Continuous analyte monitoring system with microneedle array
Described herein are variations of an analyte monitoring system, including an analyte monitoring device. For example, an analyte monitoring device may include an implantable microneedle array for use in measuring one or more analytes (e.g., glucose), such as in a continuous manner. The microneedle array may include, for example, at least one microneedle including a tapered distal portion having an insulated distal apex, and an electrode on a surface of the tapered distal portion located proximal to the insulated distal apex. At least some of the microneedles may be electrically isolated such that one or more electrodes is individually addressable.
1. A microneedle array for use in sensing an analyte, comprising:
a semiconductor substrate;
a plurality of solid microneedles extending from the substrate, wherein at least one microneedle of the plurality of microneedles is configured to sense an analyte in dermal interstitial fluid of a user and comprises:
a columnar body portion;
a tapered distal portion having an insulated distal apex; and
an annular working electrode coupled to a surface of the tapered distal portion, wherein a portion of the working electrode overlies and extends beyond an annular recess formed in the surface of the tapered distal portion, wherein the working electrode extends onto the surface of the tapered distal portion on each side of the annular recess.
2. The microneedle array of claim 1 , wherein the tapered distal portion is distal to the columnar body portion.
3. The microneedle array of claim 1 , wherein the working electrode comprises a proximal edge and a distal edge and is on only a segment of the surface of the tapered distal portion of the microneedle.
4. The microneedle array of claim 3 , wherein the distal edge of the working electrode is distal to a proximal edge of the insulated distal apex.
5. The microneedle array of claim 1 , wherein the at least one microneedle comprises a biorecognition layer arranged over the working electrode, wherein the biorecognition layer comprises a biorecognition element.
6. The microneedle array of claim 5 , wherein the biorecognition element comprises glucose oxidase.
7. The microneedle array of claim 1 , wherein the microneedle array further comprises at least one microneedle comprising a counter electrode configured to source or sink current to sustain an electrochemical reaction on the working electrode.
8. The microneedle array of claim 1 , wherein the microneedle array further comprises at least one microneedle comprising a reference electrode configured to provide a reference potential for the working electrode.
9. The microneedle array of claim 3 , wherein the distal edge of the working electrode is offset from the insulated distal apex by an offset distance of at least about 10 μm, wherein the offset distance is measured along a longitudinal axis of the at least one microneedle.
10. The microneedle array of claim 1 , further comprising an electrical contact on a backside of the substrate, wherein the columnar body portion of the at least one microneedle of the plurality of microneedles provides a conductive pathway between the electrical contact and the working electrode.
11. The microneedle array of claim 10 , wherein the columnar body portion is formed from a conductive material.
12. The microneedle array of claim 10 , wherein the columnar body portion comprises an embedded conductive pathway.
13. The microneedle array of claim 10 , wherein the columnar body portion is insulated.
14. The microneedle array of claim 1 , further comprising a biorecognition layer arranged over the working electrode extending onto the surface of the tapered distal portion.
15. The microneedle array of claim 1 , wherein the at least one microneedle comprises only one annular working electrode.
16. The microneedle array of claim 1 , wherein each of the microneedles in the plurality of solid microneedles comprises:
a columnar body portion;
a tapered distal portion having an insulated distal apex; and
an annular electrode on a surface of the tapered distal portion,
wherein the annular electrode is proximate a proximal edge of the insulated distal apex, and
wherein the annular electrode is a working electrode, a counter electrode, or a reference electrode.
17. The microneedle array of claim 1 , wherein the microneedle array comprises a plurality of working electrodes, wherein each working electrode is individually addressable and electrically isolated from every other working electrode in the microneedle array.
18. The microneedle array of claim 17 , wherein the microneedle array is configured to detect multiple analytes.
19. The microneedle array of claim 1 , wherein the plurality of solid microneedles are arranged in a square or hexagonal array.
20. An analyte monitoring system comprising:
an analyte monitoring device comprising:
the microneedle array of claim 1 ; and
a wearable housing,
wherein the microneedle array extends outwardly from the housing.
21. The system of claim 20 , wherein the at least one microneedle of the plurality of microneedles extends from the wearable housing such that the distal end of the working electrode is located less than about 1 mm from the wearable housing.
22. The system of claim 20 , wherein the wearable housing encloses an electronics system comprising a wireless communication module and the system further comprises a software application executable on a mobile computing device to be paired with the wireless communication module.
23. The system of claim 20 , wherein the housing comprises a user interface comprising one or more indicator lights configured to communicate status information.
24. The system of claim 23 , wherein at least one of the indicator lights is configured to be selectively illuminated in accordance with an illumination mode corresponding to an analyte measurement status, a status of the analyte monitoring device, or both.
25. The system of claim 24 , wherein at least one of the indicator lights is configured to be selectively illuminated to communicate a current analyte measurement level.
26. The system of claim 23 , wherein the user interface is further configured to communicate information indicative of a status of the analyte monitoring device.
27. The system of claim 20 , wherein the analyte monitoring device is a skin-adherable patch.