Electrochemical Analyte Sensor

Abstract

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.

1 . (canceled) 
     
     
         2 . An analyte sensor for measuring an analyte in a host, the sensor comprising:
 a first working electrode disposed beneath an active enzymatic portion of a membrane; and   a second working electrode disposed beneath an inactive-enzymatic portion of a membrane, wherein the inactive enzymatic portion comprises at least one of a deactivated enzyme or an inactive enzyme.   
     
     
         3 . The sensor of  claim 2 , further comprising a reference electrode. 
     
     
         4 . The sensor of  claim 3 , further comprising a counter electrode. 
     
     
         5 . The sensor of  claim 2 , wherein the membrane located over the first working electrode and the membrane located over the second working electrode each comprise an interference domain that restricts a flow of at least one interfering species. 
     
     
         6 . The sensor of  claim 5 , wherein the interference domain comprises a material selected from the group consisting of a polyurethane and a cellulosic polymer. 
     
     
         7 . The sensor of  claim 2 , wherein the membrane located over the first working electrode and the membrane located over the second working electrode each comprise a resistance domain that controls a flux of an analyte therethrough. 
     
     
         8 . The sensor of  claim 7 , wherein the resistance domain comprises a material selected from the group consisting of a polyurethane and a silicone. 
     
     
         9 . The sensor of  claim 2 , wherein the analyte sensor is a glucose sensor, and wherein the first working electrode is configured to generate a first signal associated with glucose related electroactive compounds and non-glucose related electroactive compounds, wherein the glucose related electroactive compounds and the non-glucose related electroactive compounds have a first oxidation potential. 
     
     
         10 . The sensor of  claim 9 , wherein the second working electrode is configured to generate a second signal associated with non-glucose related electroactive compounds, wherein the non-glucose related electroactive compounds have an oxidation potential that substantially overlaps with the first oxidation potential. 
     
     
         11 . An analyte sensor for measuring an analyte in a host, the sensor comprising:
 a first working electrode disposed beneath an active enzymatic portion of a membrane;   a second working electrode disposed beneath an inactive-enzymatic or non-enzymatic portion of a membrane; and   an insulator located between the first working electrode and the second working electrode, wherein the first working electrode and the second working electrode are intertwined.   
     
     
         12 . An analyte sensor for measuring an analyte concentration in a host, the sensor comprising:
 a first working electrode configured to generate a first signal associated with analyte related electroactive compounds and non-analyte related electroactive compounds, wherein the analyte related electroactive compounds and the non-analyte related electroactive compounds have a first oxidation potential; and   a second working electrode configured to generate a second signal associated with non-analyte related electroactive compounds, wherein the non-analyte related electroactive compounds have an oxidation potential that substantially overlaps with the first oxidation potential.   
     
     
         13 . An analyte sensor for measuring an analyte concentration in a host, the sensor comprising:
 a first working electrode configured to generate a first signal associated with analyte related electroactive compounds and non-analyte related electroactive compounds, wherein the analyte related electroactive compounds and the non-analyte related electroactive compounds have a first oxidation potential; and   a second working electrode configured to generate a second signal associated with non-analyte related electroactive compounds.   
     
     
         14 . The sensor of  claim 13 , wherein the non-analyte related electroactive compounds have an oxidation potential that substantially overlaps with the first oxidation potential. 
     
     
         15 . An analyte sensor for measuring an analyte in a host, the sensor comprising:
 a first working electrode comprising a first electroactive surface disposed beneath an active enzymatic portion of a membrane, wherein the first working electrode defines a first longitudinal axis;   a second working electrode comprising a second electroactive surface disposed beneath an inactive-enzymatic portion of a membrane or a non-enzymatic portion of a membrane; and   a flow path diffusion barrier configured to substantially block diffusion of at least one of an analyte and a co-analyte between the first electroactive surface and the second electroactive surface by an offset of the first electroactive surface and the second electroactive surface along a longitudinal axis of the sensor.   
     
     
         16 . The sensor of  claim 15 , wherein the second working electrode defines a second longitudinal axis that is co-linear with the first longitudinal axis, wherein both the first longitudinal axis and the second longitudinal axis define the longitudinal axis of the sensor. 
     
     
         17 . The sensor of  claim 15 , wherein the sensor is configured for contact with a blood flow from a circulatory system of a host. 
     
     
         18 . An analyte sensor for measuring an analyte in a host, the sensor comprising:
 a first working electrode comprising a first electroactive surface disposed beneath an active enzymatic portion of a membrane, wherein the first working electrode defines a first longitudinal axis;   a counter electrode comprising a second electroactive surface disposed beneath an inactive-enzymatic portion of a membrane or a non-enzymatic portion of a membrane, wherein the second working electrode defines a second longitudinal axis that is co-linear with the first longitudinal axis, wherein both the first longitudinal axis and the second longitudinal axis define a longitudinal axis of the sensor; and   a flow path diffusion barrier configured to substantially block diffusion of at least one of an analyte and a co-analyte between the first electroactive surface and the second electroactive surface by an offset of the first electroactive surface and the second electroactive surface along the longitudinal axis of the sensor.   
     
     
         19 . The sensor of  claim 18 , wherein the sensor is configured for contact with a blood flow from a circulatory system of a host.