POLYMER MEMBRANES FOR CONTINUOUS ANALYTE SENSORS
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.
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.