Temperature-compensated in-vivo sensor

• US 20100010323A1
• Filed: 09/21/2009
• Published: 01/14/2010
• Est. Priority Date: 03/21/2008
• Status: Abandoned Application

• Current Assignee: Sanvita Medical Corporation
• Original Assignee: Nova Biomedical Corporation (Nova Chemicals)
• Inventors: Jobst, Gerhard
• Application Number:
  US12/563,685
• Publication Number:
  US 20100010323A1
• Time in Patent Office: Days
• US Class Current: 600/309
• CPC Class Codes: A61B 2560/0252 using ambient temperature
• 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: A61B 5/1495 Calibrating or testing of in-vivo probes
• CPC Class Codes: A61B 5/6848 Needles

Abstract

A reagent matrix composition disposed on an electrically conductive electrode to form an in-vivo sensor for a predefined analyte includes a first hydrogel layer containing an enzyme that is a substrate for the analyte adjacent the electrically conductive electrode and a composite membrane layer disposed onto the first hydrogel layer where the composite layer includes a membrane hydrogel containing a plurality of microspheres. The plurality of microspheres is made of a material having no or little permeability to the analyte and a substantially high permeability to oxygen.

Claims

1. An in-vivo sensor for measuring an analyte, the sensor comprising:

a base insulating layer;

an electrically conductive electrode disposed on the base insulating layer;

a semi-permeable layer disposed over the electrode;

a first hydrogel layer containing an enzyme that is a substrate for the analyte disposed on the semi-permeable layer;

a composite membrane layer disposed on the first hydrogel layer wherein the composite layer includes a hydrogel containing a plurality of microspheres, the plurality of microspheres being made of a material having no or little permeability to the analyte and substantially high permeability to oxygen.

2. The sensor of claim 1 further comprising a second hydrogel layer disposed over the composite membrane layer.

3. The sensor of claim 2 wherein the second hydrogel layer further includes a catalase.

4. The sensor of claim 1 wherein the material of the microspheres is polydimethylsiloxane.

5. The sensor of claim 1 wherein the first hydrogel layer is one of a polyurethane or a poly-2-hydroxyethyl methylacrylate.

6. The sensor of claim 2 wherein the second hydrogel layer is one of polyurethane or poly-2-hydroxyethyl methacrylate.

7. The sensor of claim 1 wherein the composite membrane layer has a ratio of the quantity of microspheres to the quantity of membrane hydrogel selected for a predefined dynamic measurement range of the analyte.

8. A reagent matrix composition disposed on an electrically conductive electrode to form an in-vivo sensor for a predefined analyte, the composition comprising:

a first hydrogel layer containing an enzyme that is a substrate for the analyte adjacent the electrically conductive electrode; and

a composite membrane layer disposed onto the first hydrogel layer wherein the composite layer includes a membrane hydrogel containing a plurality of microspheres, the plurality of microspheres being made of a material having no or little permeability to the analyte and a substantially high permeability to oxygen.

9. The composition of claim 8 further comprising a semi-permeable layer between the first hydrogel layer and the electrically conductive electrode.

10. The composition of claim 8 further comprising a second hydrogel layer disposed onto the composite membrane layer.

11. The composition of claim 10 wherein the second hydrogel layer contains a catalase.

12. The composition of claim 8 wherein the first hydrogel layer, the membrane hydrogel and the second hydrogel layer are one of polyurethane or poly-2-hydroxyethyl methacrylate.

13. The composition of claim 8 wherein the material of the microspheres is polydimethylsiloxane.

14. The composition of claim 8 wherein the composite membrane layer has a ratio of the quantity of microspheres to the quantity of membrane hydrogel selected for a predefined dynamic measurement range of the analyte.

15. A method of making a sensor for in-vivo measurement of an analyte, the method comprising:

obtaining an electrically conductive electrode;

disposing a first hydrogel layer containing an enzyme onto the electrically conductive electrode; and

disposing a composite membrane layer onto the first hydrogel layer wherein the composite membrane layer includes a membrane hydrogel containing a plurality of microspheres, the plurality of microspheres being made of a material having no or little permeability to the analyte and a substantially high permeability to oxygen.

16. The method of claim 15 further comprising disposing a semi-permeable layer between the first hydrogel layer and the electrically conductive electrode.

17. The method of claim 15 further comprising disposing a second hydrogel layer onto the composite membrane layer.

18. The method of claim 15 further comprising formulating the first hydrogel layer and the membrane hydrogel from polyurethane or poly-2-hydroxyethyl methacrylate.

19. The method of claim 15 further comprising formulating the microspheres from polydimethylsiloxane.

20. The method of claim 17 further comprising formulating the second hydrogel layer from polyurethane or poly-2-hydroxyethyl methacrylate.

21. The method of claim 17 further comprising formulating the second hydrogel layer containing a catalase.