Implantable glucose sensor

• US 5,165,407 A
• Filed: 04/09/1991
• Issued: 11/24/1992
• Est. Priority Date: 04/19/1990
• Status: Expired due to Term

• Current Assignee: University of Kansas
• Original Assignee: University of Kansas
• Inventors: Hill, Brian S., Bindra, Dilbir S., Zhang, Yanan, Sternberg, Robert, Reach, Gerard, Thevenot, Daniel R., Wilson, George S.
• Primary Examiner(s): Cohen, Lee S.
• Application Number:
  US07/682,560
• Time in Patent Office: 595 Days
• Field of Search: 128/635, 204/403, 204/415
• US Class Current: 600/345
• CPC Class Codes: A61B 5/14865 invasive, e.g. introduced into the body by a catheter or needle or using implanted sensors
• CPC Class Codes: A61B 5/6848 Needles
• CPC Class Codes: C12Q 1/006 for glucose

Abstract

Implantable enzymatic sensors (25, 43, 44) for biochemicals such as glucose are provided having an ideal size and geometry for optional long term implantation and linear responses over the concentration ranges of interest. The sensors (25, 43, 44) include an elongated body (10, 26, 46) supporting an indicating electrode section having an appropriate enzyme immobilized thereon to present an enzymatic indicating surface (21, 33, 54). A permeable synthetic polymer membrane (24, 42, 56) is applied over the sensor body (10, 26, 46) to protect the enzyme and regulate diffusion of analyte therethrough, to ensure linearity of sensor response. The sensors (25, 43) are of flexible design and can be implanted using a catheter. Alternately, the sensor (44) includes an internal indicating electrode body (46) housed within an apertured, hollow needle (48). A holder (66) affixed to the needle (48) allows for easy manipulation and implantation of the sensor (44).

Claims

1. A sensor adapted for positioning in an environment characterized by the presence of biological molecules which are substrates for or products produced by enzymes in order to determine the presence of said molecules, said sensor comprising:

an elongated flexible body comprising a length of electrically conductive indicating electrode wire covered with an electrically insulative material, there being a portion of said material removed from said electrode wire to define an enzyme-receiving zone;

an enzyme operably immobilized on said zone to present an enzymatic indicating surface;

a reference electrode supported on said body and presenting a section adapted for exposure to said environment,

said indicating surface and said reference electrode section being laterally spaced apart along the length of said body and each substantially circumscribing the body,

substantially the entireties of said circumscribing indicating surface and said circumscribing reference electrode section being exposed for reaction with said environment when the sensor is placed therein,

said indicating electrode wire serving to support said sensor within said environment without the need for a carrier.

2. The sensor of claim 1, said indicating surface being located intermediate the ends of said length of electrode wire with respective segments of said insulating material being on opposite sides of and defining said enzyme receiving zone.

3. The sensor of claim 1, said reference electrode comprising a coil disposed about said body.

4. The sensor of claim 1, including an outer synthetic polymer membrane disposed over said indicating surface and reference electrode section, said membrane being permeable to said biological molecules.

5. The sensor of claim 4, said membrane being formed of polyurethane.

6. The sensor of claim 4, said membrane having a thickness of from about 5 to 10 microns.

7. The sensor of claim 1, including an inner membrane applied to said electrode wire along the length of said enzyme-receiving zone.

8. The sensor of claim 7, said membrane being negatively charged.

9. The sensor of claim 1, said sensor being a glucose sensor, said enzyme being glucose oxidase.