Photometric glucose measurement system using glucose-sensitive hydrogel
First Claim
1. A biosensor for measuring the concentration of a free analyte in a body fluid, comprising:
- a polymeric hydrogel filament that changes its displacement in proportion to the concentration of the free analyte;
a photoreceptor arranged in relation to the polymer hydrogel filament so that the intensity of light received by the photoreceptor varies with the displacement of the polymer hydrogel filament; and
means for reporting a data signal reflective of the measured light intensity on the photoreceptor.
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Accused Products
Abstract
An implantable biosensor for detecting an analyte in vivo in body fluids comprises an analyte-sensitive hydrogel filament chemically configured to vary its displacement volume according to changes in concentration of an analyte, such as glucose, in a patient'"'"'s body fluid. A photometric displacement transducer placed inside the biosensor is configured to quantifiably detect changes in the displacement volume of the hydrogel filament, such as by detecting the light intensity on a photoreceptor arranged to receive light of varying intensity depending upon the displacement of the hydrogel filament. A battery powered telemeter operably engaged to the photometric displacement transducer sends a radio data signal representing glucose concentration level to a receiver containing an alarm system. The alarm system can automatically notify a person that the analyte level is outside desired predetermined parameters, and/or to automatically inject an agent to counteract the adverse analyte levels.
50 Citations
40 Claims
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1. A biosensor for measuring the concentration of a free analyte in a body fluid, comprising:
a polymeric hydrogel filament that changes its displacement in proportion to the concentration of the free analyte;
a photoreceptor arranged in relation to the polymer hydrogel filament so that the intensity of light received by the photoreceptor varies with the displacement of the polymer hydrogel filament; and
means for reporting a data signal reflective of the measured light intensity on the photoreceptor.- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 36, 37, 39, 40)
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35. A sensor for measuring the concentration of free molecules of an analyte in a fluid, comprising:
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a rigid enclosure having an open end and a closed end, the open end being covered by a semipermeable membrane adapted to be placed in the fluid;
a hydrogel positioned within the enclosure between the semipermeable membrane and the closed end, said hydrogel changing its displacement in the enclosure depending upon analyte concentration in the fluid; and
a photoreceptor positioned with respect to the enclosure so that changes in displacement of the hydrogel are accompanied by changes in light intensity detected by the photoreceptor.
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38. A method of determining the concentration of free analyte in a fluid, comprising the steps of:
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providing a hydrogel filament having pendant charged or uncharged moieties, analyte molecules, and analyte-specific binding molecules covalently immobilized therein so that the hydrogel filament will swell to varying degrees upon exposure to varying concentrations of analyte;
enclosing the hydrogel in a rigid structure which has at least one permeable portion for contacting the fluid, the permeable portion permitting free analyte in the fluid to diffuse into the hydrogel, the rigid structure allowing displacement of the hydrogel therein in response to the swelling of the hydrogel inresponse to analyte concentration in the fluid;
positioning a photoreceptor with respect to the rigid structure so that light intensity on thephotoreceptor varies with displacement of the hydrogel;
inserting the permeable portion of the biosensor into the fluid and allowing sufficient time forfree analyte molecules to diffuse to equilibrium within the hydrogel;
sensing the light intensity on the photoreceptor and providing a data signal reflective thereof,which is also reflective of the displacement of the hydrogel; and
comparing the sensed hydrogel displacement with a calibration curve to determine analyteconcentration of the test fluid.
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Specification