Implantable biosensor

• US 20050107677A1
• Filed: 09/24/2004
• Published: 05/19/2005
• Est. Priority Date: 09/24/2003
• Status: Active Grant

• Current Assignee: Michael D. Wood, Ward W. Kenneth
• Original Assignee: Michael D. Wood, Ward W. Kenneth
• Inventors: Ward, W. Kenneth, Wood, Michael D.
• Granted Patent: US 7,433,727 B2
• Time in Patent Office: Days
• US Class Current: 600/347
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• 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: C12Q 1/005 involving specific analytes or enzymes including groups of enzymes, e.g. oxydases; C12Q1/004 takes precedence

Abstract

The invention consists of a sensor with multiple indicating (sensing) electrodes covered with a selectively permeable membrane for monitoring fluid concentrations in a biological environment. The indicating electrodes respond to changes in certain analytes, such as glucose, through an enzyme-mediated reaction. The currents generated from the enzyme-mediated reactions are transmitted through radio signals to an external receiver where the information is processed and recorded. Through the use of various biomaterials and biochemicals associated with the sensor, the monitoring accuracy is improved and the overall viability is prolonged. The process of foreign body fibrosis (formation of a scar capsule around the implanted sensor) eventually limits the functional life of the device. We teach methods of delivery of certain biochemicals that can increase the functional life of the sensor by inhibiting the formation of the foreign body capsule or by stimulating the growth of capillaries into the capsule.

Claims

1. A system for monitoring analyte levels in an individual comprising

an implantable biosensor that uses an oxidoreductase enzyme and has multiple electrodes, and

a processor that receives data from the electrodes, excludes outlying signals based on a statistical analysis, and calculates a mean or median from the remaining signals.

2. The system of claim 1, wherein the statistical analysis uses a Z-statistic, Median of Absolute Deviations.

3. The system of claim 1, wherein the enzyme comprises glucose oxidase.

4. A system for monitoring analyte levels in an individual comprising

an implantable biosensor that uses an oxidoreductase enzyme, multiple electrodes, and a semi-porous membrane that promotes vascularization around the biosensor.

5. The system of claim 4, wherein the membrane comprises ePTFE.

6. A system for monitoring analyte levels in an individual comprising

an implantable biosensor that uses an oxidoreductase enzyme and has multiple electrodes, and

one or more growth factors associated with the biosensor in a configuration effective for promoting vascularization around the biosensor.

7. The system of claim 6, wherein the one or more growth factors comprises VEGF.

8. A system for monitoring analyte levels in an individual comprising

an implantable biosensor that uses an oxidoreductase enzyme and has multiple electrodes, and

one or more collagen inhibitors associated with the biosensor in a configuration effective for inhibiting collagen formation around the biosensor.

9. The system of claim 8, wherein the one or more collagen inhibitors is selected from the group consisting of antibodies to TGF-beta, soluble TGF-beta receptors, pirfenidone, decorin, halofuginone, interferon gamma, an angiotensin converting enzyme inhibitor, an angiotensin II receptor blocker, and mixtures thereof.