Integral interstitial fluid sensor

• US 5,161,532 A
• Filed: 04/19/1990
• Issued: 11/10/1992
• Est. Priority Date: 04/19/1990
• Status: Expired due to Term

• Current Assignee: SRI International, Inc.
• Original Assignee: Teknekron Sensor Development Corporation
• Inventors: Joseph, Jose P.
• Primary Examiner(s): Cohen, Lee S.
• Assistant Examiner(s): Pfaffie, Krista M.
• Application Number:
  US07/511,329
• Time in Patent Office: 936 Days
• Field of Search: 128/635, 128/760, 204/403
• US Class Current: 600/345
• CPC Class Codes: A61B 2010/008 Interstitial fluid
• CPC Class Codes: A61B 5/14514 using means for aiding extraction of interstitial fluid, e.g. microneedles or suction
• CPC Class Codes: A61B 5/1486 using enzyme electrodes, e.g. with immobilised oxidase
• CPC Class Codes: A61B 5/441 Skin evaluation, e.g. for skin disorder diagnosis

Abstract

An integral interstitial fluid sensor for application to the skin of a person or an animal for the detection of chemical components of tissue fluid is disclosed. The fluid sensor comprises a substrate of a porous material for the passage of the interstitial fluid therethrough. At least two electrodes are provided. One of the electrodes has two sides, with one side mounted on the substrate. The electrode is also of a porous material and permits the passage of the interstitial fluid from one side through to the second side which is generally opposite the one side. A layer of chemical is on the second side. The layer of chemical comprises a chemical for reaction with one component of the fluid, mixed in a mediating agent. The electrodes generate an electrical signal upon the detection of the reaction of the one component of the fluid with the chemical. The electrical signal is received by a detector and a display is generated, indicating the amount of the one component detected. Finally, a pump for sucking the fluid from the skin into the sensor is disclosed.

Claims

1. An integral interstitial fluid sensor for application to the skin of a person or an animal for detection of chemical components of an interstitial fluid, said sensor, comprising:

a substrate of a porous material for passage of the interstitial fluid therethrough;

at least two electrodes;

a first electrode and a second electrode;

said first electrode has two sides;

a first side and a second side, said first side is mounted on said substrate with said second side generally opposite said first side, said first electrode is of a porous material for passage of the interstitial fluid through the two sides;

a layer of chemical in contact with said second side of said first electrode for reaction with one component of said interstitial fluid, mixed in a mediating agent;

said second electrode in contact with said layer of chemical;

said two electrodes for generating an electrical signal in response to the reaction of the one component of said interstitial fluid with said layer of chemical;

detecting means for receiving said electrical signal;

means for generating a display in response to said detecting means; and

means for sucking said fluid from the skin through said substrate into said layer of chemical.

2. The sensor of claim 1 wherein said second electrode is mounted on said substrate, said second electrode has two sides with one side on said substrate and the other side generally opposite thereto, for the passage of the interstitial fluid through said two sides, and with said layer of chemical in contact with said other side of said second electrode.

3. The sensor of claim 1 wherein said second electrode has two sides with one side in contact with said layer of chemical, and the other side, generally opposite said one side, said second electrode for the passage of the interstitial fluid through the two sides.

4. The sensor of claim 1 wherein said substrate is ceramic.

5. The sensor of claim 1 wherein said first electrode comprises Pt mounted on said porous substrate.

6. The sensor of claim 5 wherein said second electrode is AgCl mounted on said porous substrate.

7. The sensor of claim 1 wherein said layer of chemical is glucose oxidase and said one component is glucose.