Bio-sensor using ion sensitive field effect transistor with platinum electrode

• US 5,387,328 A
• Filed: 04/15/1993
• Issued: 02/07/1995
• Est. Priority Date: 01/15/1993
• Status: Expired due to Fees

• Current Assignee: Sensor Technology Research Center Of Kyungpook National University
• Original Assignee: Sensor Technology Research Center Of Kyungpook National University
• Inventors: Sohn, Byung-ki
• Primary Examiner(s): Niebling, John
• Assistant Examiner(s): Bell, Bruce F.
• Application Number:
  US08/046,751
• Time in Patent Office: 663 Days
• Field of Search: 204/403, 204/416, 204/418, 204/419, 435/288, 435/291, 435/817
• US Class Current: 257/253
• CPC Class Codes: C12Q 1/001 Enzyme electrodes
• CPC Class Codes: C12Q 1/005 involving specific analytes or enzymes including groups of enzymes, e.g. oxydases; C12Q1/004 takes precedence
• CPC Class Codes: G01N 27/4145 specially adapted for biomolecules, e.g. gate electrode with immobilised receptors
• CPC Class Codes: Y10S 435/817 Enzyme or microbe electrode

Abstract

A bio-sensor employs an ion senstive field effect transistor (ISFET) comping a source 1 and a drain 3 formed in a substrate, an ion sensitive gate 2 placed between the source 1 and drain 3, an ion sensitive film 4 formed on the ion sensing gate 2, an immobilized enzyme membrane 5 defined on the ion sensitive film 4 and, a Pt electrode 6 formed on the ion sensitive film 4. The sensor has a Pt eleletrode being capable of sensing all biological substances which generate H₂ O₂ in enzyme reaction, whereby having the high sensitivity and the rapid reaction time.

Claims

1. A bio-sensor employing an ion-sensitive field effect transistor (ISFET) comprising:

a substrate comprising a source and a drain;

an ion sensing gate disposed between the source and the drain;

an ion-sensitive film formed on the surface of the substrate and the ion sensing gate;

a Pt electrode domain formed on the ion-sensitive film surrounding the periphery of the ion sensing gate; and

an immobilized enzyme membrane disposed on the ion-sensitive film and the Pt electrode domain.

2. The bio-sensor according to claim 1, wherein said immobilized enzyme membrane is an immobilized glucose oxidase membrane when the bio-sensor is a glucose sensor, a co-immobilized β

-galactosidase and glucose oxidase membrane when the bio-sensor is a lactose sensor, a co-immobilized invertase, mutarotase, and glucose oxidase membrane when the bio-sensor is a sucrose sensor, or an immobilized L-amino acid oxidase membrane when the bio-sensor is an L-amino acid sensor.

3. The bio-sensor according to claim 2, wherein said immobilized enzyme membrane is an immobilized glucose oxidase membrane.