Subcutaneous glucose electrode
First Claim
1. A biosensor for measuring the concentration of a biochemical, comprising:
- a non-corroding metal or carbon electrode;
a sensing layer comprising a redox polymer and a redox enzyme, adjacent to and in electrical contact with the electrode; and
a biocompatible layer overcoating the sensing layer, comprising a polymer and not less than 20% water by weight when in equilibrium with physiological body fluids.
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Accused Products
Abstract
A small diameter flexible electrode designed for subcutaneous in vivo amperometric monitoring of glucose is described. The electrode is designed to allow "one-point" in vivo calibration, i.e., to have zero output current at zero glucose concentration, even in the presence of other electroreactive species of serum or blood. The electrode is preferably three or four-layered, with the layers serially deposited within a recess upon the tip of a polyamide insulated gold wire. A first glucose concentration-to-current transducing layer is overcoated with an electrically insulating and glucose flux limiting layer (second layer) on which, optionally, an immobilized interference-eliminating horseradish peroxidase based film is deposited (third layer). An outer (fourth) layer is biocompatible.
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Citations
31 Claims
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1. A biosensor for measuring the concentration of a biochemical, comprising:
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a non-corroding metal or carbon electrode; a sensing layer comprising a redox polymer and a redox enzyme, adjacent to and in electrical contact with the electrode; and a biocompatible layer overcoating the sensing layer, comprising a polymer and not less than 20% water by weight when in equilibrium with physiological body fluids. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A biosensor for detecting a biochemical comprising:
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two or more non-corroding metal or carbon biochemical-responsive electrodes; an electrically insulating polymer coating at least a part of each electrode; a sensing layer adjacent to and in electrical contact with a part of each metal or carbon electrode that is not coated by the insulating polymer, the sensing layer comprising a redox enzyme and redox couple, neither of which is leached by a physiological buffer solution consisting of water, sodium chloride and sodium phosphates at a pH between 6.8 and 7.6 or by serum at about 37°
C., wherein the sensing layer generates an electrical signal in the presence of the biochemical; and
,a biocompatible polymer coating on an outer surface of each of the electrodes. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
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29. An electrode comprising:
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a non-corroding, conducting wire coated with an insulating polymer; a recess forming a channel in the insulating polymer coat, the recess bounded at one end by exposed wire and at an opposite end by the environment adjacent the coated wire; a multilayered polymeric composition within said channel, the composition comprising; a redox layer adjacent to and contacting said wire, the redox layer comprising a redox enzyme cross-linked to a redox polymer; and a biocompatible polymer layer adjacent to the environment outside the coated wire. - View Dependent Claims (30)
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31. A method for producing an in vivo biosensor to measure the concentration of an analyte, comprising the steps of:
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coating a non-corroding metal or carbon wire with a biocompatible insulating polymer containing less than 5% water when in equilibrium with physiological body fluids at 37°
C. to form a coated wire;etching said coated wire to form a recess, said recess devoid of metal or carbon; immobilizing within said recess, adjacent to said wire, a redox composition comprising a redox enzyme and a redox polymer; and overcoating the contents of the recess with a biocompatible polymer; wherein said etched wire with said polymer overcoated recess and contents form a biosensor producing substantially no electrical signal output at zero concentration of the analyte to be measured, even in the presence of ascorbate, urate or acetaminophen in their normal concentration range in plasma, serum or blood.
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Specification