Hermetic Implantable Sensor

• US 20110137142A1
• Filed: 02/09/2011
• Published: 06/09/2011
• Est. Priority Date: 02/13/2004
• Status: Active Grant

• Current Assignee: Mcnair Interests Limited
• Original Assignee: GlySens, Incorporated
• Inventors: Lucisano, Joseph Y., Catlin, Mark B.
• Granted Patent: US 10,041,897 B2
• Time in Patent Office: Days
• US Class Current: 600/347
• CPC Class Codes: A61B 2562/02 Details of sensors specially adapted for in-vivo measurements
• CPC Class Codes: A61B 2562/12 Manufacturing methods specially adapted for producing sensors for in-vivo measurements
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/1473 invasive, e.g. introduced into the body by a catheter A61B5/1482 takes precedence
• 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 5/25 Bioelectric electrodes therefor
• CPC Class Codes: G01N 27/12 of a solid body in dependence upon absorption of a fluid; of a solid body in dependence upon reaction with a fluid , for detecting components in the fluid

Abstract

At least one conductor is formed at a preselected location on a substrate made of a first insulating material having a high temperature resistance. The conductor is made from a solidified electrically conductive thick film material. A coating made of a second insulating material is formed over the substrate to hermetically seal at least a portion of the conductor. An exposed distal region of the conductor provides a detection electrode. The conductor has a reduced porosity that inhibits migration of fluid or constituents thereof through the conductor.

Claims

1. A sensor, comprising:

a substrate made of a first insulating material having a high temperature resistance;

at least one conductor formed at a preselected location on the substrate and made from a solidified electrically conductive thick film material which contains particles a metal selected from the group consisting of platinum, palladium, rhodium, ruthenium, iridium and osmium;

a coating made of a second insulating material formed over the substrate to hermetically seal at least a portion of the conductor;

an exposed distal region of the conductor providing a detection electrode; and

the conductor having a reduced porosity that inhibits migration of fluid or constituents thereof through the conductor.

2. The sensor of claim 1 wherein the first insulating material is selected from the group consisting of ceramic and glass/ceramic combinations.

3. The sensor of claim 2 wherein the ceramic is selected from the group consisting of oxides, carbides, borides, nitrides, and silicides of aluminum, zirconium, beryllium, silicon, titanium, yttrium, and zinc and mixtures thereof.

4. The sensor of claim 1, wherein the second insulating material is selected from the group consisting of glass, ceramic, glass/ceramic combinations, and polymers.

5. The sensor of claim 1 wherein the substrate has a generally planar configuration.

6. The sensor of claim 1 wherein there are at least two conductors that are elongated and substantially parallel.

7. The sensor of claim 1 wherein at least one insulation-testing conductor is formed on the substrate in addition to the at least one conductor, and the coating of the second insulating material hermetically seals at least a portion of the integrity testing conductor that may come into contact with a fluid.

8. The sensor of claim 1 and further comprising a source of glucose oxidase (GO) positioned in operative contact with the detection electrode for catalyzing the reaction of glucose and oxygen.

9. The sensor of claim 1 wherein an exposed proximal region of the conductor provides a contact pad.

10. The sensor of claim 1 wherein an electrical contact connects to the conductor, the contact being selected from the group consisting of a metal wire, sintered metal particles, a sintered mixture of metal and inorganic oxide particles, and a metal plug.

11. A method of fabricating a sensor, comprising the steps of:

providing a substrate made of a first insulating material having a high temperature resistance;

depositing an electrically conductive thick film material on the substrate to form at least one un-solidified conductor, said thick film material containing particles of a metal selected from the group consisting of platinum, palladium, rhodium, ruthenium, iridium and osmium;

heating the electrically conductive thick film material to a first predetermined temperature, below a second predetermined melting temperature thereof, which is sufficient to sinter a plurality of metal particles in the electrically conductive thick film material;

allowing the thick film material to cool to produce at least one solidified conductor having a porosity that is sufficiently low such that it may become hermetic when coated; and

coating a portion of the conductor with a second insulating material leaving at least one exposed region that provides a detection electrode.

12. The method of claim 11 wherein the first insulating material is selected from the group consisting of ceramic and glass/ceramic combinations.

13. The method of claim 12 wherein the ceramic is selected from the group consisting of oxides, carbides, borides, nitrides, and silicides of aluminum, zirconium, beryllium, silicon, titanium, yttrium, and zinc and mixtures thereof.

14. The method of claim 11 wherein the second insulating material is selected from the group consisting of glass, ceramic, glass/ceramic combinations, and polymers.

15. The method of claim 11 wherein the thick film material contains platinum particles and wherein the thick film material is heated to a peak temperature between about 1500 degrees C. and about 1700 degrees C.

16. The method of claim 15 wherein the thick film material is heated to the peak temperature for a dwell time between about ten minutes and about sixty minutes.

17. The method of claim 15 wherein the thick film material is heated to a temperature within a range that extends from below a melting point of a plurality of metal particles in the thick film material to approximately three hundred degrees C. below said melting point of a plurality of metal particles in the thick film material.

18. A sensor suitable for implanting in living tissue for monitoring the level of a biological agent in a tissue fluid, comprising:

a substrate made of a first biocompatible insulating material having a high temperature resistance selected from the group consisting of ceramic and glass/ceramic combinations;

at least one conductor formed at a preselected location on the substrate and made from an electrically conductive thick film material containing particles of a metal selected from the group consisting of platinum, palladium, rhodium, ruthenium, iridium and osmium;

a coating made of a second biocompatible insulating material selected from the group consisting of glass, ceramic, glass/ceramic combinations, and polymers, and formed over the substrate to hermetically seal at least a portion of the conductor leaving at least one exposed region thereof to provide a detection electrode; and

the conductor being made of sintered metal particles having a reduced porosity that inhibits migration of the bodily fluid or any constituents thereof through the conductor;

whereby instances of sensor failure and/or inaccuracy during implanted operation are minimized.

19. An electrochemical sensor, comprising:

a substrate made of a first insulating material having a high temperature resistance;

at least once conductor formed at a preselected location on the substrate and made from an electrically conductive thick film material containing particles of a metal selected from the group consisting of platinum, palladium, rhodium, ruthenium, iridium and osmium;

a coating made of a second insulating material formed over the substrate to hermetically seal at least a portion of the at least one conductor leaving at least one exposed region to provide a detection electrode; and

the conductor having a reduced porosity that inhibits migration of fluid or gaseous diffusion through the at least one conductor.

20. A method of fabricating an electrochemical sensor, comprising the steps of:

providing a substrate made of a first insulating material having a high temperature resistance;

depositing on the substrate an electrically conductive thick film material containing particles of a metal selected from the group consisting of platinum, palladium, rhodium, ruthenium, iridium and osmium to form at least one un-solidified conductor;

heating the electrically conductive thick film material to a first predetermined temperature m a range that extends from below a melting point of a plurality of metal particles in the thick film material to a temperature approximately 300 degrees C. below the melting point in order to sinter a plurality of metal particles in the electrically conductive thick film material;

allowing the thick film material to cool to produce at least one solidified conductor having a first porosity which is substantially less than a second porosity that would result from heating the electrically conductive thick film material to a temperature below the range; and

coating at least a portion of the at least one conductor with a second insulating material and leaving at least one exposed region thereof to provide a detection electrode.

21. A device, a portion of which relies on the conduction of electricity for its function, suitable for implanting in living tissue, which may come into contact with tissue fluid, comprising:

a substrate made of a first biocompatible insulating material having a high temperature resistance;

at least one conductor formed at a preselected location on the substrate and made from a solidified electrically conductive thick film material containing particles of a metal selected from the group consisting of platinum, palladium, rhodium, ruthenium, iridium and osmium;

a coating made from a second biocompatible insulating material formed over the substrate to hermetically seal at least a portion of the conductor;

the conductor having a reduced porosity that inhibits migration of the tissue fluid or constituents thereof through the conductor;

a sealed internal portion of the device containing electrical circuitry; and

means for making an electrical connection to the conductor from the exterior of the device.

22. A device as in claim 21 wherein the means for making an external electrical connection comprises a hole in said second biocompatible insulating material adjacent to the conductor.

23. A device as in claim 21 wherein the means for making an external electrical connection comprises a wire.

24. A device as in claim 21 wherein the means for making an external electrical connection comprises an inductive coupling.

25. A device as in claim 21 wherein the means for making an external electrical connection comprises a radiative coupling.

26. A method of fabricating a device implantable in living tissue for conveying electrical signals, comprising the steps of:

providing a substrate made of a first biocompatible insulating material having a high temperature resistance;

depositing on the substrate an electrically conductive thick film material containing particles of a metal selected from the group consisting of platinum, palladium, rhodium ruthenium, iridium and osmium to form at least one un-solidified conductor;

heating the electrically conductive thick film material to a first predetermined temperature below a second predetermined melting temperature thereof which is sufficient to sinter a plurality of metal particles in the electrically conductive thick firm material;

allowing the thick film materials to cool to produce at least one solidified conductor having a porosity that is sufficiently low such that it may become hermetic when coated; and

coating at least a portion of the at least one solidified conductor with a second biocompatible insulating material.

27. An antenna, comprising:

a substrate made of a first insulating material having a high temperature resistance;

at least one conductor made of sintered metal particles and formed at a preselected location on the substrate and made from a solidified electrically conductive thick film material having metal particles sintered to provide reduced porosity in the conductor, said thick film material containing particles of a metal selected from the group consisting of platinum, palladium, rhodium, ruthenium, iridium and osmium;

a coating made of a second insulating material formed over the substrate in order to hermetically seal at least a portion of the conductor; and

the conductor having a predetermined geometry for transmitting or receiving RF signals at a predetermined frequency.

28. The antenna of claim 27 wherein the first insulating material is selected from the group consisting of ceramic and glass/ceramic combinations.

29. The antenna of claim 28 wherein the ceramic is selected from the group consisting of oxides, carbides, borides, nitrides, and silicides of aluminum, zirconium, beryllium, silicon, titanium, yttrium, and zinc and mixtures thereof.

30. The antenna of claim 28 wherein the second insulating material is selected from the group consisting of glass, ceramic, glass/ceramic combinations, and polymers.

31. The antenna of claim 27 wherein the substrate has a generally planar configuration.

32. The antenna of claim 27 and further comprising means extending through a hole in the substrate for providing an electrical connection to the conductor.

33. A sensor, comprising:

a substrate made of a first insulating material having a high temperature resistance;

at least one conductor formed at a preselected location on the substrate and made from a solidified electrically conductive thick film material containing particles of a metal selected from the group consisting of platinum, palladium, rhodium, ruthenium, iridium and osmium;

a coating made of a second insulating material formed over the substrate to hermetically seal at least a portion of the conductor;

a conductive filled via formed in an aperture in the substrate and in electrical contact with the conductor; and

the conductor having a reduced porosity that inhibits migration of fluid or constituents thereof through the conductor.