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 1/15/2026, 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 1/15/2026.
Claims 1-20 are the currently pending claims hereby under examination.
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
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 1-5 and 13-18 are rejected under 35 U.S.C. 103 as being unpatentable over Barat et al. (Barat, David et al. “Simultaneous High Speed Optical and Impedance Analysis of Single Particles with a Microfluidic Cytometer.” Lab on a chip 12.1 (2012): 118–126. Web.), hereto referred as Barat, and further in view of Elbadry et al. (US 20190358387 A1), hereto referred as Elbadry.
Regarding claim 1, with respect to a system for characterizing an effluent sample from a patient undergoing peritoneal dialysis (PD), Barat teaches a microfluidic cytometer that measures optical extinction/side-scatter and electrical impedance of particles flowing through a sealed microchannel, using a laser light source, photomultipliers, and pairs of electrodes with lock‑in detection; the signals are captured and analyzed in software (Barat, FIG. 1, Abstract). However, Barat does not expressly disclose that the sample is PD effluent or that the system is used to characterize PD dialysate.
Elbadry teaches patient monitoring devices in PD that receive drained dialysate and measure effluent fluid characteristics including optical scatter, absorption, color, conductivity, cell count, and related parameters, and further teaches controller/processor analysis of the sensor signals (Elbadry, ¶[0026], ¶[0116]–[0121]; ¶[0063] and ¶[0369]). Elbadry’s disclosures show PD-specific application contexts and sensor modalities that directly correspond to the sensor measurements performed in Barat (including optical and capacitive electrode based) (Elbadry, ¶[0013]; ¶[0022]; ¶[0009]; ¶[0219]).
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 Barat in view of Elbadry to adapt Barat’s optical/electrical measurement channel to characterize PD effluent flowing in-line with a PD drainage conduit. The combination would have been feasible because Barat’s sealed microchannel with integrated optical path and electrode pairs can be implemented as an inline sensing region or sampling cell within or attached to a PD fluid conduit, and Elbadry expressly teaches PD systems with optical and electrical sensing of dialysate characteristics and processor-based analysis. A person of ordinary skill in the art would have been motivated to apply Barat’s simultaneous optical and impedance sensing to PD effluent to enable real‑time characterization (e.g., turbidity/optical scatter for cell content and impedance/imaginary component related to ionic content) during PD, improving early detection of complications and enabling automated monitoring. The benefit of the combination would be enhanced, real‑time PD effluent assessment using a compact, integrated sensor that jointly analyzes optical and electrical responses for robust characterization.
For the remainder of the claim 1 limitations below, Barat teaches the recited structural features; per the obviousness bridge above, the term “sample” in Barat corresponds to the claimed PD effluent.
Also regarding claim 1, Barat teaches that the system comprises: a container for enclosing the effluent sample (Barat. FIG, 1, p. 119, System Overview: “Pairs of wafers were aligned and bonded using a thermo-compression technique to form sealed microfluidic structures”, shows a sealed channel structure functioning as a container for the fluid sample; p. 120, Beads/microfluidic chip: “Fluidic connections were made by clamping the chip within a block machined from PEEK. The block uses a gasket to seal to the glass chip”, shows a sealed assembly enclosing fluid during measurement; (which also corresponds to the PD effluent per the obviousness bridge above)); an optical system comprises a light source and a photodetector, the light source configured to emit a beam of radiation that passes through the container and irradiates the effluent sample, and the photodetector configured to detect the radiation after it irradiates the effluent sample to generate an optical signal (Barat, FIG. 1-2; p. 120, Optical system: “Light from a 532 nm, 20 mW solid-state laser was launched into the incident light fibre”, teaches a light source launching light into the channel region; p. 120, Optical system: “The detection fibres were coupled to photomultipliers”, teaches photodetectors coupled to collect optical signals; p. 121, Integrated optics: “Light passing through the microfluidic channel… The two sharp dips in intensity occur because the impedance electrodes obscure the light in these regions”, shows the beam passing through the container/channel and interacting with the sample region; 120, Measurement principle: “A 7° fibre was used to measure the optical extinction (EX) signal”, shows detection of an optical signal generated by passage/irradiation of the sample; (which also corresponds to the PD effluent per the obviousness bridge above)); an electrical system comprises a first pair of electrodes and a second pair of electrodes, wherein the first pair of electrodes and second pair of electrodes are attached to the container and configured to measure a capacitance of the effluent sample to generate a capacitance signal (Barat, FIG. 1; p. 119, Measurement principle: "Two pairs of electrodes are fabricated on the top and bottom of the channel, forming a differential measurement system”, teaches first and second electrode pairs attached to the channel/container; p. 121, Impedance system: “The output from the lock-in consists of the real component (in phase) and imaginary component (90° out of phase) of the impedance”, shows that the electrical measurement includes the imaginary (capacitive) component of impedance, which corresponds to a capacitance-derived signal; One of ordinary skill in the art would understand that the imaginary component of impedance corresponds to the capacitive response of the sample, such that Barat’s impedance represents a capacitance-derived signal, especially at the high frequencies that Barat’s system is driven at (Barat, p. 119, Measurement principle: “1 MHz"); (which corresponds to the PD effluent per the obviousness bridge above)); and a processor operating an algorithm configured to collectively process the optical signal and the capacitance signal to characterize the effluent sample (Barat: p. 120-121, Optical system and Impedance system: “captured and analysed with software written in Matlab and LabVIEW”, shows processor/software analysis of acquired signals; p. 119, System overview: "Particles are hydrodynamically focused into the middle of the channel, passing through the detection region where their electrical and optical properties are measured”, shows concurrent acquisition enabling collective processing of optical and electrical signals, FIG. 3: “Scatter plots for fluorescent 15 μm beads… fluorescence vs. impedance… side scatter signal vs. impedance”, shows combined analysis of optical and electrical signals; (which also corresponds to the PD effluent per the obviousness bridge above)).
Regarding claim 2, Barat teaches that the container is a sample cell comprising at least two surfaces (Barat, p. 119: “The microfluidic chips were fabricated using photolithography and full wafer thermal bonding… Two SU-8 layers (one on each wafer) were each 40 μm thick, giving a total channel depth of 80 μm… Pairs of wafers were aligned and bonded… to form sealed microfluidic structures”, shows a bonded sample cell formed by two wafers/layers providing at least two surfaces enclosing the sample; FIG. 1: depicts the sample cell with at least two sides).
Regarding claim 3, Barat teaches that each surface of the sample cell comprises an optically transparent material (Barat, p. 119-120, Measurement principle: “Details of the optics are shown in Fig. 1(e). A groove in the SU-8 holds a fibre which launches incident light perpendicular to the channel. This light is focused into a sheet across the width of the channel using an air compound lens”, teaches that SU-8 structures form the optical path components and allow light to traverse the sample region, supporting that the sample cell surfaces participating in the optical path are optically transmissive; Barat, Fig. 1e: “the refractive index of SU-8 and water are at 532 nm”, shows that SU-8’s optical properties at the operating wavelength are explicitly considered, consistent with SU-8 being optically transmissive at the laser wavelength; p. 119, System overview: “SU-8 resist was used to define the fluidic channel, grooves for the fibres and the air lens”, teaches that SU-8 defines the channel walls and integrated optical features through which the beam is launched and collected, supporting that the surfaces are made of optically transmissive material; p. 119: “Photograph of a chip fabricated from glass and SU-8”, confirms that the sample cell is formed of glass and SU-8, both used in the optical pathway and both are optically transparent for the intended purpose).
Regarding claim 4, Barat teaches that the optically transparent material is selected from a group consisting of glass, plastic, ceramic, diamond-based material, or derivatives thereof (Barat, p. 119, System overview: “SU-8 resist was used to define the fluidic channel, grooves for the fibres and the air lens”, teaches that SU-8 forms the channel walls and integrated optical features that guide light through the detection region, reading on plastic within the claimed group; p. 120, Measurement principle: “Details of the optics are shown in Fig. 1(e). A groove in the SU-8 holds a fibre which launches incident light perpendicular to the channel”, shows that the optical path is implemented within SU-8 features that transmit and direct the incident light across the sample region, reading on plastic within the claimed group; p. 119, System overview: “Metal electrodes consisting of 200 nm thick platinum with a 20 nm Ti seed layer were fabricated on 100 mm diameter glass wafers by photolithography”, teaches that the sample cell is built on glass, which is within the claimed group).
Regarding claim 5, Barat teaches that the first pair of electrodes and the second pair of electrodes are a thin film deposited on at least one of the two surfaces (Barat, p. 119, Measurement principle: “Two pairs of electrodes are fabricated on the top and bottom of the channel, forming a differential measurement system”, teaches first and second electrode pairs located on opposing channel surfaces; p. 119, System overview: “Metal electrodes consisting of 200 nm thick platinum with a 20 nm Ti seed layer were fabricated on 100 mm diameter glass wafers by photolithography”, teaches thin-film metal electrodes deposited onto the wafer surface by photolithography, reading on thin film deposited on at least one surface).
Regarding claim 13, Barat teaches that the optical system is further configured to measure an optical absorption of the effluent sample (Barat, p. 120, Measurement principle: “A 7° fibre was used to measure the optical extinction (EX) signal - light loss due to absorption or scatter out of the field of view of the detector when a particle passes through an incident beam”, teaches that the optical system measures light loss due to absorption, which corresponds to measuring optical absorption).
Regarding claim 14, Barat teaches that the light source is configured to emit the beam of radiation that passes into the effluent sample, the photodetector is configured to receive the radiation after it irradiates the effluent sample, and the processor is configured to analyze the radiation after it irradiates the effluent sample and determine the amount of radiation absorbed by the effluent sample (Barat, p. 120, Optical system: “Light from a 532 nm, 20 mW solid-state laser was launched into the incident light fibre”, shows the light source emitting light into the channel region to irradiate the sample; p. 120, Measurement principle: “This light is focused into a sheet across the width of the channel”, shows the emitted beam passes into and across the sample region, p. 120, Optical system: “The detection fibres were coupled to photomultipliers”, teaches photodetectors receiving the radiation after it irradiates the sample; p. 120, Measurement principle: “A 7° fibre was used to measure the optical extinction (EX) signal - light loss due to absorption or scatter out of the field of view of the detector when a particle passes through an incident beam”, teaches that the optical system measures light loss after the light irradiates the sample; the measured reduction in detected light intensity corresponds to the amount of light absorbed by the sample; p. 120-121, Optical system: “The photomultiplier signals were sampled at 120 kHz with a 16-bit A–D card… captured and analysed with software written in Matlab and LabVIEW”, shows processor-based analysis of the detected optical signals to determine scattering; FIG. 1e: depicts a beam of light radiation entering the sample and leaving the sample to be collected for analysis).
Regarding claim 15, Barat teaches that the optical system is further configured to measure an optical scattering caused by the effluent sample (Barat, FIG. 1e; p. 120, Measurement principle: “A 7° fibre was used to measure the optical extinction (EX) signal - light loss due to absorption or scatter out of the field of view of the detector when a particle passes through an incident beam”, shows that the measured light loss includes both absorption and scatter components; therefore, Barat teaches an optical system configured to measure optical scattering caused by the sample).
Regarding claim 16, Barat teaches that the light source is configured to emit the beam of radiation that passes into the effluent sample, the photodetector is configured to receive the radiation after it irradiates the effluent sample, and the processor is configured to analyze the radiation after it irradiates the effluent sample and determine the amount of optical scattering caused by the effluent sample (Barat, p. 120, Optical system: “Light from a 532 nm, 20 mW solid-state laser was launched into the incident light fibre”, shows the light source emitting light into the channel region to irradiate the sample; p. 120, Measurement principle: “This light is focused into a sheet across the width of the channel”, shows the emitted beam passes into and across the sample region, p. 120, Optical system: “The detection fibres were coupled to photomultipliers”, teaches photodetectors receiving the radiation after it irradiates the sample; p. 120, Measurement principle: “A 7° fibre was used to measure the optical extinction (EX) signal - light loss due to absorption or scatter out of the field of view of the detector when a particle passes through an incident beam”, shows that the optical system measures scattering as part of the detected signal, supporting determination of optical scattering; p. 120, Measurement principle: “The chip was designed for two more collection fibres to be placed at 22° and 45°, to measure side scattered light (SSC)”, teaches explicit collection of side scattered light for scattering measurement; p. 120-121, Optical system: “The photomultiplier signals were sampled at 120 kHz with a 16-bit A–D card… captured and analysed with software written in Matlab and LabVIEW”, shows processor-based analysis of the detected optical signals to determine scattering; FIG. 1e: depicts a beam of light radiation entering the sample and leaving the sample to be collected for analysis).
Regarding claim 17, Barat teaches that the electrical system is further configured to measure at least one additional electrical property of the effluent sample (Barat, p. 121, Impedance system: “The output from the lock-in consists of the real component (in phase) and imaginary component (90° out of phase) of the impedance”, teaches that in addition to the capacitive (imaginary) component used for capacitance, the system also resolves the real (resistive) component as an additional electrical property; FIG. 5a, p. 122, Single populations: “A density plot of transit time vs. impedance magnitude for 25 μm diameter beads is shown in Fig. 5(a)”, shows explicit measurement and analysis of impedance magnitude |Z| as an additional electrical property beyond capacitance).
Regarding claim 18, Barat teaches that the processor is further configured to operate an algorithm configured to collectively process the optical signal and the capacitance signal to determine an amount of a compound in the effluent sample. Barat teaches simultaneous optical extinction/side‑scatter and electrical impedance acquisition with software analysis, including combined plots of optical signals versus impedance for particle measurements and reporting of sample concentration (Barat, p. 120–121, Impedance/optics capture; p. 119, System overview; FIG. 3; p. 118, Introduction). However, Barat does not specify collectively processing optical signals with a capacitance‑derived signal to determine an amount of a compound in peritoneal dialysis effluent.
Elbadry teaches PD patient monitoring in which a controller estimates total particle concentration and leukocyte concentration from sensor signal data and lists dialysate characteristics including optical and electrical properties and compound concentrations (Elbadry, ¶[0022]: “A controller may be configured to estimate total particle concentration and leukocyte concentration using the signal data”; ¶[0026]). These disclosures directly address determining amounts of compounds in PD effluent from sensor data and provide the PD‑specific application and processing objective lacking in Barat.
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 Barat and Elbadry in view of Elbadry to collectively process Barat’s optical signals together with the capacitance‑derived component of its impedance signal to determine an amount (e.g., concentration or count) of a compound in PD effluent. The combination would have been feasible because Barat already acquires optical and impedance signals concurrently and analyzes them in software, and Elbadry teaches processor‑based estimation of particle and leukocyte concentrations from sensor signal data in a PD drainage conduit. A person of ordinary skill in the art would have been motivated to implement the combined optical‑capacitance processing in the PD context to quantify clinically relevant compounds such as leukocytes or proteins for infection detection and therapy monitoring, leveraging Barat’s joint optical/electrical sensing while achieving Elbadry’s PD‑specific concentration estimation. The benefit would be robust, quantitative characterization of PD effluent by fusing optical scattering/absorption with capacitance‑sensitive electrical measurements, improving sensitivity and reliability of compound quantification for early complication detection and ongoing dialysis adequacy assessment.
Claims 6-12 and 19-20 are rejected under 35 U.S.C. 103 as being unpatentable over Barat et al. (Barat, David et al. “Simultaneous High Speed Optical and Impedance Analysis of Single Particles with a Microfluidic Cytometer.” Lab on a chip 12.1 (2012): 118–126. Web.), hereto referred as Barat, and further in view of Elbadry et al. (US 20190358387 A1), hereto referred as Elbadry, and further in view of Choi et al. (Choi, Chang K et al. “Opto-Electric Cellular Biosensor Using Optically Transparent Indium Tin Oxide (ITO) Electrodes.” Sensors (Basel, Switzerland) 8.5 (2008): 3257–3270. Web.), hereto referred as Choi.
The combined Barat and Elbadry teaches claim 5 as described above.
Regarding claim 6, the combined Barat and Elbadry does not fully teach that the thin film is a material that is both optically transparent and electrically conductive. Rather, Barat discloses deposited thin‑film electrodes on the channel surfaces and simultaneous optical/electrical measurement (as shown above in claim 5), and shows that the electrodes are used for electrical measurements and are made of material that is electrically conductive (Barat, p. 119, System overview). However, it does not disclose that the electrode thin film is optically transparent. In addition, Barat’s electrode geometry places metal electrodes on the top and bottom of the channel in the optical measurement region and produces optical occlusion in the beam path (Barat, p. 119, Measurement principle: “Two pairs of electrodes are fabricated on the top and bottom of the channel, forming a differential measurement system”; Barat, p. 121, Integrated optics: “Light passing through the microfluidic channel… The two sharp dips in intensity occur because the impedance electrodes obscure the light in these regions”).
Choi teaches an indium tin oxide (ITO) thin film electrode that is explicitly transparent and electrically conductive. Choi’s ITO thin film (100 nm thick) deposition demonstrates a transparent conductive layer compatible with optical transmission, as shown in Fig. 2 where the light beam passes through the electrode region (Choi, p. 3258-3259, Sec 2.1; p. 3266, Sec 3.3). This directly addresses Barat’s occlusion by placing a transparent conductive electrode in the optical path, allowing the light to traverse the electrode region while maintaining electrical functionality.
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 Barat and Elbadry in view of Choi to implement the channel electrodes as transparent, electrically conductive ITO thin films, thereby relocating or substituting Barat’s opaque top/bottom electrodes with transparent ITO at the optical measurement plane so that the optical path passes through the electrode region while preserving electrical measurement. The combination is feasible because Barat already fabricates thin‑film electrodes on glass/SU‑8 using standard microfabrication, and Choi demonstrates ITO thin‑film deposition on glass using compatible sputter and patterning processes. The benefit is a unified, co‑located sensing interface that eliminates optical occlusion at the measurement plane and enables simultaneous optical interrogation and electrical sensing with improved integration, transparency, and signal quality.
Regarding claim 7, as shown above in claim 6, the combined Barat, Elbadry, and Choi already teach that the thin film is composed primarily of one of gold, In2O5Sn, or derivatives thereof. Specifically, the combined Barat, Elbadry, and Choi use an optically transparent thin film made of indium tin oxide (ITO) (Choi, p. 3258, Sec 1). 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 Barat in view of Choi to implement the thin-film electrodes as indium–tin–oxide (ITO) to satisfy the claimed composition, using the same thin-film deposition and patterning workflows as Barat; this substitution is feasible and provides transparent, conductive electrodes that improve the optical path through the measurement region.
Regarding claim 8, the combined Barat, Elbadry, and Choi partially teaches a first surface of the at least two surfaces comprises the first pair of electrodes, which is a first optically transparent electrode pair, and wherein a second surface of the at least two surfaces comprises the second pair of electrodes, which is a second optically transparent electrode pair. Barat discloses a first and second electrode pair on opposing channel surfaces (perpendicular from the light beam penetrating surfaces) but these electrodes partially obstruct the light path and are not transparent (Barat, p. 119: “Two pairs of electrodes are fabricated on the top and bottom of the channel, forming a differential measurement system”; Barat, p. 121 (Fig. 2(c) context): “The two sharp dips in intensity occur because the impedance electrodes obscure the light in these regions”). In Barat, the optical sheet is launched across the channel so that the beam traverses the SU‑8 sidewalls in the measurement region. Barat does not disclose optically transparent, electrically conductive electrodes at those SU‑8 sidewalls or any reconfiguration to eliminate the occlusion at the measurement plane.
Choi teaches implementing electrodes as a 100 nm indium tin oxide (ITO) thin film on a surface through which light is transmitted, with images through the ITO film comparable to bare glass (Choi, FIG. 1: “A 90 % In2O3/10 % SnO2 100 nm layer was sputter coated onto a slide glass”; FIG. 4: “All the microscopic images through the ITO film are comparable to those of a bare glass surface”). This demonstrates a transparent, electrically conductive thin‑film electrode positioned directly in the optical path. Building on the geometric configuration established in Claim 6, the combination applies Choi’s electrode material and placement such that the electrodes are on the surfaces that the optical beam traverses (Choi, FIG. 1-2). The substitution relocates the optically transparent ITO thin‑film electrodes into the optical path, aligning the electrode surfaces with the direction of beam propagation. This preserves Barat’s paired‑electrode architecture but adopts Choi’s planar ITO configuration to enable co‑located optical and electrical sensing through the same transparent surfaces.
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 Barat in view of Choi to form the first and second electrode pairs as transparent, electrically conductive ITO thin‑film electrodes on the SU‑8 sidewalls that the beam traverses, so the optical path passes through the electrode regions on those same SU‑8 surfaces while maintaining electrical functionality. The combination is feasible because Barat already employs thin‑film microfabrication on glass/SU‑8, and Choi demonstrates sputtered ITO thin films compatible with the same process flows. The benefit is elimination of occlusion at the measurement plane and co‑located optical/electrical sensing through the same SU‑8 sidewall electrodes, improving alignment, integration, and signal quality.
Regarding claim 9, the combined Barat, Elbadry, and Choi teaches that the light source is configured to emit the beam of radiation that passes through the first optically transparent electrode pair and into the effluent sample, and the photodetector is configured to receive the radiation after it irradiates the effluent sample and then passes through the second optically transparent electrode pair. As shown above in claim 8, Barat teaches optical transmission across the channel but its electrodes in the beam path are opaque, causing occlusion. Choi teaches a transparent, electrically conductive ITO thin film electrode through which transmitted imaging is performed.
Consistent with the geometry established in Claim 8, the first and second electrode pairs are implemented as transparent ITO thin-film electrodes on the SU-8 sidewalls that the beam traverses.
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 Barat, Elbadry, and Choi in view of Choi to position transparent, electrically conductive ITO thin-film electrode pairs on the SU-8 sidewalls in the optical path, such that Barat's emitted beam passes through the first transparent electrode pair into the sample and, after irradiating the sample, passes through the second transparent electrode pair to the detector, thereby eliminating Barat’s occlusion while maintaining electrical functionality and enabling integrated opto-electric sensing.
Regarding claim 10, the combined Barat, Elbadry, and Choi partially teaches that the electrical system comprises a capacitor comprising two capacitor electrodes, wherein the first optically transparent electrode pair is a first capacitor electrode pair, and the second optically transparent electrode pair is a second capacitor electrode pair. Barat teaches opposing electrode pairs that function as capacitor electrodes across the sample and includes the capacitive (imaginary) component in the impedance measurement (as shown above in claim 1), but it does not teach that those capacitor electrodes are optically transparent.
Choi teaches a transparent, electrically conductive ITO thin film through which a light beam traverses, evidencing optical transmission through the electrode region (as shown above in claim 9).
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 Barat, Elbadry, and Choi in view of Choi to implement the first and second capacitor electrode pairs as transparent ITO thin-film electrodes on the SU-8 sidewalls, thereby maintaining their capacitor-electrode function while allowing the optical beam to pass through those electrode regions. This is feasible because Barat already fabricates thin-film electrodes and measures the capacitive component with lock-in detection, and Choi demonstrates transparent ITO thin films compatible with microfabrication on glass. The benefit is simultaneous optical transmission through both capacitor electrode pairs with robust capacitive sensing across the sample, improving co-located opto-electric measurement and eliminating occlusion.
Regarding claim 11, the combined Barat and Elbadry does not fully teach that both the first pair of electrodes and second pair of electrodes comprise an optically transparent opening. Barat teaches paired electrodes positioned on opposing channel surfaces in the optical measurement region and shows that these electrodes cause partial optical occlusion in the beam path, but Barat does not disclose that the electrode structures include an optically transparent opening or otherwise permit optical transmission through the electrode regions (as shown above in claim 1; Barat, p. 121, Integrated optics: “Light passing through the microfluidic channel… The two sharp dips in intensity occur because the impedance electrodes obscure the light in these regions”).
Choi teaches an indium tin oxide (ITO) thin film electrode that is explicitly transparent and electrically conductive. Choi’s ITO thin film (100 nm thick) deposition demonstrates a transparent conductive layer compatible with optical transmission, as shown in Fig. 2 where the light beam passes through the electrode region (Choi, p. 3258-3259, Sec 2.1; p. 3266, Sec 3.3). This directly addresses Barat’s occlusion by placing a transparent conductive electrode in the optical path, allowing the light to traverse is optically transparent (i.e. open) electrode region (i.e. optically transparent opening) while maintaining electrical functionality.
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 Barat and Elbadry in view of Choi to implement the electrode pairs with an optically transmissive ITO region along the optical path so that, in functional effect, each electrode structure comprises an optically transparent opening through which the beam passes. The combination is feasible because Barat already employs thin‑film microfabrication on glass/SU‑8 surfaces, and Choi demonstrates sputtered, patterned ITO thin films on surfaces that are compatible with optical light transmission. The benefit is elimination of electrode‑induced occlusion at the measurement plane while preserving electrical sensing, thereby improving co‑located opto‑electric characterization and alignment of the optical and electrical interrogation regions.
Regarding claim 12, the combined Barat, Elbadry, and Choi partially teaches that the light source is configured to emit the beam of radiation that passes through a first optically transparent opening in the first pair of electrodes and into the effluent sample, and the photodetector is configured to receive the radiation after it irradiates the effluent sample and then passes through a second optically transparent opening in the second pair of electrodes. Barat discloses the optical beam launched into the channel and simultaneous impedance sensing but shows that electrodes in the optical region are opaque and obscure light, and does not teach that the beam passes through optically transparent openings in electrode pairs at both the incident and exit sides (as shown above in claim 11, see also Barat, FIG. 1).
Choi teaches optically transparent, electrically conductive ITO electrodes that allow light transmission through the electrode region, filling the deficiency in Barat (as shown above in claim 11, see also Choi FIG. 1-2).
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 Barat, Elbadry, and Choi in view of Choi to implement the first and second electrode pairs as transparent ITO thin‑film electrodes positioned along the incident and exit optical paths so that the emitted beam passes through the first electrode region into the sample and, after irradiating the sample, passes through the second electrode region to the detector. The combination is feasible because Barat already uses thin‑film microfabrication on glass/SU‑8 surfaces in the detection region, and Choi demonstrates sputtered, patterned ITO thin film deposition that allows optical transmission while providing electrical functionality as electrodes. The benefit is elimination of electrode‑induced occlusion while enabling co‑located optical/electrical sensing through the same electrode regions, improving alignment and signal integrity.
Regarding claim 19, with respect to a system for characterizing an effluent sample from a patient undergoing peritoneal dialysis (PD), Barat teaches a microfluidic cytometer that measures optical extinction/side-scatter and electrical impedance of particles flowing through a sealed microchannel, using a laser light source, photomultipliers, and pairs of electrodes with lock‑in detection; the signals are captured and analyzed in software (Barat, FIG. 1, Abstract). However, Barat does not expressly disclose that the sample is PD effluent or that the system is used to characterize PD dialysate.
Elbadry teaches patient monitoring devices in PD that receive drained dialysate and measure effluent fluid characteristics including optical scatter, absorption, color, conductivity, cell count, and related parameters, and further teaches controller/processor analysis of the sensor signals (Elbadry, ¶[0026], ¶[0116]–[0121]; ¶[0063] and ¶[0369]). Elbadry’s disclosures show PD-specific application contexts and sensor modalities that directly correspond to the optical and electrical property measurements performed in Barat (Elbadry, ¶[0013]; ¶[0022]; ¶[0009]; ¶[0219]).
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 Barat in view of Elbadry to adapt Barat’s optical/electrical measurement channel to characterize PD effluent flowing in-line with a PD drainage conduit. The combination would have been feasible because Barat’s sealed microchannel with integrated optical path and electrode pairs can be implemented as an inline sensing region or sampling cell within or attached to a PD fluid conduit, and Elbadry expressly teaches PD systems with optical and electrical sensing of dialysate characteristics and processor-based analysis. A person of ordinary skill in the art would have been motivated to apply Barat’s simultaneous optical and impedance sensing to PD effluent to enable real‑time characterization (e.g., turbidity/optical scatter for cell content and impedance/imaginary component related to ionic content) during PD, improving early detection of complications and enabling automated monitoring. The benefit of the combination would be enhanced, real‑time PD effluent assessment using a compact, integrated sensor that jointly analyzes optical and electrical responses for robust characterization.
For the limitations below, Barat teaches the recited structural features; per the obviousness bridge above, the term “sample” in Barat corresponds to the claimed PD effluent.
Also regarding claim 19, Barat teaches that a container for enclosing the effluent sample (Barat. FIG, 1, p. 119, System Overview: “Pairs of wafers were aligned and bonded using a thermo-compression technique to form sealed microfluidic structures”, shows a sealed channel structure functioning as a container for the fluid sample; p. 120, Beads/microfluidic chip: “Fluidic connections were made by clamping the chip within a block machined from PEEK. The block uses a gasket to seal to the glass chip”, shows a sealed assembly enclosing fluid during measurement; (which also corresponds to the PD effluent per the obviousness bridge above)); and a processor operating an algorithm configured to collectively process the optical property and the electrical property to characterize the effluent sample (Barat: p. 120-121, Optical system and Impedance system: “captured and analysed with software written in Matlab and LabVIEW”, shows processor/software analysis of acquired signals; p. 119, System overview: "Particles are hydrodynamically focused into the middle of the channel, passing through the detection region where their electrical and optical properties are measured”, shows concurrent acquisition enabling collective processing of optical and electrical signals, FIG. 3: “Scatter plots for fluorescent 15 μm beads… fluorescence vs. impedance… side scatter signal vs. impedance”, shows combined analysis of optical and electrical signals; see also p. 118, Introduction;(which also corresponds to the PD effluent per the obviousness bridge above)).
Also regarding claim 19, the combined Barat and Elbadry partially teaches that an electrical system comprises a first pair of electrodes and a second pair of electrodes, with both the first pair of electrodes and second pair of electrodes: comprising a portion that is optically transparent, attached directly to the container, and configured to measure an electrical property of the effluent sample. Specifically, Barat discloses two electrode pairs fabricated on the channel surfaces and used for electrical measurements but shows that these electrodes partially obstruct light and are not transparent in the optical region (Barat, p. 119, Measurement principle; p. 121, Integrated optics; FIG. 2).
Choi teaches optically transparent, electrically conductive ITO thin‑film electrodes formed on glass and demonstrates optical transmission through the electrode area with images comparable to bare glass (Choi, FIG. 1-2, 4; p. 3258-3259, 2.1; p. 3266, Sec 3.3).
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 Barat and Elbadry in view of Choi to implement the first and second electrode pairs as ITO thin‑film electrodes that include an optically transparent portion in the optical path while remaining attached to the channel surfaces to measure electrical properties. The combination would have been feasible because Barat already employs thin‑film microfabrication and lock‑in impedance measurement, and Choi demonstrates sputtered ITO films compatible with optical transmission and electrical sensing. The benefit would be elimination of optical occlusion at the measurement region and improved co‑located opto‑electric sensing enabling light to pass through the electrode regions while maintaining electrical measurement.
Also regarding claim 19, the combined Barat, Elbadry, and Choi partially teaches that an optical system comprises a light source and a photodetector, the light source configured to emit a beam of radiation that passes through the first pair of electrodes and irradiates the effluent sample, and the photodetector configured to detect the radiation after it irradiates the effluent sample and passes through the second pair of electrodes to generate an optical property of the effluent sample. Barat teaches launching and detecting light across the channel while measuring impedance with electrode pairs but shows opaque electrodes that obscure the beam where they cross the optical path (Barat, p. 120–121, Details of the optics, Optical system, and Integrated optics).
Choi teaches transparent, conductive ITO electrodes through which transmitted optical imaging is performed, evidencing that a beam can pass through the electrode region on both entry and exit sides (Choi, p. 3268, Discussion; p. FIG. 4).
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 Barat, Elbadry, and Choi in view of Choi to configure the optical path to pass through a first transparent electrode pair into the sample and, after irradiation, through a second transparent electrode pair to the detector. The combination would have been feasible because Barat’s electrode locations and optical grooves enable co‑located opto‑electric geometry, and Choi’s ITO thin films provide transparent, conductive electrode regions at the optical plane. The benefit would be a unified optical/electrical interrogation region without occlusion, improving alignment and measurement quality for jointly acquired optical properties.
Regarding claim 20, with respect to a system for measuring leukocytes from an effluent sample from a patient undergoing peritoneal dialysis (PD), Barat teaches a microfluidic cytometer that measures optical extinction/side-scatter and electrical impedance of particles flowing through a sealed microchannel, using a laser light source, photomultipliers, and pairs of electrodes with lock‑in detection; the signals are captured and analyzed in software (Barat, FIG. 1, Abstract). However, Barat does not disclose measuring leukocytes in a PD effluent context.
Elbadry teaches PD dialysate monitoring in which sensor arrangements (including optical and electrode based) generates signal data that a controller uses to estimate leukocyte concentration of patient fluid flowing in a conduit (Elbadry, ¶[0013]; ¶[0022]; ¶[0009]; ¶[0219]).
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 Barat in view of Elbadry to apply Barat’s joint optical/impedance measurement channel to PD effluent to measure leukocytes by estimating leukocyte concentration from optical signal data while concurrently acquiring electrical measurements. The combination would have been feasible because Barat already captures and analyses optical and electrical signals in software, and Elbadry provides the PD application and leukocyte estimation objective using optical characteristics in a drain conduit. The benefit would be clinically relevant leukocyte monitoring in PD effluent for early detection of peritonitis and therapy tracking.
For the limitations below, Barat teaches the recited structural features; per the obviousness bridge above, the term “sample” in Barat corresponds to the claimed PD effluent.
Also regarding claim 20, Barat teaches that a container for enclosing the effluent sample (Barat. FIG, 1, p. 119, System Overview: “Pairs of wafers were aligned and bonded using a thermo-compression technique to form sealed microfluidic structures”, shows a sealed channel structure functioning as a container for the fluid sample; p. 120, Beads/microfluidic chip: “Fluidic connections were made by clamping the chip within a block machined from PEEK. The block uses a gasket to seal to the glass chip”, shows a sealed assembly enclosing fluid during measurement; (which also corresponds to the PD effluent per the obviousness bridge above)); and a processor operating an algorithm configured to collectively process the optical signal and the electrical signal to characterize the effluent sample(Barat: p. 120-121, Optical system and Impedance system: “captured and analysed with software written in Matlab and LabVIEW”, shows processor/software analysis of acquired signals; p. 119, System overview: "Particles are hydrodynamically focused into the middle of the channel, passing through the detection region where their electrical and optical properties are measured”, shows concurrent acquisition enabling collective processing of optical and electrical signals, FIG. 3: “Scatter plots for fluorescent 15 μm beads… fluorescence vs. impedance… side scatter signal vs. impedance”, shows combined analysis of optical and electrical signals; see also p. 118, Introduction;(which also corresponds to the PD effluent per the obviousness bridge above)).
Also regarding claim 20, the combined Barat and Elbadry partially teaches that an electrical system comprises a first pair of electrodes and a second pair of electrodes, with both the first pair of electrodes and second pair of electrodes being optically transparent and attached directly to the container, with the first pair of electrodes configured to induce an electrical current into the effluent sample, and the second pair of electrodes configured to measure an electrical signal of the effluent sample that depends on the electrical current that is induced into the sample. Specifically, Barat discloses two electrode pairs on the channel for impedance measurement and describes applying AC voltages to one pair and measuring the resulting signal with a lock‑in amplifier, indicating drive and sense functionality, but shows opaque electrodes that partially obscure light at the optical region (Barat, FIG.1, p. 119, Measurement principle; p. 121, Integrated optics; FIG. 2).
Choi teaches transparent, conductive ITO electrodes that support driven current and lock‑in voltage measurement while allowing light transmission through the electrode region (Choi, FIG. 1-2, 4; p. 3258-3259, 2.1; p. 3266, Sec 3.3).
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 Barat and Elbadry in view of Choi to implement the first and second electrode pairs as transparent ITO thin‑film electrodes attached directly to the container, with the first pair providing the drive current and the second pair measuring the resulting electrical signal. The combination would have been feasible because Barat already uses thin‑film electrodes and lock‑in detection, and Choi provides compatible ITO thin‑film electrodes exhibiting optical transparency and impedance measurement capability in the light beam path. The benefit would be co‑located opto‑electric sensing without optical occlusion while preserving a drive/sense electrode configuration for robust electrical measurements.
Also regarding claim 20, the combined Barat, Elbadry, and Choi partially teaches that an optical system comprises a light source and a photodetector, the light source configured to emit a beam of radiation that passes through one of the first pair of electrodes or second pair of electrodes and irradiates the effluent sample, and the photodetector configured to detect the radiation after it irradiates the effluent sample and passes through one of the first pair of electrodes and second pair of electrodes to generate an optical signal. Barat teaches launching and detecting light across the channel while measuring impedance with electrode pairs but shows opaque electrodes that obscure the beam where they cross the optical path (Barat, p. 120–121, Details of the optics, Optical system, and Integrated optics).
Choi teaches transparent, conductive ITO electrodes through which light beams are transmitted, evidencing that a beam can pass through the electrode region on both entry and exit sides (Choi, p. 3268, Discussion; p. FIG. 4).
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 Barat, Elbadry, and Choi in view of Choi to configure the optical path to pass through a first transparent electrode pair into the sample and, after irradiation, through a second transparent electrode pair to the detector. The combination would have been feasible because Barat’s electrode locations and optical grooves enable co‑located opto‑electric geometry, and Choi’s ITO thin films provide transparent, conductive electrode regions at the optical plane. The benefit would be a unified optical/electrical interrogation region without occlusion, improving alignment and measurement quality for jointly acquired optical properties.
Response to Arguments
Objections
Applicant's arguments filed 1/15/2026, page 7, regarding the previous Objections of claims 7-8 and 19-20 have been fully considered and are persuasive. The previous Objections have been withdrawn.
35 U.S.C. §103
Applicant's arguments filed 1/15/2026, pages 8-9, regarding the previous 103 Rejections of claims 1-20 have been fully considered but are not persuasive. Specifically:
Argument. The Office Action relies on Barat for the claimed opto-electrical characterization system, and relies on Elbadry for the PD effluent application. Applicant argues that the combination would not have been made because Barat's microfluidic cytometer is designed for single particle analysis and a small microchannel with 1-D hydrodynamic focusing and sheath flow conditions, which applicant contends are incompatible with PD drain-line use and expected PD effluent volumes and flow conditions.
Response. The argument is not persuasive because it is premised on limitations that are not recited in claim 1 and on an unduly narrow interpretation of the Office’s rationale. Claim 1 recites a system for characterizing an effluent sample from a patient undergoing peritoneal dialysis, including a container enclosing the effluent sample, an optical system configured to irradiate the effluent sample through the container and generate an optical signal, an electrical system with electrode pairs attached to the container and configured to measure capacitance of the effluent sample, and a processor configured to collectively process the optical and capacitance signals to characterize the effluent sample. Claim 1 does not require that an entire PD drainage volume traverse the container, does not require a particular flow rate, and does not recite hydrodynamic focusing or sheath flow. Accordingly, Applicant’s reliance on Barat’s example microchannel dimensions and example flow regime does not limit the scope of the claim system. As stated in the Office Action, the modification was that Barat’s measurement channel “can be implemented as an inline sensing region or sampling cell within or attached to a PD fluid conduit" (Non-Final OA, 10/24/2025, 103 Rejection, Claim 1, p. 4-5). In this modification, Barat’s sealed microfluidic measurement structure remains the claimed “container” that encloses the effluent sample at the sensing region, while the PD drainage conduit provides the fluid pathway that delivers PD effluent to and through the container. The Office’s use of the term “in-line” in this context was intended to denote integration of the sealed measurement channel into the PD drainage flow path, rather than requiring adoption of Barat’s specific example flow conditions or single particle cytometry configuration to the system at large. Elbadry provides the PD effluent monitoring context and motivation, while Barat provides a working opto-electrical measurement container and signal processing arrangement. The proposed modification applies Barat’s known opto-electrical characterization architecture to the PD effluent context taught by Elbadry and does not require importing Barat’s specific example operating parameters into the claim.
Argument. Applicant further argues that it would not have been feasible to implement Barat’s sealed microchannel in a PD drainage application because peritoneal dialysis involves draining more than 2 to 3 liters of fluid, and a skilled artisan would not have used Barat’s narrow flow path and example operating conditions. And that, using Barat’s example flow rate of 50 μL/min, it would take an impractically long time to drain the effluent, such that a skilled artisan would not have had a reasonable expectation of success.
Response. The argument is not persuasive because it assumes that claim 1 requires passing the full PD drainage volume through Barat’s microchannel at a specific example flow rate, which is not required by the claim language or by the Office’s rationale. Claim 1 broadly recites a “container for enclosing the effluent sample” and does not require that the container be the primary drain conduit, does not require that the entire drainage volume pass through the container, and does not recite any flow rate, drain-phase duration, or microfluidic focusing requirement. Consistent with the Office Action, the asserted modification places Barat’s sealed microfluidic measurement channel as an inline sensing region within or attached to the PD drainage conduit, such that PD effluent sample flows through the enclosed measurement region without requiring the entire drainage system to operate at Barat’s example flow conditions. The Office Action’s “inline sensing region or sampling cell within or attached to a PD fluid conduit” encompasses a flow-through measurement cell integrated into the drainage path, in which the effluent is enclosed in the sealed measurement channel (the claimed container) at the sensing region, without requiring that the entire PD drainage volume be processed through the microchannel at Barat’s example flow conditions. Elbadry teaches monitoring drained PD dialysate using optical and electrical sensing modalities, evidencing that PD effluent characterization in connection with a drain conduit was a known application context (Elbadry, Abstract, FIG. 1A, 2-5). In view of Elbadry’s PD context and Barat’s demonstrated opto-electrical measurement cell, one of ordinary skill in the art would have had a reasonable expectation of success in adapting Barat’s measurement arrangement to characterize PD effluent samples.
Argument. With respect to claims relying on Choi, Applicant argues that Choi fails to remedy the alleged deficiencies of Barat and Elbadry because Choi is merely relied upon for optically transparent electrodes and does not motivate a skilled artisan to modify Barat or Elbadry to arrive at the claimed systems.
Response. The argument is not persuasive because Choi is not relied upon to supply the PD context or the motivation to monitor PD effluent. The PD application and motivation are provided by Elbadry in combination with Barat’s opto-electrical characterization architecture as shown above. Choi is relied upon for a limited and specific purpose, namely teaching optically transparent, electrically conductive electrode structures suitable for use in optical interrogation regions. A person of ordinary skill in the art would have found it obvious before the effective filing date of the claimed invention to implement known transparent conductive electrodes, as taught by Choi, in the combined Barat and Elbadry system to reduce optical occlusion while maintaining electrical measurement capability. The benefit would have been improved co-located optical and electrical sensing by allowing the irradiating beam to pass through electrode regions without obstruction while preserving capacitance measurement functionality.
Argument. Applicant requests withdrawal of the rejections.
Response. For at least the reasons set forth above, the arguments are not persuasive. The rejections are maintained.
Conclusion
THIS ACTION IS MADE FINAL. 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
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