Patent Publication Number: US-2023145155-A1

Title: Implantable micro-electrochemical cell

Description:
INCORPORATION BY REFERENCE TO ANY PRIORITY APPLICATIONS 
     Any and all applications for which a foreign or domestic priority claim is identified in the Application Data Sheet as filed with the present application are hereby incorporated by reference under 37 CFR 1.57. For example, this application claims priority to U.S. Provisional Application No. 63/273,517 and U.S. Provisional Application No. 63/263,284, the entire content of which is incorporated by reference herein in its entirety and for all purposes and forms a part of this specification. 
    
    
     BACKGROUND 
     Field 
     The general field of this disclosure is glucose sensing and disease management systems. 
     Description 
     Diabetes is a chronic disease that impacts many individuals, both adults and children. The management of diabetes may include the measurement of glucose within the interstitial space including blood and/or interstitial fluid of a patient and administration of insulin to the patient. A closed loop insulin administration system includes both a sensor to take glucose measurements from the interstitial space including blood and/or interstitial fluid of the patient and an insulin administration device which administers insulin to the patient based on the glucose measurements. Closed loop insulin administration systems allow individuals impacted by diabetes to go about daily life with much less worry about their insulin or glucose levels which can vastly improve a diabetic&#39;s quality of life. 
     SUMMARY 
     Various aspects of systems, methods and devices within the scope of the appended claims each have several aspects, no single one of which is solely responsible for the desirable attributes described herein. Without limiting the scope of the appended claims, some prominent features are described herein. 
     In some aspects, a disease management device can include an implantable micro-electrochemical cell. In some aspects, the implantable micro-electrochemical cell may include a tube configured to be implanted in a tissue site of a patient, the tube comprising: at least one sidewall; a closed end configured to be implanted in the patient; an open end configured to receive a feedthrough for at least one electrode lead; a seal configured to seal the open end of the tube; wherein the at least one sidewall comprises at least one porous interface; a fluid medium configured to be in fluid communication with bodily fluid at a tissue site of the patient through at least one porous interface; an analyte sensor in fluid communication with the fluid medium and configured to measure at least one analyte from the bodily fluid; and at least one electrical connection to the analyte sensor at the feedthrough. 
     In some examples, the porous interface may serve as a medium between surrounding electrodes. Additionally, in some examples, the porous interface contains a cross-linked water absorbing polymer matrix that may further include a hydrogel formed by cross-linking polyethylene glycol diglycidyl ether and polyethlene glycol diamine. In some examples, the tube may include an outer diameter of 300 micrometers and an inner diameter of 250 micrometers. Furthermore, in some examples, the tube may be formed with a mold and polymer resin. In some examples, the porous interface may include a diameter that ranges between 10-50 micrometers. Furthermore, in some examples, the porous interface may be created by laser drilling the tube. 
     In some examples, the analyte electrode may have a diameter of 100 micrometers, an insulting layer with a thickness of 15 micrometers, and a top modified with a suitable sensing element. In some examples, the tip of the analyte electrode may be immersed in the cross-linked water absorbing polymer matrix, In some examples, the sensing element may include an enzyme. Furthermore, in some examples, at least one electrode lead is complimented by a reference electrode and a counter electrode that is immersed in the cross-linked water absorbing polymer matrix. In some examples, the reference electrode may include Ag/AgCl and have a diameter of 20 micrometers. In some examples, the counter electrode may include Pt wire and have a diameter of 20 micrometers. In some examples, the electrode leads are sealed with a polymer resin such that an inner side of the tube is isolated from the electrode leads. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other features, aspects, and advantages of the present application are described with reference to drawings of certain aspects, which are intended to illustrate, but not limit, the present disclosure. It is to be understood that the attached drawings are for the purpose of illustrating concepts disclosed in the present application and may not be to scale: 
         FIG.  1    illustrates an example disease management system that may be part of a disease management environment or used as an interleaved device. 
         FIG.  2    illustrates an example implementation of a disease management system. 
         FIG.  3   . Illustrates an example of an implantable micro-electrochemical cell. 
         FIG.  4    illustrates an example layout of an example analyte sensor system. 
         FIG.  5    illustrates example layout of electrodes in an example analyte sensor system. 
         FIG.  6    illustrates an example embodiment of an analyte sensor that may be included in an implantable electrochemical cell. 
     
    
    
     DETAILED DESCRIPTION 
     Although certain preferred aspects and examples are disclosed below, inventive subject matter extends beyond the specifically disclosed embodiments to other alternative aspects and/or uses and to modifications and equivalents thereof. Thus, the scope of the claims that may arise here from is not limited by any of the particular aspects described below. For example, in any method or process disclosed herein, the acts or operations of the method or process may be performed in any suitable sequence and are not necessarily limited to any particular disclosed sequence. Various operations may be described as multiple discrete operations in turn, in a manner that may be helpful in understanding certain embodiments; however, the order of description should not be construed to imply that these operations are order dependent. Additionally, the structures, systems, and/or devices described herein may be embodied as integrated components or as separate components. For purposes of comparing various aspects, certain aspects and advantages of these aspects are described. Not necessarily all such aspects or advantages are achieved by any particular aspect. Thus, for example, various aspects may be carried out in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other aspects or advantages as may also be taught or suggested herein. 
       FIG.  1    shows a block diagram of an example disease management system  1101 . In some examples, the disease management system  1101  may be part of a disease management environment, such as described above. A disease management system  1101  may be configured to measure one or more physiological parameters of a patient (such as pulse, skin temperature, or other values), measure one or more analytes present in the blood of a patient (such as glucose, lipids, or other analyte) and administer medication (such as insulin, glucagon, or other medication). In some examples, a disease management system  1101  may be configured to communicate with one or more hardware processors that may be external to the disease management system  1101 , such as a cloud based processor or user device. A disease management system  1101  may include an NFC tag to support authentication and pairing with a user device (for example, smart phone or smart watch), Bluetooth communication with additional disease management systems or devices, and Bluetooth communication with a paired user device running an associated control application. To support ease of use and safe interaction with the patient, the system may incorporate user input through a tap-detecting accelerometer and provide feedback via an audio speaker, haptic vibration, and/or optical indicators. The system may operate on battery power and support both shelf-life and reliable operation once applied to the patient. Battery life may be managed through control of several planned levels of sleep and power consumption. To support this reliability, a controller can monitor several system-health parameters, and monitor temperatures of the included medication, and ambient temperature for the life of the device. 
     As illustrated in  FIG.  1   , a controller  1138  of the disease management system  1101  may be configured to communicate and control one or more components of the disease management system  1101 . The controller  1138  may include one or more hardware processors, such as a printed circuit board (PCB) or the like. The controller  1138  may be configured to communicate with peripheral devices or components to support the accurate measurement of physiological parameters and blood analytes, such as patient pulse, temperature, and blood glucose, using detector electronics. The controller  1138  may subsequently calculate dose or receive a calculated dose value and administer medication, such as insulin, by actuation of an actuated pump. The controller  1138  may record device activity and transfer the recorded data to non-volatile secure memory space. At the end of the life of a device or system, the controller can be configured to lock operation, and create a data recovery module to permit authenticated access to the recorded data if needed. 
     A disease management system  1101  may include an analyte sensor  1120 . The analyte sensor  1120  may be configured to detect analytes in the patient&#39;s blood. For example, an analyte sensor  1120  can include a glucose sensing probe configured to pierce the surface of the skin  1121 . In some examples, a disease management system  1101  may include a plurality of analyte sensors  1120  to detect one or more analytes. In some examples, an analyte sensor  1120  may be configured to detect a plurality of analytes. Sensed analytes may include, but are not limited to, glucose, insulin, and other analytes. An analyte sensor  1120  may be configured to communicate with an analyte detector  1126 . The analyte detector  1126  may be configured to receive a signal of one or more analyte sensors  1120  in order to measure one or more analytes in the blood of the patient. The analyte detector  1126  may be configured to communicate with the controller  1138 . For example, the analyte detector  1126  may be configured to, for example, send analyte values to the controller  1138  and receive control signals from the controller. 
     A disease management system  1101  may include a medication catheter  1122 . The medication catheter  1122  may be configured to administer medication, including, but not limited to insulin, to the patient. The medication catheter  1122  may receive medication from a medication bladder  1128  configured to contain medication to be administered. The medication bladder  1128  may be configured to contain medication for a prolonged period, such as 1 day, 3 days, 6 days, or more. The medication bladder  1128  may be configured to contain certain medication types, such as insulin. In some examples, a disease management system  1101  may include a plurality of medication bladders  1128  for one or more reservoirs of the same or different medications. In some examples, a disease management system  1101  may be configured to mix medications from medication bladders  1128  prior to administration to the patient. A pump  1130  may be configured to cause medication to be administered from the bladder  1128  to the patient through the insulin catheter  1122 . A pump  1130  may include, but is not limited to, a pump such as described herein. 
     A disease management system  1101  may optionally include a physiological sensor  1124 . The physiological sensor  1124  may include a pulse rate sensor, temperature sensor, pulse oximeter, the like or a combination thereof. In some examples, a disease management system  1101  may be configured to include a plurality of physiological sensors. The physiological sensor  1124  may be configured to communicate with a physiological detector  1134 . The physiological detector  1134  may be configured to receive a signals of the physiological sensor  1124 . The physiological detector  1134  may be configured to measure or determine and communicate a physiological value from the signal. The physiological detector  1134  may be configured to communicate with the controller  1138 . For example, the physiological detector  1134  may be configured to, for example, send measured physiological values to the controller  1138  and receive control signals from the controller. 
     A disease management system  1101  may include one or more local user interfacing components  1136 . For example, a local user interfacing component  1136  may include, but is not limited to one or more optical displays, haptic motors, audio speakers, and user input detectors. In some examples, an optical display may include an LED light configured to display a plurality of colors. In some examples, an optical display may include a digital display of information associated with the disease management system  1101 , including, but not limited to, device status, medication status, patient status, measured analyte or physiological values, the like or a combination thereof In some examples, a user input detector may include an inertial measurement unit, tap detector, touch display, or other component configured to accept and receive user input. In some examples, audio speakers may be configured to communicate audible alarms related to device status, medication status user status, the like or a combination thereof. A controller  1138  may be configured to communicate with the one or more local interfacing components  1136  by, for example, receiving user input from the one or more user input components or sending control signals to, for example, activate a haptic motor, generate an output to the optical display, generate an audible output, or otherwise control one or more of the local user interfacing components  1136 . 
     A disease management system  1101  may include one or more communication components  1140 . A communication component  1140  can include, but is not limited to one or more radios configured to emit Bluetooth, cellular, Wi-Fi, or other wireless signals. In some examples, a communication component  1140  can include a port for a wired connection. Additionally, a disease management system  1101  may include an NFC tag  1142  to facilitate in communicating with one or more hardware processors. The one or more communication components  1140  and NFC tag  1142  may be configured to communicate with the controller  1138  in order to send and/or receive information associated with the disease management system  1101 . For example, a controller  1138  may communicate medication information and measured values through the one or more communication components  1140  to an external device. Additionally, the controller  1138  may receive instructions associated with measurement sampling rates, medication delivery, or other information associated with operation of the management system  1101  through the one or more communication components  1140  from one or more external devices. 
     A disease management system  1101  may include one or more power components  1144 . The power components may include, but are not limited to one or more batteries and power management components, such as a voltage regulator. Power from the one or more power components  1144  may be accessed by the controller and/or other components of the disease management system  1101  to operate the disease management system  1101 . 
     A disease management system  1101  may have one or more power and sleep modes to help regulate power usage. For example, a disease management system  1101  may have a sleep mode. The sleep mode may be a very low power mode with minimal functions, such as the RTC (or real time clock) and alarms to wake the system and take a temperature measurement of the system, or the like. In another example, a disease management system  1101  may include a measure temperature mode which may correspond to a low power mode with reduced functions. The measure temperature mode may be triggered by the RTC where the system is configured to take a temperature measurement, save the value, and return the system to a sleep mode. In another example, a disease management system  1101  may include a wake up mode. The wake up mode may be triggered by an NFC device and allow the system to pair with an external device with, for example, Bluetooth. If a pairing event does not occur, the system may return to sleep mode. In another example, a disease management system  1101  may include a pairing mode. The pairing mode may be triggered by an NFC device. When a controlling application is recognized, the system may proceed to pair with the application and set the system to an on condition and communicate to the cloud or other external device to establish initial data movement. In another example, a disease management system  1101  may include a rest mode where the system is configured to enter a lower power mode between measurements. In another example, a disease management system  1101  may include a data acquisition mode where the system is configured to enter a medium power mode where data acquisition takes place. In another example, a disease management system  1101  may include a parameter calculation mode where the system is configured to enter a medium power mode where parameter calculations, such as a blood glucose calculations, are performed and data is communicated to an external device and/or the cloud. In another example, a disease management system  1101  may include a pump mode where the system is configured to enter a higher power mode where the pump draws power to deliver medication to the patient. 
     A disease management system  1101  may include one or more connector test points  1146 . The connecter test points may be configured to aid in programming, debugging, testing or other accessing of the disease management system  1101 . In some examples, connector test points  1146  may include, for example, a GPIO spare, UART receiver or transmitter, the like or a combination thereof. 
       FIG.  2    illustrates an example implementation of a disease management system  1103  and applicator  1190  for applying a disease management system  1103  to a patient. Disease management system  1103  can include any one or more of the features discussed above with respect to the disease management system  1101  in addition to the features described below. In the illustrated example, an applicator  1190  may be configured to mate with the disease management system  1103 . In some examples, an applicator  1190  may include a safety button  1192  for release or other interaction with the applicator  1190 . In the illustrated example, a disease management system  1103  may include one or more LEDs  1160  that may be configured to output information using one or more of color, frequency, and length of display. In some examples, the disease management system  1103  may include a buzzer  1176 , haptic actuator  1170 , or other feedback mechanism, such as a speaker to output information to the patient, such as an alarm. In some examples, a disease management system  1103  may include a battery  1174 , controller  1172 . In some examples, a disease management system  1103  may include aspects of a medication administration system, such as a bladder  1180 , a bladder pressure applicator  1178  to provide pressure on the bladder (such as a component of a pump), actuator  1182 , pump gears  1184 , and a pump  1186 . In some examples, a disease management system  1103  may include one or more needles  1158  that may include one or more analyte sensors (such as a glucose sensor)  1156 . In some examples, a disease management system  1103  may include one or more needles  1162  that may include one or more cannulas  1164  configured to administer medication to the patient. In some examples, a disease management system  1103  may include an air bubble sensor  1152  configured to detect the presence of air bubbles in the medication prior to delivery to the patient. In some examples, a glucose control system  1103  may include one or more physiological sensors  1154 , such as a non-invasive physiological sensor including but not limited to a pulse sensor. In some examples, the disease management system  1103  may include a base plate  1106  and an adhesive layer  1168  below the base plate  1106  to provide adhesion of the disease management system  1103  to the patient&#39;s skin. As described below, a housing of the disease management system  1103  may consist of a combination of flexible and rigid material so as to both provide support for the components of the disease management system  1103  and allow conforming, at least in part, of the disease management system  1103  to the skin of the patient. 
     The adhesive layer  1168  may be configured to provide adhesion for a prolonged period. For example, the adhesive layer  1168  may be configured to adhere the disease management system  1103  to the skin of a patient for a period of 1 day, 3 days, 6 days, or more or fewer days or hours. In some examples, the adhesive layer may be configured to have an adhesive force sufficient to prevent accidental removal or movement of the disease management system  1103  during the intended period of use of the disease management system  1103 . In some examples, the adhesive layer  1168  may be a single layer of adhesive across at least a portion of a surface the disease management system  1103  that is configured to interface with the patient. In some examples, the adhesive layer  1168  may include a plurality of adhesive areas on a surface of the disease management system  1103  that is configured to interface with the patient. In some examples, the adhesive layer  1168  may be configured to be breathable, adhere to the patient&#39;s skin after wetting by humidity or liquids such as tap water, saltwater, and chlorinated water. A thickness of the adhesive may be, for example, in a range of 0.1 to 0.5 mm or in a range of more or less thickness. 
     In some examples, a needle  1158 ,  1162  may be inserted at different depths based on a patient age, weight, or other parameter. For example, a depth of insertion of a medication cannula may be approximately 3 mm for 7 to 12 year olds. In another example, a depth of insertion of a medication cannula may be approximately 4 mm for 13 year olds and older. In another example, a depth of insertion of a medication needle may be approximately 4 to 4.5 mm for 7 to 12 year olds. In another example, a depth of insertion of a medication needle may be approximately 5 to 5.5 mm for 13 year olds and older. In another example, a depth of insertion of an analyte sensor may be approximately 3 mm for 7 to 12 year olds. In another example, a depth of insertion of an analyte sensor may be approximately 4 mm for 13 year olds and older. In another example, a depth of insertion for a needle associated with an analyte sensor may be approximately 4 to 4.5 mm for 7 to 12 year olds. In another example, a depth of insertion for a needle associated with an analyte sensor may be approximately 5 to 5.5 mm for 13 year olds and older. However, other values or ranges for any of the inserted components are also possible. 
     In some examples, an analyte sensor  1156 , such as illustrated in  FIG.  2   , can include a micro-electrochemical cell configured to at least partially implantable into the tissue of the patient. The micro-electrochemical cell may include one or more sensor components enclosed at least in part in a permeable cell. The permeable cell may include one or more permeable portions configured to allow passage of analyte containing fluid from the surrounding tissue of the patient to a portion of the permeable cell containing the one or more sensor components. The one or more sensor components may be configured to measure at least one analyte, such as glucose or other analyte present at the tissue site of the patient. 
       FIG.  3    illustrates an example of an implantable micro-electrochemical cell  3000 . The implantable micro-electrochemical cell may be implanted at least in part under the skin of the human body. The implantable micro-electrochemical cell can vary in depth of which it is implanted under the skin. For example, the implanted micro-electrochemical cell can be anywhere between up to and including 100% implanted underneath the skin. In some examples, the cell  3000  may be implanted so that at least a permeable sidewall portion  3060  may be implanted below the skin. In some examples, the cell  3000  may be implanted at a depth such that the permeable sidewall portion  3060  is in contact with bodily fluid containing analytes. In some instances, the implantable micro-electrochemical cell  3000  may be injected or inserted into the human body using a needle, such as described above with reference to  FIG.  2   , and connect to a device, such as a combined glucose sensor and insulin pump, that is located outside of the human body. In some example, one or more elements or substances inside the implantable micro-electrochemical cell  3000  may be protected from the outside. The implantable micro-electrochemical cell  3000  is configured to prevent contact of at least some of the interior components of the cell with portions of the tissue of the patient. In some examples, the cell  3000  may include a smooth outer surface. Advantageously, the smooth outer surface of the cell may protect tissue surrounding the outer surface of the cell  3000  from being irritated or injured from contact with the cell  3000 . In some examples, the smooth outer surface may be made of, for example, silicones, polyethylene, polyimide, or the like. Furthermore, the longevity of the cell  3000  may be enhanced from reduced friction or other contact with tissue of the patient. In some examples, the cell  300  may be coated with a material to enhance biocompatibility upon implantation of the cell. 
     The implantable micro-electrochemical cell may include a permeable cell. The permeable cell may include a component that is at least partially closed to outside material. The geometry of the permeable cell may include a three dimensional shape having at least one smooth surface, such as a cuboid, a pyramid, a cylinder, or other object with at least one flat or curvilinear geometric shape or side. In some examples, the permeable cell shape may include a container portion  3010 . The container portion  3010  may be tubular shape, such as illustrated in  FIG.  3   . A tubular shape for the permeable cell may provide greater surface area for the sensors compared to a flat surface. Additionally, a tubular shape may be easier to manufacture than a different shape, for example rectangular. Furthermore, a tubular shape may ease implantation of the permeable cell, such that a tubular shape may increase comfortability of the patient and/or a tubular shape may achieve a greater implantation depth than a shallower shape. 
     The permeable cell may be at least partially composed of a biocompatible material, such as a biocompatible plastic or the like. For example, the permeable cell may include at least one layer of a polyamide, other polymer, or the like. In some examples, the tube  3010  may have a length between approximately 3 mm to approximately 8 mm, such as 5 mm , an outer diameter between approximately 100 micrometers to approximately 500 micrometers, such as 300 mm, and an inner diameter between approximately 150 micrometers to approximately 450 micrometers, such as 250 mm. However, the cell may have smaller or larger dimensions. In some examples, preferably, the tube  3010  may have a length of approximately 5 mm. In some examples, preferably, the tube  3010  may have an outer diameter of approximately 300 micrometers. In some examples, preferably, the tube  3010  may have an inner diameter of approximately 250 micrometers. Advantageously the diameter of the cell may be sufficiently small so as to reduce the likelihood of a painful insertion or implantation of the micro-electrochemical cell in the tissue of the patient. Additionally, in some cases, the diameter of the cell may be sufficiently small to reduce damage or injury caused by the implantation of the cell. Furthermore, the overall size of the cell  3000  may be designed or sized to simplify the implantation procedure, such that the need for bulkier, less user friendly, tools may be minimized or eliminated. 
     The permeable cell may have at least one open end  3003  and a closed end  3005 . The permeable cell may be sealed at the open end  3003  by a seal  3020 . The seal  3020  may be used to close off the open end  3003  of the permeable cell or tube  3010  to prevent elements of the tube and substances within the tube from being misplaced. Additionally, the seal  3020  may be configured to include at least one electrical feedthrough to allow for electrode leads to pass through the seal and make an electrical connection with components of the at least one analyte sensor within the permeable cell. The electrode leads  3025  may then be configured to connect to one or more electrical components of a connected device, such as a combination insulin pump and analyte sensor and/or disease management device described with reference to  FIG.  2   . In some examples, the electrical feedthrough may at least partially not be implanted in the patient. This may provide easy access to the electrode without having to remove the permeable cell. 
     The open end  3003  may be located at the top portion of the permeable cell  3010 . The closed end  3005  may be located at the bottom portion of the permeable cell  3010 . In some examples, the open end  3003  may be positioned outside of the patient&#39;s body. In some examples, the closed end  3005  may be positioned inside of the patient&#39;s body. The open end  3003  positioned outside of the patient&#39;s body can provide a user access to the internal compartment of the permeable cell  3010  without have to remove the permeable cell  3010  from the patient&#39;s body. This can minimize the number of times the cell  3010  may be implanted and/or reimplanted after the initial implantation of the cell  3010 . Additionally, the open end  3003  positioned outside of the patient&#39;s body and the closed end  3005  positioned inside of the patient&#39;s body can help to ensure that the internal elements of the permeable cell  3010  remain inside the permeable cell  3010 . 
     In some examples, the closed end  3005  may be curved. This can increase the comfortability of the patient. For example, a curved closed end  3005  can help to ensure no sharp edges come in contact with the tissue site. This may minimize the irritation that the tissue site may experience. 
     An implantable micro-electrochemical cell  3000  may include one or more physiological sensors, including but not limited to an analyte sensor  3007 . Furthermore, in some examples, the at least one electrode may include a non-electrochemical electrode or other sensor configured to measure a physiological parameter of a patient (e.g., optical sensor). An analyte sensor  3007  may include some combination of electrodes connected to one or more electrode leads  3025 . For example, an analyte sensor  3007  may include at least one electrode, such as at least one reference electrode  3030 , at least one counter electrode  3040 , and/or at least one sensor electrode  3035 . 
     An analyte sensor  3007  may include one or more sensor electrodes. U.S. Provisional Application No. 63/263,277, filed Oct. 29, 2022, is herein incorporated by reference in it&#39;s entirety. The one or more sensor electrodes may be used to measure the presence and/or amount of the analyte within the bodily fluid. In some examples, the one or more sensor electrodes may include nanomaterials, polymers and/or polymeric composites such as chitosan, cellulose, and conducting polymers. In some examples, the one or more sensor electrodes may be rectangular in shape. In other examples, the one or more sensor electrodes may be cylindrical, conical, triangular, etc. in shape. The one or more sensor electrodes may have a thickness between approximately 10 micrometers to 50 micrometers. The one or more sensor electrodes may have a length between approximately XX. In some examples, the one or more sensor electrodes may be located within the internal compartment of the permeable cell  3010 . The one or more sensor electrodes may be positioned in the center of the cell  3010 . This may increase the ability for the one or more sensor electrodes to measure analytes at the tissue site by allowing the bodily fluid to come in contact with all sides of the sensor electrodes. 
     A sensor electrode  3035  may be configured to measure one or more analytes at the tissue site of the patient. For example, a sensor electrode may be configured to measure glucose, insulin, and/or other analytes.[ The one or more analytes may, in some examples, be in fluid  3060  within the cell  3000 . In some examples, the sensor electrode  3035  may contain an insulting layer with a thickness of between approximately 10 micrometers to approximately 20 micrometers, such as 15 mm. The sensor electrode  3035  may have a tip  3036  that is modified with a suitable sensing element (e.g., an enzyme or the like). In some examples, preferably, the insulating layer may have a thickness of approximately 15 micrometers. The sensor electrode may have a diameter of approximately 80 micrometers to 120 micrometers. In some examples, the sensor electrode may have a diameter of approximately 100 micrometers. 
     An analyte sensor, such as a glucose sensor, is an amperometric electrochemical biosensor generating a current from the electrochemical reaction between an analyte, such as glucose and a glucose oxidase layer on working electrode (WE). An analyte sensor such as those described above can include some combination of electrodes, including a reference electrode, counter electrode, and working electrode. In general, the reference electrode (RE) eliminates the potential arising from a solution medium. In general, the counter electrode (CE) acts as a reference half-cell to supply the required current for the electrochemical reaction, whereas the WE acts as a sensing half-cell to produce current. The sensor system described herein may include at least two electrodes—the working electrode and the reference electrode. 
     In some aspects, the working electrode and/or the reference electrode may comprise one or more metals. In some further aspects, the working electrode and/or the reference electrode may comprise platinum (Pt), gold (Au), silver (Ag), rhodium (Rh), iridium (Ir), or combinations thereof. 
     In one aspect, the working electrode may comprise Pt. In some aspects, the working electrode may comprise both Pt and Au. In another aspect, the working electrode comprises both Pt and Ir. In some aspects, the working electrode may comprise two different metal layers. In some aspects, the bottom metal layer of a working electrode may be Au and the top metal layerof the working electrode may be Pt. In some aspects, the bottom metal layer of a working electrode may be Ag and the top metal layer of the working electrode may be Pt. In some aspects, the bottom metal layer of a working electrode may be Pt and the top metal layer of the working electrode may be Au or Ag. In some aspects, the thickness of the bottom metal layer may be about 2 μm, about 2.5 nm, about 3 nm, about 3.5 nm, about 4 μm, or any other thickness. In some aspects, the thickness of the top metal layer may be about 50Å, about 70 Å, about 90 Å, about 100 Å, about 120 Å, about 150 Å, or any other thickness. In some aspects, the thickness of the top metal layer may be much less than the thickness of the bottom metal layer. The ratio of the thickness of the top metal layer to the thickness of the bottom metal layer may be less than about 1/500, 1/300, 1/100, or less than any other ratio. 
     An analyte sensor  3007  may include one or more reference electrodes. The one or more reference electrodes may include Ag/AgCl, or the like In some examples, the reference electrode  3030  may be rectangular in shape. In other examples, the one or more reference electrodes may be cylindrical, conical, triangular, etc. in shape. . . . [describe material, shape, size, location, and function]. The one or more reference electrodes may be located within the internal compartment of the cell  3010  The reference electrode  3030  of the analyte sensor may have a diameter of approximately 10 micrometers to 30 micrometers. In some examples, the diameter of the analyte sensor may be approximately 20 micrometers. . . . In some examples, a plurality of electrodes may be contained within the cell  3000 . The reference electrode  3030  may have an accurately maintained potential to be used as a reference other sensor electrodes within the cell 
     In one embodiment, the reference electrode may comprise silver and silver chloride (Ag/AgCl), Hydrogen, SCE, or the like. In some aspects, the thickness of the metal layer in the reference electrode may be about 2 μm, about 2.5 μm, about 3 μm, about 3.5 μm, about 4 μm, or any other thickness. This can advantageously affect the size and shape of the cell. For example, the thinner the metal layer in the reference electrode, the smaller the overall size of the cell may be. 
     In some aspects, the thickness of the reference electrode  520  may be about 2 μm, about 2.5 μm, about 3 μm, about 3.5 μm, about 4 μm, and or other thickness. In some aspects, the reference electrode  520  may comprise silver. In some aspects, the reference electrode  520  may comprise a bottom metal layer and a top metal layer. In some aspects, the bottom metal layer may be about 2 μm, about 2.5 μm, about 3 μm, about 3.5 μm, about 4 μm, and or other thickness. In some aspects, the reference electrode  520  may comprise a top metal later. The top metal layer may be about 50Å, about 70 Å, about 90 Å, about 100 Å, about 120 Å, about 150 Å, or any other thickness. In some aspects, the thickness of the working electrode  510  and the reference electrode  520  may be similar. 
     An analyte sensor  3007  may include one or more counter electrodes. The one or more counter electrodes may be rectangular in shape. In other examples, the one or more counter electrodes may be cylindrical, conical, triangular, etc. in shape. The one or more counter electrodes may be located within the internal compartment of the cell  3010 . The counter electrode  3040  may have a diameter of approximately 10 micrometers to 40 micrometers. In some examples, the counter electrode may have a diameter of approximately 30 micrometers. In some examples the counter electrode  3040  may consist of platinum or the like. The one or more counter electrodes can be an inert conductor. 
     In some aspects, the device may further comprise a counter electrode. The counter electrode may comprise one or more metals described herein. In one embodiment, the counter electrode comprises Au. In another embodiment, the counter electrode comprises Pt. In another embodiment, the counter electrode comprises carbon. In some aspects, the thickness of the metal layer in the counter electrode may be about 2 μm, about 2.5 μm, about 3 μm, about 3.5 μm, about 4 μm, and or other thickness. This can advantageously affect the size and shape of the cell. For example, the thinner the metal layer in the counter electrode, the smaller the overall size of the cell may be. 
     The at least one electrode lead  3025  may be sealed, such that an inner side of the tube is isolated from the at least one electrode leads  3025 . In some examples, the at least one electrode lead  3025  may be sealed with a polymer resin or the like. 
     The implantable micro-electrochemical cell  3000  may include at least one porous interface  3060 . The at least one porous surface  3060  may include at least a portion of the permeable cell that is configured to allow at least some transmission of analytes at the implantation site of the cell to access an interior portion of the cell  3000  and make contact with an analyte sensor inside the interior portion. In some examples, a porous interface  3060  may be a mesh or other permeable membrane. In some examples, the porous interface  3060  may be generated by laser drilling the tube  3010  so as to create a plurality of holes or pores in the surface of the tube  3010 . In other examples, the tube  3010  may be formed with a mold and polymer resin to encompass the porous interface  3060 . The diameter of pores or holes in the porous interface  3060  may range between 10-50 micrometers or more or less than that range. In some examples, the porous interface  3060  may be adequately sizable enough to allow for diffusion of glucose into a fluid medium  3080  within the cell with minimal resistance, which may increase the ability for fresh glucose or other analytes to enter the cell  3000  from surrounding tissue of the patient when the cell  3000  is implanted. 
     The sensor electrode  3050  may be configured to measure analytes within a fluid medium  3080 . The fluid medium  3080  may be provided into the interior of the permeable cell at the site of the porous interface. The fluid medium  3080  may be configured to act as an interface and provide fluid communication with bodily fluid or analytes entering the permeable cell through the porous interface and at least a portion of the at least one analyte sensor. some examples, the fluid medium  3080  may contain a cross-linked water absorbing polymer matrix. For example, the cross-linked water absorbing polymer matrix may include a hydrogel formed by cross-linking polyethylene glycol diglycidyl ether and polyethylene glycol diamine. 
     Example Analyte Sensor Configuration 
       FIG.  4    illustrates an example configuration of an analyte sensor system  4000  that may be used in within the cell  3000  referenced in  FIG.  3   . An analyte sensor system  4000  may include some combination of electrodes  4102  and connector(s)  4104 . The electrodes, at least in part, may be implanted into a tissue of a patient such that interstitial fluid containing one or more analytes comes into contact with the one or more electrodes  4102 . This can allow for an accurate measurement of the interstitial fluid and/or collection of data. The connector(s)  4104  may be disposed outside the human body and/or may be in electrical connection with a disease management system, such as described above. The connector(s)  4104  may allow for continuous and real-time monitoring of the analytes measured within the interstitial fluid. In some examples, a width, D, of the sensor system  4000  may be approximately 1 mm or more or fewer mm. In some examples, a height, H, of the sensor system  4000  may be approximately 10 mm, 20 mm, or more or fewer mm. At least part of the sensor system  4000  may be configured to be formed into a non-flat configuration, such as a cylindrical or otherwise curved shape. In some examples, at least a portion of the electrodes  4102  may be curved along a vertical or horizontal axis. This can advantageously contribute to the size and/or shape of the cell. For example, a non-flat configuration of the sensor system  4000  may fit into a smaller space, which can minimize any negative implantation effects due to the size and/or shape of the implantable cell. 
     The electrodes  4102  may have a layout or pattern in one or more configurations.  FIG.  5    illustrates some example configurations  4102 A,  4102 B,  4102 C of electrodes  4102 . In a first configuration  4102 A, an analyte sensor includes a combination of two electrodes. In the configuration of two electrodes, a sensor electrode may include platinum and a reference electrode may include silver. The reference electrode may be larger than the sensor electrode. In a two electrode configuration, the electrodes may be patterned onto a flexible or semi-flexible substrate and configured to be wrapped around or curved around a cylindrical or other shape such that the reference and sensor electrodes face outwards towards interstitial fluid. 
     In a second  4102 B and third  4102 C configuration, an analyte sensor may include three electrodes. In a three electrode configuration, the analyte sensor can include a sensor electrode, reference electrode, and counter electrode. In a second configuration  4102 B, the reference electrode and the counter electrode may be silver and the sensor electrode may be platinum. In a third configuration  4102 C, the reference electrode may be silver and the counter electrode and sensor electrode may be platinum. It is of note that use of a metal other than silver for, for example, a counter electrode, may result in microscopic bubbles of air, which can cause problems in measurements. In the second and third configuration, the electrodes may be patterned onto a flexible or semi-flexible substrate and configured to be wrapped around or curved around a cylindrical or other shape such that the electrodes either face outwards or face inwards. The electrodes can measure the bodily fluids containing analytes when facing either direction. With a pattern of electrodes facing towards the outside, the electrodes may have more access to bodily fluids containing analytes. However, while the implantable cell and/or electrodes may include a biocompatible coating to increase biocompatibility of the cell, the body can attack the electrodes and the layers of chemistry associated with the sensor due to an immune response. With a pattern of electrodes facing towards the inside, the electrodes may continue to have access towards bodily fluids and the configuration may be placed in an electrochemical cell, such as described herein and illustrated, for example, in  FIG.  6   . Advantageously, the use of an interior facing configuration in an electrochemical cell using a hydrogel or other medium to transmit interstitial fluids and/or analytes to the electrodes of the sensor can allow use of either a platinum or silver counter electrode with reduced issues (such as the presence of microscopic bubbles) than if the electrodes of the sensor system were in direct contact with tissue. 
       FIG.  6    illustrates example configurations of an analyte sensor system, such as described above. The configurations illustrated in  FIG.  6    may include a cylindrical or curved configuration of an analyte sensor system  4000 . In some examples, at least a portion of the sensor system  4000  may be curved or shaped around a core  4100 . In some examples, such as shown in configuration  4002 , the core  4100  may provide shape, structure, and/or stability for the sensor system  4000 . In providing shape, structure, and/or stability for the sensor system  4000 , the core  4100  may allow the sensor system to more accurately measure the analytes within the bodily fluid. In some examples, such as shown in configuration  4004 , some or all of the sensor system  4000  may be freely standing from the core  4100 . In some examples one or more electrodes  4102  may be positioned on an outer surface of the sensor system  4000 , such as shown in configuration  4002  and in some examples, one or more electrodes  4102  may be positioned on an inner surface (such as facing a core  4100  or center portion of the sensor system  4000 ) such that analytes in a medium surrounding the sensor system  4000  may be measured on the interior portion of the sensor system  4000 . In some examples, a curved analyte sensor system  4000  may be configured to measure analytes in the interior of an electrochemical cell  3000 , such as described above with reference to  FIG.  3   . Electrodes  4102  of the sensor system may be configured to point towards an interior of the cell and analytes may come into contact with the electrodes through the hydrogel or other medium in the interior of the electrochemical cell. This configuration may protect the electrodes from being attacked by the immune response produced upon implantation of the cell. 
     Terminology 
     Unless defined otherwise, all technical and scientific terms used herein have the same meaning as is commonly understood by one of ordinary skill in the art. The use of the term “including” as well as other forms, such as “include”, “includes,” and “included,” is not limiting. The use of the term “having” as well as other forms, such as “have”, “has,” and “had,” is not limiting. The terms “comprising,” “including,” “having,” and the like are synonymous and are used inclusively, in an open-ended fashion, and do not exclude additional elements, features, acts, operations, and so forth. That is, the above terms are to be interpreted synonymously with the phrases “having at least” or “including at least.” For example, when used in the context of a process, the term “comprising” means that the process includes at least the recited steps, but may include additional steps. When used in the context of a device, the term “comprising” means that the device includes at least the recited features or components, but may also include additional features or components. Also, the term “or” is used in its inclusive sense (and not in its exclusive sense) so that when used, for example, to connect a list of elements, the term “or” means one, some, or all of the elements in the list. Further, the term “each,” as used herein, in addition to having its ordinary meaning, can mean any subset of a set of elements to which the term “each” is applied. 
     Conditional language, such as “can,” “could,” “might,” or “may,” unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain embodiments include, while other embodiments do not include, certain features, elements, or steps. Thus, such conditional language is not generally intended to imply that features, elements, or steps are in any way required for one or more embodiments or that one or more embodiments necessarily include logic for deciding, with or without user input or prompting, whether these features, elements, or steps are included or are to be performed in any particular embodiment. 
     Conjunctive language such as the phrase “at least one of X, Y, and Z,” unless specifically stated otherwise, is otherwise understood with the context as used in general to convey that an item, term, etc. may be either X, Y, or Z. Thus, such conjunctive language is not generally intended to imply that certain embodiments require the presence of at least one of X, at least one of Y, and at least one of Z. 
     Language of degree used herein, such as the terms “approximately,” “about,” “generally,” and “substantially” as used herein represent a value, amount, or characteristic close to the stated value, amount, or characteristic that still performs a desired function or achieves a desired result. For example, the terms “approximately”, “about”, “generally,” and “substantially” may refer to an amount that is within less than 10% of, within less than 5% of, within less than 1% of, within less than 0.1% of, and within less than 0.01% of the stated amount. 
     The term “and/or” as used herein has its broadest least limiting meaning which is the disclosure includes A alone, B alone, both A and B together, or A or B alternatively, but does not require both A and B or require one of A or one of B. As used herein, the phrase “at least one of” A, B, “and” C should be construed to mean a logical A or B or C, using a non-exclusive logical or. 
     The term “temperature independent” as used herein, means that the reading or measurement of the glucose level by the glucose monitoring device or the response of the glucose sensor is not affect or not substantially affected by the change of temperature. In other words, the sensor is insensitive the change of temperature (e.g., change of body temperature as a result of physiological conditions such as hypothermia and hyperpyrexia). In some embodiments, the temperature independent property of the glucose monitoring device is maintained within the operating temperature range of the device (e.g., from about 30° C. to about 45° C., from about 33° C. to about 43° C., from about 35° C. to about 41° C., or from about 36° C. to about 40° C. In some embodiments, the change of temperature (per ° C.) results in less than 5%, 4%, 3%, 2%, 1%, 0.5%, 0.1% or 0.01% change in the response of the sensor, or the measurement/reading provided by the device, when all the other parameters remain the same (e.g., the glucose concentration is constant). 
     Any methods disclosed herein need not be performed in the order recited. The methods disclosed herein include certain actions taken by a practitioner; however, they can also include any third-party instruction of those actions, either expressly or by implication. 
     Conditional language used herein, such as, among others, “can,” “could,” “might,” “may,” “e.g.,” and the like, unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain, certain features, elements and/or steps are optional. Thus, such conditional language is not generally intended to imply that features, elements and/or steps are in any way required or that one or more implementations necessarily include logic for deciding, with or without other input or prompting, whether these features, elements and/or steps are included or are to be always performed. The terms “comprising,” “including,” “having,” and the like are synonymous and are used inclusively, in an open-ended fashion, and do not exclude additional elements, features, acts, operations, and so forth. Also, the term “or” is used in its inclusive sense (and not in its exclusive sense) so that when used, for example, to connect a list of elements, the term “or” means one, some, or all of the elements in the list. 
     Conjunctive language such as the phrase “at least one of X, Y, and Z,” unless specifically stated otherwise, is otherwise understood with the context as used in general to convey that an item, term, etc. may be either X, Y, or Z. Thus, such conjunctive language is not generally intended to imply that certain implementations require the presence of at least one of X, at least one of Y, and at least one of Z. 
     Language of degree used herein, such as the terms “approximately,” “about,” “generally,” and “substantially” as used herein represent a value, amount, or characteristic close to the stated value, amount, or characteristic that still performs a desired function or achieves a desired result. For example, the terms “approximately”, “about”, “generally,” and “substantially” may refer to an amount that is within less than 10% of, within less than 5% of, within less than 1% of, within less than 0.1% of, and within less than 0.01% of the stated amount. As another example, in certain implementations, the terms “generally parallel” and “substantially parallel” refer to a value, amount, or characteristic that departs from exactly parallel by less than or equal to 15 degrees, 10 degrees, 5 degrees, 3 degrees, 1 degree, 0.1 degree, or otherwise. 
     Any methods disclosed herein need not be performed in the order recited. The methods disclosed herein include certain actions taken by a practitioner; however, they can also include any third-party instruction of those actions, either expressly or by implication. 
     The methods and tasks described herein may be performed and fully automated by a computer system. The computer system may, in some cases, include multiple distinct computers or computing devices (for example, physical servers, workstations, storage arrays, cloud computing resources, etc.) that communicate and interoperate over a network to perform the described functions. Each such computing device typically includes a processor (or multiple processors) that executes program instructions or modules stored in a memory or other non-transitory computer-readable storage medium or device (for example, solid state storage devices, disk drives, etc.). The various functions disclosed herein may be embodied in such program instructions, and/or may be implemented in application-specific circuitry (for example, ASICs or FPGAs) of the computer system. Where the computer system includes multiple computing devices, these devices may, but need not, be co-located. The results of the disclosed methods and tasks may be persistently stored by transforming physical storage devices, such as solid state memory chips and/or magnetic disks, into a different state. The computer system may be a cloud-based computing system whose processing resources are shared by multiple distinct business entities or other users. 
     While the above detailed description has shown, described, and pointed out novel features, it can be understood that various omissions, substitutions, and changes in the form and details of the devices or algorithms illustrated can be made without departing from the spirit of the disclosure. As can be recognized, certain portions of the description herein can be embodied within a form that does not provide all of the features and benefits set forth herein, as some features can be used or practiced separately from others. The scope of certain implementations disclosed herein is indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.