Glucose sensor and assay method

• US 5,645,710 A
• Filed: 03/18/1996
• Issued: 07/08/1997
• Est. Priority Date: 10/07/1994
• Status: Expired due to Fees

• Current Assignee: Biomedix, Inc.
• Original Assignee: Biomedix, Inc.
• Inventors: Shieh, Paul
• Primary Examiner(s): Gorgos, Kathryn L.
• Assistant Examiner(s): NOGUEROLA, ALEXANDER STEPHAN
• Application Number:
  US08/617,278
• Time in Patent Office: 477 Days
• Field of Search: 435/14, 435/28, 435/817, 204/403, 205/777.5, 205/787, 205/792, 205/778
• US Class Current: 205/778
• CPC Class Codes: C12Q 1/006 for glucose
• CPC Class Codes: Y10S 435/817 Enzyme or microbe electrode

Abstract

A redox electrode for the rapid detection of glucose in aqueous media and a method for its use are provided. The redox electrode comprises an electrically conductive member such as copper, and a redox membrane in direct contact with said electrically conductive member. The redox membrane comprises a polymer matrix such as PVC containing a plasticizer, and a complex of 7,7,8,8-tetracyanoquinodimethane and tetrathiafulvalene with the complex having a burgundy-red coloration and characterized by a broad absorption from about 340 nm to about 550 nm and weaker absorption between about 650 nm to about 800 nm having about six small peaks with an absorption maximum at about 750 nm. Glucose is rapidly assayed by bringing the redox electrode and a reference electrode into simultaneous contact with an aqueous medium containing KCl, phosphate buffer, glucose oxidase, peroxidase, and 3,3'"'"',5,5'"'"'-tetramethylbenzidine dihydrochloride. The potential of the redox membrane is then monitored until it is stable. A sample containing glucose is added to the aqueous medium, and the change of potential of the redox electrode, which is related to glucose concentration, is then observed. In a variant of this method, the redox electrode is treated with ascorbic acid before a glucose oxidation to magnify the potential difference generated, and after oxidation to rapidly collapse the potential and prepare the electrode for another analysis.

Claims

1. A method for the assay of glucose in aqueous media comprising:

a) forming an electrolytic cell by bringing a redox electrode and a reference electrode into simultaneous contact with an aqueous medium containing KCl, phosphate buffer mixture, glucose oxidase, peroxidase, and 3,3'"'"',5,5'"'"'-tetramethylbenzidine dihydrochloride, said redox electrode comprising;

an electrically conductive member,

a redox membrane in direct contact with said electrically conductive member, said redox membrane comprising;

a polymer matrix, said polymer matrix containing;

a plasticizer, and

a complex of 7,7,8,8-tetracyanoquinodimethane and tetrathiafulvalene wherein the complex comprises a complex having an ultraviolet absorption spectrum with broad absorption from about 340 nanometers to about 550 nanometers,

said redox membrane having an electrical potential; and

b) monitoring the electrical potential of said redox membrane until it is stable; and

c) adding a sample containing glucose to said aqueous medium; and

d) observing a change of the electrical potential of said redox membrane.