Polymer membranes for continuous analyte sensors

Abstract

Devices and methods are described for providing continuous measurement of an analyte concentration. In some embodiments, the device has a sensing mechanism and a sensing membrane that includes at least one surface-active group-containing polymer and that is located over the sensing mechanism. The sensing membrane may have a bioprotective layer configured to substantially block the effect and/or influence of non-constant noise-causing species.

What is claimed is: 
     
         1 . A device for continuous measurement of an analyte concentration, the device comprising:
 a sensing mechanism configured to continuously measure a signal associated with an analyte concentration in a host; and   a membrane located over the sensing mechanism, wherein the membrane comprises a polyurethane and a hydrophilic portion;   wherein the device is configured to provide, at analyte concentrations of from about 40 mg/dL to about 400 mg/dL, a level of accuracy corresponding to a mean absolute relative difference of no more than about 8% over a sensor session of at least about 3 days, wherein one or more reference measurements associated with calculation of the mean absolute relative difference are determined by analysis of blood.   
     
     
         2 . The device of  claim 1 , wherein the sensor session is at least about 5 days. 
     
     
         3 . The device of  claim 1 , wherein the sensor session is at least about 6 days. 
     
     
         4 . The device of  claim 1 , wherein the sensor session is at least about 7 days. 
     
     
         5 . The device of  claim 1 , wherein the sensor session is at least about 10 days. 
     
     
         6 . The device of  claim 1 , wherein the mean absolute relative difference is no more than about 7% over the sensor session. 
     
     
         7 . The device of  claim 1 , wherein the membrane comprises an enzyme configured to react with the analyte. 
     
     
         8 . The device of  claim 1 , wherein the membrane comprises a copolymer comprising a fluorocarbon segment. 
     
     
         9 . The device of  claim 1 , wherein the membrane comprises a copolymer comprising a silicone segment. 
     
     
         10 . The device of  claim 1 , wherein the membrane comprises a polycarbonate segment. 
     
     
         11 . A system for continuous measurement of an analyte concentration, the system comprising:
 a sensor comprising:
 a sensing region configured to continuously produce sensor data associated with an analyte concentration in a host; and 
   a membrane located over the sensing region, wherein the membrane comprises a polyurethane and a hydrophilic portion;   a processor configured to process continuous sensor data; and   a user interface configured to display information associated with continuous sensor data;   wherein the sensor is configured to provide, at analyte concentrations of from about 40 mg/dL to about 400 mg/dL, a level of accuracy corresponding to a mean absolute relative difference of no more than about 8% over a sensor session of at least about 3 days, wherein one or more reference measurements associated with calculation of the mean absolute relative difference are determined by analysis of blood.   
     
     
         12 . The system of  claim 11 , wherein the sensor session is at least about 5 days. 
     
     
         13 . The system of  claim 11 , wherein the sensor session is at least about 6 days. 
     
     
         14 . The system of  claim 11 , wherein the sensor session is at least about 7 days. 
     
     
         15 . The system of  claim 11 , wherein the sensor session is at least about 10 days. 
     
     
         16 . The system of  claim 11 , wherein the mean absolute relative difference is no more than about 7% over the sensor session. 
     
     
         17 . The system of  claim 11 , wherein the membrane comprises an enzyme configured to react with the analyte. 
     
     
         18 . The system of  claim 11 , wherein the membrane comprises a copolymer comprising a fluorocarbon segment. 
     
     
         19 . The system of  claim 11 , wherein the membrane comprises a copolymer comprising a silicone segment. 
     
     
         20 . The system of  claim 11 , wherein the membrane comprises a polycarbonate segment.