Implantable glucose sensor
DC CAFCFirst Claim
1. An implantable sensor for sensing a concentration of an organic substrate, the sensor comprising:
- a conductive electrode; and
a stabilized enzyme emulsion in contact with the electrode, the enzyme emulsion comprising;
an oxidase enzyme that quantitatively oxidizes the organic substrate;
a water immiscible oxygen dissolving substance emulsified into intimate contact with the enzyme to provide oxygen; and
a protein crosslinking agent to crosslink and insolubilize the enzyme forming a stabilized gel comprising crosslinked protein and particles of said oxygen dissolving substance.
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Abstract
The sensitivity of enzyme-based polarographic electrodes to oxygen concentration can be significantly reduced or eliminated by providing an oxygen-reservoir in intimate contact with the oxidative enzyme. This is achieved by making a stabilized emulsion between the enzyme and a compound in which oxygen is extremely soluble. An aqueous glucose oxidase solution is emulsified with a perfluorocarbon liquid, and the resulting emulsion is stabilized by chemically crosslinking the mixture to form a gel. Thin layers of the emulsion are fabricated by spreading a layer of the liquid emulsion before gelation occurs. Additional carrier proteins such as albumin may be added to the enzyne prior to crosslinking to protect enzymatic activity and enhance gel strength. Additional electron transport compounds may be added to further reduce sensitivity to oxygen concentration.
687 Citations
18 Claims
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1. An implantable sensor for sensing a concentration of an organic substrate, the sensor comprising:
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a conductive electrode; and
a stabilized enzyme emulsion in contact with the electrode, the enzyme emulsion comprising;
an oxidase enzyme that quantitatively oxidizes the organic substrate;
a water immiscible oxygen dissolving substance emulsified into intimate contact with the enzyme to provide oxygen; and
a protein crosslinking agent to crosslink and insolubilize the enzyme forming a stabilized gel comprising crosslinked protein and particles of said oxygen dissolving substance. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. An implantable glucose sensor for sensing a concentration of glucose, the sensor comprising:
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a metal electrode; and
a stabilized enzyme emulsion in contact with the electrode, the enzyme emulsion comprising;
a solution of glucose oxidase protein for oxidizing glucose to quantitatively produce hydrogen peroxide;
a perfluorocarbon liquid emulsified with the glucose oxidase; and
a crosslinking agent to crosslink covalently said protein to form a stabilized gel comprising crosslinked protein and particles of the perfluorocarbon liquid. - View Dependent Claims (15, 16, 17, 18)
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Specification