Patent ID: 8050731

Claim:
An implantable electrochemical sensor for measuring glucose in a bodily fluid, the sensor comprising: at least one electrode having at least a portion configured to be implanted in a host; and a membrane disposed over the at least one electrode, the membrane comprising: a first layer comprising a blend of (i) a hydrophobic polymer that forms a hydrophobic matrix and (ii) a hydrophobic-hydrophilic copolymer comprising hydrophilic polymer segments that traverse a thickness of the first layer, wherein the first layer is further configured to reduce a flux of glucose through the membrane, wherein the hydrophobic polymer and the hydrophobic-hydrophilic copolymer are soluble with each other, and wherein the hydrophilic polymer segments comprise hydrophilic microdomains that are substantially distributed evenly throughout the hydrophobic matrix; and a second layer comprising an enzyme capable of reacting with glucose, wherein the second layer is more proximal to the electrode than the first layer.