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Non-invasive glucose biosensor: determination of glucose in urine

  • US 5,876,952 A
  • Filed: 12/08/1997
  • Issued: 03/02/1999
  • Est. Priority Date: 12/08/1997
  • Status: Expired due to Fees
First Claim
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1. A non-invasive method which measures the glucose concentration of a sample for determining the glycemic state of a patient which measures the glucose concentration of a sample comprising the stepsa) providing an amperometric biosensor for glucose comprising;

  • a sensing electrode, the sensing electrode comprising;

    a non-conductive support member, with the non-conductive support member comprising;

    a non-conductive polymeric film;

    the non-conductive polymeric film coated with an electrically conductive layer, and the electrically conductive layer comprising;

    an electrically conductive carbon or graphite formulation containing a first redox mediator, with the first redox mediator selected from the group consisting of;

    dimethylferrocene, ferricinium, ferrocene monocarboxylic acid, 7,7,8,8-tetracyanoquinodimethane, tetrathiafulvalene, nickelocene, N-methylacridinium, tetrathiatetracene, N-methylphenazinium, hydroquinone and mixtures thereof,and a reference electrode comprising;

    a non-conductive polymeric film, the polymeric film coated with an electrically conductive formulation comprising Ag/AgCl dispersed in a resin formulation, and with the reference electrode having an opening; and

    a reagent strip, the reagent strip comprising;

    a carrier strip that is a porous or fibrous water absorbent matrix, the carrier strip impregnated with a mixture comprising;

    glucose oxidase,horseradish peroxidasea second redox mediator, the second redox mediator selected from the group consisting of;

    3,3'"'"'5,5'"'"'-tetramethylbenzidine, 3-methyl-2-benzothiazolinone hydrazone hydrochloride and 3-dimethylaminobenzoic acid, o-dianisidine, o-toluidine, sulfonated 2,4-dichloro-phenol and 4-amino phenazone benzidine, 3-methyl-2-benzothiozolinone hydrazone and 3-(dimethylamino) benzoic acid, 3-methyl-2-benzothiozolinone hydrazone and 2-methoxy-4-allyl phenol, 4-aminoantipyrene-dimethylaniline and 4-aminoantipyrene-4-methoxynaphthol, (Fe(CN)6-4), HCN, I-, Co(NH3)6+2, Sn+2, S-2, Tl+2 and mixtures thereof,at least one surfactant, the surfactant selected from the group consisting of;

    cholic acid, Triton X-100, polyethylene glycol, sodium lauryl sulfate, sodium lauryl sarcosinate, hydroxypropyl methylcellulose, tetrapropylene diphenyloxide disulphonate sodium salt,capryloamphocarboxypropionate, polyoxyethylene-2-cetyl ether, 2,4,7,9-tetramethyl-5-decyne-4,7-diol ethoxylate, octanoyl-N-methyl-D-glucamide, decanoyl-N-methyl-D-glucamide and mixtures thereof,at least one stabilizer, the stabilizer selected from the group consisting of;

    gelatin, bovine serum albumin, glutamate, L-arginine, Gantrez, mannitol, gum arabic, low viscosity polypep, methocel and mixtures thereof,a buffering agent to maintain a pH from about 4 to about 8, the buffering agent selected from the group consisting of;

    citrate, succinate, tris-(hydroxymethyl) aminomethane, phosphate, 2(N-morpholino) ethanesulfonic acid and mixtures thereof,with the electrically conducting layer of the sensing electrode and the electrically conductive formulation of the reference electrode facing each other; and

    with the reagent strip superimposed on and in physical contact with the electrically conducting layer of the sensing electrode, and with the reference electrode superimposed on the reagent strip so that the electrically conductive formulation coating the reference electrode is superimposed on the reagent strip and in physical contact with the reagent strip;

    so that the sensing electrode and the reagent strip and the reference electrode form a sandwich;

    b) maintaining a potential of about -80 mV to about -125 mV across the sensing electrode and the reference electrode;

    c) introducing a non-invasively obtained biological fluid sample into the opening of the reference electrode;

    d) measuring the current passing between the sensing electrode and the reference electrode;

    e) comparing the current measured to a calibration curve of the concentration of glucose versus current at the potential used in step c) to obtain the concentration of glucose in the non-invasively obtained biological fluid sample.

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