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 in vivo measurement of a glucose concentration, the device comprising:
an implantable sensor configured to continuously measure a signal indicative of a glucose concentration in a host;
an enzyme-containing membrane located over the sensor, wherein the enzyme-containing membrane comprises both hydrophilic and hydrophobic regions, and wherein the enzyme-containing membrane comprises:
an enzyme configured to catalyze a reaction that has glucose as a reactant; and
a polyurethane comprising a plurality of repeating hard segments and repeating soft segments, wherein a soft segment of the plurality of repeating soft segments has a molecular weight from about 200 Daltons to about 50,000 Daltons, wherein a hard segment of the plurality of repeating hard segments has a molecular weight from about 160 Daltons to about 10,000 Daltons; and
sensor electronics operably connected to the sensor, wherein the sensor electronics are configured to measure a current flow produced by the sensor to generate sensor data indicative of glucose concentration.
2. The device of claim 1 , wherein the polyurethane is a polyurethaneurea.
3. The device of claim 1 , wherein the polyurethane comprises silicone.
4. The device of claim 3 , wherein the polyurethane comprises from about 5 to about 50% silicone by weight.
5. The device of claim 1 , wherein the hydrophilic region is formed of a material selected from the group consisting of polyvinyl acetate, poly(ethylene glycol), polyacrylamide, polyethylene oxide, poly ethyl acrylate, and polyvinylpyrrolidone.
6. The device of claim 1 , wherein the membrane comprises a domain configured to reduce permeation therethrough of an interfering species.
7. The device of claim 1 , wherein the domain is located between the sensor and the first domain.
8. The device of claim 1 , wherein the domain comprises a polymer comprising ionic components.
9. The device of claim 1 , wherein the domain is configured to limit diffusion of interfering species with a molecular weight greater than a molecular weight of hydrogen peroxide.