Techniques to improve polyurethane membranes for implantable glucose sensors
AssigneeDexCom, Inc.
InventorsMark A. Tapsak, Rathbun K. Rhodes, Mark C. Shults, Jason D. McClure
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Abstract
The invention provides an implantable membrane for regulating the transport of analytes therethrough that includes a matrix including a first polymer; and a second polymer dispersed throughout the matrix, wherein the second polymer forms a network of microdomains which when hydrated are not observable using photomicroscopy at 400× magnification or less. In one aspect, the homogeneous membrane of the present invention has hydrophilic domains dispersed substantially throughout a hydrophobic matrix to provide an optimum balance between oxygen and glucose transport to an electrochemical glucose sensor.
Claims19
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.
Dependencies are inferred from the claim text.