Glucose sensor assembly

  • US 5,660,163 A
  • Filed: 05/18/1995
  • Issued: 08/26/1997
  • Est. Priority Date: 11/19/1993
  • Status: Expired due to Term
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First Claim
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1. A sensor assembly adapted for insertion into the venous system of a patient to measure the concentration of one or more substances in the patient'"'"'s blood, said sensor assembly comprising:

  • a substrate;

    first and second working electrodes bonded to said substrate;

    a reference electrode bonded to said substrate;

    a collector electrode bonded to said substrate;

    means for making electrical contact with said first and second working electrodes, reference electrode, and collector electrode;

    a layer of insulation deposited on said substrate and means for making electrical contact so as to be interspersed between the electrodes bonded to said substrate, a prescribed surface area of each of said electrodes being exposed through said layer of insulation, whereby said first and second working electrodes, reference electrode and collector electrode are all electrically isolated from each other on said substrate;

    first membrane means covering said substrate and electrodes;

    a saline solution held within said first membrane, said saline solution being in contact with said electrodes bonded to said substrate;

    second membrane means covering said first membrane means, said second membrane means having a window pocket therein above the exposed surface area of said first working electrode;

    a prescribed enzyme placed within said window pocket;

    means for applying a prescribed reference voltage between said collector electrode and said reference electrode, and between said first and second working electrodes and said reference electrode, and for measuring the electrical current that flows from said first and second working electrodes;

    whereby when said sensor assembly is inserted in the patient'"'"'s venous system, oxygen and other substances in the blood of the patient may penetrate said first and second membrane means and electrochemically react in the presence of the prescribed enzyme held in said window pocket with the current flowing through said first working electrode, and electrochemically react in the absence of said enzyme with the current flowing through said second working electrode;

    said currents flowing through said first and second working electrodes thereby providing a measure of oxygen and other substances in the blood of the patient as a function of the electrochemical reactions that occur at said first and second working electrodes.

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