Analyte Monitoring Device and Methods of Use

Abstract

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.

1 . (canceled) 
     
     
         2 . A glucose sensor system configured for insertion into a host for measuring a glucose concentration in the host, the sensor comprising:
 a first working electrode configured to generate a first signal associated with glucose and non-glucose related electroactive compounds, the glucose and non-glucose related electroactive compounds having a first oxidation potential;   a second working electrode configured to generate a second signal associated with noise of the glucose sensor comprising signal contribution due to non-glucose related electroactive compounds with an oxidation potential that substantially overlaps with the first oxidation potential; and   electronics operably connected to the first working electrode and the second working electrode and configured to process the first signal and the second signal to generate a glucose concentration substantially without signal contribution due to non-glucose related noise.   
     
     
         3 . The system of  claim 1 , wherein the non-glucose related noise is substantially non-constant. 
     
     
         4 . The system of  claim 1 , wherein the electronics are configured to substantially remove noise caused by at least one of biochemical factors and chemical factors. 
     
     
         5 . The system of  claim 4 , wherein at least one of the biochemical factors and the chemical factors are substantially non-constant and are selected from the group consisting of compounds with electroactive acidic groups, compounds with electroactive amine groups, compounds with electroactive sulfhydryl groups, urea, lactic acid, phosphates, citrates, peroxides, amino acids, amino acid precursors, amino acid break-down products, nitric oxide, nitric oxide-donors, nitric oxide-precursors, electroactive species produced during cell metabolism, electroactive species produced during wound healing, and electroactive species that arise during body pH changes. 
     
     
         6 . The system of  claim 4 , wherein the first working electrode and the second working electrode are configured to substantially equally measure noise due to at least one of the biochemical factors and the chemical factors whereby noise caused by at least one of the biochemical factors and the chemical factors can be substantially removed. 
     
     
         7 . The system of  claim 1 , wherein the electronics are configured to subtract the second signal from the first signal, whereby a differential signal comprising at least one glucose sensor data point is determined. 
     
     
         8 . The system of  claim 7 , wherein the electronics are configured to electronically subtract the second signal from the first signal. 
     
     
         9 . The system of  claim 7 , wherein the electronics comprise at least one of hardware and software configured to digitally subtract the second signal from the first signal. 
     
     
         10 . The system of  claim 1 , wherein the first working electrode and the second working electrode are configured to be impacted by biochemical factors to substantially the same extent. 
     
     
         11 . The system of  claim 10 , wherein the first working electrode and the second working electrode have a symmetrical configuration. 
     
     
         12 . The sensor of  claim 1 , further comprising a non-conductive material positioned between the first working electrode and the second working electrode. 
     
     
         13 . The sensor of  claim 1 , wherein each of the first working electrode, the second working electrode, and the non-conductive material are configured provide at least two functions selected from the group consisting of electrical conductance, insulative property, structural support, and diffusion barrier. 
     
     
         14 . The sensor of  claim 1 , wherein the sensor comprises a diffusion barrier configured to substantially block diffusion of at least one of the analyte and the co-analyte between the first working electrode and the second working electrode. 
     
     
         15 . The sensor of  claim 1 , wherein the first working electrode, the second working electrode, and an insulator integrally form a substantial portion of the sensor configured for insertion in the host. 
     
     
         16 . The sensor of  claim 15 , further comprising a reference electrode, wherein the first working electrode, the second working electrode, and the reference electrode integrally form a substantial portion of the sensor configured for insertion in the host. 
     
     
         17 . An analyte sensor configured for insertion into a host for measuring an analyte in the 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, wherein the first working electrode and the second working electrode are configured to substantially equally measure non-analyte related noise, whereby the noise is substantially removed; and   electronics operably connected to the first working electrode and the second working electrode, and configured to process the first signal and the second signal to generate sensor analyte data substantially without signal contribution due to non-analyte related noise.   
     
     
         18 . The system of  claim 17 , wherein the non-glucose related noise is substantially non-constant. 
     
     
         19 . The system of  claim 17 , wherein the non-analyte related noise is due to a factor selected from the group consisting of biochemical factors, chemical factors, and combinations thereof. 
     
     
         20 . The system of  claim 19 , wherein the electronics are configured to substantially remove noise caused by at least one of biochemical factors and chemical factors. 
     
     
         21 . The system of  claim 20 , wherein at least one of the biochemical factors and the chemical factors are substantially non-constant and are selected from the group consisting of compounds with electroactive acidic groups, compounds with electroactive amine groups, compounds with electroactive sulfhydryl groups, urea, lactic acid, phosphates, citrates, peroxides, amino acids, amino acid precursors, amino acid break-down products, nitric oxide, nitric oxide-donors, nitric oxide-precursors, electroactive species produced during cell metabolism, electroactive species produced during wound healing, and electroactive species that arise during body pH changes. 
     
     
         22 . The system of  claim 19 , wherein the first working electrode and the second working electrode are configured to substantially equally measure noise due to at least one of biochemical factors and chemical factors, whereby noise caused by at least one of the biochemical factors and the chemical factors is substantially removed. 
     
     
         23 . The sensor of  claim 17 , further comprising at least one of a reference electrode and a counter electrode. 
     
     
         24 . The sensor of  claim 23 , wherein at least one of the reference electrode and the counter electrode, together with the first working electrode and the second working electrode, integrally form at least a portion of the sensor. 
     
     
         25 . The sensor of  claim 23 , wherein at least one of the reference electrode and the counter electrode is located at a position remote from the first working electrode and the second working electrode. 
     
     
         26 . The sensor of  claim 23 , wherein a surface area of at least one of the reference electrode and the counter electrode has a surface area that is substantially equal to at least one of the first working electrode and the second working electrode. 
     
     
         27 . The sensor of  claim 26 , wherein a surface area of at least one of the reference electrode and the counter electrode is at least six times a surface area of at least one of the first working electrode and the second working electrode. 
     
     
         28 . The sensor of  claim 17 , wherein the sensor is configured for implantation into the host. 
     
     
         29 . The sensor of  claim 28 , wherein the sensor is configured for subcutaneous implantation in a tissue of the host. 
     
     
         30 . The sensor of  claim 28 , wherein the sensor is configured for indwelling in a blood stream of the host. 
     
     
         31 . The sensor of  claim 17 , wherein the sensor substantially continuously measures an analyte concentration of the host. 
     
     
         32 . The sensor of  claim 17 , wherein the analyte sensor comprises a glucose sensor, and wherein the first working electrode is configured to generate a first signal associated with glucose and non-glucose related electroactive compounds, the glucose and the non-glucose related electroactive compounds having a first oxidation potential. 
     
     
         33 . The sensor of  claim 32 , wherein the second working electrode is configured to generate a second signal associated with noise of the glucose sensor comprising signal contribution due to non-glucose related electroactive compounds with an oxidation potential that substantially overlaps with the first oxidation potential. 
     
     
         34 . The sensor of  claim 33 , wherein the non-glucose related electroactive species comprises at least one species selected from the group consisting of interfering species, and other electroactive species. 
     
     
         35 . The sensor of  claim 17 , further comprising a non-conductive material positioned between the first working electrode and the second working electrode. 
     
     
         36 . The sensor of  claim 17 , wherein each of the first working electrode, the second working electrode, and the non-conductive material are configured provide at least two functions selected from the group consisting of: electrical conductance, insulative property, structural support, and diffusion barrier. 
     
     
         37 . The sensor of  claim 17 , wherein the sensor comprises a diffusion barrier configured to substantially block diffusion of at least one of an analyte and a co-analyte between the first working electrode and the second working electrode. 
     
     
         38 . The sensor of  claim 17 , wherein the first working electrode, the second working electrode, and an insulator integrally form a substantial portion of the sensor configured for insertion in the host. 
     
     
         39 . The sensor of  claim 38 , further comprising a reference electrode, wherein the first working electrode, the second working electrode, and the reference electrode integrally form a substantial portion of the sensor configured for insertion in the host. 
     
     
         40 . The system of  claim 17 , wherein the first working electrode and the second working electrode are configured to be impacted by biochemical factors to substantially the same extent. 
     
     
         41 . The system of  claim 40 , wherein the first working electrode and the second working electrode have a symmetrical configuration. 
     
     
         42 . An analyte sensor system configured for insertion into a host for measuring an analyte in the host, the system comprising:
 a continuous analyte sensor comprising a first working electrode and a second working electrode, wherein the first working electrode is disposed beneath an active enzymatic portion of a membrane; wherein the second working electrode is disposed beneath an inactive-enzymatic or non-enzymatic portion of a membrane, and wherein the first working electrode and the second working electrode are configured to measure interfering biochemical species such that signal contribution associated with the interfering biochemical species can be substantially removed continuously for a time period, wherein the time period is between about a few hours and about 10 days; and   electronics operably connected to the first working electrode and the second working electrode, and configured to process the first signal and the second signal to generate continuous sensor analyte data substantially without signal contribution due the biochemical species for said time period.   
     
     
         43 . The system of  claim 42 , wherein the signal contribution associated with the interfering biochemical species is substantially non-constant. 
     
     
         44 . The system of  claim 42 , wherein at least one of the interfering biochemical species is substantially non-constant and is selected from the group consisting of compounds with electroactive acidic groups, compounds with electroactive amine groups, compounds with electroactive sulfhydryl groups, urea, lactic acid, phosphates, citrates, peroxides, amino acids, amino acid precursors, amino acid break-down products, nitric oxide, nitric oxide-donors, nitric oxide-precursors, electroactive species produced during cell metabolism, electroactive species produced during wound healing, and electroactive species that arise during body pH changes. 
     
     
         45 . The system of  claim 42 , further comprising at least one of a reference electrode and a counter electrode. 
     
     
         46 . The system of  claim 45 , wherein at least one of the reference electrode and the counter electrode, together with the first working electrode and the second working electrode, integrally form at least a portion of the sensor. 
     
     
         47 . The system of  claim 45 , wherein at least one of the reference electrode and the counter electrode is located at a position remote from the first working electrode and the second working electrode. 
     
     
         48 . The system of  claim 45 , wherein a surface area of at least one of the reference electrode and the counter electrode is at least six times a surface area of at least one of the first working electrode and the second working electrode. 
     
     
         49 . The system of  claim 42 , wherein the sensor is configured for implantation into the host. 
     
     
         50 . The system of  claim 49 , wherein the sensor is configured for subcutaneous implantation in a tissue of the host. 
     
     
         51 . The system of  claim 49 , wherein the sensor is configured for indwelling in a blood stream of the host. 
     
     
         52 . The system of  claim 42 , wherein the analyte sensor comprises a glucose sensor, and wherein the first working electrode is configured to generate a first signal associated with glucose and non-glucose related electroactive compounds, the glucose and the non-glucose related electroactive compounds having a first oxidation potential. 
     
     
         53 . The system of  claim 52 , herein the second working electrode is configured to generate a second signal associated with non-glucose related electroactive compounds with an oxidation potential that substantially overlaps with the first oxidation potential. 
     
     
         54 . The system of  claim 53 , wherein the non-glucose related electroactive species comprises at least one species selected from the group consisting of interfering species, non-reaction-related hydrogen peroxide, and other electroactive species. 
     
     
         55 . The system of  claim 42 , further comprising an insulator positioned between the first working electrode and the second working electrode. 
     
     
         56 . The system of  claim 54 , wherein each of the first working electrode, the second working electrode, and the insulator are configured provide at least two functions selected from the group consisting of: electrical conductance, insulative property, structural support, and diffusion barrier. 
     
     
         57 . The system of  claim 42 , wherein the sensor comprises a diffusion barrier configured to substantially block diffusion of at least one of an analyte and a co-analyte between the first working electrode and the second working electrode. 
     
     
         58 . The system of  claim 42 , wherein the sensor further comprises an insulator located between the first and second working electrodes, and wherein the first working electrode, the second working electrode, and the insulator integrally form a substantial portion of the sensor configured for insertion in the host. 
     
     
         59 . The system of  claim 57 , further comprising a reference electrode, wherein the first working electrode, the second working electrode, and the reference electrode integrally form a substantial portion of the sensor configured for insertion in the host. 
     
     
         60 . The system of  claim 59 , wherein the first working electrode and the second working electrode have a symmetrical configuration. 
     
     
         61 . The system of  claim 42 , wherein the first working electrode and second working electrode are substantially identical. 
     
     
         62 . The system of  claim 42 , wherein the first working electrode and the second working electrode are configured and arranged with a symmetry about the central, longitudinal axis of the sensor, 
     
     
         63 . The system of  claim 42 , wherein each of the first working electrode and the second working electrode comprises a wire with a diameter from about 0.001 inches to about 0.010 inches. 
     
     
         64 . The system of  claim 42 , wherein a surface area of the first working electrode is equal to a surface area of the second working electrode. 
     
     
         65 . The system of  claim 42 , wherein the membrane comprises an interference domain located over the first and second working electrodes. 
     
     
         66 . The system of  claim 42 , wherein the system is configured and arranged to remove noise caused by at least one of biochemical factors and chemical factors. 
     
     
         67 . The system of  claim 66 , wherein the first working electrode and the second working electrode are configured to substantially equally measure noise due to at least one of the biochemical factors and the chemical factors. 
     
     
         68 . The system of  claim 42 , wherein the electronics are configured to subtract the second signal from the first signal, whereby a differential signal comprising at least one glucose sensor data point is determined. 
     
     
         69 . The system of  claim 68 , wherein the electronics comprise a differential amplifier configured to electronically subtract the second signal from the first signal. 
     
     
         70 . The system of  claim 68 , wherein the electronics comprise at least one of hardware and software configured to digitally subtract the second signal from the first signal. 
     
     
         71 . The system of  claim 42 , wherein the first working electrode and the second working electrode are configured to be impacted by mechanical factors and biochemical species to substantially the same extent.