DEVICES, SYSTEMS, METHODS AND TOOLS FOR CONTINUOUS GLUCOSE MONITORING

• US 20090131778A1
• Filed: 11/20/2008
• Published: 05/21/2009
• Est. Priority Date: 03/28/2006
• Status: Abandoned Application

• Current Assignee: ArKal Medical, Inc.
• Original Assignee: ArKal Medical, Inc.
• Inventors: Tierney, Michael J., Jina, Arvind N., Desai, Shashi P., Chua, Beelee, Tamada, Janet
• Application Number:
  US12/275,145
• Publication Number:
  US 20090131778A1
• Time in Patent Office: Days
• US Class Current: 600/365
• CPC Class Codes: A61B 5/14514 using means for aiding extraction of interstitial fluid, e.g. microneedles or suction
• 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

Abstract

One aspect of the invention provides a glucose monitor having a plurality of tissue piercing elements, each tissue piercing element having a distal opening, a proximal opening and interior space extending between the distal and proximal openings; a sensing volume in fluid communication with the proximal openings of the tissue piercing elements; sensing fluid extending into the sensing volume; and a glucose sensor adapted to detect a concentration of glucose in the sensing fluid within the sensing volume. Another aspect of the invention provides A method of in vivo monitoring of an individual'"'"'s interstitial fluid glucose concentration comprising: inserting distal ends of a plurality of tissue piercing elements through a stratum corneum area of the individual'"'"'s skin, the tissue piercing elements each comprising a distal opening, a proximal opening, and an interior space extending between the distal and proximal opening; allowing interstitial fluid to flow into the interior space of the tissue piercing elements to substantially fill the interior space; filling substantially the entire interior space of the sensing area; and sensing a glucose concentration of the sensing fluid.

Claims

1. A glucose monitor comprising:

a plurality of tissue piercing elements, each tissue piercing element comprising a distal opening,

a proximal opening and an interior space extending between the distal and proximal openings;

a sensing volume in fluid communication with the proximal openings of the tissue piercing elements;

sensing fluid extending into the sensing volume; and

a glucose sensor adapted to detect a concentration of glucose in the sensing fluid within the sensing volume.

2. The glucose monitor of claim 1 wherein the glucose sensor is an electrochemical sensor.

3. The glucose monitor of claim 1 wherein an area of a surface that faces the tissue piercing elements of the glucose sensor is substantially similar to an area covering the tissue piercing elements.

4. The glucose monitor of claim 1 wherein an area of a surface that faces the tissue piercing elements of the glucose sensor is larger than the area covering the tissue piercing elements.

5. The glucose monitor of claim 1 wherein an area of a surface that faces the tissue piercing elements of the glucose sensor is in the range of 10 mm² to 100 mm².

6. The glucose monitor of claim 1 wherein a thickness of the sensing volume is in the range of 50 microns to 3000 microns.

7. The glucose monitor of claim 1 wherein the glucose sensor is adapted to detect a concentration of glucose in the sensing fluid within the sensing volume without extracting interstitial fluid.

8. The glucose monitor of claim 1 wherein the sensing fluid comprises multiple calibration fluids.

9. The glucose monitor of claim 1 wherein the glucose sensor is configured to operate continuously.

10. The glucose monitor of claim 1 wherein the glucose sensor is configured to operate periodically.

11. The glucose monitor of claim 1 wherein the glucose sensor is configured to operate intermittently.

12. A method of in vivo monitoring of an individual'"'"'s interstitial fluid glucose concentration comprising:

inserting distal ends of a plurality of tissue piercing elements through a stratum corneum area of the individual'"'"'s skin, the tissue piercing elements each comprising a distal opening, a proximal opening, an interior space extending between the distal and proximal openings, and a sensing fluid filling substantially the entire interior space;

allowing glucose to diffuse into a sensing volume without extracting interstitial fluid; and

sensing a glucose concentration of the sensing fluid within the sensing volume.

13. The method of claim 12 wherein sensing the glucose concentration further comprises continuing to monitor the glucose concentration over time.

14. The method of claim 12 wherein sensing the glucose concentration comprises continuously sensing the glucose concentration over time.

15. The method of claim 14 wherein continuous sensing of the glucose concentration proceeds until calibration.

16. The method of claim 13 wherein sensing the glucose concentration comprises periodically sensing the glucose concentration.

17. The method of claim 16 wherein periodically sensing the glucose concentration comprises having a sensing cycle with regular timing.

18. The method of claim 13 wherein sensing the glucose concentration comprises intermittently sensing the glucose concentration.

19. The method of claim 18 wherein intermittently sensing the glucose concentration comprises a sensing cycle having irregular timing.

20. The method of claim 12 wherein a glucose sensor senses the glucose concentration, the method further comprising calibrating the glucose sensor prior to the sensing step.

21. The method of claim 20 wherein the calibrating step occurs at a predetermined time point.

22. The method of claim 20 wherein the calibrating step occurs at a predetermined time interval.

23. The method of claim 20 wherein the calibrating step occurs when the glucose sensor detects a drift in the glucose concentration measurement.

24. The method of claim 23 wherein the drift is determined by monitoring a sensor signal from the glucose sensor.

25. The method of claim 20 wherein the calibrating step comprises moving the sensing fluid into the sensing volume.

26. The method of claim 25 wherein the calibrating step further comprises acquiring a sensor signal indicating the concentration of glucose in the sensing fluid.

27. The method of claim 26 further comprising moving sensing fluid out of the sensing area as sensing fluid is moved into the sensing volume.

28. The method of claim 27 wherein the sensing fluid remains in the glucose sensor after the calibrating step.

29. The method of claim 27 wherein the step of moving sensing fluid comprises moving sensing fluid having a glucose concentration of between about 0 mg/dl and about 400 mg/dl.

30. The method of claim 12 wherein sensing a glucose concentration comprises:

diffusing glucose through the tissue piercing elements; and

detecting hydrogen peroxide formation.

31. The method of claim 30 further comprising detecting hydrogen peroxide formation coulometrically.

32. The method of claim 30 wherein the hydrogen peroxide formation is reduced to substantially zero.

33. The method of claim 12 wherein sensing a glucose concentration comprises:

diffusing glucose through the tissue piercing elements; and

detecting oxygen consumption.

34. A method of in vivo monitoring of an individual'"'"'s interstitial fluid glucose concentration comprising:

inserting distal ends of a plurality of tissue piercing elements through a stratum corneum area of the individual'"'"'s skin, the tissue piercing elements each comprising a distal opening, a proximal opening, and an interior space extending between the distal and proximal opening;

allowing interstitial fluid to flow into the interior space of the tissue piercing elements to substantially fill the interior space;

filling substantially the entire interior space of the sensing area with sensing fluid; and

sensing a glucose concentration of the sensing fluid.

35. The method of claim 34 wherein the interstitial fluid does not flow past the proximal opening.

36. The method of claim 34 wherein the interstitial fluid flows immediately into the interior space of the tissue piercing elements.