ENCLOSURE FOR A WIRELESS IMPLANTABLE DEVICE WITH EMBEDDED POWER SOURCE

An implantable device including a housing, circuitry within the housing, and a power source attached to the housing and electrically connected to the circuitry. The device may include electrically conductive connectors configured to electrically connect positive and negative terminals of the power source to the circuitry. The device may include a power source terminal enclosure attached to the power source and configured to enclose the positive and negative terminals of the power source. The power source terminal enclosure may include holes through which the electrically conductive connectors pass. The device may include a housing cap enclosure attached to the power source terminal enclosure and to an open end of the housing. The housing cap enclosure may enclose the circuitry within the housing and includes passages through which the electrically conductive connectors pass.

BACKGROUND

Field of Invention

The present invention relates generally to analyte monitoring and to implantable devices including a power source.

Discussion of the Background

An implantable sensor that has no charge storage device may rely exclusively on an external device for operational power (e.g., to operate its circuitry for making measurements and conveying the data to the external device). The sensor and the external device may each include an inductive element (e.g., coil). The sensor may receive power from the external device when the external device uses its inductive element to generate an electrodynamic field and the inductive elements of the sensor and external device are magnetically coupled within the electrodynamic field. However, with no internal power source, the sensor is dormant if the sensor is not located in the proximity of the external device (i.e., if the inductive elements of the sensor and the external device are not coupled within the electrodynamic field generated by the external device).

For instance, the sensor having no charge storage device may be implanted in the arm of a human patient, and the sensor may be located in the proximity of the external device when the human patient wears an armband having the external device therein. The sensor would be able to take analyte measurements and convey data to the external device while the patient is wearing the armband, but the sensor would not be able to able to take analyte measurements while the patient was not wearing the armband (e.g., because the human patient is swimming or showering), and the result would be a gap in analyte measurement information.

Accordingly, there is a need for an improved sensor and methods for using the same that improve the ability of the sensor to take analyte measurements.

SUMMARY

One aspect of the invention may provide an implantable device including a housing, circuitry, a power source, electrically conductive connectors, a power source terminal enclosure, and a housing cap enclosure. The power source may be attached to the housing. The power source may include positive and negative terminals electrically connected to the circuitry. The electrically conductive connectors may be configured to electrically connect the positive and negative terminals of the power source to the circuitry. The power source terminal enclosure attached to the power source and configured to enclose the positive and negative terminals of the power source. The housing cap enclosure attached to the power source terminal enclosure and to an open end of the housing, wherein the housing cap enclosure encloses the circuitry within the housing.

In some embodiments, the power source terminal enclosure may include holes through which the electrically conductive connectors pass. In some embodiments, the housing cap enclosure may include passages through which the electrically conductive connectors pass. In some embodiments, the housing cap enclosure may include passages through which one or more supports attached to and extending from the power source pass.

In some embodiments, the device may further include a spring configured to establish an electrical connection between a connector of the electrically conductive connectors and the positive terminal of the power source. In some embodiments, the power source terminal enclosure may enclose the spring.

In some embodiments, the device may further include one or more supports attached to and extending from the power source, and the one or more supports may be configured to support the attachment of the power source to the housing. In some embodiments, the one or more supports may have a larger diameter than a diameter of the electrically conductive connectors. In some embodiments, the supports may be made from a material that is not electrically conductive. In some embodiments, the power source terminal enclosure may include holes through which the supports pass. In some embodiments, the housing cap enclosure may include passages through which the supports pass.

In some embodiments, the device may further include one or more substrates within the housing, and the circuitry may include one or more circuit components mounted on or fabricated in the one or more substrates. In some embodiments, the one or more circuit components may include one or more light sources and one or more photodetectors.

In some embodiments, the circuitry may include an inductive element. In some embodiments, the inductive element may include a conductor and a magnetic core. In some embodiments, the device may further include comprising one or more analyte indicators on or in a portion of an exterior surface of the housing. In some embodiments, the power source may be a battery. In some embodiments, the device may be hermetically sealed. In some embodiments, the implantable device may further include a drug-eluting polymer matrix covering at least a portion of the power source terminal enclosure and/or the housing cap enclosure.

Another aspect of the invention may provide a method of manufacturing an implantable device. The method may include placing circuitry within a housing. The method may include, after placing the circuitry in the housing, filling the housing with an epoxy to an initial epoxy fill line. The method may include, after filling the housing with the epoxy to the initial epoxy fill line, curing the epoxy. The method may include connecting electrically conductive connectors to contact pads of the circuitry. The method may include placing the electrically conductive connectors in passages of a housing cap enclosure. The method may include, after placing the electrically conductive connectors in the passages of the housing cap enclosure, filling a remaining space in the housing between the initial epoxy fill line and an end of the housing with epoxy. The method may include curing the epoxy in the remaining space in the housing between the initial epoxy fill line and an end of the housing.

In some embodiments, the method may further include placing one or more supports attached to and extending from a power source in the passages of the housing cap enclosure. In some embodiments, the method may further include connecting the electrically conductive connectors to positive and negative terminals of a power source.

In some embodiments, connecting the electrically conductive connectors to the positive and negative terminals of the power source may include pushing a spring at an end of a connector of the electrically conductive connectors against the positive terminal of the power source and compressing the spring. In some embodiments, after placing the electrically conductive connectors in the passages of the housing cap enclosure, a surface of the housing cap enclosure abuts a power source terminal enclosure that is attached to a power source and encloses positive and negative terminals of the power source.

Yet another aspect of the invention may provide an implantable device including a housing, circuitry at least partially within the housing, a power source, first and second electrically conductive connectors, and a coupler. The power source may include positive and negative terminals electrically connected to the circuitry. The first electrically conductive connector may be configured to electrically connect the positive terminal of the power source to the circuitry. The second electrically conductive connector may be configured to electrically connect the negative terminal of the power source to the circuitry. The coupler may be between the housing and the power source. The coupler may be attached to the power source and may include one or more supports that extend from the coupler into the housing.

In some embodiments, the coupler may include the second electrically conductive connector. In some embodiments, the one or more supports may be made from a material that is not electrically conductive. In some embodiments, the coupler may have a cylindrical portion with the one or more supports extending from the cylindrical portion.

In some embodiments, the device may include one or more substrates within the housing, and the circuitry may include one or more circuit components mounted on or fabricated in the one or more substrates. In some embodiments, the one or more circuit components may include one or more light sources and one or more photodetectors.

In some embodiments, the circuitry may include an inductive element. In some embodiments, the inductive element may include a conductor and a magnetic core. In some embodiments, the inductive element may extend into the coupler.

In some embodiments, the circuitry may include contact pads, and the device may further include bonding wires that electrically connect the first and second electrically conductive connectors to the contact pads. In some embodiments, the device may include one or more analyte indicators on or in a portion of an exterior surface of the housing. In some embodiments, the power source may be a battery. In some embodiments, the device may be hermetically sealed. In some embodiments, the device may include a spring configured to establish an electrical connection between the first electrically conductive connector and the positive terminal of the power source. In some embodiments, the implantable device may further include a drug-eluting polymer matrix covering at least a portion of the coupler.

Still another aspect of the invention may provide a method of manufacturing an implantable device. The method may include placing circuitry within a housing. The method may include, after placing the circuitry in the housing, filling the housing with an epoxy to an initial epoxy fill line. The method may include, after filling the housing with the epoxy to the initial epoxy fill line, curing the epoxy. The method may include inserting one or more supports of a coupler into the housing. The method may include, with the one or more supports of the coupler inserted into the housing, connecting first and second electrically conductive connectors to contact pads of the circuitry. The method may include attaching the coupler to a power source. The method may include filling at least a remaining space in the housing between the initial epoxy fill line and an end of the housing with epoxy. The method may include curing the epoxy in at least the remaining space in the housing between the initial epoxy fill line and an end of the housing.

In some embodiments, attaching the coupler to the power source may include connecting the first electrically conductive connector to a positive terminal of the power source. In some embodiments, connecting the first electrically conductive connector to the positive terminal of the power source may include pushing a spring at an end of the first electrically conductive connector against the positive terminal of the power source and compressing the spring.

In some embodiments, attaching the coupler to the power source may include connecting the second electrically conductive connector to a negative terminal of the power source. In some embodiments, after inserting the one or more supports of the coupler into the housing, a surface of coupler abuts a surface of the housing.

Further variations encompassed within the systems and methods are described in the detailed description of the invention below.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

FIG. 1is a schematic view of an exemplary system50embodying aspects of the present invention. In some embodiments, the system50may be an analyte monitoring system. In some embodiments, the system50may be a continuous analyte monitoring system (e.g., a continuous glucose monitoring system). In some embodiments, the system50may include one or more of an implantable device100, an external device101, and a display device107. In some embodiments, the implantable device100may be an analyte sensor. In some embodiments, the implantable device100may be a small, fully subcutaneously implantable sensor that measures the amount or concentration of an analyte (e.g., glucose) in a medium (e.g., interstitial fluid) of a living animal (e.g., a living human). However, this is not required, and, in some alternative embodiments, the implantable device100may be a partially implantable (e.g., transcutaneous) device. In addition, although embodiments of the invention are described with respect to an analyte monitoring system in which the implantable device100is an analyte sensor, this is not required. In some alternative embodiments, the implantable device100is not a sensor and is instead a different type of implantable device, such as, for example and without limitation, an insulin pump, pacemaker, or electrical/heat therapy device.

In some embodiments, the external device101may be an externally worn device (e.g., attached via an armband, wristband, waistband, or adhesive patch). In some embodiments, the external device101may remotely communicate with the implantable device100(e.g., via near field communication (NFC)). In some embodiments, the external device101may communicate with the implantable device100to initiate and receive the measurements from the implantable device100. In some embodiments, the external device101may be a transceiver. In some embodiments, the external device101may be a smartphone (e.g., an NFC-enabled smartphone). In some embodiments, the external device101may communicate information (e.g., one or more analyte measurements) wirelessly (e.g., via a Bluetooth™ communication standard such as, for example and without limitation Bluetooth Low Energy) to a hand held application running on a display device107(e.g., smartphone).

FIG. 2Ais a perspective view of an implantable device100of the system50according to some embodiments.FIG. 2Bis a perspective view of portion A of the implantable device100as shown inFIG. 2A.FIG. 3Ais a side view of an implantable device100of the system50according to some alternative embodiments.FIG. 3Bis a side view of portion B of the implantable device100as shown inFIG. 3A. In some embodiments, the implantable device100may be a wireless analyte sensor. In some embodiments, the implantable device100may be an analyte sensor. In some embodiments, the analyte sensor may detect the presence, amount, and/or concentration of an analyte (e.g., glucose, oxygen, cardiac markers, low-density lipoprotein (LDL), high-density lipoprotein (HDL), or triglycerides). In some embodiments, the implantable device100may be an optical sensor (e.g., fluorometers). In some embodiments, the implantable device100may be a chemical or biochemical sensor.

In some embodiments, as shown inFIGS. 2A, 2B, 3A, and 3B, the implantable device100may include a power source202, an inductive element204, one or more substrates206, and/or a housing208. In some embodiments, the housing208may be a body, shell, capsule, or encasement. In some embodiments, the housing208may be rigid and/or biocompatible. In some embodiment, the housing208may include a polymer (e.g., PMMA) sleeve or a silicon tube. However, this is not required, and, in other embodiments, different materials and/or shapes may be used for the housing208.

In some embodiments, the implantable device100may include one or more analyte indicators (e.g., analyte indicators334inFIG. 3E), such as, for example, a polymer graft or hydrogel coated, diffused, adhered, embedded, or grown on or in at least a portion of the exterior surface of the housing208. In some embodiments, as shown inFIGS. 2A and 3A, the housing208may include one or more cutouts or recesses209, and the one or more analyte indicators may be located (partially or entirely) in the cutouts or recesses209. In some embodiments, the one or more analyte indicators may be porous and may allow the analyte (e.g., glucose) in a medium (e.g., interstitial fluid) to diffuse into the one or more analyte indicators.

In some embodiments, the one or more analyte indicators may exhibit one or more detectable properties (e.g., optical properties) that vary in accordance with the amount or concentration of the analyte in proximity to the one or more indicators. In some embodiments, the one or more analyte indicators may emit an amount of emission light that varies in accordance with the amount or concentration of the analyte in proximity to the one or more analyte indicators. In some embodiments, the one or more analyte indicators may include one or more analyte indicator molecules (e.g., fluorescent analyte indicator molecules), which may be distributed throughout the one or more analyte indicators. In some embodiments, the one or more analyte indicators may be a phenylboronic-based analyte indicators. However, a phenylboronic-based analyte indicator is not required, and, in some alternative embodiments, the implantable device100may include a different analyte indicator, such as, for example and without limitation, a glucose oxidase-based indicator, a glucose dehydrogenase-based indicator, or a glucose binding protein-based indicator.

In some embodiments, as shown inFIGS. 2A and 3A, the implantable device100may include one or more light sources210that emit excitation light over an excitation wavelength range. In some embodiments, the excitation wavelength range may be a range of wavelengths that interact with an analyte indicator (e.g., one or more of analyte indicators334ofFIG. 3E). In some embodiments, the excitation light may be ultraviolet (UV) light.

In some embodiments, as shown inFIGS. 2A and 3A, the implantable device100may include one or more photodetectors212(e.g., photodiodes, phototransistors, photoresistors, or other photosensitive elements). In some embodiments, the one or more photodetectors212may be configured to detect a detectable property of an analyte indicator and output an analyte signal indicative of the amount or concentration of the analyte in the medium within the living animal. In some embodiments, the one or more photodetectors212may be configured to output an analyte signal indicative of an amount of the emission light (e.g., fluorescent light) received by the one or more photodetectors212.

In some embodiments, as shown inFIGS. 2A, 2B, 3A, and 3B, the implantable device100may include one or more substrates206on one side of the inductive element204. In some embodiments, although not shown inFIGS. 2A, 2B, 3A, and 3B, the implantable device100may additionally include one or more substrates206on an opposite side of the inductive element204. In some embodiments, one or more substrates206may be a circuit board (e.g., a printed circuit board (PCB) or flexible PCB) on which one or more of circuit components (e.g., analog and/or digital circuit components) may be mounted or otherwise attached. However, in some alternative embodiments, one or more substrates206may be a semiconductor substrate.

In embodiments where a substrate206is a semiconductor substrate, the substrate206may have one or more of circuit components fabricated therein. For instance, the fabricated circuit components may include analog and/or digital circuitry. Also, in some embodiments in which a substrate206is a semiconductor substrate, in addition to the circuit components fabricated in the semiconductor substrate, circuit components may be mounted or otherwise attached to the semiconductor substrate. In other words, in some semiconductor substrate embodiments, a portion or all of the circuit components, which may include discrete circuit elements, an integrated circuit (e.g., an application specific integrated circuit (ASIC)) and/or other electronic components (e.g., a non-volatile memory), may be fabricated in the semiconductor substrate with the remainder of the circuit components is secured to the semiconductor substrate, which may provide communication paths between the various secured components.

In some embodiments, as shown inFIGS. 2A and 3A, one or more of the light sources210may be mounted on or fabricated within in the one or more substrates206. In some embodiments, one or more of the photodetectors212may be mounted on or fabricated in the one or more substrates206. In some embodiments, one or more light sources210may be mounted on one more substrates206, one or more photodetectors212may be fabricated within one or more substrates206, and all or a portion of the circuit components may be fabricated within the one or more substrates206. In some embodiments, as shown inFIGS. 2B, 3A, and 3B, the implantable device100may additionally or alternatively have one or more circuit components214(e.g., capacitors) mounted to the inductive element204.

In some embodiments, the implantable device100may communicate with the external device101. In some embodiments, the external device101may be an electronic device that communicates with the implantable device100to provide commands (e.g., measurement commands) to the implantable device100and/or receive measurement data (e.g., photodetector and/or temperature sensor readings) from the implantable device100. The measurement data may include one or more readings from one or more photodetectors212of the implantable device100and/or one or more readings from one or more temperature sensors of the implantable device100. In some embodiments, the external device101may calculate analyte concentrations from the measurement data received from the implantable device100. However, it is not required that the external device101perform the analyte concentration calculations itself, and, in some alternative embodiments, the external device101may instead convey/relay the measurement data received from the implantable device100to another device for calculation of analyte concentrations. In other alternative embodiments, the implantable device100may perform the analyte concentration calculations.

In some embodiments, the inductive element204of the implantable device100may act an antenna. In some embodiments, the external device101may implement a passive telemetry for communicating with the implantable device100via an inductive magnetic link for data transfer. In some embodiments, the inductive element204may be, for example, a ferrite based micro-antenna. In some embodiments, as shown inFIG. 2A, the inductive element204may include a conductor216in the form of a coil and a magnetic core218. In some embodiments, the core218may be, for example and without limitation, a ferrite core. In some embodiments, the inductive element204may be connected to circuitry (e.g., an application specification integrated circuit (ASIC)) of the implantable device100. In some embodiments, the implantable device100may rely on the external device101to provide a data link to convey data from the implantable device100to the external device101.

In some embodiments, circuitry of the implantable device100may include the inductive element204, the circuit components mounted on or fabricated in the one or more substrates206(e.g., the one or more light sources210and/or the one or more photodetectors212), and/or the one or more circuit components214mounted to the inductive element204. In some embodiments, the circuitry of the implantable device100may be powered by the power source202.

In some embodiments, the power source202may be a charge storage device. In some embodiments, the power source202may be a battery (e.g., a rechargeable battery such as a lithium-ion battery), a capacitor, or a super capacitor. In some embodiments, at least the exterior of the power source202may be made of a biocompatible material such as, for example and without limitation, stainless steel or a titanium alloy. In some embodiments, the power source202may include a positive terminal (cathode)220and a negative terminal (anode)222.

In some embodiments, as shown inFIGS. 2A, 2B, 3A, and 3B, one or more couplers may attach the power source202to the housing208. In some embodiments, as shown inFIG. 2A and 2B, the one or more couplers that attach the power source202to the housing208may include a power source terminal enclosure224and a housing cap enclosure226. In some embodiments, electrically conductive connectors228and230may electrically connect the positive and negative terminals220and222, respectively, of the power source202to the circuitry of the implantable device100. In some embodiments, the attachment of the power source202to the housing208may be supported by one or more supports232. In some embodiments, as shown inFIG. 2A, the circuitry of the implantable device100may extend away from the power source202along the longitudinal axis of the power source.

In some embodiments, the electrically conductive connectors228and230may be rods or beams including or made out of a conductive material. In some embodiments, a bonding wires234may electrically connect the electrically conductive connectors228and230to contact pads236on the inductive element204. In some embodiments, a spring238(e.g., a V-shaped spring) may be attached (e.g., welded) to one end of the electrically conductive connector228. In some embodiments, the spring238may be made of an electrically conductive material and may establish an electrical connection between the connector228and the positive terminal220of the power source202. In some embodiments, when the housing208and power source202are brought together for attachment, the spring238may be pushed against the positive terminal220of the power source202and compressed.

In some embodiments, the one or more supports232may be reinforcement rods, bars, or beams. In some embodiments, the one or more supports232may be attached to and extend from the power source202. In some embodiments, the one or more supports232may have a larger diameter than the electrically conductive connectors228and230. In some embodiments, the one or more supports232may be made from a material that is not electrically conductive.

In some embodiments, as shown inFIG. 2B, the power source terminal enclosure224may be cup-shaped (e.g., a hollow cylinder with a flat bottom224band an open top). However, other shapes (e.g., a hollow rectangular prism with a flat bottom and an open top) may be used in alternative embodiments. In some embodiments, the power source terminal enclosure224may enclose the positive and negative terminals220and222of the power source202. In some embodiments, the power source terminal enclosure224may enclose the spring238. In some embodiments, the bottom224bof the power source terminal enclosure224may have holes224cthrough which the electrically conductive connectors228and230and the one or more supports232pass. In some embodiments, the power source terminal enclosure224may be made of a biocompatible material. In some embodiments, the power source terminal enclosure224may be made of a biocompatible metal such as, for example and without limitation, stainless steel or titanium. In some embodiments, the power source terminal enclosure224may be attached (e.g., welded) to the power source202. In some embodiments, the power source terminal enclosure224may be attached to the power source202by laser welding.

In some embodiments, the housing cap enclosure226may have a solid cylindrical shape. However, other shapes (e.g., a solid rectangular prism shape) may be used in alternative embodiments. In some embodiments, the housing cap enclosure226may be made of a biocompatible material such as, for example and without limitation, glass or ceramic. In some embodiments, the housing cap enclosure226may include passages or feedthroughs240through which the electrically conductive connectors228and230and the one or more supports232pass. In some embodiments, the housing cap enclosure226may include a first flat surface that abuts and is attached to the bottom224bof the power source terminal enclosure224. In some embodiments, the housing cap enclosure226may be attached to the bottom224bof the power source terminal enclosure224by brazing. In some embodiments, the housing cap enclosure226may include a first flat surface that abuts and is attached to an open end208aof the housing208. In some embodiments, the housing cap enclosure226may enclose the circuitry of the implantable device100in the housing208.

In some embodiments, after the circuitry of the implantable device100is placed in the housing208, the housing208may be filled with an epoxy to the initial epoxy fill line242. In some embodiments, epoxy may create a transmissive optical cavity within the housing208. In some embodiments, the transmissive optical cavity may be formed from a suitable, optically transmissive polymer material, such as, for example, acrylic polymers (e.g., polymethylmethacrylate (PMMA)). However, this is not required, and, in other embodiments, different materials may be used for the transmissive optical cavity.

In some embodiments, after the housing208has been filled with an epoxy to the initial epoxy fill line242, the epoxy may be cured. In some embodiments, the electrically conductive connectors228and230may be connected to the contact pads236of the circuitry of the implantable device100(e.g., by soldering the bonding wires234to the contact pads236). In some embodiments, after the electrically conductive connectors228and230and the one or more supports232are in place in the passages or feedthroughs240of the housing cap enclosure226, the remaining space in the housing208between the initial epoxy fill line242and the open end208aof the housing208is filled with epoxy, which is then cured.

In some embodiments, the implantable device100including the power source202, the power source terminal enclosure224, the housing cap enclosure226, and the housing208may be hermetically sealed.

In some alternative embodiments, as shown inFIG. 3A and 3B, a coupler324may attach the housing208and the power source202. In some embodiments, the coupler324may be between the housing208and the power source202. In some embodiments, the implantable device100including the power source202, the coupler324, and the housing208may be hermetically sealed. In some embodiments, as shown inFIG. 3B, the implantable device100may include first and second electrically conductive connectors228and230. In some embodiments, the first electrically conductive connector228may be configured to electrically connect the positive terminal220of the power source202to the circuitry. In some embodiments, the second electrically conductive connector230may be configured to electrically connect the negative terminal222of the power source202to the circuitry. In some embodiments, as shown inFIG. 3B, the coupler324may include a flat surface326that abuts the power source202. In some embodiments, the coupler324may be attached to the power source202(e.g., by laser welding). In some embodiments, as shown inFIG. 3A, the circuitry of the implantable device100may extend away from the power source202along the longitudinal axis of the power source202.

In some embodiments, the first electrically conductive connector228may be a rod or beam including or made out of a conductive material. In some embodiments, the second electrically conductive connector230may include a conductive material (e.g., a gold plating). In some embodiments, a bonding wires234may electrically connect the first and second electrically conductive connectors228and230to contact pads236of the circuitry (e.g., contact pads236on the inductive element204). In some embodiments, as shown inFIG. 3B, one or both of the first and second electrically conductive connectors228and230not extend from the coupler324and may instead be contained with the coupler324. However, this is not required, and, in some alternative embodiments, the one or both of the first and second electrically conductive connectors228and230may extend from the coupler324into the housing208. In some embodiments, as shown inFIG. 3B, the inductive element204may extend into the coupler324.

In some embodiments, a spring (e.g., a V-shaped spring such as the spring238illustrated inFIG. 2B) may be attached (e.g., welded) to one end of the electrically conductive connector228. In some embodiments, the spring238may be made of an electrically conductive material and may establish an electrical connection between the connector228and the positive terminal220of the power source202. In some embodiments, when the housing208and power source202are brought together for attachment, the spring238may be pushed against the positive terminal220of the power source202and compressed.

FIG. 3CandFIG. 3Dare perspective and cross-sectional views, respectively, of the coupler324according to some embodiments. In some embodiments, as shown inFIGS. 3B-3D, the coupler324may include one or more supports232. In some embodiments, the one or more supports232may be reinforcement rods, bars, or beams. In some embodiments, the one or more supports232may be attached to and/or integral with the coupler324. In some embodiments, the one or more supports232may be made from a material that is not electrically conductive. Although the coupler324of the illustrated embodiment include three supports232, this is not required, and, in some alternative embodiments, the coupler324may include more or fewer supports232(e.g., one, two, four, five, six, or ten supports232). In some embodiments, as shown inFIGS. 3A and 3B, the one or more supports232may extend from the coupler324into the housing208.

In some embodiments, as shown inFIGS. 3B-3D, the coupler324may include the second electrically conductive connector230. In some embodiments, as shown inFIG. 3C, the coupler may have a cylindrical portion with the one or more supports232extending from the cylindrical portion. In some embodiments, as shown inFIG. 3B, the coupler324may include a flat surface328that abuts the housing328. In some embodiments, the coupler324and housing208may be held together (e.g., by cured epoxy within the housing208and/or the coupler324).

In some embodiments, a process of manufacturing the implantable device100may include placing circuitry (e.g., circuitry including the inductive element204, circuit elements mounted on the inductive element204, and/or circuit elements mounted on or fabricated in one or more substrates206) at least partially within the housing208. The process may include, after placing the circuitry at least partially within the housing208, filling the housing208with an epoxy to an initial epoxy fill line. In some embodiments, the initial epoxy fill line may be such that the contact pads236are not exposed and not covered by the epoxy. In some embodiments, the initial epoxy fill line may additionally or alternatively be such that, after the epoxy is cured, there will still be space in the housing208for insertion of the one or more supports232into the housing208.

In some embodiments, the process may include, after filling the housing with the epoxy to the initial epoxy fill line, curing the epoxy. In some embodiments, cured epoxy may create a transmissive optical cavity within the housing208. In some embodiments, the transmissive optical cavity may be formed from a suitable, optically transmissive polymer material, such as, for example, acrylic polymers (e.g., polymethylmethacrylate (PMMA)). However, this is not required, and, in other embodiments, different materials may be used for the transmissive optical cavity.

In some embodiments, the process may include inserting the one or more supports232of the coupler324into the housing208(e.g., into the remaining space of the housing208not filled with the cured epoxy). In some embodiments, after inserting the one or more supports232of the coupler324into the housing208, a surface of coupler328may abut a surface of the housing208.

In some embodiments, the process may include, with the one or more supports232of the coupler324inserted into the housing208, connecting the first and second electrically conductive connectors228and230to the contact pads236of the circuitry (e.g., contact pads236on the inductive element204). In some embodiments, the first and second electrically conductive connectors228and230may be connected to the contact pads236of the circuitry by soldering the bonding wires234to the contact pads236.

In some embodiments, the process may include attaching the coupler324to the power source202(e.g., by laser welding with the flat surface326of the coupler324). In some embodiments, attaching the coupler324to the power source202may include connecting the first electrically conductive connector228to a positive terminal220of the power source202. In some embodiments, connecting the first electrically conductive connector228to the positive terminal220of the power source202may include pushing a spring (e.g., a spring238) at an end of the first electrically conductive connector238against the positive terminal220of the power source202and compressing the spring238. In some embodiments, attaching the coupler324to the power source202may include connecting the second electrically conductive connector230to a negative terminal222of the power source202.

In some embodiments, the process may include filling at least a remaining space in the housing208between the initial epoxy fill line and an end of the housing208with epoxy. In some embodiments, the epoxy may additionally fill all or a portion of the coupler324. In some embodiments, all or a portion of the remaining space in the housing208and/or all or a portion of the coupler324may be filled with the epoxy using a small hole in the coupler324.

In some embodiments, the process may include curing the epoxy in at least the remaining space in the housing208between the initial epoxy fill line and an end of the housing208. In some embodiments, because the one or more supports232of the coupler324were inserted into the housing208, the cured epoxy in the remaining space and/or the coupler324may hold the coupler324and the housing208together.

In some embodiments, the implantable device100may include one or more drug-eluting polymer matrices. In some embodiments, the implantable device100may include one or more drug-eluting polymer matrices (e.g., the drug-eluting polymer matrix330shown inFIG. 3E), on all or a portion of the external surface of the housing208. In some embodiments, the one or more drug-eluting polymer matrices on the housing208may be located in one or more recesses in the housing208. In some embodiments, the implantable device100may additionally or alternatively include one or more drug-eluting polymer matrices (e.g., the drug-eluting polymer matrix332shown inFIG. 3E), on all or a portion of an external surface of the one or more couplers attaching the power source202and the housing208. In some embodiments, one or more drug-eluting polymer matrices may be located on all or a portion of one or both of the power source terminal enclosure224and the housing cap enclosure226. In some embodiments, as shown inFIG. 3E, one or more drug-eluting polymer matrices332may be located on all or a portion of the coupler324.

In some embodiments, the one or more drug-eluting polymer matrices may be applied to the sensor housing208and/or one or more couplers (e.g., the coupler324or power source terminal enclosure224and the housing cap enclosure226) via dip or spray coating. In some alternative embodiments, the one or more drug-eluting polymer matrices may have a pre-formed shape such as, for example, a ring or sleeve. In some alternative embodiments, the one or more drug-eluting polymer matrices may have a different shape. In some embodiments, as shown inFIG. 3E, the one or more one or more drug-eluting polymer matrices330and332may wrap around a portion of the sensor housing208and/or a portion of the coupler324. In some alternative embodiments, the one or more drug-eluting polymer matrices330and332may be wider or narrower than the drug-eluting polymer matrices330and332illustrated inFIG. 3E.

One or more therapeutic agents may be dispersed within the one or more drug eluting polymer matrices (e.g., one or more inert polymer matrices). In some embodiments, the one or more therapeutic agents may reduce or stop the migration of neutrophils from entering the wound space and, thus, reduce or stop the production of hydrogen peroxide and fibrotic encapsulation. Accordingly, in some embodiments, the one or more therapeutic agents may reduce deterioration of the one or more analyte indicators (e.g., analyte indicators334). In some embodiments, the one or more therapeutic agents, which may be dispersed within the drug eluting polymer matrix, may include one or more anti-inflammatory drugs, such as, for example, non-steroidal anti-inflammatory drug (e.g., acetylsalicylic acid (aspirin) and/or isobutylphenylpropanoic acid (ibuprofen)). In some non-limiting embodiments, the one or more therapeutic agents dispersed within the drug-eluting polymer matrix may include one or more glucocorticoids. In some non-limiting embodiments, the one or more therapeutic agents may include one or more of dexamethasone, triamcinolone, betamethasone, methylprednisolone, beclometasone, fludrocortisone, derivatives thereof, and analogs thereof. In some embodiments, the one or more therapeutic agents may reduce the production of hydrogen peroxide by neutrophils and macrophages.

Embodiments of the present invention have been fully described above with reference to the drawing figures. Although the invention has been described based upon these preferred embodiments, it would be apparent to those of skill in the art that certain modifications, variations, and alternative constructions could be made to the described embodiments within the spirit and scope of the invention. For example, in some embodiments, the implantable device100may include a bridging material with insulation.