Analyte and environment sensors
Disclosed are devices, systems and methods for in vivo monitoring of localized environment conditions within a patient user by measuring analytes, including glucose, oxygen, and/or other analytes. In some aspects, a sensor device includes a wafer-based substrate, at least one electrochemical sensor two-electrode contingent including a working electrode and a reference electrode on the substrate and configured to detect a target analyte in a body fluid when the sensor device is deployed within a subject's body, where the working electrode is functionalized by a chemical layer configured to facilitate a reaction involving the target analyte that produces an electrical signal; and an electronics unit in communication with the electrochemical sensor electrode contingent to transmit the electrical signal to an external processor.
1. A sensor device for in vivo monitoring of analytes, comprising:
a substrate comprising an electrically non-conductive material, wherein the substrate is a wafer-based substrate comprising silicon oxide and includes an upper surface having a plurality of ridges to provide a three-dimensional profile to the sensor device;
an electrochemical sensor electrode contingent disposed on the substrate and configured to detect a target analyte in a body fluid when the electrochemical sensor electrode contingent is deployed fully within a subject's body, the electrochemical sensor electrode contingent comprising, and optionally consisting of, a working electrode and a reference electrode associated with the working electrode, wherein the electrochemical sensor electrode contingent has a morphology corresponding to the three-dimensional profile provided by the substrate, wherein the working electrode is functionalized by a chemical layer configured to facilitate a reaction involving the target analyte that produces an electrical signal at the electrochemical sensor electrode contingent, wherein the reference electrode includes iridium oxide and the working electrode includes platinum and iridium, and wherein the sensor device is operable to detect the target analyte at a low power consumption based on an applied voltage at the reference electrode of greater than or equal to about 110 mV and less than 300 mV, less than 285 mv, or less than 175 mV,
wherein the chemical layer includes a membrane comprising (i) an outer layer exposed to the body fluid configured to regulate permeation of reactive species including the target analyte and (ii) an inner layer coupled between the outer layer and the surface of the working electrode to immobilize a catalyst able to facilitate the reaction by the permeated reactive species for detection of the target analyte at the working electrode, wherein the membrane includes a plurality of ripples on a top surface of the outer layer;
a plurality of electrodes disposed on the substrate and configured to detect a parameter associated with electrical conductivity of the body fluid across at least two electrodes of the plurality of electrodes when the sensor device is deployed within the subject's body, wherein the at least two electrodes are configured to operate as an AND gate, such that when the body fluid is in contact with both of the two electrodes, a short circuit occurs across the two electrodes that corresponds to a one and one signal of the AND gate detectable by the sensor device; and
an electronics unit in communication with the electrochemical sensor electrode contingent, the electronics unit comprising a wireless communications unit including a wireless transmitter or wireless transceiver to transmit data associated with the electrical signal to an external processor,
wherein, the external processor is operable to determine a parameter associated with the target analyte based on the electrical signal measured at the electrochemical sensor electrode contingent, and wherein the processor is configured to determine from the same electrical signal produced at the electrochemical sensor electrode contingent a change in an environmental condition including temperature within a deployment zone when the electrochemical sensor electrode contingent is deployed within the subject's body.
2. The sensor device of claim 1 , wherein the determined change in temperature is indicative of stability of the temperature within the deployment zone and potential infection at least in or proximate the deployment zone.
3. The sensor device of claim 1 , wherein the determined change in temperature is compared to a threshold value to generate an alert when the determined change exceeds the threshold value.
4. The sensor device of claim 1 , wherein the determined change in the environmental condition includes a change in osmolality.
5. The sensor device of claim 1 , wherein at least some electrodes of the plurality of electrodes are at least partially covered by a permeable membrane.
6. The sensor device of claim 1 , wherein the working electrode and the reference electrode are disposed over at least a portion of one or more ridges of the plurality of ridges of the substrate.
7. The sensor device of claim 1 , wherein the chemical layer has a morphology corresponding to the three-dimensional profile.
8. The sensor device of claim 1 , wherein the reference electrode includes iridium.
9. The sensor device of claim 1 , wherein the sensor device is able to maintain a constant and stable reference signal with respect to the detected electrical signal over a period of time of at least 12 months.
10. The sensor device of claim 1 , wherein the sensor device is configured to prevent detectable interference signals caused by secondary chemistry elements including dopamine, aspirin, acetaminophen, or a numbing chemical for pain treatment.
11. The sensor device of claim 1 , wherein the working electrode further includes at least one of gold, silver, titanium, single- or multi-walled carbon nanotubes, or an alloy.
12. The sensor device of claim 1 , wherein the working electrode is functionalized by the chemical layer configured to interact with the target analyte to facilitate a reaction that results in a change in electrical charge potential or flow at or proximate the surface of the working electrode, such that an electrical signal associated with the reaction is detectable at the working electrode with respect to the reference electrode to measure a parameter associated with the target analyte.
13. The sensor device of claim 12 , wherein the chemical layer includes (i) an outer layer exposed to the body fluid configured to regulate permeation of reactive species including the target analyte and (ii) an inner layer coupled between the outer layer and the surface of the working electrode to immobilize a catalyst able to facilitate the reaction by the permeated reactive species for detection of the target analyte at the working electrode.
14. The sensor device of claim 1 , wherein the membrane includes a thickness of 10 μm or less or of 5 μm to 10 μm.
15. The sensor device of claim 1 , wherein the plurality of ripples on the top surface of the outer layer includes a height in a range of 10 μm to 20 μm.
16. The sensor device of claim 1 , wherein the plurality of ripples on the top surface of the outer layer are configured to promote functional longevity of electrochemical sensor electrode contingent based on increased signal stability of the detected electrical signal and prevention of fouling of the working electrode.
17. The sensor device of any of claim 1 , wherein the plurality of ripples of the membrane are formed at least partially by the membrane conformed on a three-dimensional surface of the substrate.
18. The sensor device of claim 1 , wherein the electronics unit further comprises a signal conditioning unit in communication with the electrochemical sensor electrode contingent via one or more electrical interface components, the signal conditioning unit comprising an electrical circuit configured to process the detected electrical signal by one or more of amplifying the electrical signal, filtering the electrical signal, or converting the electrical signal from analog to digital.
19. The sensor device of claim 18 , wherein the electronics unit further comprises a data processing unit in communication with the signal conditioning unit, the data processing unit comprising a processor and a memory and configured to process the electrical signal as analyte data representative of one or more parameters of the target analyte.
20. The sensor device of claim 1 , comprising electrical interconnection wires and electrical interfacing contact sites disposed on the substrate, wherein the electrical interconnection wires are coupled between the electrochemical sensor electrode contingent and the electrical interfacing contact sites.
21. The sensor device of claim 20 , wherein the electrical interconnection wires disposed on the substrate are hermetically sealed by a non-permeable material that covers the electrical interconnection wires to provide an electrical shield from the body fluid.
22. The sensor device of claim 21 , wherein the non-permeable material includes at least one of a parylene, a urethane, or a Teflon material.
23. The sensor device of claim 1 , comprising a casing that encompasses the electronics unit to protect the electronics unit from exposure to the body fluid and that at least partially encompasses the electrochemical sensor electrode contingent such that the working electrode and reference electrode are exposed to the body fluid when the sensor device is deployed in the body of the subject.
24. The sensor device of claim 23 , wherein the casing includes one or both of flat sides or curved sides to provide a form factor of the sensor device.
25. The sensor device of claim 23 , wherein the from factor of the sensor device includes at least one of rectangular, a cylindrical, a conical, an elliptical, a pyramidal, a trapezoidal, or a non-uniform shape.
26. The sensor device of claim 1 , comprising:
a second electrochemical sensor electrode contingent disposed on the substrate and configured to detect a second target analyte in the body fluid when the second electrochemical sensor electrode contingent is deployed fully within the subject's body, the second electrochemical sensor electrode contingent comprising, and optionally consisting of, a second working electrode and a second reference electrode associated with the second working electrode, wherein the second working electrode is functionalized by a second chemical layer configured to facilitate a reaction involving the second target analyte that produces a second electrical signal at the second electrochemical sensor electrode contingent.
27. The sensor device of claim 1 , comprising:
one or more electrically conductive pads disposed on the substrate configured to be electrically stimulated so as to detect parameters associated with the body fluid exposed to the electrochemical sensor electrode contingent.
28. The sensor device of claim 27 , wherein the one or more electrically conductive pads are capable of ensuring the detected electrical signal is detected in a fluid rich environment, and/or are capable of decreasing noise associated with the detected signal to a negligible level.
29. The sensor device of claim 1 , wherein the target analyte comprises glucose.