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 area in fluid communication with the proximal openings of the tissue piercing elements; sensing fluid extending from the sensing area into substantially the entire interior space of the tissue piercing elements; and a glucose sensor adapted to detect a concentration of glucose in the sensing fluid within the sensing area. Another aspect of the invention provides a method of in vivo monitoring of an individual's interstitial fluid glucose concentration including the following steps: 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 having 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; and sensing a glucose concentration of the sensing fluid.
1. A method of in vivo monitoring of an individual's interstitial fluid comprising:
creating a plurality of fluid paths through a stratum corneum area of the individual's skin, the fluid paths each comprising a distal end in fluid communication with interstitial fluid of the individual, a proximal end in analyte communication with a sensing area located outside of the patient's body, and an interior space extending between the distal and proximal ends of the fluid path;
moving sensing fluid out of a sensing fluid reservoir and into the sensing area;
holding the sensing fluid in the sensing area in a non-flowing manner;
allowing at least one analyte to passively diffuse from the patient's interstitial fluid through the fluid paths and into the sensing area;
sensing a concentration of the at least one analyte in the sensing fluid using a sensor located at least partially in the sensing area during the holding step.
2. The method of claim 1 wherein fluid in the fluid paths is not moving when the at least one analyte is passively diffusing there-through.
3. The method of claim 1 wherein there is no fluid movement between the distal ends of the fluid paths and the sensor when the at least one analyte is passively diffusing through the fluid paths and into the sensing area.
4. The method of claim 1 wherein no interstitial fluid is extracted from the individual during the diffusion and sensing steps.
5. The method of claim 1 further comprising displaying analyte concentration information remote from the stratum corneum area of the individual's skin.
6. The method of claim 5 further comprising wirelessly communicating analyte concentration information to a display.
7. The method of claim 1 wherein the sensing step is performed by a sensor in fluid communication with the sensing area and the interior spaces of the fluid paths, the method further comprising calibrating the sensor by moving sensing fluid into the sensing area.
8. The method of claim 7 further comprising moving sensing fluid out of the sensing area as sensing fluid is moved into the sensing area.
9. The method of claim 1 further comprising attaching a device comprising the sensor area and the sensor to the individual with adhesive.
10. The method of claim 1 further comprising providing a membrane located between the distal ends of the fluid paths and the sensor.
11. The method of claim 1 wherein creating the plurality of fluid paths through the stratum corneum area of the individual's skin comprises applying a microneedle array to the stratum corneum area.
12. The method of claim 1 wherein the proximal ends of the fluid paths are in fluid communication with the sensing area.
13. The method of claim 1 wherein the step of moving sensing fluid comprises operating an actuator.
14. The method of claim 1 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.
15. The method of claim 1 wherein the sensing fluid reservoir, sensing area, and at least part of the sensor being supported by a first part of a housing, the method further comprising attaching the first part of the housing to a second part of the housing prior to the moving sensing fluid step, the second part of the housing comprising an electrical connection to the at least part of the sensor in the first part of the housing.
16. The method of claim 15 further comprising separating the second part of the housing from the first part of the housing after the sensing step.