomolecule is provided as a second electron transfer agent.

Small volume in vitro analyte sensor

An electrochemical analyte sensor formed using conductive traces on a substrate can be used for determining and/or monitoring a level of analyte in in vitro or in vivo analyte-containing fluids. For example, an implantable sensor may be used for the continuous or automatic monitoring of a level of an analyte, such as glucose, lactate, or oxygen, in a patient. The electrochemical analyte sensor includes a substrate and conductive material disposed on the substrate, the conductive material forming a working electrode. In some sensors, the conductive material is disposed in recessed channels formed in a surface of the sensor. An electron transfer agent and/or catalyst may be provided to facilitate the electrolysis of the analyte or of a second compound whose level depends on the level of the analyte. A potential is formed between the working electrode and a reference electrode or counter/reference electrode and the resulting current is a function of the concentration of the analyte in the body fluid.

Electrochemical analyte sensor

Method of using a small volume in vitro analyte sensor

A new group of Os(II) and Os(III) compounds useful as redox mediators in electrochemical biosensors is presented. These compounds have 1) low oxidation potential, 2) fast reaction kinetics between the electroactive center of an enzyme and the compound, 3) slow oxidation of osmium by oxygen, and 4) excellent solubility in aqueous medium. The figure shows is a cyclic voltammagram of the compound [Os(III)(bpy)2imCl]Cl2, wherein im is imidazolyl. These mediator compounds are particularly useful as a component of a reagent for measuring analytes from a biological fluid, such as blood.

Osmium-containing redox mediator

A new group of Os(II) and Os(III) compounds useful as redox mediators in electrochemical biosensors. These compounds have 1) low oxidation potential, 2) fast reaction kinetics between the electroactive center of an enzyme and the compound, 3) slow oxidation of osmium by oxygen, and 4) excellent solubility in aqueous medium. These mediators are particularly useful as a component of a reagent used in an electrochemical biosensor, wherein the biosensor is useful for measuring analytes from a biological fluid, such as blood.

Reagent including an osmium-containing redox mediator

An immunoassay diagnostic kit, method, and apparatus for electrochemically determining the concentration of an analyte in a sample. A mixture is formed which includes the sample, an enzyme-acceptor polypeptide, an enzyme-donor polypeptide linked to an analyte analog (enzyme-donor polypeptide conjugate), a labeled substrate, and an antibody specific for the analyte to be measured. The analyte and the enzyme-donor polypeptide conjugate competitively bind to the antibody. When the enzyme-donor polypeptide conjugate is not bound to antibody, it will spontaneously combine with the enzyme acceptor polypeptide to form an active enzyme complex. The active enzyme hydrolyzes the labeled substrate, resulting in the generation of an electroactive label, which can then be oxidized at the surface of an electrode. A current resulting from the oxidation of the electroactive compound can be measured and correlated to the concentration of the analyte in the sample.

An electrochemical enzymatic complementation immunoassay

A diagnostic kit, method, and apparatus for electrochemically determining the presence or concentration of an analyte in a sample. A mixture is formed which includes the sample, an enzyme acceptor polypeptide, an enzyme donor polypeptide, and a labeled substrate. The enzyme donor polypeptide is capable of combining with the enzyme acceptor polypeptide to form an active enzyme complex. The formation of such the active enzyme complex is responsive to the presence or concentration of the analyte in the fluid sample. The active enzyme hydrolyzes the labeled substrate, resulting in the generation of an electroactive label, which can then be oxidized at the surface of an electrode. A current resulting from the oxidation of the electroactive compound can be measured and correlated to the concentration of the analyte in the sample.

Electrochemical enzyme assay

L'invention presente un nouveau groupe de composes a base d'osmium (II) et osmium (III) efficaces en tant que mediateurs redox dans des biocapteurs electrochimiques. Ces composes presentent 1) un faible potentiel d'oxydation, 2) une cinetique de reaction rapide entre le centre electro-actif d'une enzyme et le compose, 3) une oxydation lente de l'osmium par l'oxygene et 4) une remarquable solubilite en milieu aqueux. La figure represente un voltamperogramme cyclique du compose [Os(III)(bpy)2imCl]C12, ou im est imidazolyl. Ces composes mediateurs s'averent des plus utiles comme constituant d'un reactif permettant de mesurer des analytes provenant d'un fluide biologique, tel que le sang.

Robert J. Mcenroe

Papers

Osmium-containing redox mediator

Reagent including an osmium-containing redox mediator

An electrochemical enzymatic complementation immunoassay

Electrochemical enzyme assay

Mediateur redox contenant de l'osmium