DEVICES, SYSTEMS, METHODS AND TOOLS FOR CONTINUOUS GLUCOSE MONITORING
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.
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 mm 2 to 100 mm 2 .
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.