DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Applicant' s arguments, filed 5/12/2026, have been fully considered. The following rejections and/or objections are either reiterated or newly applied. They constitute the complete set presently being applied to the instant application.
Applicants have amended their claims, filed 5/12/2026, and therefore rejections newly made in the instant office action have been necessitated by amendment.
Claims 1-20 are the currently pending claims hereby under examination. Claims 1, 8, 12, and 17-19 have been amended.
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
Claims 1-3, 5-6, and 8 are rejected under 35 U.S.C. 103 as being unpatentable over Becerra-Fajardo et al. (Becerra-Fajardo, Laura, and Antoni Ivorra. “Bidirectional Communications in Wireless Microstimulators Based on Electronic Rectification of Epidermically Applied Currents.” 2015 7th International IEEE/EMBS Conference on Neural Engineering (NER). IEEE, 2015. 545–548. Web), hereto referred as Becerra-Fajardo, and further in view of Ivorra et al. (Ivorra, Antoni, Laura Becerra-Fajardo, and Quim Castellví. “In Vivo Demonstration of Injectable Microstimulators Based on Charge-Balanced Rectification of Epidermically Applied Currents.” Journal of neural engineering 12.6 (2015): 066010–066010. Web.), hereto referred as Ivorra, and further in view of Goldshtein et al. (US-20150282720-A1), hereto referred as Goldshtein.
Regarding claim 1, Becerra-Fajardo teaches that a sensing system comprising: at least one non-bioresorbable implant adapted to be deployed in a medium of a living body by injection or by catheterization (Becerra-Fajardo, Title/Abstract, Fig. 1 and 2: "implants act as rectifiers... for picking up the HF current and for performing electrical stimulation", p. 2, ‘I. Introduction’, last ¶: “an uplink to send sensing data from the implants to the external unit is a beneficial feature for the proposed method, here we present a proof-of-concept prototype of a bidirectional communication link”, demonstrating an implantable sensing system; p. 545, 'I Introduction', ¶3: “We conceive ultrathin elongated implant bodies (diameter < 300 µm) that can be easily deployed in tissues (e.g. by injection)”, this explicitly teaches deployment by injection; Becerra-Fajardo further discloses implants comprising electronic circuitry and electrodes for rectifying externally applied HF current bursts and enabling sensing and communication with an external unit, and does not disclose biodegradable, bioresorbable, or transient construction, such that under the broadest reasonable interpretation the implant reasonably corresponds to a non-bioresorbable implant); wherein the implant comprises an electronic circuit and at least two electrodes connected to the electronic circuit (Becerra-Fajardo 2015, Fig. 2: depicts implant circuitry with two electrodes, "Electrode 1", "Electrode 2"); and a reading unit for reading the implant when the implant is deployed in a medium (Becerra-Fajardo 2015, Fig. 4 "External receiver" (i.e., reading unit) and Fig. 2: reading unit depicted at the top of the figure with the implant inside a human arm, thus deployed in a medium); wherein the reading unit comprises two or more electrodes (Becerra-Fajardo 2015, Fig. 2: depicts reading unit using brown electrodes connected to "sensing resistors"; Fig. 5: depicts two "external electrode[s]" which are part of the reading unit); an alternating voltage generator to generate an alternating voltage across the two or more electrodes (Becerra-Fajardo 2015, Fig. 5: depicts an alternating voltage generator with "Amplitude: 75 V" and "Frequency: 1 MHz", connected to the two electrodes); and a control and processing module (Becerra-Fajardo 2015, p. 547, Col. Right, ¶1-2: "LabVIEW... using an ACQ board... and modulated by a function generator... and then amplified (WMA-300 by Falco Systems)", where the PC runs LabVIEW coupled with external components acts as the control and processing module); wherein the reading unit is configured for emitting an interrogation signal comprising at least one burst of an alternating current suitable to reach the implant by volume conduction through the medium (Becerra-Fajardo 2015, p. 545, Col. Right, ¶1-2: "current burst"; Fig. 1: depicts AC generator with bursts of AC current through an arm for reaching the implant (i.e., medium) where the "stimulation method proposes the use of implants as rectifiers of innocuous high frequency current bursts (> 1 MHz), which are conductively supplied to the tissues through external electrodes").
Also regarding claim 1, Becerra-Fajardo does not fully teach that the electronic circuit comprises both a capacitor and a device of asymmetric conductance connected in series between the at least two electrodes such that the device of asymmetric conductance rectifies an alternating current received at the at least two electrodes to charge the capacitor. Rather, as shown above, Becerra-Fajardo teaches an implant including rectifying circuitry between two electrodes for producing implant stimulation/communication current (Becerra-Fajardo 2015, Fig. 2). Becerra-Fajardo further recognizes the same underlying rectifier-based implant approach using capacitive circuitry, teaching that “an implant with a simple circuit consisting of a rectifier, a capacitor and a resistor is able to deliver charge-balanced low frequency currents capable of stimulating tissues” (Becerra-Fajardo, p. 545, 'I. Introduction'). However, Becerra-Fajardo does not teach the complete claimed capacitor/asymmetric-conductance charging arrangement. In particular, Becerra-Fajardo does not expressly teach, in the embodiment relied upon for the external readout architecture, that the capacitor is arranged with a particular asymmetric-conductance device in the claimed series charging path such that the asymmetric-conductance device rectifies the alternating current received at the implant electrodes to charge that capacitor, nor does Becerra-Fajardo expressly teach that the same capacitor then participates in the claimed post-burst discharge through the medium.
Ivorra supplies these missing teachings. Ivorra teaches an implant circuit that includes a diode, resistor, and capacitors arranged between two electrodes for rectifying applied high-frequency current bursts and performing charge balance (Ivorra, Figs. 1-2). Ivorra further expressly states: “During the HF bursts, rectified current will flow from a to b through the diode, thus progressively charging CB” (Ivorra, §2.1), thereby directly teaching rectification of an alternating current received at the implant electrodes to charge the capacitor. Accordingly, Becerra-Fajardo provides the external burst-powered implant platform, while Ivorra provides the specific passive diode/capacitor charging arrangement missing from Becerra-Fajardo.
It would have been prima facie obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified Becerra-Fajardo 2015 in view of Ivorra to include Ivorra's passive rectifier arrangement having a capacitor charged through a device of asymmetric conductance, together with a resistor between the implant electrodes. It would have been possible to combine these teachings because Becerra-Fajardo and Ivorra are directed to the same rectifier-based implant approach in which high-frequency bursts are conductively supplied through tissue by external electrodes and picked up by two implant electrodes. Becerra-Fajardo already teaches the external burst-powered implant platform and external readout architecture, while Ivorra teaches a compatible implant-side passive diode, capacitor, and resistor arrangement operating from the same type of applied high-frequency bursts. Thus, incorporating Ivorra's passive diode/capacitor/resistor implant circuit into Becerra-Fajardo's burst-interrogated implant system would have required only the substitution or adaptation of known passive rectifier components performing the same rectification and charge-balancing functions in the same operating environment. The benefit of making this combination would be to simplify the charge-balancing circuitry by using passive components, reducing implant complexity, improving miniaturization, lowering power consumption, and increasing reliability while maintaining compatibility with the external volume-conduction burst interrogation already taught by Becerra-Fajardo.
Also regarding claim 1, Becerra-Fajardo does not fully teach that the electronic circuit further comprises a discharge network connected in parallel with the device of asymmetric conductance for discharging the capacitor through the medium between bursts of alternating current, wherein the discharge network comprises at least one electronic component. Rather, as shown above, Becerra-Fajardo discloses rectifier-based implant circuitry, acknowledges a prior simple implant circuit including “a rectifier, a capacitor and a resistor,” and teaches an external receiver in a burst-based volume-conduction system (Becerra-Fajardo, p. 545, 'I. Introduction'; Fig. 2). Thus, Becerra-Fajardo is not deficient merely because it lacks capacitors, resistors, or rectifying components. However, Becerra-Fajardo does not teach the complete claimed discharge-network arrangement. In particular, Becerra-Fajardo does not expressly teach, in the embodiment relied upon for the external readout architecture, that the implant capacitor is discharged after burst cessation through a discharge network connected in parallel with the particular asymmetric-conductance device, nor does Becerra-Fajardo expressly teach that this discharge network discharges that capacitor through the surrounding tissue or medium between alternating-current bursts for the claimed sensing/readout purpose.
Ivorra supplies these missing discharge-network teachings. Ivorra expressly teaches that after each burst “the capacitor will slowly discharge through the implant resistor RD and the tissues until the next burst” (Ivorra, p. 3, ¶2) and shows in Fig. 1 that RD lies across the same electrode nodes as the diode, i.e., in parallel (Ivorra, FIG. 1). Thus, Ivorra teaches a resistor RD, which is an electronic component of the discharge network, connected in parallel with the asymmetric-conductance device and arranged so that the capacitor discharges through the surrounding tissue or medium between bursts. Becerra-Fajardo supplies the external burst interrogation and readout architecture into which Ivorra's passive capacitor discharge arrangement would be incorporated.
It would have been prima facie obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the combined Becerra-Fajardo and Ivorra to use Ivorra's discharge resistor RD as an electronic component of a discharge network connected in parallel with the device of asymmetric conductance, such that the capacitor discharges through the surrounding tissue or medium between alternating-current bursts. It would have been possible to combine these teachings because Becerra-Fajardo and Ivorra use the same general operating environment of externally applied high-frequency bursts conducted through tissue to implant electrodes, and Ivorra's passive RD discharge path is electrically compatible with the same implant-side diode/capacitor rectification arrangement already discussed above. Incorporating the RD discharge path would not require changing Becerra-Fajardo's external volume-conduction interrogation or external readout architecture, but would merely provide the known passive post-burst charge-balancing path taught by Ivorra within the implant circuit. The benefit of the combination would be to ensure capacitor charge balance and safety by allowing full or near-full discharge between bursts, thereby avoiding DC offsets and electrochemical damage in tissue and providing predictable implant behavior.
Also regarding claim 1, the combined Becerra-Fajardo and Ivorra does not fully teach that at least the capacitor, the device of asymmetric conductance or the electronic component is a transducer configured such that an operational parameter of the transducer is variable depending on at least one of a physical and a chemical condition of the medium when the implant is deployed in the medium, wherein the transducer is arranged such that said variable operational parameter modulates a time course of the capacitor discharge through the medium. Rather, as shown above, the combined Becerra-Fajardo and Ivorra disclose an implant with two electrodes and a rectifying circuit including a diode and capacitor, together with a discharge resistor RD, interrogated via externally applied HF bursts and read by an external receiver measuring signals across a sensing resistor RS (e.g., “The external HF current generator is connected in series to a sensing resistor RS… The electrodes of the implants pick up the HF current… amplitude modulation… can be detected across the external sensing resistor”, Becerra-Fajardo, p. 546, 'II. PROOF-OF-CONCEPT PROTOTYPE'). Becerra-Fajardo and Ivorra therefore supply the burst-powered implant and capacitor discharge framework. However, the combined Becerra-Fajardo and Ivorra do not teach the complete claimed transducer/discharge-time-course arrangement. In particular, the combined Becerra-Fajardo and Ivorra do not expressly teach: (1) that any one of the capacitor, asymmetric-conductance device, or discharge-network electronic component is itself configured as a transducer; (2) that an operational parameter of that component varies depending on a physical or chemical condition of the surrounding medium; and (3) that the variation in that operational parameter modulates the time course of the capacitor discharge through the medium.
Goldshtein supplies the missing condition-responsive transducer feature. Goldshtein is relied upon for the limited teaching of a known implantable variable-capacitance pressure transducer, not for bodily incorporation of Goldshtein's inductive powering, antenna telemetry, oscillator circuitry, or complete cardiac monitoring architecture. Goldshtein is relied upon for the claim alternative in which the capacitor is the transducer. Goldshtein teaches an implanted capacitance-based pressure transducer, stating that ambient pressure is sensed using “a pressure sensor (36, 90, 174), which has a capacitance that varies in response to the ambient pressure, so as to produce a time-varying waveform” (Goldshtein, Abstract). Goldshtein further teaches that implant 24 includes “a capacitance-based pressure sensor 36,” and that “[o]ne of the electrodes of this capacitor comprises a membrane that is exposed to the ambient blood pressure", where “[t]he pressure applied by the blood to the membrane sets the spacing between the capacitor electrodes, and therefore sets the capacitor's capacitance” (Goldshtein, ¶[0035]). Thus, Goldshtein teaches the missing capacitor-as-transducer limitation because the capacitor has an operational parameter, capacitance, that varies depending on pressure, which is a physical condition of the living body.
Goldshtein further evidences that pressure-dependent capacitance was known to be processed to obtain a pressure measurement. Goldshtein teaches that the implant “produces a time-varying waveform that is indicative of the time-varying capacitance of sensor 36, and thus the time-varying pressure” (Goldshtein, ¶[0036]) and that a processor in the external unit “processes the received waveform so as to estimate the actual blood pressure sensed by sensor 36” (Goldshtein, ¶[0037]). Goldshtein further teaches that “[s]ystem 20 measures the ambient blood pressure in heart 28 by assessing the capacitance of sensor 36", and that “the capacitance varies as a function of the pressure in accordance with some known dependence” (Goldshtein, ¶[0042]). Accordingly, Goldshtein teaches an implantable capacitor transducer whose variable capacitance represents a physical condition and is processed to obtain a pressure measurement. Ivorra supplies the charge and discharge time course through the tissue or medium, and Goldshtein supplies the known pressure-responsive capacitor whose capacitance would predictably alter that time course. For example, in an RC discharge path such as the Ivorra discharge path, the post-burst discharge time constant corresponds to τ = C(RD + Rtissue) when the tissue path is modeled as a resistance, so changing the capacitor value C using Goldshtein's pressure-responsive capacitor predictably changes the time course of the capacitor discharge through the medium.
It would have been prima facie obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the combined Becerra-Fajardo and Ivorra in view of Goldshtein to configure the capacitor as a pressure-responsive transducer whose capacitance varies with pressure, such that the variable capacitance modulates the time course of capacitor charge and discharge through the medium. As discussed above, Becerra-Fajardo provides the volume-conduction burst interrogation and external electrical readout architecture for implant-dependent signals, and Ivorra provides the passive capacitor, asymmetric-conductance device, and discharge-network architecture in which the capacitor is charged during the burst and discharges through the implant resistor and tissues between bursts. Goldshtein teaches the remaining pressure-responsive capacitor-transducer feature by showing an implanted capacitance-based pressure sensor whose capacitance varies with ambient pressure. Thus, one of ordinary skill would have found it obvious to implement Ivorra's capacitor as a known capacitive pressure transducer as taught by Goldshtein so that the RC charging and discharging behavior would depend on a physical condition of the medium. This is a component-level substitution because Goldshtein's MEMS membrane capacitor has a pressure-variable capacitance property that is independent of the broader oscillator and telemetry circuitry in which Goldshtein uses it.
It would have been possible to combine these teachings because the modification uses Goldshtein for the limited teaching of a known implantable variable-capacitance pressure transducer, not for bodily incorporation of Goldshtein's inductive powering, telemetry, or complete cardiac monitoring architecture into Becerra-Fajardo and Ivorra. The proposed modification would retain the burst-based volume-conduction interrogation and external electrode readout taught by Becerra-Fajardo, retain the diode/capacitor/discharge-network architecture taught by Ivorra, and implement the capacitor in that circuit as a pressure-dependent capacitor as taught by Goldshtein. Electrically, this is a compatible modification because Ivorra already teaches that the implant capacitor is charged by rectified burst current and then discharges through a discharge path, while Goldshtein teaches that implantable pressure sensors were known in which the capacitance of the capacitor varies with pressure. Changing the capacitance of the capacitor in Ivorra's RC circuit would predictably change the RC charge and discharge time course because capacitance is a determining variable of the RC time constant. The benefit of the combination would be to allow the existing burst-based interrogation and external processing chain to provide diagnostic sensing of a physical parameter of the medium while preserving a compact implant form factor suitable for minimally invasive deployment.
Also regarding claim 1, the combined Becerra-Fajardo, Ivorra, and Goldshtein does not fully teach that the reading unit is adapted for measuring the physical and/or chemical parameters of the living body by measuring electrical signals at the two or more electrodes of the reading unit. Rather, as shown above, Becerra-Fajardo teaches electrode-based electrical measurement of implant-dependent signals using the external electrodes and sensing resistor, and Ivorra teaches that the implant capacitor produces a predictable post-burst discharge through tissue. However, the combined Becerra-Fajardo and Ivorra do not teach the complete claimed parameter-measurement arrangement. In particular, the combined Becerra-Fajardo, Ivorra, and Goldshtein do not expressly teach: (1) that a physical or chemical parameter of the living body is represented by a variable operational parameter of a transducer in the implant discharge network; (2) that the discharge response varies with that physical or chemical parameter; and (3) that the reading unit determines the physical or chemical parameter by measuring the resulting pressure-dependent electrical signal at the reading-unit electrodes.
Goldshtein supplies the missing physical-parameter sensing relationship. Goldshtein teaches that implant 24 measures ambient blood pressure using a capacitance-based pressure sensor, and that “[t]he pressure applied by the blood to the membrane sets the spacing between the capacitor electrodes, and therefore sets the capacitor's capacitance” (Goldshtein, ¶[0035]). Goldshtein further teaches that implant 24 “produces a time-varying waveform that is indicative of the time-varying capacitance of sensor 36, and thus the time-varying pressure” (Goldshtein, ¶[0036]) and that external unit 32 processes the received waveform to estimate the actual blood pressure sensed by the sensor (Goldshtein, ¶[0037]). In the proposed combination, Becerra-Fajardo's external electrodes and sensing resistor measure implant-dependent electrical effects produced during burst interrogation, Ivorra's implant circuit produces a predictable capacitor charge and discharge response through tissue, and Goldshtein's pressure-responsive capacitor causes that charge/discharge response to vary with pressure. Thus, Goldshtein supplies the missing physical-parameter dependency, while Becerra-Fajardo supplies the claimed electrode-based readout.
It would have been prima facie obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the combined Becerra-Fajardo, Ivorra, and Goldshtein in view of Goldshtein to adapt the reading unit's existing electrode-based electrical measurements to determine a physical parameter of the medium based on the pressure-responsive capacitor transducer taught by Goldshtein. As discussed above, Becerra-Fajardo already measures implant-dependent electrical signals using the external electrode/sensing-resistor pathway, and Ivorra provides a capacitor charge/discharge response through the tissue or medium. Goldshtein teaches the remaining sensing relationship by making capacitance pressure-dependent. In the proposed combination, the reading unit would measure a pressure-dependent change in the burst-associated or post-burst electrical response at the external electrode/sensing-resistor pathway because the Goldshtein pressure-responsive capacitor would change the Ivorra RC charge/discharge behavior through the medium. Becerra-Fajardo supplies the electrode-based electrical measurement pathway required by the claim, while Goldshtein supplies the known pressure-capacitance relationship that causes the measured electrical response to encode the physical parameter. This does not require Goldshtein's own received waveform or telemetry path to be the same waveform or readout path used in the proposed combination.
It would have been possible to combine these teachings because no separate Goldshtein inductive telemetry or complete Goldshtein readout system would need to be imported into Becerra-Fajardo and Ivorra. Rather, Goldshtein's variable-capacitance pressure sensor would be used as the capacitor in the implant circuit already provided by Ivorra, and Becerra-Fajardo's existing external receiver would continue to measure implant-dependent electrical behavior through the external electrode/sensing-resistor pathway. The measured pressure-dependent RC response could then be processed by the control and processing module already present in Becerra-Fajardo. The benefit of the combination would be to extend the existing electrical measurement pathway to yield diagnostic information about the medium without changing the fundamental interrogation method, improving utility while preserving system simplicity.
Also regarding claim 1, the combined Becerra-Fajardo, Ivorra, and Goldshtein does not fully teach that said electrical signals depend on the variable operational parameter of the transducer of the implant during, after or during and after delivering the at least one burst of the alternating current. Rather, as shown above, the combined Becerra-Fajardo, Ivorra, and Goldshtein generates and measures electrical signals at the external electrodes during burst-based interrogation and during post-burst discharge behavior of the implant circuitry. However, the combined Becerra-Fajardo, Ivorra, and Goldshtein do not teach the complete claimed signal-dependency arrangement. In particular, the combination does not expressly teach: (1) a pressure-responsive capacitor having a variable capacitance; (2) a burst-associated or post-burst RC time course that changes based on that variable capacitance; and (3) an electrode-measured signal that depends on that variable capacitance.
Goldshtein supplies the missing dependency of the electrical signal on the operational parameter of the transducer. Goldshtein teaches that pressure changes the capacitance of the implanted pressure sensor, and that the resulting waveform is indicative of the time-varying capacitance and pressure (Goldshtein, ¶[0035]-[0037]). Thus, when Goldshtein's pressure-responsive capacitor is used as the capacitor in Ivorra's implant circuit, the burst-associated and post-burst electrical response depends on the operational parameter of the transducer, namely the capacitance of the capacitor.
It would have been prima facie obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the combined Becerra-Fajardo, Ivorra, and Goldshtein in view of Goldshtein such that the electrical signals measured at the reading unit during and/or after delivery of the interrogation burst depend on the operational parameter of the implant transducer that varies with the physical condition of the medium. As discussed above, Ivorra teaches that the capacitor is charged during the burst and discharges after the burst through RD and tissues. Goldshtein teaches that capacitance depends on pressure. Therefore, when Goldshtein's pressure-responsive capacitor is used as the capacitor in Ivorra's implant circuit, the electrical signal measured through Becerra-Fajardo's external readout path would depend on the variable capacitance of the pressure-responsive capacitor during charging, after burst cessation, or both.
It would have been possible to combine these teachings because Becerra-Fajardo already applies burst-based electrode interrogation and acquires implant-dependent electrical signals at the external electrodes, Ivorra provides implant circuitry suitable for predictable burst-time charging and post-burst discharge behavior, and Goldshtein teaches an implantable pressure-responsive capacitor whose capacitance changes with a physical condition. The modification merely uses Goldshtein's pressure-responsive capacitor as the capacitor in the same type of RC behavior that Ivorra already provides, while Becerra-Fajardo's reader continues to sense implant-dependent electrical signals through its existing external electrode/sensing-resistor pathway. The benefit of the combination would be to enable physical sensing using the same burst-based interrogation and external processing infrastructure, improving diagnostic capability while maintaining compact implant deployment by injection or catheterization.
Regarding claim 2, the combined Becerra-Fajardo, Ivorra, and Goldshtein teaches that wherein the reading unit is adapted to emit bursts of the alternating current at a frequency between 100 kHz and 100 MHz, with bursts duration between 0.1 μs and 10 ms, and a repetition frequency between 0 Hz and 100 kHz (Becerra-Fajardo, Fig. 1; p. 1, 'I. Introduction': "electrical stimulation method... The implant acts as a rectifier of innocuous high frequency (HF) current bursts [> 1 MHz] that are conductively supplied to the tissues using external electrodes"; Fig. 5: depicting the high frequency current generator connected to external electrodes for delivering bursts of alternating current at “Amplitude: 75 V” and “Frequency: 1 MHz”, confirming that the reading unit emits a burst of alternating current in the specified frequency range; p. 546, 'A. Uplink Communications Scheme': "the stimulators generated 500 µs current pulses at a repetition rate of 20 Hz”, showing that the burst duration and repetition frequency fall within the claimed ranges; collectively disclosing that the external generator system and external electrodes (i.e., the reading unit) emit bursts of alternating current at the claimed frequency, burst duration, and repetition frequency).
Regarding claim 3, the combined Becerra-Fajardo, Ivorra, and Goldshtein teaches that the implant further comprises an elongated and flexible body made of an electrically isolating material, and wherein the electronic circuit is housed within the body, and wherein the implant further comprises two metallic electrodes at opposite ends of the body which are electrically connected to the electronic circuit. Rather the combined Becerra-Fajardo, Ivorra, and Goldshtein discloses an implantable device comprising an electronic circuit connected to two peripheral electrodes and designed to interact with external high frequency currents (Becerra-Fajardo, Section I. Introduction, p. 1, right column; Fig. 2). However, it does not disclose that the implant body is flexible, elongated, made of an electrically insulating material, or that the electronic circuit is explicitly housed within the implant body.
Ivorra discloses an implant structure consisting of a tubular silicone body approximately 1 mm in diameter, containing an embedded electronic circuit with two peripheral electrodes located at opposite ends of the body (Ivorra, Abstract, Fig. 5). Silicone is known to be both flexible (as depicted in Fig. 5) and electrically insulating, and Ivorra depicts that the electronic components are located within the implant body and electrically connected to the peripheral electrodes, thereby providing both the structure and electrical functionality consistent with the claimed invention.
It would have been prima facie obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the combined Becerra-Fajardo, Ivorra, and Goldshtein in view of Ivorra to provide an implant comprising an elongated, flexible, electrically insulating body with an embedded electronic circuit. One of ordinary skill in the art would have found it obvious to do so because the use of flexible, insulating materials and embedded electronics, as taught by Ivorra, would enhance biocompatibility, facilitate implantation through minimally invasive techniques such as injection, and protect the internal circuitry from environmental damage. It would have been possible to integrate the structural aspects of Ivorra's implant into Becerra-Fajardo’s implant design without changing the basic operation of rectifying and stimulating through external HF bursts. The benefit of the combination would be improved flexibility and biocompatibility of the implant, enabling less invasive delivery and longer-term functionality within biological tissue.
Regarding claim 5, the combined Becerra-Fajardo, Ivorra, and Goldshtein teaches that the device of asymmetric conductance is a diode, a p-n junction of a transistor or a smart diode (Becerra-Fajardo, Fig. 2: schematic diagram showing a bridge rectifier between Electrode 1 and Electrode 2, where the diode symbols are that of Schottky diodes, confirming that the device of asymmetric conductance includes Schottky diodes).
Regarding claim 6, the combined Becerra-Fajardo, Ivorra, and Goldshtein teaches that the capacitor is a transducer whose capacitance is variable depending on the physical and/or chemical condition of the medium (As disclosed in claim 1 above, the electrical properties vary in response to physical or chemical conditions of the environment it is exposed to (i.e. medium)), but does not teach that wherein the electrical or electronic component of the discharge network is a resistor of a given nominal value. As described in claim 1 above, the combined Becerra-Fajardo, Ivorra, and Goldshtein teach a sensing implant utilizing a diode, resistor, and capacitor that responds to physical or chemical conditions of a medium, but do not expressly describe the resistor having nominal value.
Ivorra teaches a discharge network that includes “an SMD 1 kΩ resistor (ERJXGNJ102Y by Panasonic)” ('2.1. The implants', p. 3, L-col., last 2 ¶ to p. 4, L-col., first ¶), demonstrating that a specific resistor value is used in the implant circuit to control the discharge behavior.
It would have been prima facie obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the combined Becerra-Fajardo, Ivorra, and Goldshtein in view of Ivorra to include a resistor of a given nominal value in the discharge network. The benefit of making this combination would be to achieve a controlled discharge rate and stable electrical behavior necessary for reliable sensor performance, thereby enhancing system predictability and allowing the implant to maintain safe and consistent operation conditions.
Regarding claim 8, the combined Becerra-Fajardo, Ivorra, and Goldshtein does not fully teach that wherein a capacitance of the capacitor is within the range 10 pF to 10 nF, and wherein a resistance of the discharge network is within the range 1 kΩ to 10 MΩ, wherein the capacitance and the resistance are selected such that a discharge time constant of the capacitor through the discharge network and the medium falls within a range that produces a detectable post-burst voltage decay at the two or more electrodes of the reading unit. Rather, as shown above in claim 1, Becerra-Fajardo teaches a burst-based volume-conduction implant system with an external reading unit that detects implant-dependent electrical signals at an external sensing resistor and external electrodes. Ivorra teaches the implant-side capacitor/discharge path and expressly teaches that, after each burst, “the capacitor will slowly discharge through the implant resistor RD and the tissues until the next burst” (Ivorra, §2.1). Ivorra also teaches a discharge resistor in the claimed resistance range by using “an SMD 1 kΩ resistor (ERJXGNJ102Y by Panasonic)” in the implant discharge path (Ivorra, §2.1). Goldshtein teaches a capacitance-based pressure sensor whose capacitance varies with pressure, teaches that the pressure sensor is read by processing a pressure-dependent waveform, and further teaches a capacitance-based pressure sensor in an exponential charge/discharge configuration using pF-scale capacitance and kΩ resistance, including a voltage-mode configuration in which “the 5.6 pF capacitor is charged/discharged exponentially via the 10K ohm resistor” (Goldshtein, ¶[0079]). However, the combined Becerra-Fajardo, Ivorra, and Goldshtein does not expressly teach that the implant capacitor in the Becerra-Fajardo/Ivorra circuit, as modified to be a Goldshtein pressure-responsive capacitor, is specifically selected together with the discharge-network resistance in the claimed sensing context such that the resulting discharge time constant through the discharge network and medium produces a detectable post-burst voltage decay at the reading-unit electrodes. Ivorra’s 0.6 μF capacitor is a stimulation-context capacitor and is not the pressure-sensing capacitor supplied by Goldshtein in the present combination.
Goldshtein supplies additional support for both claimed numerical ranges and the RC timing relationship. Goldshtein teaches that the pressure sensor capacitance is the measured parameter, stating that the pressure sensor has “a capacitance that varies in response to the ambient pressure” (Goldshtein, Abstract), and that “[t]he pressure applied by the blood to the membrane sets the spacing between the capacitor electrodes, and therefore sets the capacitor's capacitance” (Goldshtein, ¶[0035]). Goldshtein further teaches pF-scale capacitance in pressure-sensor circuitry, including a capacitance-based pressure sensor modeled by a variable capacitor of 5.6 pF, and teaches that the capacitor is charged and discharged exponentially through a 10 kΩ resistor (Goldshtein, ¶[0078]-[0079]). Specifically, Goldshtein teaches that “the capacitance-based pressure sensor is modeled by the variable capacitor denoted C=5.6 pF” and that, in the voltage-mode configuration, “the 5.6 pF capacitor is charged/discharged exponentially via the 10K ohm resistor” (Goldshtein, ¶[0078]-[0079]). Thus, Goldshtein’s own characterization of a representative MEMS pressure sensor capacitance and resistance in a charge/discharge circuit supplies values within the claimed ranges and confirms that pF-scale capacitance and kΩ-scale resistance were known and suitable for pressure-sensor charge/discharge timing circuits.
It would have been prima facie obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have further modified the combined Becerra-Fajardo, Ivorra, and Goldshtein to select the capacitance of the Goldshtein pressure-responsive capacitor to be within 10 pF to 10 nF and to select the discharge-network resistance to be within 1 kΩ to 10 MΩ such that the capacitor discharge time constant through the discharge network and medium produces a detectable post-burst voltage decay at the reading-unit electrodes. As discussed above, Ivorra already teaches that the capacitor discharges through RD and tissues after the burst, and Goldshtein teaches that a pF-scale pressure-sensor capacitance is charged and discharged exponentially through a kΩ resistor. In an RC discharge path such as the Ivorra path, the discharge time constant corresponds to τ = C(RD + Rtissue) when the tissue path is modeled as a resistance. Therefore, capacitance and resistance are recognized result-effective variables for setting the post-burst discharge duration and making the decay detectable while still allowing discharge between successive bursts.
It would have been possible to combine these teachings because the modification is a component-value selection within the same RC charge/discharge framework already established by Ivorra and Goldshtein. Becerra-Fajardo's external reader already detects implant-dependent electrical responses, Ivorra supplies a discharge resistor in the claimed range and teaches post-burst discharge through tissue, and Goldshtein teaches a pressure-responsive capacitor at the pF scale and exponential charge/discharge behavior through a kΩ resistor. Selecting a capacitance within 10 pF to 10 nF and a discharge resistance within 1 kΩ to 10 MΩ would have required only routine adjustment of known RC component values to produce a measurable time constant compatible with the burst timing and external readout. Goldshtein's own disclosure of a 5.6 pF capacitance and a 10 kΩ resistance in an exponential charge/discharge context confirms that values in the claimed ranges were known to produce exponential time courses amenable to measurement. Becerra-Fajardo's external receiver already captures and processes implant-dependent electrical signals, and adapting that receiver to detect a sub-microsecond to microsecond-scale exponential voltage decay would have been within the ordinary skill in the art. The benefit of the combination would be to provide a compact pressure-responsive implant capacitor with a post-burst discharge waveform that is long enough to be detected by the external reading unit and short enough to permit repeated burst interrogation without undesirable residual charge accumulation.
Claim 4 is rejected under 35 U.S.C. 103 as being unpatentable over Becerra-Fajardo et al. (Becerra-Fajardo, Laura, and Antoni Ivorra. “Bidirectional Communications in Wireless Microstimulators Based on Electronic Rectification of Epidermically Applied Currents.” 2015 7th International IEEE/EMBS Conference on Neural Engineering (NER). IEEE, 2015. 545–548. Web), hereto referred as Becerra-Fajardo, and further in view of Ivorra et al. (Ivorra, Antoni, Laura Becerra-Fajardo, and Quim Castellví. “In Vivo Demonstration of Injectable Microstimulators Based on Charge-Balanced Rectification of Epidermically Applied Currents.” Journal of neural engineering 12.6 (2015): 066010–066010. Web.), hereto referred as Ivorra, and further in view of Goldshtein et al. (US-20150282720-A1), hereto referred as Goldshtein, and further in view of Foutz et al. (Foutz, Thomas J et al. “Energy Efficient Neural Stimulation: Coupling Circuit Design and Membrane Biophysics.” PloS one 7.12 (2012): e51901–e51901. Web.), hereto referred as Foutz, and further in view of Siliconix (Siliconix, “The FET Constant-Current Source/Limiter,” Application Note AN103 Siliconix, www.vishay.com/docs/70596/70596.pdf, Mar. 10, 1997., Mar. 10, 1997.), hereto referred as Siliconix.
The combined Becerra-Fajardo, Ivorra, and Goldshtein teaches claim 1 as described above.
Regarding claim 4, the combined Becerra-Fajardo, Ivorra, and Goldshtein does not fully teach that the discharge network of the implant further comprises a current controlling device for controlling a discharge current of the capacitor and makes a discharge process independent of impedance of the medium and of the at least two electrodes of the implant. Rather, as shown above in claim 1, the combined Becerra-Fajardo, Ivorra, and Goldshtein provides the burst-based volume-conduction interrogation system, the external electrode/sensing-resistor pathway for detecting implant-dependent electrical signals, the capacitor/asymmetric-conductance charging arrangement, the capacitor discharge framework, the pressure-responsive capacitance relationship inherited from Goldshtein, and the processing of sensed voltage and/or current to calculate characteristic electrical values and obtain a measurement of interest. Ivorra teaches that after each burst, “the capacitor will slowly discharge through the implant resistor RD and the tissues until the next burst” (Ivorra, p. 3, §2.1), and therefore supplies a discharge path for the capacitor through the implant resistor and surrounding tissue. However, while Ivorra teaches a resistor in the discharge path, the combined Becerra-Fajardo, Ivorra, and Goldshtein does not expressly teach that the discharge network further comprises a current controlling device that controls discharge current and makes the discharge process independent of impedance of the medium and implant electrodes.
Foutz teaches the general current-control principle and the benefit of using FET-based current regulation in implantable biomedical circuits. Foutz teaches that the power consumed during constant-current stimulation is dictated by the current source and the electrode/tissue load, and that the current source is typically implemented with transistor technologies to deliver a constant current over the stimulus pulse regardless of the voltage generated across the electrodes (Foutz, p. 1, right column to p. 2, left column, Introduction). Foutz further teaches that adjustable compliance voltage can be used so that the FET remains in the desired operating region while reducing wasted energy, and that operation of the FET in saturation is related to current regulation (Foutz, p. 6, right column, Discussion). Thus, Foutz teaches the known desirability of FET-based current control in implantable biomedical circuits to reduce current variation caused by electrode/tissue load conditions.
Siliconix supplies the current-controlling device that is directly applicable to the inter-burst discharge path. Siliconix teaches that “[a]n adjustable-current source (Figure 1) may be built with a FET, a variable resistor, and a small battery” (Siliconix, p. 1, Introduction). Siliconix further teaches that “[w]henever the FET is operated in the current saturated region, its output conductance is very low,” and that “[t]he FET may be biased to operate as a constant-current source at any current below its saturation current IDSS” (Siliconix, p. 1). Siliconix then teaches that “the series resistor RS required between source and gate is” calculated from the gate-source voltage and drain current (Siliconix, p. 1, Basic Source Biasing). Siliconix also teaches that “[a] change in supply voltage or a change in load impedance, will change ID by only a small factor because of the low output conductance goss” (Siliconix, p. 1). Thus, Siliconix teaches a FET/JFET current source or current limiter in which the source-gate biasing resistor sets the regulated current and changes in load impedance change the controlled current by only a small factor.
Under the broadest reasonable interpretation, the claimed phrase “makes a discharge process independent of impedance of the medium and of the at least two electrodes of the implant” is satisfied by a discharge-network component that substantially reduces the dependence of the discharge current or discharge process on such impedance variations. Complete mathematical independence from impedance is not physically achievable in a real circuit path that includes the medium and electrodes. Accordingly, a current-controlling device that makes load-impedance changes alter the controlled current by only a small factor reasonably corresponds to making the discharge process independent of, or at least substantially independent of, the impedance of the medium and implant electrodes.
Siliconix therefore addresses the inter-burst discharge concern that would not be fully answered by Foutz alone. Foutz is relied upon only for the general teaching that FET-based current regulation was known and beneficial in implantable biomedical circuitry for stabilizing current against electrode/tissue load variation. Siliconix is relied upon for the specific self-biased FET/JFET current-limiter topology itself. Siliconix’s current-limiter topology is applicable to Ivorra’s inter-burst discharge path because the current limiter is self-biased by the gate-source voltage developed across the source-gate resistor and therefore does not require Foutz’s externally powered compliance-voltage regulation or active stimulation-control phase. Accordingly, Siliconix supplies a passive current-controlling device suitable for controlling the capacitor discharge current in the Ivorra discharge network.
It would have been prima facie obvious before the effective filing date of the claimed invention to have further modified the combined Becerra-Fajardo, Ivorra, and Goldshtein in view of Foutz and Siliconix so that the discharge network further comprises a current controlling device for controlling the discharge current of the capacitor and making the discharge process independent of, or at least substantially less dependent on, impedance of the medium and the implant electrodes. As discussed above, Becerra-Fajardo provides the external burst-based interrogation and electrical readout architecture, Ivorra provides the passive capacitor discharge path through the implant resistor and tissues, and Goldshtein provides the inherited pressure-responsive sensing framework. Foutz teaches the benefit of FET-based current regulation in implantable biomedical circuits to reduce sensitivity to electrode/tissue load variation. Siliconix teaches the specific self-biased FET/JFET current-source topology in which the regulated current is set by the source-gate resistor and changes in load impedance change the current by only a small factor. One of ordinary skill in the art would have found it obvious to incorporate the Siliconix self-biased current-limiter topology into Ivorra’s discharge network so that the capacitor discharge current would be controlled and the discharge process would be substantially independent of, or at least less dependent on, changing tissue, medium, and electrode impedance.
It would have been possible to combine these teachings because the modification does not require importing Foutz’s entire active stimulation system or compliance-voltage control architecture into the implant. Foutz is relied upon for the limited teaching that FET-based current control was known in implantable biomedical circuitry for stabilizing current against load variation. Siliconix is relied upon for the self-biased current-limiter topology that performs current control using the FET/JFET operating region and source-gate resistor biasing. The Becerra-Fajardo/Ivorra/Goldshtein combination already supplies the passive implant discharge path. Incorporating the Siliconix FET/JFET current-control element into that discharge path would have amounted to using a known current-control topology for its known current-limiting function in a predictable RC discharge environment. Because Siliconix teaches that load impedance changes alter the controlled current only by a small factor, using Siliconix’s current limiter in the discharge path would have predictably made the capacitor discharge process substantially independent of variations in the impedance of the medium and implant electrodes.
The benefit of the combination would be to reduce discharge-current dependence on uncontrolled tissue, medium, and electrode impedance, thereby improving stability, sensing accuracy, and measurement repeatability while preserving the compact burst-powered implant architecture and passive inter-burst discharge framework supplied by Becerra-Fajardo and Ivorra.
Claim 7 is rejected under 35 U.S.C. 103 as being unpatentable over Becerra-Fajardo et al. (Becerra-Fajardo, Laura, and Antoni Ivorra. “Bidirectional Communications in Wireless Microstimulators Based on Electronic Rectification of Epidermically Applied Currents.” 2015 7th International IEEE/EMBS Conference on Neural Engineering (NER). IEEE, 2015. 545–548. Web), hereto referred as Becerra-Fajardo, and further in view of Ivorra et al. (Ivorra, Antoni, Laura Becerra-Fajardo, and Quim Castellví. “In Vivo Demonstration of Injectable Microstimulators Based on Charge-Balanced Rectification of Epidermically Applied Currents.” Journal of neural engineering 12.6 (2015): 066010–066010. Web.), hereto referred as Ivorra, and further in view of Goldshtein et al. (US-20150282720-A1), hereto referred as Goldshtein, and further in view of Besling et al. (US-20130233086-A1 ), hereto referred as Besling.
The combined Becerra-Fajardo, Ivorra, and Goldshtein teaches claim 1 as described above.
Regarding claim 7, the combined Becerra-Fajardo, Ivorra, and Goldshtein does not fully teach that the capacitor has a given nominal capacitance, and the electrical or electronic component of the discharge network is a resistive transducer. Rather, as shown above in claim 1, the combined Becerra-Fajardo, Ivorra, and Goldshtein provides the burst-based volume-conduction interrogation system, the external electrode/sensing-resistor pathway for detecting implant-dependent electrical signals, the capacitor/asymmetric-conductance charging arrangement, the capacitor discharge framework, the pressure-responsive capacitance relationship inherited from Goldshtein, and the processing of sensed voltage and/or current to calculate characteristic electrical values and obtain a measurement of interest. As discussed in the rejection of claim 1, the combination already teaches an implant circuit including a capacitor having a defined capacitance value and a resistor in the discharge path. In particular, Ivorra teaches that the implant circuit includes capacitors, a Schottky diode, and an SMD resistor, including “an SMD 1 kΩ resistor (ERJ-XGNJ102Y by Panasonic)” (Ivorra, §2.1), and further teaches a capacitor value of approximately 0.6 µF (Ivorra, §2.1), corresponding to a capacitor having a given nominal capacitance. These teachings are relied upon in the base combination and are not newly added for claim 7. However, the combination does not expressly teach that the resistor in the discharge network is a resistive transducer whose resistance varies in response to a physical or chemical condition.
Besling supplies the resistive-transducer teaching. Besling teaches a pressure sensor that includes a capacitive MEMS pressure sensor and a second pressure sensor element that may be implemented as a Pirani gauge, and teaches that “FIG. 6 shows a normalized resistance change for three different configurations of Pirani sensor” (Besling, ¶[0049]). Besling further teaches that “[t]he heat loss can be determined by measuring the resistance change over the Suspended beam using a four point probe” (Besling, ¶[0116]). Besling explains that the gas molecules colliding with the wire transfer heat away from it and unbalance the bridge relative to a reference state, and that “[s]ince the frequency of the collisions is proportional to the gas pressure, the Voltage to keep the bridge in balance is proportional to the pressure” (Besling, ¶[0116]). Besling also teaches that “[t]he Piranigauge sensing element needs a low electrical resistance ... and at the same time a large temperature coefficient (to detect the pressure difference)” (Besling, ¶[0119]). Thus, Besling teaches the broader concept that an electrical resistor in a sensing structure may be implemented as a pressure-responsive resistive transducer whose resistance-related electrical behavior varies with a physical condition.
It would have been prima facie obvious before the effective filing date of the claimed invention to have further modified the combined Becerra-Fajardo, Ivorra, and Goldshtein in view of Besling so that the electrical or electronic component of the discharge network is implemented as a resistive transducer, while retaining a capacitor having a given nominal capacitance as taught by Ivorra. As discussed above, Becerra-Fajardo provides the external burst-based interrogation and electrical readout architecture, Ivorra provides the implant-side capacitor and resistor discharge path, and Goldshtein provides the inherited pressure-responsive sensing framework. Besling teaches that a resistive sensing element, such as a Pirani gauge element, can provide a pressure-dependent resistance change or resistance-related output. Because the discharge time course of an RC circuit depends on the resistance in the discharge path, implementing Ivorra’s discharge resistor as a condition-responsive resistive transducer would have caused the monitored discharge response to vary with the sensed physical condition.
It would have been possible to combine these teachings because the modification is a component-level substitution within an existing discharge network, not a wholesale bodily incorporation of Besling’s complete pressure sensor structure into Ivorra. Ivorra already uses a resistor to control capacitor discharge after burst charging. Besling teaches a resistive pressure-sensing element whose resistance-related electrical behavior varies with pressure. Replacing or implementing Ivorra’s discharge resistor as a functional equivalent resistive transducer would have preserved the same basic RC discharge architecture while causing the discharge time course, current, or voltage response to vary with the sensed condition. The external reading unit of Becerra-Fajardo would then detect the implant-dependent electrical response using the same external electrode/sensing-resistor pathway already used for burst-based readout. The benefit of the combination would be to enable the implant to sense a physical condition through resistance variation in the discharge network while preserving the simple rectifier-based implant architecture, the capacitor having a given nominal capacitance, predictable capacitor charging and discharging behavior, and a compact form factor suitable for injection or catheter-based deployment.
Claims 9 and 10 are rejected under 35 U.S.C. 103 as being unpatentable over Becerra-Fajardo et al. (Becerra-Fajardo, Laura, and Antoni Ivorra. “Bidirectional Communications in Wireless Microstimulators Based on Electronic Rectification of Epidermically Applied Currents.” 2015 7th International IEEE/EMBS Conference on Neural Engineering (NER). IEEE, 2015. 545–548. Web), hereto referred as Becerra-Fajardo, and further in view of Ivorra et al. (Ivorra, Antoni, Laura Becerra-Fajardo, and Quim Castellví. “In Vivo Demonstration of Injectable Microstimulators Based on Charge-Balanced Rectification of Epidermically Applied Currents.” Journal of neural engineering 12.6 (2015): 066010–066010. Web.), hereto referred as Ivorra, and further in view of Goldshtein et al. (US-20150282720-A1), hereto referred as Goldshtein and further in view of Toumazou et al. US-20130273664-A1), hereto referred as Toumazou.
The combined Becerra-Fajardo, Ivorra, and Goldshtein teaches claim 1 as described above.
Regarding claim 9, the combined Becerra-Fajardo, Ivorra, and Goldshtein teach the limitations of claim 1 as set forth above. As discussed above, Goldshtein is used in the claim 1 rejection for the capacitor-as-transducer alternative. Claim 9 further narrows the claimed implant to a different transducer configuration in which the capacitor has a given nominal capacitance and the discharge network comprises a transistor whose gate or base terminal is arranged to be in contact with the medium using a third electrode. Thus, claim 9 is additionally rejected based on the further teachings of Toumazou directed to a transistor sensing arrangement in which the transistor conductance depends on a voltage or ion-sensitive gate condition associated with the medium.
For claim 9, Goldshtein remains part of the inherited claim 1 combination, but the specific narrowed transducer configuration of claim 9 is supplied by Toumazou rather than by Goldshtein’s variable-capacitance capacitor. In particular, claim 9 no longer relies on the capacitor itself being the variable transducer. Instead, Ivorra supplies the capacitor having a given nominal capacitance and capacitor discharge path, while Toumazou supplies the electronic-component-of-the-discharge-network transducer. The variable operational parameter is the conductance of the transistor, which depends on the medium-related voltage at the third electrode. Because the transistor is implemented as a component of the discharge network, variation in transistor conductance changes the effective resistance/conductance of the capacitor discharge path and thereby modulates the capacitor discharge time course and measured electrical response.
The combined Becerra-Fajardo, Ivorra, and Goldshtein does not fully teach that wherein the sensing system is suitable for measuring biopotentials, wherein the capacitor has a given nominal capacitance, and wherein the discharge network comprises a transistor, whose gate or base terminal is arranged to be in contact with the medium using a third electrode, wherein conductance of the transistor depends on a voltage at the third electrode. Rather, as shown above in the claims from which claim 9 depends, Becerra-Fajardo provides the burst-based volume-conduction implant system with an external reading unit, and Ivorra provides the implant-side capacitor, device of asymmetric conductance, and discharge path. Ivorra further teaches a fixed capacitor value in the implant circuit, disclosing a capacitor value of approximately 0.6 µF in the implant circuit (Ivorra, §2.1). Thus, Ivorra teaches that the capacitor has a given nominal capacitance. However, the combined Becerra-Fajardo, Ivorra, and Goldshtein does not expressly teach the claim 9 transistor-based discharge-network sensing embodiment in which a transistor gate or base terminal is arranged to contact the medium using a third electrode and transistor conductance depends on a voltage at that third electrode.
Toumazou supplies the transistor gate sensing arrangement. Toumazou teaches that an ISFET is a field effect transistor “whose gate is exposed to ionic charges in a electrolyte” and that “[a] reference electrode is immersed in the electrolyte solution which comes into contact with the gate oxide of the transistor” (Toumazou, ¶[0003]). Toumazou further teaches that “the combination of the electrolyte and the reference electrode plays the role of the gate in a normal MOSFET” (Toumazou, ¶[0003]). Toumazou also teaches that the electrical operating modes of the FET may be expressed by current-voltage relations in which the drain-source current depends on gate-source voltage and threshold voltage (Toumazou, ¶[0003]). Thus, Toumazou teaches a transistor structure in which the medium-contacting gate condition controls transistor current or conductance.
Toumazou further supports the claim 9 feature that conductance depends on a voltage at the third electrode. Toumazou teaches that “[t]he voltage drops arising from interactions of the reference electrode, the electrolyte and the ion sensitive membrane can be viewed as part of either the gate-source voltage (V) or the threshold voltage (V)” because their difference appears in the MOSFET current-voltage relations (Toumazou, ¶[0004]). Toumazou further explains that the reference electrode and electrolyte may remotely play the role of the MOS gate, and that the electrolyte becomes part of the gate system (Toumazou, ¶[0005]). Accordingly, Toumazou teaches that a medium-contacting electrode and gate/electrolyte interface affect the effective gate voltage or threshold voltage of the transistor, and therefore affect transistor conductance.
Toumazou is relied upon for the limited teaching that a transistor gate terminal exposed to, or electrically coupled to, a medium through a medium-contacting electrode has conductance that depends on a medium-related gate voltage or ion-sensitive gate condition. Toumazou is not relied upon for bodily incorporation of Toumazou’s complete active ISFET readout system into the Becerra-Fajardo/Ivorra implant. Rather, Toumazou supplies the transistor-as-transducer principle: a gate/electrolyte/reference-electrode arrangement exposed to the medium produces a gate condition that changes transistor conduction. In the proposed combination, that transistor sensing element is used as the electronic component of the discharge network, while Becerra-Fajardo supplies the external burst interrogation and readout pathway and Ivorra supplies the nominal capacitor and discharge-network framework.
It would have been prima facie obvious before the effective filing date of the claimed invention to have further modified the combined Becerra-Fajardo, Ivorra, and Goldshtein in view of Toumazou so that the discharge network comprises a transistor whose gate or base terminal is arranged to be in contact with the medium using a third electrode, wherein conductance of the transistor depends on a voltage at the third electrode, while retaining a capacitor having a given nominal capacitance as taught by Ivorra. As discussed above, Becerra-Fajardo provides the burst-based interrogation and external electrode readout architecture, Ivorra provides the capacitor and discharge network, and Toumazou teaches a transistor sensing structure in which a medium-contacting electrode/electrolyte interface controls the effective gate condition and transistor conductance. One of ordinary skill in the art would have found it obvious to use Toumazou’s medium-sensitive transistor arrangement as a discharge-network electronic component so that the capacitor discharge current, discharge time course, or measured electrical response would vary with the local medium voltage or biopotential at the third electrode.
It would have been possible to combine these teachings because the modification uses Toumazou for the limited teaching of a medium-sensitive transistor gate structure, not for wholesale incorporation of Toumazou’s complete readout electronics. Ivorra already provides a discharge network through which the capacitor discharges after burst charging. A transistor is an electrical component whose conductance can control current in a circuit path, and Toumazou teaches that the transistor conductance can depend on a medium-related gate condition. Implementing the discharge-network component as such a transistor would have preserved the same basic capacitor discharge architecture while making the discharge response dependent on the voltage or biopotential at the medium-contacting third electrode. The external reading unit of Becerra-Fajardo would then detect the resulting implant-dependent electrical response using the same external electrode/sensing-resistor pathway already used for burst-based readout. The benefit of the combination would be to enable localized biopotential-dependent modulation of the capacitor discharge response using a transistor component in the discharge network, thereby improving spatial selectivity and sensing functionality while preserving the compact burst-powered implant architecture and the nominal capacitor/discharge-network framework supplied by Ivorra.
Regarding claim 10, the combined Becerra-Fajardo, Ivorra, and Goldshtein teach the limitations of claim 1 as set forth above. As discussed above, Goldshtein is used in the claim 1 rejection for the capacitor-as-transducer alternative. Claim 10 further narrows the claimed implant to a different transducer configuration in which the capacitor has a given nominal capacitance and the discharge network comprises a ChemFET transistor or Ion Selective Field Effect Transistor whose gate contacts the medium and whose conductance depends on a concentration of chemical species at the gate. Thus, claim 10 is additionally rejected based on the further teachings of Toumazou directed to ISFET/ChemFET sensing of ion concentration through a medium-exposed gate structure.
For claim 10, Goldshtein remains part of the inherited claim 1 combination, but the specific narrowed transducer configuration of claim 10 is supplied by Toumazou rather than by Goldshtein’s variable-capacitance capacitor. In particular, claim 10 no longer relies on the capacitor itself being the variable transducer. Instead, Ivorra supplies the capacitor having a given nominal capacitance and capacitor discharge path, while Toumazou supplies the electronic-component-of-the-discharge-network transducer. The variable operational parameter is the conductance of the ChemFET/ISFET, which depends on the concentration of chemical species at the gate. Because the ChemFET/ISFET is implemented as a component of the discharge network, variation in transistor conductance changes the effective resistance/conductance of the capacitor discharge path and thereby modulates the capacitor discharge time course and measured electrical response.
The combined Becerra-Fajardo, Ivorra, and Goldshtein does not fully teach that wherein the sensing system is suitable for measuring chemical species, wherein the capacitor has a given nominal capacitance, and wherein the discharge network comprises a ChemFET transistor or an Ion Selective Field Effect Transistor adapted such that a gate of the transistor is in contact with the medium when the implant is deployed in the medium, and wherein conductance of the transistor depends on a concentration of chemical species at the gate of the transistor. Rather, as shown above in the claims from which claim 10 depends, Becerra-Fajardo provides the burst-based volume-conduction implant system with an external reading unit, and Ivorra provides the implant-side capacitor, device of asymmetric conductance, and discharge path. Ivorra further teaches a fixed capacitor value in the implant circuit, disclosing a capacitor value of approximately 0.6 µF in the implant circuit (Ivorra, §2.1). Thus, Ivorra teaches that the capacitor has a given nominal capacitance. However, the combined Becerra-Fajardo, Ivorra, and Goldshtein does not expressly teach the claim 10 chemical-sensing discharge-network embodiment in which the discharge network comprises a ChemFET or ISFET with a gate in contact with the medium and conductance dependent on chemical species concentration at the gate.
Toumazou supplies the ChemFET/ISFET chemical-sensing transistor. Toumazou teaches that the invention relates to “a device and method for Switching an electrical output according to the ion concentration of a sample” (Toumazou, ¶[0001]). Toumazou teaches that an ISFET is a FET “whose gate is exposed to ionic charges in a electrolyte” and that a reference electrode is immersed in the electrolyte solution that contacts the gate oxide of the transistor (Toumazou, ¶[0003]). Toumazou further teaches that the gate oxide becomes the ion-sensitive membrane and that the electrolyte/reference-electrode arrangement plays the role of the gate in a MOSFET (Toumazou, ¶[0003]). Thus, Toumazou teaches an ISFET or ChemFET-type transistor with a gate exposed to the medium.
Toumazou further teaches that the transistor conductance depends on chemical species concentration at the gate. Toumazou teaches that, in an ISFET, the electrolyte becomes part of the gate system and makes the threshold voltage dependent on electrolyte properties (Toumazou, ¶[0005]). Toumazou further teaches that the chemical parameter of the ion-sensitive membrane/electrolyte interface potential is a function of electrolyte ion concentration, where pH is a possible measure of it, and that “[t]he ISFETs threshold voltage can be modified using electrolyte ion concentration” (Toumazou, ¶[0006]). Because the FET current-voltage relations depend on the gate-source voltage and threshold voltage, a threshold-voltage change caused by ion concentration changes the transistor current or conductance. Toumazou therefore teaches that the conductance of an ISFET/ChemFET transistor depends on a concentration of chemical species at the gate.
Toumazou is relied upon for the limited teaching that an ISFET/ChemFET gate exposed to a medium has transistor conductance that depends on ion concentration or chemical species concentration at the gate. Toumazou is not relied upon for bodily incorporation of Toumazou’s complete active ISFET readout system into the Becerra-Fajardo/Ivorra implant. Rather, Toumazou supplies the transistor-as-transducer principle: a medium-exposed ion-sensitive gate changes the transistor’s effective threshold voltage and conductance based on chemical species concentration. In the proposed combination, that ISFET/ChemFET sensing element is used as the electronic component of the discharge network, while Becerra-Fajardo supplies the external burst interrogation and readout pathway and Ivorra supplies the nominal capacitor and discharge-network framework.
It would have been prima facie obvious before the effective filing date of the claimed invention to have further modified the combined Becerra-Fajardo, Ivorra, and Goldshtein in view of Toumazou so that the discharge network comprises a ChemFET transistor or Ion Selective Field Effect Transistor having a gate in contact with the medium, wherein conductance of the transistor depends on a concentration of chemical species at the gate, while retaining a capacitor having a given nominal capacitance as taught by Ivorra. As discussed above, Becerra-Fajardo provides the burst-based interrogation and external electrode readout architecture, Ivorra provides the capacitor and discharge network, and Toumazou teaches a ChemFET/ISFET sensing structure in which the gate is exposed to the medium and transistor conductance depends on ion concentration or chemical species concentration. One of ordinary skill in the art would have found it obvious to use Toumazou’s medium-exposed ChemFET/ISFET transistor as a discharge-network electronic component so that the capacitor discharge current, discharge time course, or measured electrical response would vary with the local concentration of chemical species in the medium.
It would have been possible to combine these teachings because the modification uses Toumazou for the limited teaching of a medium-sensitive chemical transistor gate structure, not for wholesale incorporation of Toumazou’s complete readout electronics. Ivorra already provides a discharge network through which the capacitor discharges after burst charging. A transistor is an electrical component whose conductance can control current in a circuit path, and Toumazou teaches that a ChemFET/ISFET transistor’s conductance can depend on chemical species concentration at a medium-exposed gate. Implementing the discharge-network component as such a transistor would have preserved the same basic capacitor discharge architecture while making the discharge response dependent on the concentration of chemical species in the medium. The external reading unit of Becerra-Fajardo would then detect the resulting implant-dependent electrical response using the same external electrode/sensing-resistor pathway already used for burst-based readout. The benefit of the combination would be to enable chemical-species-dependent modulation of the capacitor discharge response using a ChemFET or ISFET component in the discharge network, thereby improving chemical sensing functionality while preserving the compact burst-powered implant architecture and the nominal capacitor/discharge-network framework supplied by Ivorra.
Claims 11-13 are rejected under 35 U.S.C. 103 as being unpatentable over Becerra-Fajardo et al. (Becerra-Fajardo, Laura, and Antoni Ivorra. “Bidirectional Communications in Wireless Microstimulators Based on Electronic Rectification of Epidermically Applied Currents.” 2015 7th International IEEE/EMBS Conference on Neural Engineering (NER). IEEE, 2015. 545–548. Web), hereto referred as Becerra-Fajardo, and further in view of Ivorra et al. (Ivorra, Antoni, Laura Becerra-Fajardo, and Quim Castellví. “In Vivo Demonstration of Injectable Microstimulators Based on Charge-Balanced Rectification of Epidermically Applied Currents.” Journal of neural engineering 12.6 (2015): 066010–066010. Web.), hereto referred as Ivorra, and further in view of Goldshtein et al. (US-20150282720-A1), hereto referred as Goldshtein, and further in view of Colvin et al. (US-5517313-A), hereto referred as Colvin.
The combined Becerra-Fajardo, Ivorra, and Goldshtein teaches claim 1 as described above.
Regarding claim 11, the combined Becerra-Fajardo, Ivorra, and Goldshtein teach the limitations of claim 1 as set forth above. As discussed above, Goldshtein is used in the claim 1 rejection for the capacitor-as-transducer alternative. Claim 11 further narrows the claimed implant to a different optoelectronic transducer configuration in which the capacitor has a given nominal capacitance, the device of asymmetric conductance itself is a light emitting semiconductor device, the discharge network comprises a light sensitive conductive device, and an optical material is arranged to transmit, reflect, or refract light from the light emitting semiconductor device to the light sensitive conductive device. Thus, claim 11 is additionally rejected based on the further teachings of Colvin directed to a light emitting diode, a photodetector, and an optically responsive material arranged so that emitted light interacts with the optical material and is detected by the photodetector.
For claim 10, Goldshtein remains part of the inherited claim 1 combination, but the specific narrowed transducer configuration of claim 10 is supplied by Toumazou rather than by Goldshtein’s variable-capacitance capacitor. In particular, claim 10 no longer relies on the capacitor itself being the variable transducer. Instead, Ivorra supplies the capacitor having a given nominal capacitance and capacitor discharge path, while Toumazou supplies the electronic-component-of-the-discharge-network transducer. The variable operational parameter is the conductance of the ChemFET/ISFET, which depends on the concentration of chemical species at the gate. Because the ChemFET/ISFET is implemented as a component of the discharge network, variation in transistor conductance changes the effective resistance/conductance of the capacitor discharge path and thereby modulates the capacitor discharge time course and measured electrical response.
The combined Becerra-Fajardo, Ivorra, and Goldshtein does not fully teach that wherein the capacitor has a given nominal capacitance, and wherein the device of asymmetric conductance is a light emitting semiconductor device, wherein the discharge network comprises a light sensitive conductive device, and wherein an optical material is arranged to transmit, reflect or refract light from the light emitting semiconductor device to the light sensitive conductive device. Rather, as shown above in the claims from which claim 11 depends, Becerra-Fajardo provides the burst-based volume-conduction implant system with an external reading unit, and Ivorra provides the implant-side capacitor, device of asymmetric conductance, and discharge path. Ivorra further teaches a fixed capacitor value in the implant circuit, disclosing a capacitor value of approximately 0.6 µF in the implant circuit (Ivorra, §2.1). Thus, Ivorra teaches that the capacitor has a given nominal capacitance. However, the combined Becerra-Fajardo, Ivorra, and Goldshtein does not expressly teach the claim 11 optoelectronic embodiment in which the same component that serves as the device of asymmetric conductance is also a light emitting semiconductor device, and in which the discharge network includes a separate light sensitive conductive device optically coupled through an optical material.
Colvin supplies the missing optoelectronic sensing components and optical material. Colvin teaches a fluorescence sensor having “a photodetector, a high pass filter located adjacent the photodetector, and a glass layer located adjacent the high pass filter,” with “an indicator layer” adjacent the glass layer and “a light emitting diode” embedded in the indicator layer (Colvin, Abstract). Colvin further teaches that the indicator layer has molecules that provide fluorescent emission as a result of light from the light emitting diode, and that the presence of an analyte reduces the amount of emitted light passing through the glass and high pass filter to the photodetector, where the photodetector current depends on incident light and is used to detect the analyte (Colvin, Abstract). Colvin also teaches a waveguide embodiment having a photodetector layer, an indicator layer, and a light emitting diode, where the waveguide layer is in optical contact with the indicator layer and the light emitting diode emits excitation light (Colvin, col. 4, ll. 1 to 65; col. 5, ll. 1 to 65). Thus, Colvin teaches a light emitting semiconductor device, a light sensitive conductive device, and an optical material arranged so that light from the light emitting semiconductor device is transmitted, reflected, refracted, or otherwise optically communicated through an optical material to the light sensitive conductive device.
Colvin further supports arranging the optical material to interact with the medium and to vary with a physical or chemical condition. Colvin teaches that the indicator layer allows an analyte to diffuse into it and that the presence of the analyte alters the amount of light emitted from the indicator molecules that passes to the photodetector (Colvin, Abstract). Colvin also teaches that the fluorescence sensor can be used for a multitude of analytes by immobilizing a specific indicator molecule on or within the indicator layer and calibrating the signal processing electronics (Colvin, col. 4, ll. 1 to 20). Thus, Colvin teaches an optical material whose optical response varies with a chemical condition of the surrounding medium, and a photodetector whose electrical output depends on the light affected by that material.
Colvin also supports the specific dual-function arrangement in which the device of asymmetric conductance is a light emitting semiconductor device. A light emitting diode is a semiconductor diode and therefore conducts asymmetrically like the diode device of asymmetric conductance already used in the Becerra-Fajardo/Ivorra implant architecture. Colvin expressly teaches a light emitting diode embedded in the indicator layer and used to emit excitation light. Accordingly, substituting a light emitting diode for Ivorra’s ordinary rectifying diode would have provided a single semiconductor component that performs the asymmetric-conductance function of the diode while also emitting light when forward-biased. In the proposed claim 11 arrangement, the LED is not a separate discharge-network LED as in claim 12. Rather, the LED serves the dual role of the asymmetric-conductance device and the light source, while the discharge network includes a separate light sensitive conductive device arranged in a parallel branch to detect light transmitted, reflected, or refracted through the optical material.
It would have been prima facie obvious before the effective filing date of the claimed invention to further modify the combined Becerra-Fajardo, Ivorra, and Goldshtein in view of Colvin so that the device of asymmetric conductance is implemented as a light emitting semiconductor device, the discharge network comprises a light sensitive conductive device, and an optical material is arranged to transmit, reflect, or refract light from the light emitting semiconductor device to the light sensitive conductive device, while retaining the capacitor having a given nominal capacitance supplied by Ivorra. As discussed above, Ivorra already uses a diode as the device of asymmetric conductance in the burst-powered implant circuit, and Colvin teaches a light emitting diode optically coupled to an indicator material and photodetector. One of ordinary skill in the art would have found it obvious to use a light emitting diode as the asymmetric-conductance device because an LED is itself a diode and would perform rectification/asymmetric conduction while additionally emitting light during forward-biased conduction. The emitted light would interact with the optical material, and the light sensitive conductive device would provide a corresponding light-dependent electrical response in the discharge network.
It would have been possible to combine these teachings because the modification uses Colvin for the limited teaching of known optoelectronic sensing elements and optical material, while retaining the burst-based volume-conduction interrogation and passive capacitor charge/discharge architecture supplied by Becerra-Fajardo and Ivorra. Ivorra already supplies a diode-based asymmetric-conductance device in the implant circuit. Replacing that diode with a light emitting diode would have preserved the same one-way conduction function while adding the known LED light-emission function. Colvin teaches coordinated LED excitation of an indicator material and photodetector detection of light affected by that material. Although Colvin does not expressly show the photodetector connected electrically in parallel as part of Ivorra’s discharge network, one of ordinary skill in the art would have found it obvious to include the light sensitive conductive device in a parallel discharge-network branch so that the light affected by the optical material produces a light-dependent conductive or current response during the same implant operating cycle. This arrangement would allow the LED-as-asymmetric-conductance device to produce the optical excitation, while the parallel light-sensitive conductive device provides the electrical sensing response through the discharge network. The benefit of the combination would be to provide an additional optical sensing modality in the same minimally invasive, burst-interrogated implant architecture, using the same semiconductor component both for asymmetric conduction and optical excitation. This would allow the implant to sense chemical or physical conditions that are readily transduced into optical properties such as fluorescence, phosphorescence, transmissivity, reflectivity, or refractivity, while preserving a compact implant circuit with a nominal capacitor and without requiring a separate light source in the discharge network.
Regarding claim 12, the combined Becerra-Fajardo, Ivorra, and Goldshtein teach the limitations of claim 1 as set forth above. As discussed above, Goldshtein is used in the claim 1 rejection for the capacitor-as-transducer alternative. Claim 12 further narrows the claimed implant to a different transducer configuration in which the capacitor has a given nominal capacitance, the discharge network includes optoelectronic components, and an optically reactive material provides the condition-responsive sensing function. Thus, claim 12 is additionally rejected based on the further teachings of Colvin directed to an optoelectronic sensing arrangement including a light emitting semiconductor device, a light sensitive conductive device, and an optically reactive material.
For claim 10, Goldshtein remains part of the inherited claim 1 combination, but the specific narrowed transducer configuration of claim 10 is supplied by Toumazou rather than by Goldshtein’s variable-capacitance capacitor. In particular, claim 10 no longer relies on the capacitor itself being the variable transducer. Instead, Ivorra supplies the capacitor having a given nominal capacitance and capacitor discharge path, while Toumazou supplies the electronic-component-of-the-discharge-network transducer. The variable operational parameter is the conductance of the ChemFET/ISFET, which depends on the concentration of chemical species at the gate. Because the ChemFET/ISFET is implemented as a component of the discharge network, variation in transistor conductance changes the effective resistance/conductance of the capacitor discharge path and thereby modulates the capacitor discharge time course and measured electrical response.
The combined Becerra-Fajardo, Ivorra, and Goldshtein does not fully teach that the capacitor has a given nominal capacitance. Rather, as shown above in the claims from which claim 12 depends, Becerra-Fajardo provides the burst-based volume-conduction implant system with an external reading unit, and Ivorra provides the implant-side capacitor, device of asymmetric conductance, and discharge path. Ivorra further teaches a fixed capacitor value in the implant circuit, disclosing a 0.6 µF capacitor in the implant circuit (Ivorra, §2.1). Thus, Ivorra teaches that the capacitor has a given nominal capacitance. However, the combined Becerra-Fajardo and Ivorra does not expressly teach the claim 12 optoelectronic sensing embodiment in which the optoelectronic discharge network and optically reactive material provide the sensing transduction.
Also regarding claim 12, the combined Becerra-Fajardo, Ivorra, and Goldshtein does not fully teach that the implant further comprises a transmitting, reflecting, or refractive optically reactive material, wherein the optically reactive material is arranged in the implant to be in contact with the medium when the implant is deployed in the medium, and wherein the discharge network is connected in parallel with the device of asymmetric conductance, and comprises a light emitting semiconductor device, wherein the light emitting semiconductor device emits light during the capacitor discharge so as to transduce the capacitor discharge energy into a light signal that interacts with the optically reactive material, and a light sensitive conductive device connected in parallel, and wherein the optically reactive material is arranged to transmit, reflect or refract light from the light emitting semiconductor device to the light sensitive conductive device. Rather, as shown above in the claims from which claim 12 depends, Becerra-Fajardo provides the external burst interrogation and external electrode readout arrangement, and Ivorra provides the passive implant-side capacitor, device of asymmetric conductance, and discharge network connected in parallel with the device of asymmetric conductance so that the capacitor discharges after burst delivery. Thus, the combination as developed thus far teaches the burst-driven capacitor charge and discharge architecture. However, the combination does not expressly teach the claim 12 optoelectronic discharge-network embodiment. In particular, the combination does not expressly teach: (1) a transmitting, reflecting, or refractive optically reactive material arranged in the implant to contact the medium; (2) a light emitting semiconductor device in the discharge network that emits light during capacitor discharge so as to convert capacitor discharge energy into a light signal; (3) a light sensitive conductive device connected in parallel as part of the discharge network; and (4) the optically reactive material arranged to transmit, reflect, or refract light from the light emitting semiconductor device to the light sensitive conductive device.
Colvin supplies the missing optoelectronic sensing components and optical material. Colvin teaches a fluorescence sensor having “a photodetector, a high pass filter located adjacent the photodetector, and a glass layer located adjacent the high pass filter,” with “an indicator layer” adjacent the glass layer and “a light emitting diode” embedded in the indicator layer (Colvin, Abstract). Colvin further teaches that the indicator layer has molecules that provide fluorescent emission as a result of light from the light emitting diode, and that the presence of an analyte reduces the amount of emitted light passing through the glass and high pass filter to the photodetector, where the photodetector current depends on incident light and is used to detect the analyte (Colvin, Abstract). Colvin also teaches a waveguide embodiment having a photodetector layer, an indicator layer, and a light emitting diode, where the waveguide layer is in optical contact with the indicator layer and the light emitting diode emits excitation light (Colvin, col. 4, ll. 1 to 65; col. 5, ll. 1 to 65). Thus, Colvin teaches a light emitting semiconductor device, a light sensitive conductive device, and an optically reactive material arranged so that light from the light emitting device interacts with the optically reactive material and is detected by the light sensitive device.
Colvin further supports arranging the optical material to interact with a medium and to vary with a physical or chemical condition. Colvin teaches that the indicator layer allows an analyte to diffuse into it and that the presence of the analyte alters the amount of light emitted from the indicator molecules that passes to the photodetector (Colvin, Abstract). Colvin also teaches that the fluorescence sensor can be used for a multitude of analytes by immobilizing a specific indicator molecule on or within the indicator layer and calibrating the signal processing electronics (Colvin, col. 4, ll. 1 to 20). Thus, Colvin teaches an optically reactive material whose optical response varies with a chemical condition of the surrounding medium. In the claim 12 embodiment, the variable operational parameter is the optical response of the optically reactive material and the resulting light-dependent conductance/current response of the light-sensitive conductive device. The optically reactive material varies based on the physical or chemical condition of the medium, and the light-sensitive conductive device provides a corresponding electrical response in the discharge network.
It would have been prima facie obvious before the effective filing date of the claimed invention to further modify the combined Becerra-Fajardo, Ivorra, and Goldshtein in view of Colvin to include an optically reactive material, a light emitting semiconductor device, and a light sensitive conductive device arranged with the discharge network so that capacitor discharge energy drives the light emitting semiconductor device, the emitted light interacts with the optically reactive material, and the light sensitive conductive device responds to the transmitted, reflected, or refracted light. For claim 12, the inherited claim 1 transducer limitation is satisfied through the electronic component/optical assembly alternative, not through a variable-capacitance capacitor. Thus, although Goldshtein remains part of the inherited claim 1 combination, the specific narrowed transducer configuration recited in claim 12 is supplied by Colvin rather than by Goldshtein’s variable-capacitance capacitor.
It would have been possible to combine these teachings because the modification uses Colvin for the limited teaching of known optoelectronic sensing elements and optically reactive material, while retaining the burst-based volume-conduction interrogation and passive capacitor discharge architecture supplied by Becerra-Fajardo and Ivorra. Ivorra's capacitor stores energy during the burst and discharges after the burst through a discharge path. A light emitting diode is a known semiconductor device that emits light when current flows through it, and Colvin teaches LED excitation of an indicator material and photodetector detection of resulting light. Placing the LED in the Ivorra discharge path would inherently cause the LED to emit during capacitor discharge because, when forward-biased discharge current flows through an LED, the LED emits light as a matter of its basic operating principle. Thus, no additional timing modification would be required to satisfy the requirement that the light emitting semiconductor device emits light during capacitor discharge.
With respect to the light sensitive conductive device connected in parallel, Colvin teaches coordinated LED excitation of an optically reactive indicator material and photodetector detection of light affected by that material. Although Colvin does not expressly show the photodetector connected electrically in parallel with the LED within Ivorra's discharge network, one of ordinary skill in the art would have found it obvious to connect the light sensitive conductive device in parallel with the light emitting semiconductor device in the discharge network as a separate light-responsive branch. In that arrangement, the LED branch would convert discharge current into light during the capacitor discharge, while the parallel light-sensitive conductive branch would provide a separate conductive path whose conductance or current changes in response to light transmitted, reflected, or refracted by the optically reactive material. This parallel arrangement would allow the same discharge event to produce the optical excitation and simultaneously produce an electrical response dependent on the light affected by the optically reactive material. Colvin supplies the motivation for such an arrangement because it teaches LED excitation of an indicator material and photodetector detection of light affected by that material to perform optical analyte sensing. The benefit of the combination would be to provide an additional optical sensing modality in the same minimally invasive, burst-interrogated implant architecture, allowing the implant to sense chemical or physical conditions that are readily transduced into optical properties such as fluorescence, phosphorescence, transmissivity, reflectivity, or refractivity. The modification would also allow the optical sensing event to occur during the controlled capacitor discharge period, thereby using stored burst energy efficiently without requiring a separate implant battery or independent onboard power supply.
Regarding claim 13, the combined Becerra-Fajardo, Ivorra, Goldshtein, and Colvin teach the limitations of claims 11 and 12 as set forth above. As discussed above, Goldshtein remains part of the inherited claim 1 combination, but the specific optoelectronic transducer configurations of claims 11 and 12 are supplied by Colvin rather than by Goldshtein’s variable-capacitance capacitor. Claim 13 depends from claims 11 and 12 and further narrows the optoelectronic arrangement by reciting one or more optical filters.
The combined Becerra-Fajardo, Ivorra, and Goldshtein does not fully teach that the implant further comprises an optical filter arranged in the path of light between the light emitting semiconductor device, the optical material, and/or the light sensitive conductive device. Rather, as shown above for claims 11 and 12, Becerra-Fajardo provides the burst-based volume-conduction implant system with an external reading unit, Ivorra provides the implant-side capacitor, device of asymmetric conductance, and discharge path, and Colvin supplies the optoelectronic sensing arrangement including a light emitting diode, an optical/indicator material, and a photodetector. However, the combined Becerra-Fajardo, Ivorra, and Goldshtein does not expressly teach an optical filter arranged in the path of light between the light emitting semiconductor device, the optical material, and/or the light sensitive conductive device.
Colvin supplies the optical filter limitation. Colvin teaches a fluorescence sensor having “a photodetector, a high pass filter located adjacent the photodetector, and a glass layer located adjacent the high pass filter,” with an indicator layer adjacent the glass layer and a light emitting diode embedded in the indicator layer (Colvin, Abstract). Colvin further teaches that light emitted from the indicator molecules passes through the glass layer and high pass filter and is incident upon the photodetector, where the amount of current from the photodetector depends on the incident light and is used to detect the analyte (Colvin, Abstract). Thus, Colvin teaches an optical filter arranged in the light path between the optical material and the light sensitive conductive device.
Colvin also teaches additional filter placement associated with the light emitting diode. In the waveguide embodiment, Colvin teaches a photodetector layer, a high pass filter layer, a glass layer, a waveguide layer, an indicator layer, and a light emitting diode, and further teaches that the light emitting diode has a low pass filter coating surrounding upper portions of the diode (Colvin, col. 4, ll. 1 to 65; col. 5, ll. 1 to 65). Thus, Colvin further teaches an optical filter arranged in the path of light between the light emitting semiconductor device and the optical material.
It would have been prima facie obvious before the effective filing date of the claimed invention to further modify the combined Becerra-Fajardo, Ivorra, Goldshtein, and Colvin to include an optical filter arranged in the path of light between the light emitting semiconductor device, the optical material, and/or the light sensitive conductive device. As discussed above for claims 11 and 12, Colvin supplies the optoelectronic sensing arrangement used in the proposed combination, and Colvin’s own optoelectronic sensor includes optical filters in the light path to separate excitation and detected light. One of ordinary skill in the art would have found it obvious to include Colvin’s high pass filter and/or low pass filter in the optoelectronic implant arrangement so that light reaching the light sensitive conductive device is filtered according to the desired excitation and emission wavelengths. It would have been possible to combine these teachings because the modification merely retains Colvin’s known optical filtering components within the same Colvin optoelectronic sensing arrangement already used for claims 11 and 12. The optical filters do not alter the basic burst-powered capacitor and discharge-network architecture supplied by Becerra-Fajardo and Ivorra, but instead improve the optical sensing path supplied by Colvin. The benefit of the combination would be to reduce undesired optical interference between excitation light and detected light, thereby improving sensing selectivity, accuracy, and signal quality in the optoelectronic sensing arrangement.
Claim 14 is rejected under 35 U.S.C. 103 as being unpatentable over Becerra-Fajardo et al. (Becerra-Fajardo, Laura, and Antoni Ivorra. “Bidirectional Communications in Wireless Microstimulators Based on Electronic Rectification of Epidermically Applied Currents.” 2015 7th International IEEE/EMBS Conference on Neural Engineering (NER). IEEE, 2015. 545–548. Web), hereto referred as Becerra-Fajardo, and further in view of Ivorra et al. (Ivorra, Antoni, Laura Becerra-Fajardo, and Quim Castellví. “In Vivo Demonstration of Injectable Microstimulators Based on Charge-Balanced Rectification of Epidermically Applied Currents.” Journal of neural engineering 12.6 (2015): 066010–066010. Web.), hereto referred as Ivorra, and further in view of Goldshtein et al. (US-20150282720-A1), hereto referred as Goldshtein, and further in view of Edmonson et al. (US-10143847-B1), hereto referred as Edmonson.
The combined Becerra-Fajardo, Ivorra, and Goldshtein teaches claim 1 as described above.
Regarding claim 14, the combined Becerra-Fajardo, Ivorra, and Goldshtein teach the limitations of claim 1 as set forth above. As discussed above, Goldshtein is used in the claim 1 rejection for the capacitor-as-transducer alternative. Claim 14 further narrows that pressure-responsive capacitor arrangement to a vascular blood-pressure sensing configuration in which the sensing system is suitable to be implanted inside an artery or vein, the implant comprises a capsule having a flexible portion that transmits pressure from the exterior to the interior of the capsule, the capacitor is a capacitive pressure sensor whose capacitance depends on blood pressure, and the implant electrodes are flexible structures configured to anchor the implant to the artery or vein.
The combined Becerra-Fajardo, Ivorra, and Goldshtein does not fully teach that wherein the sensing system is suitable to be implanted inside an artery or a vein, further comprising a capsule having at least a part made of a flexible material that allows pressure transmission from an exterior of the capsule to an interior of the capsule, wherein the capacitor is a capacitive pressure sensor, such as the capacitor and the flexible part of the capsule are arranged relative to each other wherein the capacitance of the pressure sensor depends on the blood pressure, wherein each electrode of the at least two electrodes is a flexible structure configured to anchor the implant to the artery or vein. Rather, as shown above in claim 1, the combined Becerra-Fajardo, Ivorra, and Goldshtein provides the burst-based volume-conduction interrogation system, the implant-side capacitor/asymmetric-conductance charging arrangement, the capacitor discharge framework, the pressure-responsive capacitance relationship, and the processing of sensed electrical signals to obtain a measurement of interest. Goldshtein supplies much of the blood-pressure sensor aspect of claim 14. Goldshtein teaches an implanted capacitance-based pressure sensor for sensing ambient pressure in a living organ, and teaches a pressure sensor “which has a capacitance that varies in response to the ambient pressure” (Goldshtein, Abstract). Goldshtein further teaches that implant 24 includes “a capacitance-based pressure sensor 36,” and that “[o]ne of the electrodes of this capacitor comprises a membrane that is exposed to the ambient blood pressure,” where “[t]he pressure applied by the blood to the membrane sets the spacing between the capacitor electrodes, and therefore sets the capacitor's capacitance” (Goldshtein, ¶[0035]). Goldshtein also teaches that the implant “produces a time-varying waveform that is indicative of the time-varying capacitance of sensor 36, and thus the time-varying pressure” (Goldshtein, ¶[0036]) and that an external processor “processes the received waveform so as to estimate the actual blood pressure sensed by sensor 36” (Goldshtein, ¶[0037]). Thus, Goldshtein teaches that the capacitor is a capacitive pressure sensor and that the capacitance of the pressure sensor depends on blood pressure.
Goldshtein also supports the pressure-transmission relationship between the external blood pressure and the internal capacitive sensing element. Goldshtein teaches that blood pressure acts on a membrane of the capacitance-based pressure sensor and changes the spacing between capacitor electrodes, thereby changing capacitance (Goldshtein, ¶[0035]). This teaches the same pressure-transmission principle recited in claim 14 because pressure from the exterior blood environment is mechanically transmitted to the capacitive sensor structure so that the capacitance depends on blood pressure. However, Goldshtein does not fully teach the specific vascular anchoring configuration recited in claim 14, including that the sensing system is suitable to be implanted inside an artery or vein and that each of the at least two implant electrodes is a flexible structure configured to anchor the implant to the artery or vein.
Edmonson supplies the vascular deployment and anchoring configuration. Edmonson teaches an implantable medical device configured for tissue conductive communication and placement within a patient to facilitate communication through tissue. Edmonson teaches vascular implantation, including placement of implantable medical devices in cardiac and vascular locations, such as the pulmonary artery, and teaches electrodes/fixation elements configured to secure the implant within a blood vessel. Edmonson further teaches that the fixation/electrode structures expand from a collapsed delivery configuration to an expanded deployed configuration for contacting or engaging the vessel wall. One of ordinary skill in the art would have understood that structures capable of collapsing for delivery and expanding upon deployment must be inherently flexible or elastic, thereby satisfying the flexible anchoring electrode requirement of claim 14. Thus, Edmonson teaches the claimed suitability for implantation inside an artery or vein and teaches electrode structures that function as flexible anchoring structures for securing the implant to the vessel wall.
It would have been prima facie obvious before the effective filing date of the claimed invention to have further modified the combined Becerra-Fajardo, Ivorra, and Goldshtein in view of Edmonson so that the sensing system is suitable for implantation inside an artery or vein and includes flexible electrode structures configured to anchor the implant to the artery or vein, while using Goldshtein’s capacitance-based blood-pressure sensor as the capacitor whose capacitance depends on blood pressure. As discussed above, Becerra-Fajardo provides the external burst-based interrogation and electrical readout architecture, Ivorra provides the compact implant-side capacitor and discharge framework, and Goldshtein provides the pressure-responsive capacitive blood-pressure sensor. Edmonson supplies the vascular implantation and anchoring features by teaching implantable devices with electrode/fixation structures configured to secure an implant within a blood vessel. One of ordinary skill in the art would have found it obvious to implement the Goldshtein pressure-responsive capacitor in a vascular implant configuration as taught by Edmonson so that blood pressure within the artery or vein is transmitted to the capacitive sensor and the implant is mechanically secured by flexible electrode anchoring structures.
It would have been possible to combine these teachings because the modification uses Goldshtein for the limited teaching of a known capacitance-based blood-pressure transducer and uses Edmonson for the limited teaching of vascular deployment and flexible anchoring electrodes, while retaining the burst-based volume-conduction interrogation and implant-side capacitor/discharge architecture supplied by Becerra-Fajardo and Ivorra. The proposed modification does not require bodily incorporation of Goldshtein’s complete telemetry or calibration architecture or Edmonson’s complete implantation-positioning system. Rather, Goldshtein’s MEMS membrane capacitor supplies the pressure-variable capacitance property, and Edmonson supplies the known vascular anchoring and deployment configuration. Electrically, the modification is compatible because Ivorra already uses a capacitor in the implant circuit, and Goldshtein teaches a capacitor whose capacitance varies with blood pressure. Mechanically, the modification is compatible because a flexible capsule or flexible pressure-transmitting portion would allow external blood pressure to reach the capacitive pressure sensor while protecting the internal electronics, and Edmonson’s expandable electrode/fixation structures would secure the implant to the vessel wall.
To the extent an additional flexible-capsule teaching is needed, Ivorra teaches a compact implant body made of silicone with electrodes at opposite ends and an internal electronic circuit, and the use of a silicone body supports a flexible biocompatible capsule surrounding the internal circuit. One of ordinary skill in the art would have understood that a thin flexible silicone capsule would transmit external pressure to an internal pressure-sensitive capacitive structure while protecting the electronics and maintaining biocompatibility. Thus, Ivorra supports the flexible capsule portion of the claim, while Goldshtein supplies the blood-pressure-dependent capacitance and Edmonson supplies vascular anchoring by flexible electrode structures. The benefit of the combination would be to provide a minimally invasive vascular blood-pressure sensing implant in which blood pressure is mechanically transmitted through a flexible capsule portion to a capacitive pressure sensor, while flexible electrode anchoring structures secure the implant inside the artery or vein. This would allow blood pressure to be sensed through capacitance changes using the inherited burst-based electrical interrogation architecture while preserving a compact implant form factor suitable for vascular deployment.
Claim 15 is rejected under 35 U.S.C. 103 as being unpatentable over Becerra-Fajardo et al. (Becerra-Fajardo, Laura, and Antoni Ivorra. “Bidirectional Communications in Wireless Microstimulators Based on Electronic Rectification of Epidermically Applied Currents.” 2015 7th International IEEE/EMBS Conference on Neural Engineering (NER). IEEE, 2015. 545–548. Web), hereto referred as Becerra-Fajardo, and further in view of Ivorra et al. (Ivorra, Antoni, Laura Becerra-Fajardo, and Quim Castellví. “In Vivo Demonstration of Injectable Microstimulators Based on Charge-Balanced Rectification of Epidermically Applied Currents.” Journal of neural engineering 12.6 (2015): 066010–066010. Web.), hereto referred as Ivorra, and further in view of Goldshtein et al. (US-20150282720-A1), hereto referred as Goldshtein, and further in view of Foutz et al. (Foutz, Thomas J et al. “Energy Efficient Neural Stimulation: Coupling Circuit Design and Membrane Biophysics.” PloS one 7.12 (2012): e51901–e51901. Web.), hereto referred as Foutz, and further in view of Siliconix (Siliconix, “The FET Constant-Current Source/Limiter,” Application Note AN103 Siliconix, www.vishay.com/docs/70596/70596.pdf, Mar. 10, 1997., Mar. 10, 1997.), hereto referred as Siliconix.
The combined Becerra-Fajardo, Ivorra, and Goldshtein teaches claim 1 as described above.
Regarding claim 15, the combined Becerra-Fajardo, Ivorra, and Goldshtein teach the limitations of claim 1 as set forth above. As discussed above, Goldshtein is used in the claim 1 rejection for the capacitor-as-transducer alternative. Claim 15 further narrows the claimed implant to a different transducer configuration in which the discharge network comprises a current controlling device incorporating a transducer, current control depends on a parameter of the transducer, and the current controlling device is a JFET transistor and a resistive transducer. Thus, claim 15 is additionally rejected based on the further teachings of Foutz and Siliconix directed to current control and the specific JFET/source-gate resistor topology.
For claim 15, Goldshtein remains part of the inherited claim 1 combination, but the specific narrowed transducer configuration of claim 15 is supplied by Siliconix rather than by Goldshtein’s variable-capacitance capacitor. In particular, claim 15 no longer relies on the capacitor itself being the variable transducer. Instead, Ivorra supplies the capacitor discharge path, Foutz supports the desirability of current control in implantable biomedical circuitry, and Siliconix supplies the JFET/resistive-transducer current-control arrangement in which current depends on the resistance parameter of the transducer.
The combined Becerra-Fajardo, Ivorra, and Goldshtein does not fully teach that the discharge network comprises a current controlling device incorporating a transducer wherein current control depends on a parameter of the transducer, and wherein the current controlling device is a JFET transistor and a resistive transducer wherein a source of the JFET is connected to one terminal of the resistive transducer and a gate of the JFET transistor is connected to the other terminal of the resistive transducer. Rather, as shown above in claim 1, the combination provides the burst-based volume-conduction interrogation system, the external electrode/sensing-resistor pathway, the capacitor/asymmetric-conductance charging arrangement, the capacitor discharge framework, and the pressure-responsive capacitance relationship. However, the combination does not expressly teach a discharge network comprising a current controlling device incorporating a transducer wherein current control depends on a parameter of the transducer, nor does the combination expressly teach the specific JFET and resistive-transducer arrangement recited in claim 15.
Foutz teaches the general current-control principle and the benefit of using a FET-based current source to regulate current against load variation. Foutz teaches that the power consumed during constant-current stimulation is dictated by the current source and the electrode/tissue load, and that the current source is typically implemented with transistor technologies to deliver a constant current over the stimulus pulse regardless of the voltage generated across the electrodes (Foutz, p. 1, right column to p. 2, left column, Introduction). Foutz further teaches that adjustable compliance voltage can be used so that the FET remains in the desired operating region while reducing wasted energy, and that operation of the FET in saturation is related to current regulation (Foutz, p. 6, right column, Discussion). Thus, Foutz teaches the known use of FET-based current control in implantable biomedical circuits to reduce variation caused by electrode/tissue load conditions.
Siliconix supplies the specific JFET current-limiter topology and the source/gate resistor relationship. Siliconix teaches that “[a]n adjustable-current source (Figure 1) may be built with a FET, a variable resistor, and a small battery” (Siliconix, p. 1, Introduction). Siliconix further teaches that “[w]henever the FET is operated in the current saturated region, its output conductance is very low,” and that “[t]he FET may be biased to operate as a constant-current source at any current below its saturation current IDSS” (Siliconix, p. 1). Siliconix then expressly teaches that “the series resistor RS required between source and gate is” calculated from the gate-source voltage and drain current (Siliconix, p. 1, Basic Source Biasing). Siliconix also teaches that “[a] change in supply voltage or a change in load impedance, will change ID by only a small factor because of the low output conductance goss” (Siliconix, p. 1). Thus, Siliconix teaches a FET/JFET current source or current limiter in which a resistor between source and gate sets the regulated current and reduces current variation caused by supply or load changes.
Because Siliconix teaches that the source-gate resistor value sets the regulated current, one of ordinary skill in the art would have understood that using a resistance element whose resistance varies with a sensed condition would make the regulated current vary with that condition. Resistive transducers were known sensing elements for converting physical or chemical conditions into resistance changes, and substituting such a resistance-varying element for Siliconix’s source-gate resistor would have predictably made the current control depend on the transducer parameter. Although Siliconix’s variable resistor is used to adjust or set the current level, Siliconix is relied upon for the source-gate resistor topology and the teaching that the resistor value determines the regulated current, not for teaching that the resistor itself is a sensor. One of ordinary skill in the art would have understood that a resistive transducer is a known resistance-varying element that performs the same source-gate biasing function as Siliconix’s variable resistor while additionally varying in resistance based on a sensed physical or chemical condition. Accordingly, substituting a condition-responsive resistive transducer for Siliconix’s source-gate resistor would have predictably caused the JFET current control to depend on the transducer parameter.
It would have been prima facie obvious before the effective filing date of the claimed invention to have further modified the combined Becerra-Fajardo, Ivorra, and Goldshtein in view of Foutz and Siliconix to configure the discharge network to include a current controlling device whose current control depends on a transducer parameter, wherein the current controlling device is implemented using a JFET and a resistive transducer. As discussed above, the combined Becerra-Fajardo, Ivorra, and Goldshtein already provides the passive burst-charged capacitor and discharge-network framework for sensing. Foutz teaches the benefit of FET-based current regulation in implantable biomedical circuits to reduce sensitivity to electrode/tissue load variation. Siliconix teaches the specific FET/JFET current-source topology in which a source-gate resistor sets the regulated drain current and changes in load impedance change current by only a small factor. One of ordinary skill in the art would have found it obvious to use the known Siliconix JFET current-control topology in the discharge network and to implement the source-gate resistor as a resistive transducer so that the regulated discharge current would depend on the parameter of the resistive transducer while reducing unwanted variation from the medium and electrodes.
It would have been possible to combine these teachings because the modification does not require importing Foutz's entire active stimulation system or any unrelated architecture into the implant. Foutz is relied upon for the limited teaching that FET-based current control was known in implantable biomedical circuitry for stabilizing current against load variation. Siliconix is relied upon for the limited teaching of the self-biased JFET current-limiter topology itself, including the source-gate resistor that sets the regulated current. Siliconix’s JFET current-limiter topology is applicable to the inter-burst discharge path because the current limiter is self-biased by the gate-source voltage developed across the source-gate resistor and therefore does not require Foutz’s externally powered compliance-voltage regulation or active stimulation-control phase. The Becerra-Fajardo/Ivorra/Goldshtein combination already supplies the passive implant discharge path. Incorporating the Siliconix JFET/source-gate-resistor current-control element into that discharge path would have amounted to using a known current-control topology for its known current-limiting function in a predictable RC discharge environment. Using a resistive transducer as the source-gate resistor would have predictably caused the controlled current to depend on the sensed parameter because Siliconix teaches that the source-gate resistor value determines the regulated drain current. The benefit of the combination would be to reduce discharge-current dependence on uncontrolled tissue and electrode impedance while allowing the discharge current to vary with a desired resistive-transducer parameter, thereby improving sensing accuracy and measurement repeatability.
Claim 16 is rejected under 35 U.S.C. 103 as being unpatentable over Becerra-Fajardo et al. (Becerra-Fajardo, Laura, and Antoni Ivorra. “Bidirectional Communications in Wireless Microstimulators Based on Electronic Rectification of Epidermically Applied Currents.” 2015 7th International IEEE/EMBS Conference on Neural Engineering (NER). IEEE, 2015. 545–548. Web), hereto referred as Becerra-Fajardo, and further in view of Ivorra et al. (Ivorra, Antoni, Laura Becerra-Fajardo, and Quim Castellví. “In Vivo Demonstration of Injectable Microstimulators Based on Charge-Balanced Rectification of Epidermically Applied Currents.” Journal of neural engineering 12.6 (2015): 066010–066010. Web.), hereto referred as Ivorra, and further in view of Goldshtein et al. (US-20150282720-A1), hereto referred as Goldshtein, and further in view of Potyrailo et al. (US-20140025313-A1), hereto referred as Potyrailo.
The combined Becerra-Fajardo, Ivorra, and Goldshtein teaches claim 1 as described above.
Regarding claim 16, the combined Becerra-Fajardo, Ivorra, and Goldshtein teaches that the reading unit is additionally adapted for processing a sensed voltage and/or current(Becerra-Fajardo, p. 546, “II. PROOF-OF-CONCEPT PROTOTYPE”: “The external HF current generator is connected in series to a sensing resistor RS”, this shows the reader measures current via the voltage drop across RS; p. 546, “B. Receiver architecture”: “A receiver contained in the external unit (Fig. 4) is triggered in order to capture, demodulate and decode this signal”, this shows the reader processes the sensed electrical signal), but it does not teach calculating a capacitance of the capacitor, a resistance of the discharging network or impedance of the medium surrounding the implant when the implant is deployed in the medium, and for processing a calculated value to obtain a measurement of interest.
Rather, the combined Becerra-Fajardo, Ivorra, and Goldshtein teaches a reader that senses electrical signals (voltage/current) from the external electrodes and performs digital processing, but it does not teach calculating a capacitance of the implant capacitor, a resistance of the discharge network, or an impedance of the surrounding medium, nor processing such calculated values to obtain a measurement of interest. For example, Becerra-Fajardo states: “The external unit includes the HF current generator. This generator is connected in series with the sensing resistor RS … A receiver contained in the external unit (Fig. 4) is triggered in order to capture, demodulate and decode this signal” (Becerra-Fajardo, p. 546–547, “II. PROOF-OF-CONCEPT PROTOTYPE”; “B. Receiver architecture”), and further that “The activation of these current sources causes an amplitude modulation of the rectified HF current across the implants which can be detected across the external sensing resistor” (Becerra-Fajardo, p. 546, “II. PROOF-OF-CONCEPT PROTOTYPE”).
Potyrailo teaches acquiring an impedance spectrum with a reader, extracting sensor spectral parameters, and expressly obtaining “calculated values of C and R,” and further teaches determining environmental parameters from the impedance spectrum using multivariate analysis: “measuring a real part and an imaginary part of the impedance spectrum … calculating at least six spectral parameters … determining one or more environmental parameters from the impedance spectrum” and “determining a resistance and a capacitance of the single resonant sensor antenna coated with a sensing material,” with “calculated values of C and R” (Potyrailo, ¶[0039]; ¶[0054]; ¶[0010]; ¶[0012]; claim 8, 27).
It would have been prima facie obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the combined Becerra-Fajardo, Ivorra, and Goldshtein in view of Potyrailo to adapt the reading unit’s processing to calculate a capacitance of the capacitor, a resistance of the discharging network, or an impedance of the medium from the sensed voltage and/or current, and to process the calculated value to obtain a measurement of interest. It would have been possible to combine these teachings because Becerra-Fajardo already acquires the necessary electrical signals via a series sensing resistor and performs digital capture/demodulation in a control/processing module, while Potyrailo provides reader-side algorithms to compute C, R, and environmental parameters from measured electrical responses; implementing Potyrailo’s calculations in Becerra-Fajardo’s existing processing chain is a routine software/firmware extension of the disclosed readout path. The benefit of the combination is to endow the existing implant system with quantitative sensing capability (deriving C, R, or impedance and converting those into environmental/physiological measurements) without adding bulky hardware, thereby improving diagnostic utility while leveraging the same interrogation bursts and receiver architecture already disclosed.
Claims 17-18 are rejected under 35 U.S.C. 103 as being unpatentable over Becerra-Fajardo et al. (Becerra-Fajardo, Laura, and Antoni Ivorra. “Bidirectional Communications in Wireless Microstimulators Based on Electronic Rectification of Epidermically Applied Currents.” 2015 7th International IEEE/EMBS Conference on Neural Engineering (NER). IEEE, 2015. 545–548. Web), hereto referred as Becerra-Fajardo, and further in view of Ivorra et al. (Ivorra, Antoni, Laura Becerra-Fajardo, and Quim Castellví. “In Vivo Demonstration of Injectable Microstimulators Based on Charge-Balanced Rectification of Epidermically Applied Currents.” Journal of neural engineering 12.6 (2015): 066010–066010. Web.), hereto referred as Ivorra, and further in view of Goldshtein et al. (US-20150282720-A1), hereto referred as Goldshtein, and further in view of Potyrailo et al. (US-20140025313-A1), hereto referred as Potyrailo, and further in view of Besling et al. (US-20130233086-A1 ), hereto referred as Besling.
The combined Becerra-Fajardo, Ivorra, and Goldshtein teaches claim 1 as described above.
Regarding claim 17, the combined Becerra-Fajardo, Ivorra, Goldshtein, and Potyrailo does not fully teach that the reading unit is adapted for reading the implant by monitoring a time course of relative changes of a burst current amplitude ipeak(t) as the capacitor charges, for fitting recorded variations of the time course of relative changes of the burst current amplitude ipeak(t) to an exponential decay model of the form ipeak(t) = Ke(-t/τ) by adjusting a characteristic value, and for calculating a desired measurement from the characteristic value. Rather, as shown above in claims 1 and 16, the combination provides the burst-based volume-conduction interrogation system, the external electrode/sensing-resistor pathway for detecting implant-dependent electrical signals, the capacitor/asymmetric-conductance charging arrangement, the capacitor discharge framework, the pressure-responsive capacitance relationship, and the processing of sensed voltage and/or current to calculate capacitance, resistance, or impedance values and process a calculated value to obtain a measurement of interest. Because the external sensing-resistor pathway detects implant-dependent electrical effects during burst interrogation, changes in burst current amplitude would have been obtainable from the measured voltage or current response at the reading unit. Relative changes of burst current amplitude are derivable from recorded burst current amplitude values by comparing amplitudes over time, normalizing amplitudes, or determining ratios or differences between current amplitude values. Thus, monitoring relative changes does not require a different implant structure from monitoring the underlying burst current amplitude time course. However, the combination does not expressly teach monitoring the time course of relative changes of burst current amplitude ipeak(t) as the capacitor charges, fitting those recorded burst-current amplitude variations specifically to the exponential decay model ipeak(t) = Ke(-t/τ) by adjusting a characteristic value, and calculating the desired measurement from that characteristic value.
Besling supplies the missing time-constant/exponential-model support for the amended claim 17 limitation. Besling teaches that “[t]ime-constant methods rely on the measurement of the time constant of charge or discharge through a known resistor” (Besling, ¶[0101]). Besling further teaches that, when a voltage step is applied to an initially discharged capacitor and a resistor in series, “the charge and the Voltage on the capacitor increase exponentially toward their full magnitudes with a time constant equal in seconds to the product of the resistance in Ohms and the capacitance in Farads” (Besling, ¶[0101]). Besling also teaches that, when a charged capacitor is discharged through a resistor, “the charge and the Voltage decay with the same time constant,” and that “[t]he time or frequency of Such a charge-discharge cycle can easily be determined with standard methods” (Besling, ¶[0101]). Thus, Besling evidences that measuring an RC charge/discharge time constant and using the exponential time behavior of capacitor charging/discharging were known and standard techniques.
Although Besling does not appear to disclose the exact formula ipeak(t) = Ke(-t/τ) verbatim, one of ordinary skill in the art would have recognized that the formula is the ordinary current expression corresponding to the same RC charging process disclosed by Besling. Besling teaches that capacitor voltage increases exponentially during charging with a time constant τ = RC. In the corresponding RC charging circuit, the charging current decreases exponentially with the same time constant because the charging current is proportional to the difference between the applied voltage and the capacitor voltage, and that difference decreases exponentially as the capacitor charges. Therefore, the charging-current amplitude may be expressed as ipeak(t) = Ke(-t/τ), where K represents the initial or scaled current amplitude and τ represents the RC time constant. Thus, the claimed current-decay model is the ordinary mathematical expression for the charging-current behavior corresponding to the RC charging process taught by Besling.
The during-burst charging window is supplied by the inherited combination. Becerra-Fajardo provides the external electrode/sensing-resistor pathway for observing implant-dependent electrical effects during burst interrogation. Ivorra teaches that “[d]uring the HF bursts, rectified current will flow from a to b through the diode, thus progressively charging CB,” and further teaches that “[a]s CB becomes charged, higher voltage differences between a and b will be required in order to obtain conduction through the diode and, as a consequence, the mean voltage across the implant electrodes will decrease.” Ivorra further explains that the generated pulse “will show a decaying shape,” and that after the burst, “the capacitor will slowly discharge through the implant resistor RD and the tissues until the next burst.” Ivorra also reports recorded current behavior in which, during the HF burst, low-frequency current flows through the implant and “the magnitude of this low-frequency current diminishes as CB (CB1 in series with CB2) charges.” Thus, the inherited combination provides a burst-time current-related signal that changes as the capacitor charges, and Besling supplies the known RC exponential model for quantifying that charging behavior.
It would have been prima facie obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have further modified the combined Becerra-Fajardo, Ivorra, Goldshtein, and Potyrailo in view of Besling to monitor the time course of relative changes of the burst current amplitude ipeak(t) as the capacitor charges, fit the recorded burst-current amplitude variations to the corresponding RC exponential current model of the form ipeak(t) = Ke(-t/τ) by adjusting τ as the characteristic value, and calculate a desired measurement from that characteristic value. As discussed above, the inherited combination already provides the external electrode and sensing-resistor readout pathway for acquiring burst-time current-related signals, the burst-time capacitor charging behavior, the pressure-dependent capacitance relationship, and reader-side processing of calculated characteristic values to determine a measurement. Besling supplies the remaining teaching that time-constant methods measure capacitor charge or discharge through a known resistor, that capacitor charge and voltage increase exponentially during charging with τ = RC, and that the time or frequency of a charge-discharge cycle can be determined by standard methods.
It would have been possible to combine these teachings because the modification is a processing adaptation of signals already available in the inherited burst interrogation architecture. The reading unit already acquires implant-dependent electrical signals through the external electrode/sensing-resistor pathway, and the implant circuit already produces a changing current response as the capacitor charges during each burst. The external sensing resistor provides a current-related voltage signal, so monitoring burst current amplitude through that readout pathway would have provided the information needed to characterize the charging current time course. Relative changes in that burst current amplitude would have been obtained by routine processing of the recorded current amplitude values, such as comparing, normalizing, or calculating ratios or differences over time. Besling's time-constant method would be applied to the same RC charging behavior, not to a different circuit architecture. Fitting the burst-current amplitude decay to ipeak(t) = Ke(-t/τ) would have been a straightforward way to quantify the known RC charging behavior because the exponential form is the expected mathematical model for capacitor charging current in an RC circuit.
In the resulting combination, the fitted characteristic value τ provides the bridge between the monitored current time course and the desired measurement. Goldshtein teaches a pressure-responsive capacitance, and Ivorra supplies the RC charge/discharge path. Because τ depends on the RC characteristics of the circuit, including capacitance, using Goldshtein's pressure-variable capacitor causes τ to vary with pressure. Thus, fitting ipeak(t) to the exponential model yields τ, and τ encodes the desired physical measurement through the pressure-dependent capacitance. Potyrailo further supports using calculated characteristic values to determine a desired measurement, while Besling supplies the RC time-constant model used to obtain the characteristic value from the monitored time course.
The benefit of the combination would be to obtain a robust quantitative characteristic value τ from the burst-time current response using the same external electrode/sensing-resistor pathway, thereby allowing the reading unit to calculate a pressure or other desired measurement without adding implant complexity and while preserving the compact injection- or catheter-deployable architecture.
Regarding claim 18, the combined Becerra-Fajardo, Ivorra, Goldshtein, and Potyrailo does not fully teach that the reading unit is adapted for reading the implant by monitoring a post-burst exponential decay voltage across the two or more electrodes following cessation of the burst, wherein the post-burst exponential decay voltage arises from discharge of the capacitor through the discharge network and the medium, for fitting the recorded post-burst voltage waveform to an exponential decay model of the form v(t) = Ke(-t/τ) by adjusting a characteristic value, and for calculating a measurement from the characteristic value. Rather, as shown above in claims 1 and 16, the combination provides the burst-based volume-conduction interrogation system, the external electrode/sensing-resistor pathway for detecting implant-dependent electrical signals, the capacitor/asymmetric-conductance charging arrangement, the capacitor discharge framework, the pressure-responsive capacitance relationship, and the processing of sensed voltage and/or current to calculate capacitance, resistance, or impedance values and process a calculated value to obtain a measurement of interest. Ivorra teaches that after each burst, “the capacitor will slowly discharge through the implant resistor RD and the tissues until the next burst” (Ivorra, p. 3, §2.1). Ivorra also teaches that after the HF burst, “the charge stored in CB is discharged through RD and the tissues thus causing a current of opposite sign that slowly diminishes” (Ivorra, p. 6, §3.2). Thus, the inherited combination provides a post-burst capacitor discharge through the implant resistor and tissues following cessation of the burst, with that discharge producing a slowly diminishing electrical response after the active burst window. In this mapping, Ivorra’s implant resistor RD corresponds to at least part of the claimed discharge network, and the tissues through which the discharge occurs correspond to the claimed medium. However, the combination does not expressly teach monitoring a post-burst exponential decay voltage across the two or more electrodes following cessation of the burst, fitting the recorded post-burst voltage waveform specifically to an exponential decay model of the form v(t) = Ke(-t/τ) by adjusting a characteristic value, and calculating a measurement from the characteristic value.
Goldshtein supplies the pressure-responsive capacitance and measurement relationship. Goldshtein teaches a pressure sensor “which has a capacitance that varies in response to the ambient pressure” (Goldshtein, Abstract). Goldshtein further teaches that “[t]he pressure applied by the blood to the membrane sets the spacing between the capacitor electrodes, and therefore sets the capacitor's capacitance” (Goldshtein, ¶[0035]). Goldshtein also teaches that the implant “produces a time-varying waveform that is indicative of the time-varying capacitance of sensor 36, and thus the time-varying pressure” (Goldshtein, ¶[0036]) and that the external processor “processes the received waveform so as to estimate the actual blood pressure sensed by sensor 36” (Goldshtein, ¶[0037]). Accordingly, when Goldshtein's pressure-responsive capacitor is used as the capacitance affecting Ivorra's discharge path, the recorded post-burst voltage response varies with the pressure-dependent capacitance and therefore encodes the desired measurement. The proposed modification does not require bodily incorporation of Goldshtein’s complete pressure-sensor implant into Ivorra. Rather, Goldshtein is relied upon for the known use of a pressure-responsive capacitance whose capacitance varies with pressure and whose time-varying waveform is processed to estimate pressure.
Potyrailo further supports reader-side processing of electrical response data into characteristic values and measurements. Potyrailo teaches that “[t]he interaction between the RFID sensor 12 and the pickup coil 22 can be described using a general mutual inductance coupling circuit model” (Potyrailo, ¶[0058]). Potyrailo also teaches using calculated sensor resistance and calculated sensor capacitance in sensing determinations (Potyrailo, ¶[0096]) and teaches that “the sensor's multivariable response was modeled using the first, second, and third principal components (PCs) of the built PCA model” with “excellent correlation coefficients” between actual and predicted concentrations (Potyrailo, ¶[0092]). Thus, Potyrailo supports the limited proposition that reader-side processing can model measured electrical responses to extract characteristic values for a desired measurement, not replacing Becerra-Fajardo's volume-conduction burst interrogation architecture.
Besling supplies the missing time-constant/exponential-voltage-decay model support for the amended claim 18 limitation. Besling teaches that “[t]ime-constant methods rely on the measurement of the time constant of charge or discharge through a known resistor” (Besling, ¶[0101]). Besling further teaches that, when a voltage step is applied to an initially discharged capacitor and a resistor in series, “the charge and the Voltage on the capacitor increase exponentially toward their full magnitudes with a time constant equal in seconds to the product of the resistance in Ohms and the capacitance in Farads” (Besling, ¶[0101]). Besling also teaches that, when a charged capacitor is discharged through a resistor, “the charge and the Voltage decay with the same time constant,” and that “[t]he time or frequency of Such a charge-discharge cycle can easily be determined with standard methods” (Besling, ¶[0101]). Thus, Besling evidences that measuring an RC discharge time constant and using the exponential time behavior of capacitor voltage discharge were known and standard techniques.
Although Besling does not appear to disclose the exact formula v(t) = Ke(-t/τ) verbatim, one of ordinary skill in the art would have recognized that the formula is the direct mathematical restatement of the same RC discharge behavior expressly taught by Besling. Besling teaches that, when a charged capacitor is discharged through a resistor, the capacitor voltage decays with the discharge time constant. In an ordinary RC discharge, the capacitor voltage decreases exponentially with time, and the voltage may be expressed as v(t) = Ke(-t/τ), where K represents the initial or scaled voltage and τ represents the RC time constant. Thus, the claimed post-burst voltage-decay model is the ordinary mathematical expression for the capacitor discharge voltage behavior corresponding to the RC discharge process taught by Besling.
The post-burst discharge window and its detectability are supplied by Ivorra and the inherited external measurement pathway. Ivorra teaches that after the burst, “the capacitor will slowly discharge through the implant resistor RD and the tissues until the next burst” (Ivorra, p. 3, §2.1). Ivorra also reports recorded current behavior in which, after the HF burst, “the charge stored in CB is discharged through RD and the tissues thus causing a current of opposite sign that slowly diminishes” (Ivorra, p. 6, §3.2). Ivorra’s experimental observation of the post-burst discharge demonstrates that the external measurement arrangement was capable of detecting implant-dependent electrical behavior after burst cessation. The post-burst discharge current flows through RD and the tissues, which is the same tissue volume through which the burst current is supplied by the external reading electrodes. Because the external electrodes are positioned to apply and monitor signals through that tissue volume, the post-burst discharge current through the tissue would create a corresponding potential difference at the external electrode positions and across the associated sensing pathway. Thus, the inherited combination provides the claimed post-burst discharge of the capacitor through the discharge network and medium, and Besling supplies the known RC exponential voltage-decay model for quantifying that post-burst discharge behavior.
It would have been prima facie obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have further modified the combined Becerra-Fajardo, Ivorra, Goldshtein, and Potyrailo in view of Besling so that the reading unit monitors the post-burst exponential decay voltage in the reader electrode pathway following cessation of the burst, including a voltage response developed across the two or more reader electrodes and associated sensing circuitry, fits the recorded post-burst voltage waveform to the corresponding RC exponential voltage decay model of the form v(t) = Ke(-t/τ) by adjusting τ as the characteristic value, and calculates a measurement from that characteristic value. As discussed above, the inherited combination already provides the external electrode and sensing-resistor readout pathway, the post-burst capacitor discharge through the implant resistor and tissues, the pressure-dependent capacitance relationship, and reader-side processing of calculated characteristic values to determine a measurement. Besling supplies the remaining teaching that time-constant methods measure capacitor discharge through a known resistor, that capacitor voltage decays during discharge with the same time constant, and that the time or frequency of the charge-discharge cycle can be determined by standard methods.
It would have been possible to combine these teachings because the modification is a processing adaptation of signals already available in the inherited burst interrogation architecture. The reading unit already acquires implant-dependent electrical signals through the external electrode/sensing-resistor pathway. Although Becerra-Fajardo’s receiver is directed to detecting implant-dependent ASK modulation during the active HF burst, Ivorra’s experimental observation of the post-burst discharge demonstrates that implant-dependent electrical behavior following burst cessation was observable through an external measurement arrangement. Extending the receiver or processing window to capture the post-burst interval would have been an obvious adaptation because the same external electrodes and sensing pathway remain coupled to the same tissue volume after the burst ends, and Ivorra expressly teaches that the implant capacitor discharges through RD and the tissues during that interval. Besling's time-constant method would then be applied to that same RC discharge behavior, not to a different implant architecture. Fitting the recorded post-burst voltage waveform to v(t) = Ke(-t/τ) would have been a straightforward way to quantify the known RC discharge behavior because exponential voltage decay is the expected mathematical model for a charged capacitor discharging through a resistance.
In the resulting combination, the fitted characteristic value τ provides the bridge between the recorded post-burst voltage waveform and the desired measurement. Goldshtein teaches a pressure-responsive capacitance, and Ivorra supplies the RC discharge path through the implant resistor and tissues. Because τ depends on the RC characteristics of the circuit, including capacitance, using Goldshtein's pressure-variable capacitor causes τ to vary with pressure. Thus, fitting the recorded post-burst voltage decay to the exponential model yields τ, and τ encodes the desired physical measurement through the pressure-dependent capacitance. Potyrailo further supports using calculated characteristic values from measured electrical responses to determine a desired measurement, while Besling supplies the RC time-constant model used to obtain the characteristic value from the monitored post-burst voltage decay. The benefit of the combination would be to obtain a robust quantitative characteristic value τ from the naturally occurring post-burst discharge voltage response using the same external electrode/sensing-resistor pathway, thereby allowing the reading unit to calculate a pressure or other desired measurement without adding implant complexity and while preserving the compact injection or catheter-deployable architecture.
Claim 19 is rejected under 35 U.S.C. 103 as being unpatentable over Becerra-Fajardo et al. (Becerra-Fajardo, Laura, and Antoni Ivorra. “Bidirectional Communications in Wireless Microstimulators Based on Electronic Rectification of Epidermically Applied Currents.” 2015 7th International IEEE/EMBS Conference on Neural Engineering (NER). IEEE, 2015. 545–548. Web), hereto referred as Becerra-Fajardo, and further in view of Ivorra et al. (Ivorra, Antoni, Laura Becerra-Fajardo, and Quim Castellví. “In Vivo Demonstration of Injectable Microstimulators Based on Charge-Balanced Rectification of Epidermically Applied Currents.” Journal of neural engineering 12.6 (2015): 066010–066010. Web.), hereto referred as Ivorra, and further in view of Goldshtein et al. (US-20150282720-A1), hereto referred as Goldshtein, and further in view of Potyrailo et al. (US-20140025313-A1), hereto referred as Potyrailo, and further in view of Toumazou et al. (US-20130273664-A1.), hereto referred as Toumazou.
The combined Becerra-Fajardo, Ivorra, and Goldshtein teaches claim 1 as described above.
Regarding claim 19, the combined Becerra-Fajardo, Ivorra, Goldshtein, and Potyrailo does not fully teach that the reading unit is adapted for reading the implant by delivering bursts of different amplitude and monitoring the current unbalances between positive and negative semicycles, wherein the current unbalances arise from the non-linear behavior of the device of asymmetric conductance, for fitting recorded unbalances to a non-linear model of the device of asymmetric conductance by adjusting a characteristic value, and for calculating a measurement from the characteristic value. Rather, as shown above in claims 1 and 16, the combination provides the burst-based volume-conduction interrogation system, the external electrode/sensing-resistor pathway for detecting implant-dependent electrical signals, the capacitor/asymmetric-conductance charging arrangement, the capacitor discharge framework, the pressure-responsive capacitance relationship inherited from Goldshtein, and the processing of sensed voltage and/or current to calculate characteristic electrical values and obtain a measurement of interest. Becerra-Fajardo teaches that “[t]he external unit includes the HF current generator” and that “[t]his generator is connected in series with the sensing resistor RS (Fig. 2) for obtaining a voltage drop proportional to the modulated signal” (Becerra-Fajardo, ‘B. Receiver architecture’). Becerra-Fajardo further teaches that “[t]he extracted window is processed using an algorithm that finds local minima and maxima, therefore detecting the peaks of the signal” (Becerra-Fajardo, ‘B. Receiver architecture’) and that “[p]ositive and negative peaks were detected using the local maxima and minima algorithm described in Section IIB” (Becerra-Fajardo, ‘IV. Results’). Thus, Becerra-Fajardo teaches an external reading unit that captures current-related waveform information and distinguishes positive and negative signal features in the sensed response.
Ivorra supplies the asymmetric-conductance and semicycle-unbalance basis. Ivorra teaches an implant circuit including a diode, capacitors, and a resistor between two implant electrodes, and teaches that “[t]he implants weight 40.5 mg and they consist of a 3 cm long tubular silicone body with a diameter of 1 mm, two electrodes at opposite ends, and, within the central section of the silicone body, an electronic circuit capable of performing charge-balanced rectification” (Ivorra, §2.1). Ivorra further teaches that, when the capacitor is discharged and a sinusoidal HF current burst is forced through the tissue, “the voltage across the implant electrodes will correspond to the half-wave rectification of the HF voltage that would appear across the electrodes if the diode was not present” (Ivorra, §2.1). Ivorra also teaches that “[d]uring the HF bursts, rectified current will flow from a to b through the diode, thus progressively charging CB” (Ivorra, §2.1). Because a diode conducts preferentially in one polarity and blocks or conducts substantially less in the opposite polarity, Ivorra’s rectification creates an imbalance between positive and negative semicycles of the alternating burst current. Ivorra also teaches that “[a]s CB becomes charged, higher voltage differences between a and b will be required in order to obtain conduction through the diode and, as a consequence, the mean voltage across the implant electrodes will decrease” (Ivorra, §2.1). Thus, Ivorra teaches that the semicycle-dependent current behavior arises from the nonlinear one-way conduction behavior of the diode and changes during the burst as the circuit state changes.
Delivering bursts of different amplitude would have been an obvious implementation of the inherited burst interrogation system for characterizing the nonlinear response already taught by Ivorra. Becerra-Fajardo teaches an external HF current generator connected through the external reading pathway, and Ivorra teaches that diode conduction during the burst depends on the voltage across the implant electrodes. Varying the burst amplitude would have sampled different operating points of the same nonlinear asymmetric-conductance device. Sampling multiple operating points is the ordinary way to characterize a nonlinear electrical device because a nonlinear current-voltage relationship cannot be defined by a single operating point. Because Ivorra’s diode conducts differently during positive and negative semicycles, the difference between the positive and negative semicycle currents would vary as burst amplitude varies. The resulting amplitude-dependent current unbalances would provide the recorded data points for fitting to the nonlinear model of the same asymmetric-conductance device. In the inherited system, the reading unit already includes the external burst generator, external electrodes, sensing-resistor pathway, and digital processing used to acquire current-related waveform features, so the positive and negative semicycle current values at different burst amplitudes would have been obtainable from the same readout path.
Ivorra’s diode is the claimed device of asymmetric conductance for this mapping, and the nonlinear model is the ordinary current-voltage model of that same diode or rectifying semiconductor device. Ivorra expressly relies on diode rectification to produce the asymmetric semicycle behavior, and Becerra-Fajardo likewise uses rectifying diode circuitry in the implant. One of ordinary skill in the art would have understood that a diode does not have a linear current-voltage relationship, but instead has a nonlinear current-voltage relationship in which current increases nonlinearly with applied forward voltage while being substantially blocked or limited in the reverse direction. The standard nonlinear diode current-voltage model is commonly expressed by the Shockley diode equation, I = IS(e^(V/nVT) - 1), or an equivalent nonlinear diode relation. Thus, fitting recorded positive/negative semicycle current unbalances obtained at different burst amplitudes to the nonlinear diode model would have been the ordinary way to characterize the nonlinear asymmetric-conductance behavior that is already responsible for the observed rectification.
The characteristic value adjusted in the fit is treated as an effective circuit parameter affecting the relationship between delivered burst amplitude and positive/negative semicycle current imbalance, such as an effective path impedance or series-resistance component associated with the medium. In the inherited volume-conduction architecture, the external burst voltage is not applied directly across the diode alone. Rather, the externally delivered current reaches the implant through the tissue medium, so the voltage available at the implant electrodes to drive the diode current depends on the series path that includes the tissue/electrode medium impedance and the implant circuit. Thus, the nonlinear diode model used for fitting the recorded current unbalances would include not only the nonlinear diode current-voltage behavior, but also an effective series or path parameter that determines how the delivered burst amplitude is translated into implant-electrode voltage and diode current. Adjusting that characteristic value during the fit would allow the reading unit to identify a medium-impedance-dependent parameter from the recorded semicycle unbalances. That calculated characteristic value can then be processed to obtain the measurement required by claim 16, including an impedance of the medium.
Toumazou supplies supplemental support for the broader principle that semiconductor sensing devices are modeled using nonlinear current-voltage relations and that a characteristic value in such a model can correspond to a sensed condition. Toumazou teaches that the electrical operating modes of a FET may be expressed by current-voltage relations in weak inversion, triode region, and saturation (Toumazou, ¶[0003]). Toumazou further teaches that voltage drops arising from interactions of the reference electrode, electrolyte, and ion-sensitive membrane can be viewed as part of the gate-source voltage or threshold voltage because their difference appears in the MOSFET current-voltage relations (Toumazou, ¶[0004]). Toumazou also teaches that, in an ISFET, the threshold voltage depends on electrolyte properties and that “the ISFETs threshold voltage can be modified using electrolyte ion concentration” (Toumazou, ¶[0006]). Toumazou is not relied upon to replace Ivorra’s diode-based rectifying implant architecture or to supply the diode model itself. Rather, Toumazou supports the general and limited proposition that semiconductor device behavior can be fitted or interpreted using nonlinear current-voltage relations and that adjusted characteristic values in those relations can correspond to sensed conditions.
Potyrailo further supports reader-side model-based processing of measured electrical responses to extract characteristic values for sensing. Potyrailo teaches that reader-measured electrical responses can be related to sensor characteristics using a circuit model, teaches calculated sensor resistance and capacitance values, and teaches modeling multivariable sensor responses to predict measured concentrations. Potyrailo is not relied upon to supply the nonlinear diode model or the semicycle-unbalance teaching. Rather, Potyrailo supports the limited proposition that reader-side processing can model measured electrical responses and use extracted characteristic values to calculate a measurement, without replacing Becerra-Fajardo’s volume-conduction burst interrogation architecture.
It would have been prima facie obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have further modified the combined Becerra-Fajardo, Ivorra, Goldshtein, and Potyrailo in view of Toumazou so that the reading unit delivers bursts of different amplitude, monitors the resulting current unbalances between positive and negative semicycles, fits the recorded unbalances to a nonlinear model of the asymmetric-conductance device by adjusting a characteristic value, and calculates a measurement from the characteristic value. As discussed above, the inherited combination already provides the external burst generator, external electrode/sensing-resistor pathway, digital signal processing, and a diode-based asymmetric-conductance implant circuit that produces rectified semicycle-dependent behavior. Ivorra teaches that the current and voltage response depends on diode conduction during the burst and changes as CB charges. Varying the burst amplitude would have provided multiple response points along the nonlinear current-voltage behavior of the diode or other asymmetric-conductance device. Fitting those amplitude-dependent current unbalances to the nonlinear model of the asymmetric-conductance device would have allowed the reading unit to extract a characteristic value affected by the implant circuit and medium path. Toumazou supplies supplemental support for the use of nonlinear semiconductor device models and adjusted characteristic values associated with sensed conditions, while Potyrailo supplies additional support for reader-side model processing of measured electrical response data into calculated measurements.
It would have been possible to combine these teachings because the modification is primarily a measurement and processing adaptation of signals already available in the inherited burst interrogation architecture. Becerra-Fajardo already delivers HF signals through external electrodes and measures implant-dependent electrical effects through the external sensing resistor. Ivorra already provides a device of asymmetric conductance whose rectification creates different positive and negative semicycle behavior during the burst. Delivering bursts at different amplitudes would merely sweep the operating point of that same asymmetric-conductance device. Recording the resulting positive and negative semicycle current imbalance and fitting those values to the nonlinear diode model would have been a straightforward way to characterize the nonlinear diode response. Because the externally delivered current reaches the implant through the tissue medium, the fitted characteristic value would also reflect the impedance of the medium and could be processed to calculate the medium impedance or another inherited measurement associated with claim 16.
In the resulting combination, the delivered burst amplitude provides the controlled input, the positive and negative semicycle current imbalance provides the measured nonlinear response, and the fitted characteristic value provides the bridge to the measurement. The current imbalance arises because the asymmetric-conductance device conducts differently for opposite polarities of the alternating burst waveform. The magnitude of that imbalance changes with burst amplitude because the nonlinear current-voltage relationship of the asymmetric-conductance device is amplitude dependent. Fitting recorded unbalances obtained at different burst amplitudes to the nonlinear device model allows the reading unit to determine a characteristic value of the device and circuit path. That characteristic value is affected by the medium path because the burst current and resulting implant-electrode voltage are established by volume conduction through the medium. Accordingly, the characteristic value can be processed to calculate the measurement required by claim 16, including an impedance of the medium. The benefit of the combination would be to obtain a quantitative measurement from the amplitude-dependent nonlinear response of the asymmetric-conductance device using the same external burst generator, external electrodes, sensing-resistor pathway, and digital processing already present in the inherited system. This would improve sensing functionality without requiring bulky implant hardware, while preserving the compact injection or catheter-deployable volume-conduction implant architecture.
Claim 20 is rejected under 35 U.S.C. 103 as being unpatentable over Becerra-Fajardo et al. (Becerra-Fajardo, Laura, and Antoni Ivorra. “Bidirectional Communications in Wireless Microstimulators Based on Electronic Rectification of Epidermically Applied Currents.” 2015 7th International IEEE/EMBS Conference on Neural Engineering (NER). IEEE, 2015. 545–548. Web), hereto referred as Becerra-Fajardo, and further in view of Ivorra et al. (Ivorra, Antoni, Laura Becerra-Fajardo, and Quim Castellví. “In Vivo Demonstration of Injectable Microstimulators Based on Charge-Balanced Rectification of Epidermically Applied Currents.” Journal of neural engineering 12.6 (2015): 066010–066010. Web.), hereto referred as Ivorra, and further in view of Goldshtein et al. (US-20150282720-A1), hereto referred as Goldshtein, and further in view of Potyrailo et al. (US-20140025313-A1), hereto referred as Potyrailo, and further in view of Edmonson et al. (US-10143847-B1), hereto referred as Edmonson.
the combined Becerra-Fajardo, Ivorra, and Goldshtein teaches claim 1 as described above.
Regarding claim 20, the combined Becerra-Fajardo, Ivorra, and Goldshtein do not teach that the reading unit is an external battery powered hand-held unit, or wherein the reading unit comprises: an implantable sub-unit adapted for reading the implant; an external sub-unit adapted for presenting information related to the readings of the implantable sub-unit; wherein the implantable sub-unit and the external sub-unit are wirelessly communicated. Rather, the combined Becerra-Fajardo, Ivorra, and Goldshtein collectively teach an external system for reading implant signals and wirelessly monitoring implantable devices, but they do not explicitly describe the reading unit being battery-powered and handheld.
Edmonson teaches an external device (component 14) that is a handheld, battery-powered device (such as a smartphone or tablet) that wirelessly communicates with an implantable medical device to retrieve physiological information and present it to a user (Edmonson, Figs. 1A-B; col. 20, ll. 5–25; col. 6, ll. 10–21). Edmonson thus explicitly discloses both a battery-powered hand-held external device and a system comprising an implantable sub-unit adapted for sensing and an external sub-unit adapted for presenting readings, with wireless communication between them.
It would have been prima facie obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the combined Becerra-Fajardo, Ivorra, and Goldshtein in view of Edmonson to configure the reading unit as either (i) a battery-powered handheld external device capable of emitting interrogation bursts and receiving implant signals or (ii) a system comprising an implantable sub-unit that performs sensing and an external sub-unit that processes and presents the data, with wireless communication between the sub-units. One of ordinary skill would have found it obvious to implement this modification because Becerra-Fajardo and Ivorra already separate the sensing and control components between internal and external locations, and Edmonson provides an explicit teaching of using portable, battery-powered external units for such wireless implant monitoring and data presentation. The benefit of making this modification would be to increase the portability, usability, and clinical practicality of the implant system by enabling handheld monitoring, or distributed implant-external reader systems, with minimal additional complexity beyond known wireless telemetry and portable electronic technologies.
Response to Arguments
35 U.S.C. §103
Applicant's arguments filed 5/12/2026, pages 10-22, regarding the previous 103 Rejections of claims 1-20 have been fully considered but are moot because the new ground of rejection does not rely on any reference applied in the prior rejection of record for any teaching or matter specifically challenged in the argument. That is, there are new grounds of rejection. Additionally, they are not persuasive for the reasons discussed below.
Applicant’s Argument: Applicant argues that Becerra-Fajardo is directed to an active stimulation implant with an ASK communications uplink, not an implantable sensing system, and that the external sensing resistor detects communication signals rather than physiological parameters.
Examiner’s Response: This argument is not persuasive because Becerra-Fajardo is not relied upon as teaching every aspect of the claimed sensing mechanism. Becerra-Fajardo is relied upon for the external burst-powered volume-conduction interrogation architecture, the external electrodes, the external sensing resistor/readout pathway, and the ability to detect implant-dependent electrical effects at the external unit. The sensing relationship is supplied by the combination, including Ivorra’s passive diode/capacitor/discharge-network implant circuit and the presently applied transducer teachings. Accordingly, the fact that Becerra-Fajardo uses the detected signal for ASK communication in its own embodiment does not negate its teaching of the external volume-conduction burst interrogation and readout pathway relied upon in the rejection.
Applicant’s Argument: Applicant argues that Becerra-Fajardo is an active circuit with a microcontroller, current sources, regulation circuitry, and demodulation circuitry, whereas the claimed invention is a passive implant.
Examiner’s Response: This argument is not persuasive because the rejection does not bodily incorporate Becerra-Fajardo’s entire active implant circuit into the proposed combination. Becerra-Fajardo is relied upon for the external burst-powered interrogation and external readout architecture. Ivorra supplies the compatible passive implant-side diode/capacitor/resistor arrangement operating from the same type of externally applied high-frequency bursts. The proposed combination therefore retains Becerra-Fajardo’s external volume-conduction interrogation and readout teachings while using Ivorra’s passive implant-side rectifier and discharge framework.
Applicant’s Argument: Applicant argues that combining Becerra-Fajardo and Ivorra would require removing Becerra-Fajardo’s bridge rectifier and active electronics and replacing them with the claimed passive half-wave rectifier topology, resulting in a wholesale substitution that would render the prior art unsatisfactory for its intended purpose.
Examiner’s Response: This argument is not persuasive because Becerra-Fajardo itself recognizes the same general class of rectifier-based implants powered by high-frequency current bursts conducted through tissue. In particular, Becerra-Fajardo acknowledges “an implant with a simple circuit consisting of a rectifier, a capacitor and a resistor” as a known approach. Ivorra further teaches a compatible passive diode/capacitor/resistor implant circuit for that same operating environment. The rejection does not require preserving every component of Becerra-Fajardo’s active implant embodiment. Rather, the rejection relies on Becerra-Fajardo for the external burst interrogation and readout architecture and relies on Ivorra for the passive implant circuit. Substituting a known passive rectifier implant circuit into a known external burst-powered interrogation system would have been a predictable use of known components for their known functions.
Applicant’s Argument: Applicant argues that the cited combination fails to teach the amended claim 1 requirement that the variable operational parameter of the transducer modulates a time course of the capacitor discharge through the medium.
Examiner’s Response: This argument is not persuasive in view of the modified rejection. Ivorra supplies the capacitor discharge path by teaching that, after each burst, the capacitor discharges through RD and the tissues until the next burst. Goldshtein supplies the condition-responsive transducer by teaching a pressure-responsive capacitor whose capacitance varies with pressure. In the combined circuit, the discharge time course is governed by the RC relationship, for example τ = C(RD + Rtissue) when the tissue path is modeled as a resistance. Therefore, changing the capacitance C using Goldshtein’s pressure-responsive capacitor predictably changes τ, which is the time course of the capacitor discharge through the medium. Thus, the variable operational parameter of the transducer, namely capacitance, modulates the discharge time course as claimed.
Applicant’s Argument: Applicant argues that Jain is incompatible with the claimed invention because Jain uses optical power delivery, active multi-chip electronics, optical telemetry, and transducers read by onboard potentiostats and processors rather than transducers integrated into a passive discharge network.
Examiner’s Response: Applicant’s arguments directed to Jain have been considered. However, the present rejections have been modified and do not rely on Jain for the amended transducer and discharge-network limitations. The prior reliance on Jain has been superseded by the present combinations. The present rejections rely on the particular teachings of the newly applied or newly emphasized references as set forth in the claim rejections.
Applicant’s Argument: Applicant argues that claim 8 is allowable because the amended claim ties the 10 pF to 10 nF capacitance range and 1 kΩ to 10 MΩ resistance range to a functional sensing mechanism that produces a detectable post-burst voltage decay, and because Ivorra’s 0.6 µF capacitor is outside the claimed capacitance range.
Examiner’s Response: This argument is not persuasive in view of the modified rejection. The rejection does not rely on Ivorra alone for the claimed capacitance range. Ivorra is relied upon for the burst-driven diode/capacitor/discharge architecture and for a discharge resistor in the claimed resistance range. Goldshtein is relied upon for the known pF-scale capacitance-based pressure transducer and exponential charge/discharge behavior through a kΩ resistor. Once Ivorra’s stimulation-oriented capacitor is implemented as Goldshtein’s pressure-responsive MEMS capacitor for sensing, selecting the capacitance and resistance values to produce a detectable post-burst decay is a predictable optimization of the RC time constant, where capacitance and resistance are recognized result-effective variables.
Applicant’s Argument: Applicant argues that Foutz does not teach claim 4 because Foutz’s FET current regulator is an active compliance-voltage-regulated stimulation current source, whereas claim 4 requires a current controlling device that controls passive capacitor discharge during the inter-burst interval.
Examiner’s Response: This argument is not persuasive in view of the modified rejection. Foutz is relied upon for the limited teaching that FET-based current control was known and beneficial in implantable biomedical circuitry for stabilizing current against electrode/tissue load variation. The present rejection further relies on Siliconix for the self-biased FET/JFET current-limiter topology applicable to the inter-burst discharge path. Siliconix teaches a FET constant-current source/current limiter in which the source-gate resistor biases the device and changes in load impedance change the controlled current only by a small factor. Thus, the rejection does not require importing Foutz’s externally powered compliance-voltage regulation or active stimulation-control phase into the passive discharge network.
Applicant’s Argument: Applicant argues that Toumazou does not teach claims 9 and 10 because Toumazou’s ISFET device is a standalone electrochemical sensor read by active circuitry, not a transistor integrated into a passive rectifier implant’s discharge network.
Examiner’s Response: This argument is not persuasive because Toumazou is relied upon for a limited component-level teaching, not for bodily incorporation of Toumazou’s complete active ISFET readout system. The present rejections clarify that claims 9 and 10 use the electronic-component-of-the-discharge-network transducer alternative. Toumazou is relied upon for the teaching that a transistor gate exposed to, or electrically coupled to, a medium through an electrolyte/reference-electrode arrangement has conductance that depends on a medium-related gate voltage, ion-sensitive gate condition, or chemical species concentration. Using such a medium-sensitive transistor as the discharge-network component in the Ivorra discharge path would have predictably caused the capacitor discharge current, discharge time course, or measured electrical response to vary with the local biopotential or chemical species concentration.
Applicant’s Argument: Applicant argues that Colvin does not teach claims 11 to 13 because Colvin is a standalone fluorescent sensor with a dedicated photodetector system, not an optoelectronic transducer integrated into a passive burst-powered implant circuit.
Examiner’s Response: This argument is not persuasive because Colvin is relied upon for the limited teaching of known optoelectronic sensing elements and optical materials, not for bodily incorporation of Colvin’s complete sensor housing or complete signal-processing architecture. Becerra-Fajardo and Ivorra supply the burst-powered implant and capacitor charge/discharge framework. Incorporating Colvin’s LED, optical material, photodetector, and optical filter teachings into the Ivorra discharge-network framework is a component-level modification that preserves the passive burst-powered architecture. The present rejections also clarify the distinct structures of claims 11 and 12. For claim 11, the LED serves the dual role of the device of asymmetric conductance and the light source. For claim 12, the LED is part of the discharge network. Claim 13 further recites optical filters, which are also supplied by Colvin.
Applicant’s Argument: Applicant argues that claim 14 is allowable because Edmonson and Najafi do not cure the deficiencies alleged with respect to the base combination.
Examiner’s Response: This argument is not persuasive in view of the modified rejection and for the reasons stated above regarding claim 1. The present rejection has been modified and no longer relies on Najafi for the pressure-sensing capacitor aspect. Goldshtein is relied upon for the capacitance-based blood-pressure sensor, and Edmonson is relied upon for vascular deployment and flexible anchoring electrode structures.
Applicant’s Argument: Applicant argues that claim 15 is not taught because Foutz is architecturally incompatible with the claimed passive implant, and Miller merely lists JFETs without teaching a JFET current limiter with an integrated resistive transducer in a passive volume-conduction-activated implant discharge path.
Examiner’s Response: This argument is not persuasive in view of the modified rejection. The present rejection does not rely on Miller for the specific current-limiter topology. Siliconix is relied upon for the self-biased FET/JFET current source/current limiter in which the source-gate resistor sets the regulated current. Foutz is relied upon only for the general teaching that FET-based current control was known and beneficial in implantable biomedical circuitry. Siliconix supplies the passive self-biased topology applicable to the inter-burst discharge path, and using a resistive transducer as the source-gate resistor would have predictably caused the controlled current to depend on the transducer parameter.
Applicant’s Argument: Applicant argues that claims 17 to 19 are allowable because Potyrailo is directed to frequency-domain RFID impedance spectroscopy and does not teach the amended time-domain exponential models or nonlinear diode unbalance model recited in claims 17 to 19.
Examiner’s Response: This argument is not persuasive in view of the modified rejections. The present rejections do not rely on Potyrailo alone for the amended mathematical models. For claims 17 and 18, Besling supplies the RC time-constant and exponential charge/discharge teachings. Ivorra supplies the during-burst capacitor charging window for claim 17 and the post-burst capacitor discharge window for claim 18. For claim 19, Becerra-Fajardo and Ivorra supply the positive/negative semicycle and diode rectification teachings, while the nonlinear diode current-voltage relationship is the ordinary model of the device of asymmetric conductance. Potyrailo is relied upon only as supplemental support for reader-side model-based processing of measured electrical responses into characteristic values and measurements.
Applicant’s Argument: Applicant argues that claim 17 is patentable because the claimed burst-current amplitude decay model ipeak(t) = Ke^(-t/τ) arises from RC charging dynamics of the passive half-wave rectifier implant, not from Potyrailo’s frequency-domain resonance measurements.
Examiner’s Response: This argument is not persuasive in view of the modified rejection. Besling teaches time-constant measurement of charge or discharge through a known resistor and teaches exponential capacitor charging behavior. In the corresponding RC charging circuit, charging current decreases as the capacitor charges and is expressible as ipeak(t) = Ke^(-t/τ). Ivorra supplies the burst-time charging behavior by teaching rectified current flowing through the diode to charge the capacitor during the burst, and Becerra-Fajardo supplies the external readout path for measuring current-related waveform information.
Applicant’s Argument: Applicant argues that claim 18 is patentable because the claimed post-burst voltage decay model v(t) = Ke^(-t/τ) arises from discharge of the capacitor through the discharge network and medium, which is foreign to Potyrailo’s frequency-domain resonance approach.
Examiner’s Response: This argument is not persuasive in view of the modified rejection. Besling teaches that when a charged capacitor discharges through a resistor, charge and voltage decay with the same time constant. The claimed formula v(t) = Ke^(-t/τ) is the ordinary mathematical expression of that RC voltage decay. Ivorra supplies the post-burst discharge condition by teaching that after the burst the capacitor discharges through RD and tissues, causing a current of opposite sign that slowly diminishes. Extending the Becerra-Fajardo external readout window to capture the post-burst interval would have been an obvious processing adaptation because the same external electrodes and sensing pathway remain coupled to the same tissue volume after burst cessation.
Applicant’s Argument: Applicant argues that claim 19 is patentable because the claimed current unbalances arise from nonlinear behavior of the asymmetric-conductance device and are fitted to a nonlinear model of that device, whereas Potyrailo relies on linear passive impedance spectroscopy.
Examiner’s Response: This argument is not persuasive in view of the modified rejection. The rejection identifies the device of asymmetric conductance as the diode in the Becerra-Fajardo/Ivorra implant architecture. Becerra-Fajardo teaches detecting positive and negative peaks, and Ivorra teaches half-wave rectification and rectified current flow through the diode during the burst. The current unbalance between positive and negative semicycles arises from the nonlinear asymmetric conduction of the diode. Delivering bursts of different amplitude would have been an obvious way to sample multiple operating points of the nonlinear diode response. The diode’s nonlinear current-voltage relationship, commonly expressed by the Shockley diode equation or an equivalent nonlinear diode relation, is the ordinary model of the asymmetric-conductance device. Fitting recorded amplitude-dependent semicycle current unbalances to that model would have allowed a characteristic value affected by the implant circuit and medium path to be calculated.
Applicant’s Argument: Applicant argues that claim 20 is allowable for at least the same reasons as claim 1.
Examiner’s Response: This argument is not persuasive for the reasons stated above regarding claim 1.
For at least the reasons above, Applicant’s arguments do not overcome the rejections under 35 U.S.C. 103. The rejections are maintained.
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
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/AARON MERRIAM/Examiner, Art Unit 3791
/MATTHEW KREMER/Primary Examiner, Art Unit 3791
Prosecution Insights