Implantable sensor and methods for operating and implanting the sensor

Abstract

An implantable sensor (100) and method, the sensor comprising an energy harvesting module electrically coupled to an energy storage device, a biomarker sensor module configured to detect a biomarker binding event, a transmitter for transmitting sensing signals, and control circuitry to manage these components. The energy harvesting module utilizes one or more piezoelectric elements (180) to convert mechanical deformation into electrical energy, providing a power source derived directly from the user's physiological movements. This architecture establishes a self-powered and autonomous system, eliminating the need for external power sources and enabling long-term operation.

Description

IMPLANTABLE SENSOR AND METHODS FOROPERATING AND IMPLANTING THE SENSORFIELD OF THE INVENTION

[0001] The present disclosure relates to implantable sensor. More particularly, the present disclosure relates to a sensor for detecting biomarkers in an implantable device.BACKGROUND

[0002] Implantable biosensors have long been proposed to monitor molecular and physiological markers within the body. Such devices are attractive for applications including metabolic monitoring, stress and inflammation assessment, disease progression tracking, and closed-loop therapeutic systems. Despite significant academic and commercial interest, widespread deployment of implantable molecular sensors has been limited by a combination of power and longevity.

[0003] A fundamental limitation of implantable biosensors is long-term energy availability. Battery-powered implants are constrained by finite capacity, device volume, and the need for replacement or explantation when the battery is depleted.

[0004] There is therefore a need for implantable biosensing systems that improves the longevity of an implanted sensor.SUMMARY OFTHE INVENTION

[0005] The present disclosure relates to an implantable sensor that alleviates the above-mentioned problems.

[0006] The present disclosure addresses the limitations of existing implantable biosensors relating to power and longevity. Current implantable sensors often rely on finite-life batteries or lack efficient mechanisms for coordinating sensing, processing, and communication under intermittent power conditions. Furthermore, signal degradation in physiological environments and the limited lifespan of sensing elements pose significant challenges to long-term monitoring. This disclosure seeks to overcome these hurdles through an integrated system-level approach that prioritizes self-sufficiency and extended operational lifetime.

[0007] The core of this approach is an implantable sensor comprising an energy harvesting module electrically coupled to an energy storage device, a biomarker sensor module configured to detect a biomarker binding event, a transmitter for transmitting sensing signals, and control circuitry to manage these components. The energy harvesting module utilizes one or more piezoelectric elements to convert mechanical deformation into electrical energy, providing a power source derived directly from the user’s physiological movements. This architecture establishes a fully self-powered and autonomous system, eliminatingthe need for external power sources and enabling longterm operation.

[0008] The design further incorporates features to facilitate minimally invasive implantation and maximize energy harvesting efficiency. The energy harvesting module may be designed to transitioning between a compact delivery configuration and an expanded operational configuration, enabling easy insertion while maximizing surface area for energy capture once deployed. Several other optional features including hydrophilic, swellable, or shape-memory materials, may be utilized to automatically expand the module in vivo. This innovative design ensures a robust and continuous power source, providing an autonomous device capable of sustained, reliable operation within the physiological environment.

[0009] According to a first aspect of the invention, an implantable sensor is provided that comprises an energy harvesting module electrically coupled to an energy storage device for transferring harvested electricity to the energy storage device, a biomarker sensor module being energized by the energy storage device and being configured to detect a biomarker binding event, a transmitter configured to transmit a sensing signal from the biomarker sensor module, and a control circuitry configured to control the biomarker sensor module and transmitter, wherein the energy harvesting module comprises one or more piezoelectric elements configured to convert mechanical deformation into electrical energy.

[0010] As used herein, the term “implantable sensor” may refer to a device designed for surgical or minimally invasive insertion into a biological tissue or cavity to detect and report a change in a physiological or biochemical parameter. An energy harvesting module may be understood as an energy generating subsystem comprising one or more transducers configured to convert ambient energy, such as movements,vibrations, or flow, into electrical energy. Moreover, piezoelectric elements may refer to materials that generate an electric charge in response to applied mechanical stress, typically utilizing crystalline structures like quartz or specialized ceramics. A biomarker binding event may be a specific, preferably reversible, interaction between a biomarker and a binding partner, such as an antibody, aptamer, or other affinity molecule, resulting in detectable complex formation.

[0011] This architecture provides a fully self-powered and autonomous system, eliminating the need for finite-life batteries and enabling long-term operation by harvesting energy directly from the user’s body.

[0012] The specific inclusion of piezoelectric elements provides significant advantages for a long-term implantable device. As solid-state components with no moving parts, they offer exceptional reliability and an extended operational lifespan free from mechanical wear. Their high sensitivity enables efficient energy conversion from a broad spectrum of physiological motions, including movements in joints, subtle tissue deformations and pulsations of liquid in vivo, while their ability to be fabricated into thin, flexible forms enables creating a compact device suitable for minimally invasive implantation. Thus, the energy harvesting module for the sensor as disclosed ensures a robust and continuous power source, providing an autonomous device.

[0013] Utilizing piezoelectric elements to convert mechanical deformation into electrical energy may allow the implantable sensor to operate independently of an external power source or battery replacement, potentially extending its operational lifespan and reducing the need for invasive procedures to maintain functionality. This may facilitate continuous, long-term biomarker monitoring since harvested energy can be accumulated in the energy storage device and then selectively provided to the biomarker sensor module and transmitter, enabling sustained sensing and signal transmission even when mechanical deformation is intermittent or low. Furthermore, the decoupling of energy harvesting, storage, and sensing functions through the control circuitry may allow for optimized power management, potentially improving the sensitivity and reliability of biomarker detection by ensuring a stable and consistent power supply to the biomarker sensor module.

[0014] The implantable sensor may further include a memory module for storing data. The memory module may be a low-power memory capable of storing sensorreadings within the implanted sensor. This allows for extended, autonomous operation and eliminates the need for frequent data offloading.

[0015] The energy harvesting module may be movable between a first compact delivery configuration and a second expanded operational configuration.

[0016] This dual-configuration design enables minimally invasive implantation due to its compact form, while ensuring maximum energy harvesting efficiency postdeployment through its larger expanded state. This results in a smaller incision or injection opening in the skin of the user.

[0017] The energy harvesting module may comprise at least one of a hydrophilic material for moving the energy harvesting module from the compact delivery configuration to the expanded operational configuration.

[0018] The use of a hydrophilic material facilitates a passive and automatic deployment mechanism that is triggered by the natural fluids present in the body, simplifying the device design and increasing its reliability.

[0019] The energy harvesting module may comprise at least one of a swellable material, or shape-memory element for moving the energy harvesting module from the compact delivery configuration to the expanded operational configuration.

[0020] This provides robust and reliable alternative mechanisms for autonomous in vivo deployment without requiring external intervention.

[0021] As used herein, the term “compact delivery configuration” may refer to a minimized physical arrangement of components configured to reduce volumetric space occupied during implantation. An “expanded operational configuration” may denote an increased physical arrangement of components designed to increase area or volumetric space occupied during the operational state of the implanted sensor. A “hydrophilic material” may be a material exhibiting an affinity for fluids such as water, readily absorbing or being wetted by the fluid. Furthermore, a “swellable material” may refer to a substance that increases in volume upon absorption of a fluid, typically water, due to polymeric expansion or capillary action. A “shape-memory element” may denote a component fabricated from a material exhibiting the ability to recover a predetermined shape over time.

[0022] The energy harvesting module may be encapsulated or coated with a biocompatible layer to isolate internal electrical structures from tissue while permittingmechanical coupling. The encapsulation may be configured to provide controlled mechanical compliance to improve couplingto physiological motion.

[0023] Harvested energy may be stored in one or more energy storage elements such as capacitors, supercapacitors, thin-film batteries, or hybrid storage assemblies. While some embodiments may include a primary battery, preferred embodiments minimize reliance on a primary battery by using harvested energy as the primary operational source.

[0024] The energy harvesting module may be rolled up or folded in its first compact delivery configuration. This specific form factor achieves a high degree of compactness, making the device suitable for delivery through small-gauge injectors, trocars, or catheters, thereby minimizing the invasiveness of the implantation procedure. This enables a safe implantation process and a small incision in the skin of the user, which allows quick healing and low risks of infections.

[0025] The transmitter may be a low-band signal transmitter. The use of a low-band transmitter enhances energy efficiency and improves signal penetration through biological tissues, leadingto more reliable data communication.

[0026] The transmitter may be configured to operate in a frequency band selected for signal propagation through biological tissue. This may increase reliability and low-power communication from the implanted device to an external receiver.

[0027] The transmitter may be configured to operate at a frequency band below 1 GHz, as frequencies in this range allow passing through skin, fat, and muscle compared to higher frequency bands. Alternatively, the transmitter may be configured to operate at a frequency band at about 2000-2500 MHz, specifically in this range preferably within the medical body area network range of 2360-2400 MHz.

[0028] Additionally or alternatively, the transmitter may operate within a dedicated medical radio-communication service band, such as the MedRadio service band. In a preferred embodiment, the transmitter is configured to operate within the Medical Implant Communication Service (MICS) band, which is between 401 MHz and 406 MHz. Utilizing the MICS band provides several key technical advantages: it significantly reduces the transmission power required to establish a robust communication link, thereby conserving the limited energy harvested by the device; it operates in a protectedspectrum, minimizing interference from consumer electronics; and it allows for an antenna size that is practical for integration into a minimally invasive implantable device.

[0029] The transmitter may transmit measurement events, sensor status, or metadata to an external device. Suitable wireless modalities include low-power RF links, near-field communication, BLE, ultrasonic links, or other energy-efficient communication schemes.

[0030] The transmitter may transmit event packets or summarized data rather than continuous raw data streams to reduce energy consumption. An external device may buffer, aggregate, and / or further process data prior to onward transmission or storage.

[0031] The control circuitry may further be configured to monitor a stored energy level in the energy storage device and energizing the biomarker sensor module only when the stored energy satisfies a sensing threshold energy level. This threshold-gated operation ensures that sensing cycles are initiated only when sufficient energy is available, which prevents system brownouts and increase reliability of the sensor.

[0032] The control circuitry may be further configured to enable transmission of a sensing signal only when the stored energy level satisfies a transmission threshold energy level. This prevents failed communication attempts by ensuring the transmission function is only activated when there is enough power for it to be successfully completed.

[0033] The energy harvesting module may be configured to harvest up to 100mW per hour. In one tested example the harvesting module produces power of about 20 mW per hour. The harvesting module may be configured to produce up to 10mW per hour.

[0034] The threshold levels may correspond to enough energy to conduct a predetermined number of sensing actions and / or transmission actions. The threshold levels may be any level associated with the sensors’ and / or transmitter’s power consumption.

[0035] The transmission threshold energy level may be greater than the sensing threshold energy level. This hierarchical energy management may be used for prioritizing data acquisition over transmission. It may also be configured like this because sensing would require less energy than transmission of the sensed data. Regardless of the reason the two-leveled thresholds enables that a biomarker data may be captured even during periods of energy availability which is too low to transmit but when the level is enough to use the sensor for detecting an event. This will increase data capturing.

[0036] As used herein, the term “sensing threshold energy level” may refer to a predetermined minimum amount of energy detected by a sensor required to trigger a response or signal, typically expressed in units of power, intensity, or voltage. For example, the sensing threshold energy level may be a voltage, a current, or a power level. Moreover, the term “transmission threshold energy level” may denote the minimum amount of energy required to initiate a wireless signal transmission, typically expressed in units of power, intensity, or voltage. For instance, the transmission threshold energy level may be expressed as a radio frequency power level, or a voltage required to activate a transmitter.

[0037] The biomarker binding event may be an electrochemical biosensing detecting a change in at least one of impedance, conductance, current, or voltage.

[0038] As used herein, the term “electrochemical biosensing” may refer to the detection of a biological analyte via a change in electrical signal measured by an electrode, typically involving a bioreceptor immobilized on the electrode surface that selectively binds the analyte, resulting in redox reactions or capacitance changes. Impedance may denote the total opposition a circuit presents to alternating current, comprising resistance and reactance. Furthermore, conductance may refertoa measure of a material's ability to conduct electric current, calculated as the reciprocal of resistance. For example, conductance may be measured in units of siemens.

[0039] The system may include an energy monitoring and threshold subsystem configured to determine when stored energy is sufficient to execute one or more operational sequences. The threshold subsystem may include comparators, voltage monitors, coulomb counters, or state-of-charge estimators. When stored energy meets or exceeds a threshold condition, control circuitry enables one or more subsystems, including the sensing interface, regeneration circuitry, and wireless communication subsystem. When stored energy is below threshold, the system remains in a low-power harvesting or accumulation state.

[0040] The system may implement an energy packetization scheme in which energy is accumulated until sufficient to perform a defined packet of work, such as measurement only, measurement plus regeneration, measurement plus transmission, or measurement plus regeneration and transmission. Energy packetization reducesbrownout risk by ensuring that the energy storage element contains sufficient capacity for the intended sequence.

[0041] The system may include brownout-safe sequencing, such that operations are staged in a predetermined order and data may be checkpointed to nonvolatile memory prior to initiating higher-energy operations.

[0042] The sensing interface may generate an electrical signal indicative of binding, including changes in impedance, capacitance, conductance, current, voltage, or combinations thereof. Non-limiting sensing modalities include electrochemical impedance spectroscopy, amperometry, voltammetry, potentiometry, field-effect sensing, and hybrid techniques.

[0043] The sensor may exhibit conductive, dielectric, or otherwise field-responsive properties such that binding of a target analyte modulates an electrical or electromagnetic characteristic of the composite recognition structure. Measurable responses may include changes in impedance, capacitance, conductance, resonance behavior, coupling, or signal amplitude, and may be detected using electrochemical, impedance-based, or field-coupling techniques consistent with the sensing modalities described herein.

[0044] According to a second aspect of the inventive concept, a method for implanting a sensor is disclosed. The sensor comprises a biomarker sensor module and an energy harvesting module, the energy harvesting module being moveable between a first compact delivery configuration and a second expanded operational configuration. The method comprises the steps of implanting the sensor in a target area of a user, and expanding the energy harvesting module, in vivo, from the first compact delivery configuration into the second expanded operational configuration. This method facilitates a minimally invasive procedure that results in an optimally configured device for effective long-term energy harvesting and sensing, as has been explained above. All the benefits from explained above may be analogously applicable also to this method. Further, anyfeature or function described in relation to the sensor should be considered optionally included also in the method.

[0045] The step of implantingthe sensor may comprise implanting a sensor having an energy harvesting module with one or more piezoelectric elements configured to convert mechanical deformation into electrical energy for powering the sensor. Thisensures the implanted device is fully self-sustaining, deriving its operational power directly from the user's physiological movements. This is further a synergistic advantage with the compact and expanded configuration, as piezoelectric elements will generate more power when having a larger area.

[0046] The step of implanting the sensor may comprise injecting the sensor using an injector, trocar, or catheter. This simplifies the implantation procedure, which reduces user risk, recovery time, and associated medical costs when compared to more invasive surgical implantation techniques. After placement at a target anatomical site, such as subcutaneous, interstitial, intramuscular, or perivascular tissue, the module may expand, unfold, unroll, or otherwise increase its effective harvesting geometry.

[0047] In alternative methods, the step of implanting the sensor may comprise cutting an incision in the skin of the user for placing the sensor in the user.

[0048] The step of injecting the sensor may comprise injecting a sensor having an energy harvesting module comprising a hydrophilic material. This enables a straightforward injection procedure where the device's subsequent expansion is passively and automatically initiated by the body's natural environment.

[0049] The method may further comprise a step of injecting a fluid into the target area of the user for expediting the expansion of the energy harvesting module from the first compact delivery configuration into a second expanded operational configuration. This provides the clinician with the ability to actively control and / or to accelerate the deployment process, ensuring the device achieves its optimal operational state upon the injection of fluid or simply faster after implantation.

[0050] The energy harvesting module may be a rolled up or folded energy harvesting module when being in its first compact delivery configuration. This specified configuration allows for a highly compact device during implantation, making it suitable for delivery through standard medical needles or catheters.

[0051] The transition from delivery configuration to operational configuration may be driven by one or more deployment mechanisms. The deployment mechanism may include a hydrophilic or swellable element that absorbs physiological fluid and induces expansion.

[0052] In some embodiments, the transition from the delivery configuration to the operational configuration may be driven by a deployment mechanism that causes theenergy harvesting module to expand or unfurl following implantation. The deployment mechanism may include passive mechanical biasing, material response to physiological conditions, or other mechanisms that enable the device to transition from a compact configuration suitable for implantation to an expanded configuration suitable for energy harvesting within the body.

[0053]

[0054] According to a second aspect of the inventive concept a method for operating an implanted sensor in a person is described. The method comprises the steps of harvesting energy in vivo using an energy harvesting module; accumulating the harvested energy in an energy storage element electrically coupled to the harvesting energy module; and energizing a biomarker sensor module so as to detect a biomarker binding event, wherein the step of harvesting energy in vivo comprises mechanically deforming of one or more piezoelectric elements with natural movements of the person and converting the deformation into electrical energy.

[0055] This method establishes a complete, self-sustaining operational cycle for the implantable sensor, enabling continuous, long-term monitoring without reliance on external power sources or batteries. All the benefits from explained above may be analogously applicable also to this method. Further, any feature orfunction described in relation to the sensor should be considered optionally included also in the method.

[0056] The method may further comprise the step of monitoring a stored energy level in the energy storage device; and wherein the step of energizing a biomarker sensor module only occurs when the monitored stored energy satisfies a sensing threshold energy level. This energy-aware operational step ensures robust and reliable sensing performance by preventing the device from attempting measurements when power is insufficient, thereby avoiding brownout or data corruption.

[0057] The method mayfurther comprise a step of transmittinga sensingsignalonly when the stored energy level satisfies a transmission threshold energy level. This step further optimizes energy management by ensuring that the transmission step is only performed when there is enough energy to be successfully completed, reducing the risk for incomplete transmissions.

[0058] Detection of the biomarker binding event may trigger an electrical condition for performing an electrochemical regeneration operation on a sensing interface of thebiomarker sensor module. This event-triggered regeneration actively maintains sensor responsiveness and extends its functional lifetime by clearing the sensing surface in response to detected binding events, enabling reliable long-term use.

[0059] The control circuitry may be configured to monitor stored energy and to enable sensing, processing, regeneration, and transmission functions only when stored energy satisfies a predetermined threshold condition. The predetermined threshold condition may be a specific threshold related to the specific functions (sensing, processing, regeneration, and transmission) or may be a common threshold value.

[0060] In this manner, the system operates in a duty-cycled, energy-aware fashion, avoiding unstable operation under intermittent power conditions and supporting extended operational lifetime without reliance on a primary battery. The ratio of the duty-cycled operation may be 1 -50% or 1 -10% or even less than 1 %.

[0061] In one example, the system may use a capacitor array to create an overflow balance, where requirements for the control circuit and sensors can be supplied. The overflow capacitance generates an opportunity to send data with the transmitter only when power requirements are met; if the power requirements are met, the transmitter performs one timely cycle per time unit, such as one each minute.

[0062] The molecular sensing interface may be configured to detect binding events between target analytes and one or more recognition elements. A molecular binding event may produce a change in an electrical parameter, such as impedance, conductance, current, or voltage, that functions not only as a measurement signal but may also function as a trigger that enables a change in system state. By using molecular events to initiate sensing, processing, or communication actions, the system supports event-driven operation aligned with harvested energy availability.

[0063] One example of event-driven operation related to sensing and transmission is herein presented. Upon detection of a target analyte binding event, the control circuit initiates a data logging sequence. The change in electrical parameter not only confirms analyte presence but also triggers the activation of the low-power memory module to store the event timestamp and binding event data. Once a pre-defined threshold of events is reached, or once available harvested energy reaches a threshold value, the control circuit may initiate a transmission of the logged data to a remote receiver. This facilitates long-term, unattended monitoring of biomarkers, since the system operatesonly when events occur and energy is available, minimizing power consumption and extending operational lifespan.

[0064] Binding-induced changes in the composite recognition structure may be used in support of the event-driven operation of the system. For example, a bindingdependent change in an electrical parameter of the composite recognition structure may generate a trigger condition that initiates one or more energy-threshold-gated operations, including measurement, characterization, regeneration, or transmission.

[0065] The disclosed system may be configured to detect a wide range of analytes, including metabolic markers, stress-related markers, inflammatory markers, hormones, and other molecules of interest. The specific analytes and recognition elements may be selected based on the intended application.

[0066] The energy harvesting module, sensing interface, and conductive fieldshaping elements may be fabricated using microfabrication, printed electronics, flexible substrates, silicon-based processes, PCB-based processes, or combinations thereof, consistent with implantable biocompatibility requirements.

[0067] The biomarker sensor module may comprise a sensing interface. The sensing interface may be electrically regenerated following one or more measurement cycles. Regeneration may be achieved by applying controlled electrical stimuli to the sensing interface, including voltage pulses, current pulses, or time-varying waveforms, configured to restore sensor responsiveness.

[0068] Regeneration may act on the sensing surface to disrupt binding interactions, alter local electrochemical conditions, or reduce accumulated fouling. Regeneration operations may be coordinated with sensing and transmission cycles as part of an energy-aware operational sequence.

[0069] The system may perform electrochemical regeneration of the sensing interface following one or more measurement cycles to maintain or restore sensor responsiveness. Regeneration may be executed periodically, upon detection of sensor drift, after persistent binding events, or following a predetermined number of measurements.

[0070] Regeneration may be achieved by applying controlled electrical stimuli to the sensing interface, including voltage pulses, current pulses, AC waveforms, or timevarying sequences. The stimuli may be configured to disrupt binding interactions, alterlocal electrochemical conditions, reduce nonspecific adsorption, or restore baseline response characteristics.

[0071] Regeneration may be targeted primarily to the sensing surface and recognition element environment rather than relying on systemic biological clearance mechanisms. Regeneration parameters may be selected to be compatible with implant safety constraints and to avoid undesired tissue stimulation.

[0072] Regeneration operations may be coordinated with threshold-gated operation such that regeneration is executed only when stored energy exceeds a defined threshold, thereby controlling energy expenditure.

[0073] The deployable energy harvesting module, energy-aware control circuitry, event-driven sensing interface, and regeneration mechanisms, may operate as an integrated system. The interaction between these elements may enable synergistic longterm implantable biomarker sensing.

[0074] The sensor may be further configured to perform a regeneration operation, wherein the control circuitry applies a controlled electrical stimulus to the sensing interface to disrupt binding interactions between a recognition element and a target analyte, thereby resetting the biomarker sensor module. This enables the sensor to perform repeated measurement cycles without exhausting the available recognition sites, for the purpose of extending the operational lifetime of the implant.

[0075] The sensor may further be configured to perform a surface cleaning operation, wherein the control circuitry applies a controlled electrical stimulus to the sensing interface to reduce or remove non-specific adsorption of interfering molecules such as proteins from the sensing interface of the biomarker sensor module. This active cleaning mechanism mitigates the effects of biofouling, thereby preventing signal drift and maintaining the sensitivity and stability of the sensor over long-term in-vivo operation.

[0076] The system may have a plurality of operational states including a harvesting or accumulation state, a readiness state in which sufficient energy is available, a measurement state, an optional regeneration state, a transmission state, and a low-power sleep state. Transitions between states may be controlled by one or more threshold conditions, such as stored energy exceeding a threshold, detection of amolecular event, elapsed time, or combinations thereof. The inventive concept may comprise all or only some of these states in any combination.

[0077] The energy harvesting module may include one or more piezoelectric elements configured to convert mechanical deformation into electrical energy. Nonlimiting examples include polymer piezoelectric materials, ceramic piezoelectric materials, piezocomposites, and multilayer stacks. The piezoelectric elements may be arranged as films, beams, diaphragms, cantilevers, ribbons, corrugated structures, or folded or rolled laminates.

[0078] The disclosed embodiments are not limited to any particular sensing modality, analyte, deployment mechanism, or communication protocol, and may be adapted to a wide range of implantable monitoring applications.BRIEF DESCRIPTION OFTHE DRAWINGS

[0079] The embodiments of the present invention are illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings and in which like reference numerals refer to similar elements and in which:

[0080] FIG. 1 illustrates an example system configuration of an implantable sensor implanted in a user, showing communication with an external monitoring device.

[0081] FIG. 2 is an exploded illustration of the assembly of the implantable sensor.

[0082] FIG. 3a and 3b illustrates two operational states of the implantable sensor, a resting configuration in Fig. 3a and a deformed configuration in Fig. 3b.

[0083] FIG.4a illustrates the implantable sensor in two exemplary compact delivery configurations.

[0084] FIG.4b illustrates the implantable sensor in an expanded operational configuration.

[0085] FIG. 5 illustrates a rolled up implantable sensor and a needle-based injector.

[0086] FIG. 6 includes two graphs illustrating the relationship between harvested energy, stored energy, and a threshold-based transmission event over time.

[0087] FIG. 7 is a flow diagram illustrating the process of piezoelectric energy harvesting and threshold-gated data transmission.

[0088] FIG. 8 is a block diagram illustrating the method for implanting the sensor.

[0089] FIG. 9 is a block diagram illustrating the method for operating the sensor.DETAILED DESCRIPTION OFTHE PREFERRED EMBODIMENTS

[0090] The following description is presented to enable a person skilled in the art to make and use the disclosed systems and methods. Various modifications will be apparent to those skilled in the art, and the general principles described herein may be applied to other embodiments and applications without departing from the scope of the invention. Accordingly, the present disclosure is not intended to be limited to the embodiments shown but is to be accorded the widest scope consistent with the principles and features described herein.

[0091] Referring now to the drawings, FIG.1 illustrates a general overview of an implantable biosensing system. In a preferred embodiment, an implantable sensor 100 is shown to be implanted at a target area 210 within the tissue 202 of a user 200.

[0092] The implantation may be performed in a minimally invasive manner, for example, using an injector 300. Alternatively, the implantation may be made with a surgical incision.

[0093] Once implanted, the implantable sensor 100 is configured to operate within in vivo, in the physiological environment of the user 200. The implantable sensor 100 has a transmitter and is configured to communicate wirelessly. The transmitter transmits a wireless communication signal 600 to an external device 400. The external device may be a mobile device, a wearable device such as a smart watch or ring (not depicted), or a dedicated device such as a medical device (not depicted). This communication allows for the monitoring of biomarker data collected by the sensor 100.

[0094] FIG. 2 provides an exploded principal illustration of the core components of the implantable sensor 100. The assembly comprises a layer of piezoelectric elements 180, which serves as a substrate for converting mechanical energy into electrical energy. In the chip they will be coupled to an energy harvesting control chip 122 to commonly constitute the energy harvesting module 120.

[0095] In the illustrated example and positioned above the layer with the piezoelectric elements 180 is a flexible printed circuit board 110. Mounted on the flexible printed circuit board 110 are the primary electronic modules of the sensor. These may include the energy harvesting module 120 including the energy harvesting control chip 122, an energy storage device 130, a biomarker sensor module 140. The biomarker sensor module may have a sensor interface 144. In one example, the sensor interface surface isless than 0,5mm2in surface. The sensor interface may be smaller than 400nm x 400nm. The sensor interface may be about 50nm x 50nm. In one example, the sensor interface is about 40nm x40nm.

[0096] The sensor further comprises a transmitter 150 for managing the wireless transmissions to an external device. The sensor further comprises a control circuitry 160. Finally, the sensor may comprise a rectifier circuitry 124, for converting the electrical energy provided from the piezoelectric material and being in alternating current into direct current. The rectifier may be a functional or structural part of the energy harvesting module, and configured to convert energy from the piezoelectric material into storable energy in a desired voltage and current level for being used in the sensor.

[0097] Any of the components as illustrated and discussed above may be integrated with several different components in single components. E.g., the rectifier may be included in the control circuitry. Moreover, the control circuitry may be included in the biomarker sensor module 140 or in any other part of the PCB. Thus, the functional features of the components as described above may be achieved in any way without departing from the intended inventive concept if the sensor functions as described.

[0098] Arrows are shown to indicate the functional transfer of electrical energy generated by the piezoelectric elements 180 to the electronic components disposed on the flexible printed circuit board 110.

[0099] Fig 3a and Fig.3b illustrate the implantable sensor 100 when in vivo and in two distinct operational states. Fig 3a shows the sensor 100 in a resting configuration, where the flexible printed circuit board 110 and the underlying piezoelectric elements 180 are substantially flat. Fig.3b shows the sensor 100 in a deformed / bended configuration. This deformation is caused by mechanical motion from the surrounding tissue 202. The bending and flexing of the sensor assembly causes mechanical strain in the piezoelectric elements 180, which in turn induces the generation of electrical energy via the energy harvesting module 120.

[0100] The mechanical motion, illustrated with an arrow 500, which induces deformation in the piezoelectric elements 180, is not limited to a single type of movement but is intended to encompass a broad spectrum of physiological mechanical energy sources available within the body of a user 200. The energy harvesting module 120 isspecifically designed to be responsive to any form of motion that can cause the flexible structure of the sensor 100 to bend, stretch, compress, or otherwise deform.

[0101] In certain placements in the body, the mechanical motion 500 may originate from large-scale, voluntary movements of the user 200. This includes, for example, the movement of limbs during walking, running, or gesturing. The muscles moving during these activities can induce significant strain in the piezoelectric elements 180. Furthermore, the localized contraction and relaxation of skeletal muscles, whether during conscious activity or involuntary spasms, creates deformation in and around the muscle tissue 202 where the sensor 100 may be implanted, providing viable source of mechanical energy.

[0102] In other embodiments, the mechanical motion 500 may be derived from involuntary or autonomic physiological processes. For implant locations near arteries, the rhythmic expansion and contraction of the arterial walls with each heartbeat provides a continuous and predictable source of low-amplitude mechanical deformation. Similarly, the movement of the diaphragm and chest wall during respiration creates cyclic deformation of adjacent tissues and organs, which can be captured by the energy harvesting module 120. In embodiments where the sensor 100 is implanted near the gastrointestinal tract, the wavelike muscle contractions of peristalsis can also serve as a reliable source of mechanical motion 500.

[0103] The system may also be configured to harvest energy from more subtle movements. Even minor shifts in posture or the interaction between different layers of tissue 202 can generate shear forces and deformations sufficient to be converted into electrical energy by the sensitive piezoelectric elements 180. The flexible and conformable nature of the implantable sensor 100, particularly in its expanded operational configuration 120b, effectively captures energy from diverse and often subtle sources of physiological motion.

[0104] The device may be designed not to resist these movements, but rather to deform along with the surrounding tissue 202, thereby maximizing the strain experienced by the piezoelectric elements 180 and, consequently, maximizing the harvested energy.

[0105] The orientation and placement of the implantable sensor 100 may be chosen to align with the primary axes of expected mechanical motion at a target anatomical site, further enhancing the efficiency of the energy harvesting process.

[0106] Fig.4a illustrates the implantable sensor 100 in two examples of its compact delivery configuration 120a. In this state, the flexible assembly may be rolled into a tight, cylindrical form as shown to the left. Alternatively, as shown to the right in the figure, the sensor may be folded into its compact delivery configuration. The implantable sensor may also be compressed without being folded or rolled up in an alternative compact delivery configuration (not depicted).

[0107] This compact delivery configuration 120a is specifically well suited for minimally invasive delivery into the body of a user 200.

[0108] FIG 4b illustrates the implantable sensor 100 as it is moving into in its expanded operational configuration 120b. Upon the complete unrolled action or unfolding or swelled action, in the expanded operational configuration 120b, the sensor has unrolled to present a larger surface area after being placed inside the user.

[0109] This expanded operational configuration 120b is used for maximizing the mechanical coupling to the tissue 202 for energy harvesting. The piezoelectric elements 180 form the substrate, with the flexible printed circuit board 110 and its components, such as the biomarker sensor module 140 and energy storage device 130, disposed thereon.

[0110] Fig. 5 illustrates the principle of implanting the sensor with an injector. A rolled-up implantable sensor 100 in its compact delivery configuration 120a is shown alongside an injector 300. The injector may be a needle or similar. The compact form of the sensor 100 allows it to be loaded into and passed through the needle 300 for minimally invasive insertion into the target tissue 202 of a user 200.

[0111] Fig. 6 illustrates the principle of threshold-gated operation through two related graphs. The upper graph shows the accumulation of harvested energy 510 over time from discrete mechanical motion events. The lower graph shows the corresponding level of stored energy 520 within the energy storage device 130. The control circuitry 160 may monitor the stored energy level against at least one predefined threshold. The graph shows a transmission threshold energy level 540. When the stored energy 520 reaches this threshold, a transmission event 550 is initiated by the transmitter 150, consuming a portion of the stored energy. A similar principle applies to an optional sensing threshold energy level 530 (not explicitly graphed but functionally similar), which when implement must be met before the biomarker sensor module 140 is energized.

[0112] Fig. 7 presents a flow diagram of the energy harvesting and data transmission process. The process begins with a mechanical motion 701 , which causes deformation in the piezoelectric elements 180, leading to piezoelectric harvesting 702 of energy. This energy is processed by the energy harvesting module 120 and rectified 703 by the rectifier circuitry 124. The energy is then stored 704, causing the level of stored energy 520 in the energy storage device 130 to increase. The control circuitry 160 monitors this level in a decision loop, checking if the stored energy 520 has reached a predefined threshold. This threshold level may be e.g., sensing threshold energy level 530 or transmission threshold energy level 540. If the threshold is not reached (NO), the system continues to accumulate energy. If the threshold is reached 705 (YES), a function is executed, such as the transmission event 706, which involves energizing the biomarker sensor module 140 and the transmitter 150.

[0113] Fig. 8 is a block diagram illustrating a method for implanting the sensor 100. The method may be designed to be minimally invasive. The first step 801 involves implanting the sensor 100, which includes an energy harvesting module 120 with one or more piezoelectric elements 180, into a target area of tissue 202 within a user 200. In a preferred embodiment, this implantation step is performed by injecting 802 the sensor 100 using an injector or needle 300 while the sensor 100 is in its compact delivery configuration 120a.

[0114] Following the implantation step, the method proceeds with the step of expanding 803 the energy harvesting module 120, in vivo, from the compact delivery configuration 120a into the second expanded operational configuration 120b. In certain embodiments, where the energy harvesting module 120 comprises a hydrophilic material, this expansion may be initiated or assisted by the absorption of physiological fluids. The method may optionally include a further step of injecting a fluid 804 into the target area of tissue 202 to expedite this expansion process.

[0115] Fig. 9 is a block diagram illustrating a method for operating the implanted sensor 100. The method begins with the step 901 of harvesting energy in vivo using the energy harvesting module 120. This step comprises the mechanical deforming of one or more piezoelectric elements 180 through the natural movements and mechanical motion 500 of the user 200 and converting this deformation into electrical energy. Thenext step 902 is accumulating the harvested energy in an energy storage element 130, which is electrically coupled to the energy harvesting module 120.

[0116] The method may further comprise the step 903 of monitoring a stored energy level 520 in the energy storage device 130 using the control circuitry 160. Following this, the method includes the step of energizing 904 a biomarker sensor module 140 to detect a biomarker binding event. This energizing step preferably only occurs when the monitored stored energy 520 satisfies a predefined sensing threshold energy level 530.

[0117] The method may also include a step 905 of transmitting a sensing signal from the transmitter 150. This transmission step is also preferably gated by energy levels and only occurs when the stored energy level 520 satisfies a transmission threshold energy level 540.

[0118] The method may further comprise a step 905 of performing an electrical condition, which initiates an electrochemical regeneration operation on a sensing interface of the biomarker sensor module 140 to maintain sensor responsiveness. The detection of the biomarker binding event itself may be what triggers the electrochemical regeneration operation.

Claims

Claims1. An implantable sensor, comprising:an energy harvesting module electrically coupled to an energy storage device for transferring harvested electricity to the energy storage device,a biomarker sensor module being energized by the energy storage device and being configured to detect a biomarker binding event,a transmitter configured to transmit a sensing signal from the biomarker sensor module, anda control circuitry configured to control the biomarker sensor module and transmitter, whereinthe energy harvesting module comprises one or more piezoelectric elements configured to convert mechanical deformation into electrical energy.

2. The implantable sensor according to claim 1, wherein the energy harvesting module is movable between a first compact delivery configuration and a second expanded operational configuration.

3. The implantable sensor according to claim 2, wherein the energy harvesting module comprises at least one of a hydrophilic materialfor movingthe energy harvesting module from the compact delivery configuration to the expanded operational configuration.

4. The implantable sensor according to claim 2, wherein the energy harvesting module comprises at least one of a swellable material, or shape-memory element for moving the energy harvesting module from the compact delivery configuration to the expanded operational configuration.

5. The implantable sensor according to any one of claims 2-4, wherein the energy harvesting module is rolled up or folded in its first compact delivery configuration.

6. The implantable sensor according to any one of the previous claims, wherein the transmitter is a low-band signal transmitter.

7. The implantable sensor according to any one of the previous claims, wherein the control circuitry is further configured to monitor a stored energy level in the energy storage device and energizing the biomarker sensor module only when the stored energy satisfies a sensing threshold energy level.

8. The implantable sensor according to claim 7, wherein the control circuitry is further configured to enable transmission of a sensing signal only when the stored energy level satisfies a transmission threshold energy level.

9. The implantable sensor according to claim 8, wherein the transmission threshold energy level is greater than the sensing threshold energy level.

10. The implantable sensor accordingto any one of the previous claims, wherein the biomarker binding event is an electrochemical biosensing detecting a change in at least one of impedance, conductance, current, or voltage.

11. A method for implanting a sensor comprising a biomarker sensor module and an energy harvesting module, the energy harvesting module being moveable between a first compact delivery configuration and a second expanded operational configuration, method comprising the steps of: implantingthe sensor in a target area of a user, andexpanding the energy harvesting module, in vivo, from the first compact delivery configuration into the second expanded operational configuration.

12. The method according to claim 11 , wherein the step of implanting the sensor comprises implanting a sensor having an energy harvesting module with one or more piezoelectric elements configured to convert mechanical deformation into electrical energy for powering the sensor.

13. The method according to any one of claims 11-12, wherein the step of implantin the sensor comprises injecting the sensor using an injector.

14. The method according to claim 13, wherein the step of injecting the sensor comprises injecting a sensor having an energy harvesting module comprising a hydrophilic material.

15. The method according to any one of claims 11-14, further comprising a step of injecting a fluid into the target area for expediting the expansion of the energy harvesting module from the first compact delivery configuration into a second expanded operational configuration.

16. The method according to any one of claims 11-15, wherein the energy harvesting module is a rolled up or folded energy harvesting module when being in its first compact delivery configuration.

17. A method for operating an implanted sensor in a person, the method comprisingthe steps of:harvesting energy in vivo using an energy harvesting module; accumulating the harvested energy in an energy storage element electrically coupled to the harvesting energy module;energizing a biomarker sensor module to detect a biomarker binding event, wherein the step of harvesting energy in vivo comprises mechanically deforming of one or more piezoelectric elements with natural movements of the person and converting the deformation into electrical energy.

18. The method according to claim 17, the method further comprisingthe step of:monitoring a stored energy level in the energy storage device; and wherein the step of energizing a biomarker sensor module only occurs when the monitored stored energy satisfies a sensing threshold energy level.

19. The method according to claim 18, further comprising a step of transmitting a sensing signal only when the stored energy level satisfies a transmission threshold energy level.

20. The method according to any one of claims 17-19, wherein detection of the biomarker binding event triggers an electrical condition for performing an electrochemical regeneration operation on a sensing interface of the biomarker sensor module.

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