CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Patent Application No. 63/283059 filed on November 24, 2021; the contents of which are hereby incorporated by reference in its entirety.

BACKGROUND

Healthy kidneys keep blood urea levels at a low, relatively constant value. While hemodialysis is an effective treatment to extend the lives of patients experiencing kidney failure, there are many known problems with hemodialysis machines and treatment methods. For example, blood processing systems, e.g., single pass hemodialysis machines, require connection to a water source and use 400 liters or more of water per dialysis session, a key barrier to portable dialysis.

Such high levels of water usage, together with single-use components, present an environmental disaster. Conventional hemodialysis removes excessive metabolic waste from the body by running about 120 liters of dialysis fluid per session, which typically requires 3-4 hours of treatment. The dialysis may be required three times a week. Patients are subjected to significant life disruptions, including having to be immobilized for hours and having to arrange transportation to dialysis centers, which impact their quality of life.

Therefore, there is a need for a system that detoxifies dialysis fluid, regenerates water from dialysis fluid, and returns the detoxified dialysis fluid to the blood processing machine. Such a system would reduce reliance on high-volume water supplies, enable patients to undergo hemodialysis remotely or from the comfort of home, and reduce the environmental impact of hemodialysis treatment. SUMMARY

This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This summary is not intended to identify key features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

In various aspects, the disclosure provides a dialysis fluid processing system, comprising a filtration module configured to filter unfiltered dialysis fluid and an oxidation module configured to detoxify toxic dialysis fluid via a photo-oxidation module and/or an electro-oxidation module. The filtration module and the oxidation module are each in direct or indirect fluid communication with a fluid input for the system to receive used dialysis fluid from a hemodialysis machine and a fluid output for the system to send regenerated dialysis fluid to the hemodialysis machine. The used dialysis fluid is filtered by the filtration module and/or detoxified by the oxidation module to produce the regenerated dialysis fluid for continued use by the hemodialysis machine.

In certain advantageous embodiments, the fluid input can be positioned upstream of the filtration module, the filtration module can be positioned upstream of the oxidation module, and the oxidation module can be positioned upstream of the fluid output. By filtering the used dialysis fluid before detoxifying, the oxidation module and the patient are protected.

The oxidation module can comprise the photo-oxidation module, or both the photooxidation module and the electro-oxidation module, in which case the electro-oxidation module can be disposed upstream of the photo-oxidation module such that the dialysis fluid is electro-oxidated prior to being photo-oxidated. The oxidation module oxidizes byproducts of dialysis present in the dialysis fluid, such as urea, and releases liquids (e.g., H ₂ O) and gases e.g., O ₃ , CO ₂ , N ₂ ) as products. The water that results from regeneration of used dialysis fluid is returned to the hemodialysis machine for continued use in dialysis, and in this manner, large volumes of water are not needed for regeneration of the dialysis fluid after use.

For evaluation of fluid volume extracted during dialysis as well as performance of the system, the photo-oxidation module can further comprise an ultrafiltration monitoring module configured to sense a quantity of evaporated gas from the dialysis fluid which can be used as a basis for changing, based on the quantity of evaporated gas from the dialysis fluid, a flow rate of the dialysis fluid through the photo-oxidation module, a pressure of the dialysis fluid through the photo-oxidation module, and/or a current provided to the light source to maintain a desired rate of regeneration of the dialysis fluid. The ultrafiltration monitoring module can further be configured to sense a current draw of the photo-oxidation module, a voltage of the photo-oxidation module, and/or a thermal output of the photo-oxidation module.

In embodiments, an ultrafiltration monitoring module can be disposed downstream of the photo-oxidation module and/or the electro-oxidation module and can be configured to evaporate gas from the detoxified dialysis fluid through a membrane in fluid contact with the output fluid stream, optionally utilizing a vacuum pump. This step can help remove gaseous products that result from detoxification (e.g., O3, CO2, N2) from the liquid phase.

In embodiments, the system can include a controller operatively connected thereto, e.g., to the ultrafiltration monitoring module and/or the oxidation module. The controller can comprise a processor and processor-executable instructions that, when executed by the processor, causes the ultrafiltration monitoring module to measure, with a sensor, a quantity of gas removed from the detoxified dialysis fluid, and determine, with the processor, a quantity of liquid removed from a patient connected to the hemodialysis machine based on the quantity of gas removed from the detoxified dialysis fluid. The processor-executable instructions, when executed by the processor, can cause the oxidation module to execute a photo-oxidation process and/or an electro-oxidation process to oxidate used dialysis fluid. The processor-executable instructions can be stored or implemented in any suitable manner, such as in a non-transitory computer-readable medium.

To monitor system characteristics and a dialysis session, the system can further comprise a pH monitoring module to monitor a pH level of the dialysis fluid and regulate the pH level by adding electrolytes to the dialysis fluid. Since the pH level of the dialysis fluid can change during a dialysis session, the pH monitoring module can be configured to determine, based on a measured pH level of the dialysis fluid, a completion parameter of a hemodialysis process running on the hemodialysis machine and/or an operating condition of the dialysis fluid processing system, and/or can be configured to remove ammonia from the dialysis fluid. The determination of the pH monitoring module can be directed or carried out by a processor during execution of processor-executable instructions.

The system can be configured to filter a byproduct excess fluid stream from the dialysis fluid and to divert the byproduct excess fluid stream to an excess fluid output and can be configured to filter the byproduct excess fluid stream utilizing a membrane, such as a reverse or forward osmosis membrane.

The system can include a cleaning module in fluid communication with the fluid input and the fluid output that is configured to clean, disinfect, and/or sterilize the oxidation module utilizing a liquid sterilant and/or an ozone byproduct of the oxidation module. The cleaning module can be fluidly connected between the fluid input and the fluid output.

For monitoring physicochemical characteristics of the dialysis fluid as it flows through the system, the system can include a flow monitoring module operatively connected to the fluid input and a controller comprising a processor and processor-executable instructions for the processor to communicate with the flow monitoring module. The flow monitoring module can thereby be configured to monitor an input temperature of the dialysis fluid proximal the fluid input, an output temperature of the dialysis fluid proximal the fluid output, a pressure of the dialysis fluid, and/or a flow rate of the dialysis fluid.

For monitoring optical characteristics of the dialysis fluid as it flows through the system, the flow monitoring module can sense an input visual characteristic of the dialysis fluid in the fluid input and can sense an output visual characteristic of the dialysis fluid in the fluid output. The flow monitoring module can compare, with the processor, the input visual characteristic and the output visual characteristic to produce a comparison, and to determine, with the processor, a relative uremic toxin level of the dialysis fluid in the fluid output based on the comparison.

To improve safety for the patient undergoing dialysis, the flow monitoring module can be configured to execute a safety action when the input temperature, the output temperature, the pressure, and/or the flow rate of the dialysis fluid in the fluid input deviates from a predetermined threshold by more than a preset deviation limit. The safety action can include transmitting a safety message to a remote receiver and/or reducing a flow rate of a pump in fluid communication with the dialysis fluid. To maintain consistency or adjust performance characteristics of the system, the flow monitoring module can monitor and regulate the temperature, pressure, and/or flow rate of the dialysis fluid received in the fluid input. The flow monitoring module can monitor efficiency of the dialysis fluid processing system by monitoring a gas output of the photooxidation module, a current draw of the photo-oxidation module, a voltage of the photooxidation module, and/or a thermal output of the photo-oxidation module. The flow monitoring module can monitor and regulate an output temperature, a pressure, and/or a flow rate of the dialysis fluid sent to the fluid output.

To improve communication with the patient or a user, the system can include a communication module operatively connected to a controller, such that the communication module is configured to receive a user input and to transmit, based on the user input, a system service signal, a medical assistance signal, and/or a dialysis fluid processing system operation signal. The communication module can be configured to receive a safety signal indicative that a temperature, a pressure, and/or a flow rate of the dialysis fluid in the fluid input has deviated from a predetermined threshold by more than a preset deviation limit, and to transmit a safety message to a user interface of the dialysis fluid processing system and/or a remote receiver, based on the safety signal.

Various components of the system, such as a fluid input conduit, a fluid output conduit, and other connectors and connections, can be decoupled for system cleaning, sterilization, and maintenance. In embodiments wherein a housing contains the oxidation module and the filtration module, the housing can comprise a service hatch enabling access to the oxidation module.

In another aspect, the disclosure provides a hemodialysis system, comprising a hemodialysis machine that is supplied with water by a water supply and is configured to produce a dialysis fluid, and a dialysis fluid processing system as disclosed and/or claimed herein. The dialysis fluid processing system receives used dialysis fluid from the hemodialysis machine and provides regenerated dialysis fluid to the hemodialysis machine. In at least some embodiments, the oxidation module can be contained within a housing that is detachable from the hemodialysis machine.

In another aspect, the disclosure provides methods of processing dialysis fluid, the methods comprising: receiving used dialysis fluid from a hemodialysis machine; filtering the used dialysis fluid; converting urea in the used dialysis fluid into CO2, N2, and H ₂ O by flowing the used dialysis fluid between an anode and a cathode and illuminating the anode with a light source; and providing H ₂ O to the hemodialysis machine. The method can include flowing oxygen through the cathode toward the used dialysis fluid to facilitate conversion of urea in the oxidation module. The method can include filtering used dialysis fluid with an osmotic membrane, monitoring and/or regulating a pH of the dialysis fluid, and/or determining a completion parameter of a hemodialysis process and/or a safe operating condition of a dialysis fluid processing system based on the pH. The method can further include determining a gas output from a photo-oxidation module, a current draw of a light source, a voltage applied to an anode/cathode array, and/or a thermal output of the light source. To maintain dialysis, in embodiments of the method, the method can further comprise adjusting the flowing of the dialysis fluid and/or the illuminating of the dialysis fluid based on the gas output, the current draw, the voltage, and/or the thermal output.

Other aspects of the invention will become apparent upon review of the description, drawings, and claims.

DESCRIPTION OF THE DRAWINGS

The foregoing aspects and many of the attendant advantages of this invention will become more readily appreciated as the same become better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein:

FIG. l is a side view of a hemodialysis machine in fluid connection with a dialysis fluid processing system according to an example embodiment of the present disclosure.

FIG. 2 is a schematic of an example dialysis fluid processing system according to the present disclosure.

FIG. 3 is a schematic of an example oxidation module of a dialysis fluid processing system according to the present disclosure.

FIG. 4A is an exploded view of an example oxidation module according to the present disclosure. FIG. 4B is a side view of an example oxidation module in operation according to the present disclosure.

FIG. 5 A is an exploded view of an example oxidation module according to the present disclosure.

FIG. 5B is a perspective view of an example oxidation module in an exploded configuration according to the present disclosure.

FIG. 5C is a perspective view of another example oxidation module according to the present disclosure.

FIG. 6 is a schematic illustration of an example organizational layout of a dialysis system including a toxin-removal loop according to the present disclosure.

FIG. 7 is a schematic of an example method of processing dialysis fluid according to the present disclosure.

DETAILED DESCRIPTION

The present disclosure is directed to toxin removal from dialysis fluid. The inventive technology can be used for blood processes, for example dialysis, including kidney dialysis, hemodialysis, hemofiltration, hemodiafiltration, removal of impurities, etc. In particular, the present disclosure provides dialysis fluid processing systems that remove urea, non-urea uremic toxins, electrolytes, oxidative byproducts, radical byproducts, chlorine, and/or other toxins from dialysis fluid. The regenerated detoxified dialysis fluid can be provided to one or more dialysis machines, for example machines that carry out kidney dialysis, hemodialysis, hemofiltration, hemodiafiltration, and similar processes. This enables dialysis machines to operate without reliance on traditional water supplies (e.g., connections to municipal water supplies), thereby freeing patients to undergo dialysis treatment sessions from the comfort of home or another remote location and reducing the environmental impact of dialysis treatments.

DIALYSIS FLUID REGENERATION SYSTEMS, HEMODIALYSIS MACHINES, AND HEMODIALYSIS SYSTEMS

In general, the disclosure provides improved dialysis fluid processing systems, and hemodialysis machines in combination with such dialysis fluid processing systems, for efficient and environmentally friendly dialysis processes that can be performed at home, remotely, or in transit, with significantly reduced water consumption compared to previous efforts. Filtration modules of the systems filter unfiltered dialysis fluid and oxidation modules detoxify toxic dialysis fluid, using a photo-oxidation module and/or an electrooxidation module, to produce detoxified or regenerated dialysis fluid for reuse by the hemodialysis machine. In particular, water is produced as a product of urea degradation and is returned to the dialysis fluid for use by the hemodialysis machine during continued dialysis without need for additional water supplied from sources external to the system.

Referring to FIG. 1, there is shown a side view of a hemodialysis machine in fluid connection with a dialysis fluid processing system according to an example embodiment of the present disclosure. A hemodialysis system 100 includes a hemodialysis machine 102 fluidly connected with a dialysis fluid processing system 104 of the present disclosure. In operation, a patient 106 is connected to the hemodialysis system 100 such that the patient's blood flows through tubing 108 into the hemodialysis machine 102. The tubing 108 is threaded through a blood pump 110 (e.g., a peristaltic pump). The pumping action of the blood pump 110 pushes the patient's blood through the hemodialysis machine 102 and back into the patient's body.

Dialysis fluid (a fluid comprising water, electrolytes, and salts) is a liquid that helps remove unwanted waste products (e.g., urea) from the patient's blood. During treatment by the hemodialysis machine 102, dialysis fluid (in the form of highly purified water) and the patient's blood flow separately into the hemodialysis machine 102 via tubing 112 and tubing 108, respectively. The two flows do not physically mix. Rather, the flow of fresh dialysis fluid is separated the blood flow by a membrane. Impurities from the patient's blood are filtered out through the membrane into the dialysis fluid. For example, typically 12-24 g of urea needs to be removed daily from the blood of a normal adult, but with a reduced protein diet, removal of 15 g urea from the patient’s blood per day is a sufficient goal. Other impurities are also filtered out of the bloodstream into the dialysis fluid. Dialysis fluid containing filtered waste products (in particular, uremic toxins) and excess electrolytes then flows out of the hemodialysis machine 102.

In previous existing hemodialysis machines, dialysis fluid containing the filtered toxins and other byproducts is disposed and is not reused, leading to significant waste and continued reliance on an external supply of new dialysis fluid for continued operation. Since hemodialysis works on the principle of diffusion into the dialysis fluid which has a low target concentration of solutes, large volumes of dialysis fluid are inherently required. Conventional hemodialysis achieves the removal of excessive metabolic waste from the body by running about 120 liters of dialysis fluid per session, which typically requires 3-4 hours of treatment.

By comparison, the dialysis fluid processing system 104 of the present disclosure generates detoxified dialysis fluid by removing the uremic toxins and other unwanted elements from the used dialysis fluid. This detoxified, regenerated dialysis fluid is then returned to the hemodialysis machine 102. In particular, the dialysis fluid processing system 104 receives used dialysis fluid (e.g., via tubing 114), processes the used dialysis fluid, and then provides detoxified, regenerated dialysis fluid to the hemodialysis machine 102 (e.g., via tubing 112).

Referring to FIG. 2, there is shown a schematic of an example dialysis fluid processing system according to the present disclosure. A dialysis fluid processing system 200 is configured to provide detoxified dialysis fluid to a separate hemodialysis machine, such as described above with respect to FIG. 1. In embodiments, the dialysis fluid processing system 200 and hemodialysis machine are part of a hemodialysis system. The hemodialysis machine and the dialysis fluid processing system 200 can be primed with water from a water supply, e.g., a batch water supply of 10 L to 100 L of water.

In the shown embodiment, dialysis fluid processing system 200 is a modular unit which continuously receives used dialysis fluid from the hemodialysis machine via a fluid input (e.g., fluid input conduit 202), then processes the used dialysis fluid into detoxified, regenerated dialysis fluid (including water and other byproducts such as CO2 and N2) through a dialysis fluid processing loop under operation of at least one pump 204 (e.g., a peristaltic pump), and continuously returns the regenerated dialysis fluid to the hemodialysis machine via fluid output (e.g., fluid output conduit 206), thereby enabling the hemodialysis machine to operate without connection to a traditional water supply. To facilitate cleaning of the dialysis fluid processing system 200, one or more portions of the fluid input conduit 202 and/or the fluid output conduit 206 can be detachable from the dialysis fluid processing system 200 and can be consumable or disposable or can be sterilizable for reuse (e.g., consumable and/or sterilizable segments of fluid conduit).

The dialysis fluid processing loop and related dialysis fluid processing modules can be contained within a housing 208 which enables quick and reversible fluid connection of the dialysis fluid processing system 200 to the hemodialysis machine, for example at couplings 210, 212. In this manner, fluid input conduit 202 is decouplable from a dialysis fluid output of the hemodialysis machine at coupling 210, and the fluid output conduit 206 is decouplable from a return fluid input of the hemodialysis machine at coupling 212. In embodiments, the housing 208 has one or more service hatches 214 enabling access to the modules contained therein for cleaning and maintenance.

An oxidation module 228 is fluidly coupled to receive used dialysis fluid from the hemodialysis machine via the fluid input conduit 202. Oxidation module 228 generates an output fluid stream of detoxified dialysis fluid comprising water from the used dialysis fluid utilizing at least one of a photo-oxidation module or an electrooxidation module. That is, the oxidation module 228 utilizes at least one electrochemical process to oxidize urea in the used dialysis fluid into one or more components, namely H2O, CO2 and N2. The oxidation module 228 provides the detoxified dialysis fluid (including water) as the output fluid stream. The output fluid stream is then provided to the hemodialysis machine via the fluid output conduit 206. A representative oxidation module and sub-modules thereof are described in detail below with respect to FIGs 3, 4A, 4B, 5A, 5B, and 5C.

A filtration module 230 is fluidly coupled between the fluid input conduit 202 and the oxidation module 228, and filters select toxins from the dialysis fluid prior to processing by the oxidation module 228. Advantageously, this protects the oxidation module 228 and the patient. In embodiments, the filtration module 230 filters the dialysis fluid utilizing one or more toxin-selective membranes 232, such as a ureaselective osmotic membrane (forward or reverse osmosis membrane), nanofiltration membrane, or ion exchange membrane, to separate the dialysis fluid into a urea- containing dialysis fluid stream (which is passed to the oxidation module 228) and a byproduct excess fluid stream containing uremic toxins, sodium, and other byproducts. The filtration module 230 filters the byproduct excess fluid stream from the dialysis fluid and diverts the byproduct excess fluid stream to an excess fluid output conduit 234 and/or an optional additional filtration stage.

In at least some instances, processing of the dialysis fluid, such as with the oxidation module 228 and filtration module 230, can remove desirable electrolytes from the dialysis fluid. An optional pH monitoring module 236 can be fluidly coupled to fluid input conduit 202 and/or fluid output conduit 206 and can monitor a pH level of the dialysis fluid and, optionally, regulate the pH level, such as by adding electrolytes to the dialysis fluid, either upstream or downstream of the oxidation module 228, and/or by removing ammonia from the dialysis fluid (e.g., with ammonia-removing adsorbents). In embodiments, the pH monitoring module 236 is disposed upstream of the oxidation module 228 (e.g., between the oxidation module 228 and filtration module 230).

In embodiments, the pH monitoring module 236 determines, based on the pH level of the dialysis fluid, a completion parameter of a hemodialysis process running on the hemodialysis machine. Because the pH of the dialysis fluid will change during the course of a hemodialysis treatment as the hemodialysis machine removes less and less urea from the patient's blood, when the pH monitoring module 236 senses that the pH of the dialysis fluid either exceeds or drops below a threshold associated with a completion level of the hemodialysis treatment, the pH monitoring module 236 determines a completion parameter (e.g., percentage complete, time remaining, toxins removed, excess fluid removed).

In embodiments, pH monitoring module 236 determines an operating condition of the dialysis fluid processing system based on the sensed pH level of the dialysis fluid. For example, if residual sterilant or other chemical contaminates the fluid conduits of the hemodialysis machine and/or the dialysis fluid processing system 200, and the pH monitoring module 236 senses that the pH of the dialysis fluid exceeds or falls below a threshold of safe operation for the dialysis fluid processing system 200 and/or the patient, then the pH monitoring module 236 determines that the operating condition is unsafe. In such event, the pH monitoring module 236 sends (e.g., via communication module 226) a system service signal (e.g., to a clinician or manufacturer) indicating that the dialysis fluid processing system 200 needs service and/or a dialysis fluid processing system operation signal (to a clinician and/or a patient) indicating that the dialysis fluid processing system 200 is not ready for dialysis fluid regeneration. The pH monitoring module 236 can also send a medical assistance signal (e.g., to a clinician) indicating that a patient needs medical assistance because the pH of the dialysis fluid deviates from a predetermined threshold by more than a predetermined deviation limit.

A flow monitoring module 238 can be operatively connected to at least the fluid input conduit 202 and to a controller 216 and can include a sensor array 240 and circuitry which monitors and optionally regulates operational parameters of the dialysis fluid processing system 200. In embodiments, flow monitoring module 238 is configured to monitor at least one of an input temperature, a pressure, or a flow rate of the dialysis fluid in the fluid input conduit 202. To execute these functions, in embodiments, the sensor array 240 includes at least one of a temperature sensor, a pressure sensor, or a flow rate sensor. In embodiments, the flow monitoring module additionally or alternatively monitors at least one of an output temperature, a pressure, or a flow rate of the output fluid stream in the fluid output conduit 206 with a second temperature sensor, a second pressure sensor, and a second flow rate sensor, respectively.

In embodiments, sensor array 240 includes a first optical sensor disposed to sense an input visual characteristic of the dialysis fluid (e.g., a color, a clarity, and/or opacity) upstream of the oxidation module 228 (e.g., in the fluid input conduit 202), and a second optical sensor disposed to sense an output visual characteristic of the output fluid stream from the oxidation module 228 (e.g., in the fluid output conduit 206). In such embodiments, the flow monitoring module 238 can make a comparison between the input visual characteristic and the output visual characteristic and determine a relative urea level of the output fluid stream based on the comparison, e.g., to determine efficacy of the oxidation module 228 in removing urea.

In embodiments, flow monitoring module 238 executes a safety action when at least one of the temperature, pressure, or flow rate of the dialysis fluid in the fluid input conduit (as sensed by sensors of the sensor array 240) deviates from a threshold, such as a predetermined threshold, by more than a predetermined deviation limit (e.g., 5%, 10%, 15%, 20%, etc.). The safety action can include at least one of: transmitting a safety message via communication module 226 to a receiver (e.g., a mobile device of a clinician or patient), reducing a flow rate of pump 204, or turning off or pausing the dialysis fluid processing system 200 and/or the hemodialysis machine or hemodialysis system. In embodiments, the safety message includes an alert that the sensed parameter has deviated from the threshold and/or an alert that the dialysis fluid processing system 200 and/or hemodialysis machine have been turned off, paused, or adjusted based on the sensed parameter deviating from the threshold.

In embodiments, flow monitoring module 238 regulates at least one parameter (temperature, pressure, flow rate) of the dialysis fluid received in the fluid input conduit 202 and/or the output fluid stream in the fluid output conduit 206 using at least one of a temperature control device 242 (e.g., a heater, a thermoelectric cooler, a tortuous flow path heat exchanger, and the like), a pump 204, or a valve. For example, flow monitoring module 238 can regulate a flow rate of the dialysis fluid such that it does not exceed about 300 mL/min for a 3-4 hour treatment cycle, and/or can regulate the flow rate such that it does not exceed about 100 mL/min for a 6-8 hour treatment cycle or for a priming process. In embodiments, the flow monitoring module 238 uses temperature control device 242 to change a temperature of the dialysis fluid in the output fluid stream to approximately equal a temperature of the dialysis fluid in the input fluid stream, e.g., 37 °C or 38 °C, or to prevent a temperature of the dialysis fluid in the output fluid stream from exceeding a maximum temperature, e.g., about 45 °C.

In embodiments, flow monitoring module 238 monitors an efficiency level of the dialysis fluid processing system by monitoring at least one of the following parameters of the oxidation module 228: a gas output of the oxidation module 228 (e.g., a CO2 gas output from the electrochemical oxidation of urea in photo-oxidation module), a current draw, a voltage, or a thermal output. In embodiments, the flow monitoring module 238 monitors the gas output with at least one of an ultrasonic sensor or an optical sensor disposed to count bubbles generated by the oxidation module 228, monitors the current draw of a light source in the oxidation module 228 with a current sensor, monitors the voltage across a cathode/anode pair in the oxidation module 228 with a voltage sensor, and/or monitors the thermal output of the light source with a temperature sensor. Optionally, the flow monitoring module 238 regulates the efficiency of the oxidation module 228. For example, in embodiments, flow monitoring module 238 includes a control loop which regulates a current draw of the light source and/or a voltage provided across a cathode/anode pair based on the determined gas output, which in turn regulates an oxidation rate of urea in the dialysis fluid.

A cleaning module 244 can be in fluid communication with the fluid input conduit 202 and the fluid output conduit 206, e.g., as shown, and can be configured to clean, disinfect, and/or sterilize the oxidation module 228 utilizing a liquid sterilant and/or an ozone byproduct (O3) of the oxidation module 228. For example, in embodiments, the cleaning module 244 provides a liquid sterilant (e.g., a citrate) to the fluid input conduit 202, and circulates the liquid sterilant through the oxidation module 228 under pressure from pump 204. In embodiments, as shown, cleaning module 244 is disposed in a fluid conduit 246 between fluid input conduit 202 and fluid output conduit 206, thereby forming a fluid loop enabling liquid sterilant to recirculate through the oxidation module 228 and other modules when the dialysis fluid processing system 200 is disconnected from the hemodialysis machine.

A controller 216 can be disposed on the housing 208 and can be operably connected to one or more or every module described herein with respect to the dialysis fluid processing system 200. Controller 216 can include a processor 218 (e.g., a microprocessor) and a data store 220 (e.g., a non-transitory computer-readable storage medium, e.g., a random-access memory) storing logic or processor-executable instructions which, when executed by the processor 218, configures the processor to cause the dialysis fluid processing system 200 to perform the functions described below with respect to the different modules. Controller 216, along with the modules and hardware described herein, are connectable to a power supply 222, e.g., a D/C battery disposed in the housing 208.

An optional user interface 224 can be operably connected to the controller 216 and disposed in or on the housing 208, and can enable a user (e.g., a clinician and/or a patient) to monitor and/or control the dialysis fluid processing system 200. An optional communication module 226 can be operably connected to the controller 216 and can be configured to transmit and receive signals to and from one or more recipients and/or recipient devices (e.g., a patient, a clinician, and/or a manufacturer, a remote computer system, a remote mobile device, a remote server, etc.), consistent with the structure and functionalities described below. In embodiments, communication module 226 is configured to receive a user input (e.g., via the user interface 224 and/or a remote device such as a smartphone) and to cause the dialysis fluid processing system 200 to execute any of the functionalities described below based on the user input.

In embodiments, based on one or more signals received from any of the sensors described below, communication module 226 transmits at least one of a system service signal (e.g., to a manufacturer) indicating a diagnostic parameter of the dialysis fluid processing system 200, a medical assistance signal (e.g., to a clinician) indicating that a patient is in need of medical assistance, or a dialysis fluid processing system operation signal (to a clinician and/or a patient) indicating an operational state of the dialysis fluid processing system 200.

The foregoing modules are representative, not limiting. In embodiments, any feature described above with respect to a particular module can be associated with a different module. Certain embodiments can include additional features not described in detail above. For example, dialysis fluid processing systems can include one or more sorbent-based cartridges and/or urease conversion cartridges to further aid removal of uremic toxins from the dialysis fluid. As another example, embodiments, can include a weighing system (e.g., a scale) disposed underneath the dialysis fluid processing system 200 in order to weigh the dialysis fluid in the system.

Example structures and techniques for filtering dialysis fluid include those described in U.S. Provisional Application No. 63/171503, filed April 6, 2021, the entirety of which is hereby incorporated by reference.

Referring to FIG. 6, there is shown a schematic illustration of an example organizational layout of a dialysis system including a toxin-removal loop according to the present disclosure, in use with a patient 800 for hemodialysis. At least some embodiments of a liquid dialysis circuit include a dialysate loop 804, separated from a patient blood circuit 802 by a dialysis membrane 810. The liquid dialysis circuit can include a toxin-removal loop 806 separated by a toxin-selective membrane 812 configured to selectively pass the toxin from the dialysate loop 804 to the toxin-removal loop 806. The liquid dialysis circuit includes a toxin-removal element 818, which can include an oxidation module and/or a filtration module as disclosed herein.

The dialysate in loop 804 can be any commercial or conventional dialysate currently used. The fluid in loop 806 can include, for example, saline solutions, aqueous solution mixed with non-NaCl electrolytes, aqueous solution of acidic or basic pH values. The toxin-removal loop 806 can protect the toxin-removal element 818 by using a toxin-selective membrane 812 in contact with the dialysate. For example, the urea- removal elements described herein can benefit from a urea-selective membrane 812 separating the dialysate loop 804 and the toxin-removal loop 806. In embodiments, the toxin to be removed is a uremic toxin. In embodiments, the toxin to be removed is urea.

As used herein, "loop" or "circuit" denote one or more conduits that carry fluid through one or more devices. The blood flow in the blood circuit 802 can be single pass, meaning fresh or new blood is continuously being fed into the blood circuit 802. The dialysate and fluid flows in loops 804 and 806 is designed to be multiple pass, meaning the fluid is being regenerated and can be used for extended periods. The flow in loops 804, 806 can flow in a continuous or semi-continuous manner so that the fluid circulates repetitively through the conduit and the various devices in the loops. The flow can be created by a pump, such as a peristaltic pump. Chemical species and/or fluids are allowed to be transferred between the dialysate loop 804 and the blood circuit 802 and between the dialysate loop 804 and the toxin-removal loop 806, through membranes 810 and 812, respectively. External fluids and/or nutrients can also be introduced into the loops 804, 806, and circuit 802, and fluids within the loops 804, 806, and circuit 802 can also be removed continuously or semi-continuously. In embodiments, a loop can have a constant flow rate through the loop. In embodiments, the flow of a loop can increase or decrease over time.

Using urea as an example, the toxin-removal loop 806 is separated by a ureaselective membrane 812 configured to selectively pass urea from the dialysate loop 804 to the toxin-removal loop 806. In this case, the dialysate loop 804 in FIG. 6 includes a cartridge 814, wherein the cartridge 814 includes a similar amount of activated carbon adsorbent (bottom layer) to adsorb non-urea toxins and potentially add other selective adsorbents (top layers) as needed or developed. Activated charcoal is a typical filter material, but any other compatible filter or method can also be used.

In the liquid dialysis circuit shown in FIG. 6, the urea from the dialysate loop 804 is removed across the urea-selective membrane 812 along with other unavoidable compounds. The urea is then removed from the urea loop 812 by any of the urea- removal elements as disclosed herein. For example, the urea-removal element 818 can include a photooxidation urea removal element (POUR). When using a POUR as the urea-removal element 818, it is also advantageous to include an additional activated carbon filter 816 in the toxin-removal loop 806 to remove oxo-chloro species that can be a by-product during urea oxidation. Urea is used as a representative toxin, but it is understood that other uremic toxins can be removed from the dialysate loop 804 to the toxin-removal loop 806 by selection of the appropriate toxin-selective membrane 812. Furthermore, more than one toxin-removal loops each with a different toxin-selective membrane can be included to remove more than one toxin. Alternatively, more than one different toxin-selective membrane can be used at the interface between the dialysate loop 804 and the toxin-removal loop 806. The toxin-removal element 818 can be based on enzyme (urease)-based, bacteria-based (bioreactor), sorbent-based, and oxidationbased. FIGs 4A, 4B, 5A, 5B, and 5C show example embodiments of photooxidation urea-removal elements.

In this disclosure, the use of a toxin-removal loop 806 and toxin-selective membrane 812 described with respect to FIG. 6 can be applied to other dialysis systems, such as a hemodialysis machine, a peritoneal dialysis system, a hemofiltration system, or a hemodiafiltration system as described and envisioned herein. Further, the kidney dialysis system of this disclosure can be configured to have a form factor selected from the group of portable, wearable, movable, and fixed systems, and the kidney dialysis system can be configured for in-home or in-dialysis center use.

DIALYSIS FLUID TREATMENT AND PERFORMANCE MONITORING MODULES

The dialysis fluid processing loop includes a number of modules which are described herein. Referring to FIG. 3, there is shown a schematic of an example oxidation module of a dialysis fluid processing system according to the present disclosure. An oxidation module 300 is compatible with any dialysis fluid processing system described herein, and operates to remove urea, non-urea uremic toxins, oxidative byproducts, radical byproducts, chlorine, and/or other toxins from used dialysis fluid received from a hemodialysis machine.

Oxidation module 300 receives used dialysis fluid from the fluid input conduit 302, removes urea from the dialysis fluid using a photo- oxidation module 304 and/or an electro-oxidation module 306 to oxidize urea into components (including CO2, N2, and H2O), and provides detoxified dialysis fluid to the fluid output conduit 308. In the illustrated embodiment, oxidation module 300 includes both a photo-oxidation module 304 and an electro-oxidation module 306, with the electro-oxidation module 306 disposed upstream of the photo-oxidation module 304 in order to remove select toxins prior to processing by the photo-oxidation module 304. In another embodiment, the oxidation module 300 includes only a photo-oxidation module 304 (and not an electrooxidation module). In yet another embodiment, the oxidation module 300 includes only an electro-oxidation module 306 (and not a photo-oxidation module).

Photo-oxidation module 304 utilizes a photo-oxidation process to remove urea from the dialysis fluid. The photo-oxidation module 304 includes a photo-oxidation fluid cell having at least two electrodes (an anode and a cathode) separated by a dielectric spacer (e.g., a rubber, silicon, or plastic spacer). In operation, dialysis fluid containing urea is held in the photo-oxidation fluid cell between the two electrodes and is subjected to photo-illumination that promotes photo-oxidation of urea into CO2, H2O and N2. In embodiments, oxygen (e.g., in the form of ambient air) is pumped over the cathode and toward the anode through the dialysis fluid. Example photo-oxidation modules are described below with respect to FIGs 4A, 4B, 5A, 5B, and 5C.

Optional electro-oxidation module 306 utilizes an electro-oxidation process to remove urea from the dialysis fluid. The electro-oxidation module 306 includes an electro-oxidation fluid cell having two electrodes spaced apart therein (an anode and a cathode). In operation, dialysis fluid containing urea is held in the electro-oxidation fluid cell between the two electrodes. A voltage is applied across the two electrodes, causing formation radicals near the anode surface, which degrade urea in the dialysis fluid.

Gaseous byproducts e.g., CO2, N2, O3, and H2O vapor) result from the photooxidation process within the photo-oxidation module 304, whether from the chemical reactions taking place therein or due to evaporation resulting from thermal energy transferred to the dialysis fluid. Furthermore, in embodiments, oxygen is pumped into the photo-oxidation fluid cell, creating bubbles. Therefore, an optional ultrafiltration monitoring module 310 is configured to remove gas from the dialysis fluid loop through at least one membrane 312 in fluid contact with the output fluid stream. In embodiments, the ultrafiltration monitoring module 310 utilizes a vacuum pump 314 to create a pressure differential across the membrane 312, thereby promoting removal of the gas from the dialysis fluid. In embodiments, ultrafiltration monitoring module 310 is fluidly coupled with a cleaning module of the dialysis fluid processing system, and provides the removed gas (e.g., O3) to the cleaning module for use as a sterilant.

Advantageously, evaporation of the dialysis fluid can remove excess fluid from a patient, e.g., 0.5 L/hr. In embodiments, the ultrafiltration monitoring module 310 measures a quantity of gas removed from the output fluid stream and determines a quantity of fluid removed from a patient connected to the hemodialysis machine, based on the quantity of gas removed from the output fluid stream. The ultrafiltration monitoring module 310 senses the quantity of evaporated gas with at least one sensor 316 such as an ultrasonic sensor, an optical sensor, or an oxygen sensor disposed to count bubbles generated by the photo-oxidation module 304.

Aside from removing excess fluid from a patient, the evaporated gas indicates an efficiency of the oxidation module 300, i.e., a rate of chemical conversion of dialysis fluid into CO2 and N2 per unit time. In embodiments, based on the sensed quantity of evaporated gas, the ultrafiltration monitoring module 310 regulates at least one of a flow rate or pressure of the dialysis fluid through the oxidation module 300 (such as by controlling a pump and/or a valve disposed in the dialysis fluid loop), a current provided to a light source of the photo-oxidation module 304, and/or a voltage applied to electrodes in the oxidation module 300 and/or photo-oxidation module 304. These changes, in turn, change the rate of the oxidation processes in the photo-oxidation module 304 and electro-oxidation module 306.

Representative photo-oxidation modules include those described in U.S. Patent Application No. 16/536277, filed August 8, 2019, and U.S. Provisional Patent Application No. 63/165098, filed March 23, 2021, which are herein incorporated by reference entirety.

Referring to FIG. 4A there is shown an exploded view of an example oxidation module according to the present disclosure, such as the type used as photo-oxidation module 304 in FIG. 3. An example urea treatment unit 20, in the form of an oxidation module, is a photo-electric urea treatment unit that removes urea by an electrochemical reaction. The system 20 includes two electrodes 24, 26 that are separated by a dielectric spacer 27 (e.g., rubber, silicon, or plastic spacer). In operation, dialysate that contains urea is held between the two electrodes 24, 26, and is subjected to photo-illumination that promotes photo-oxidation of urea into CO2, H2O and N2.

The required source of light can be provided by an ultraviolet (UV) lamp 22. The reaction also requires oxygen for the electrochemical reaction. Providing required oxygen is described with reference to FIG. 4B below.

Referring to FIG. 4B, there is shown a side view of an example oxidation module in operation according to the present disclosure. An example urea treatment unit 20, in the form of an oxidation module, enables air to flow into tubing 28 and flow further to the dialysate that contains urea inside the photo-electric urea treatment unit 20. Arrows 29 indicate the incoming flow of air that produces bubbles 31 in the dialysate. While effective, in this example, the quantum efficiency for incident photons from the UV lamp 22 to electrochemical reaction can be relatively low, sometimes less than 1%. As a result, the urea treatment unit can still be impractically large if the target of about 15 to 20 g of urea removal is to be achieved in a portable device. Improved provisioning of oxygen is described with respect to FIG. 5A below.

Referring to FIG. 5 A, there is shown an exploded view of an example oxidation module according to the present disclosure. A urea treatment unit 720 is an oxidation module in accordance with embodiments of the present disclosure. In embodiments, dialysate 715 flows through a spacer 732 from an inlet 734 to an outlet 736. Dialysate 715 carries urea that is to be electrochemically decomposed into CO ₂ and N ₂ . The spacer 732 can be sandwiched between an anode 722 and a cathode 742, each individually connected to a source of voltage 792 (e.g., a source of DC voltage). In embodiments, the source of voltage 792 provides a voltage differential within a range from about 0.6 V to about 0.8 V. In embodiments of spacer 732, the entire dialysate flow is directed to flow over TiO ₂ layer.

In embodiments, the cathode can be a gas and/or air permeable cathode 742 that blocks liquids (e.g., water), but passes gases (e.g., air and/or oxygen) through. In operation, flow of gas 760 that includes oxygen can pass through the cathode 742 toward the dialysate that includes urea. In embodiments, the cathode 742 is made of conductive cloth. For example, the conductive cloth can be a platinum-coated (Pt- coated) cloth or carbon cloth. In embodiments, the cathode 742 can be a conductive paper-based cathode. The air permeable (air breathable) cathode 742 can be mechanically held in place by one or more spacers (e.g., spacer 732) having supporting elements for the cathode 742, for example, the spacer can having mesh supporting elements or other gas-permeable structural elements.

In embodiments, the anode 722 is fitted with nanostructures (e.g., TiO ₂ nanowires). In operation, the anode 722 is illuminated by a source of light that emits light (e.g., UV light) for the electrochemical reaction shown in Equation 1. One or more sources of light can be used for the light (e.g., light emitting diodes (LEDs), lasers, discharge lamps, etc.). The sources of light can be arranged in a 2-dimensional (2D) array. In embodiments, the LEDs emit light at 365 nm wavelength. In embodiments, the LEDs emit light at an ultraviolet (UV) or visible light wavelength. In embodiments, the LEDs generate light with the intensity of less than 4 mW/cm2 at the surface of the anode (e.g., at the surface of the substrate 721). In other embodiments, other, higher light intensities can be used, for example light with the intensity of more than 4 mW/cm2 at the surface of the anode. In embodiments, quantum efficiency of incident photons (incident photo-electric efficiency) is about 51%. In embodiments, the nanostructured anode 722 can operate based on the incoming natural light in conjunction with or without dedicated light array 750. At the anode, photo-excited TiO2 nanostructures provide holes for the oxidation of solution species on the surface, while electrons are collected on underlying conducting oxide (e.g., fluorine doped thin oxide or FTO), and then transported to the cathode electrode to split water into OH-. The photo-excitation can be provided by a source of light 750 or by natural light. In embodiments, a controller 794 can control operation of pumps to regulate the flow of blood input and the dialysate during use.

In embodiments, the urea treatment unit 720 can be used for preparing a dialysis fluid. For example, water to be treated can be passed between the anode 722 and the cathode 742 to oxidize impurities in the water to be treated, thereby generating the dialysis fluid. Example embodiments of the urea treatment unit 720 are described with reference to FIGs 5B and 5C below.

Referring to FIG. 5B, there is shown a perspective view of an example oxidation module in an exploded configuration according to the present disclosure. The shown photo-oxidation module 400 can form part of any oxidation module of the present disclosure. Photo-oxidation module 400 includes a photo-oxidation fluid cell 402 through which dialysis fluid flows between an anode 404 and a cathode 406. In the illustrated embodiment, dialysis fluid 408 flows through a spacer 410 from an inlet 412 to an outlet 414. Dialysis fluid 408 carries urea that is to be electrochemically decomposed into CO2 and N2. In embodiments, the spacer 410 is disposed between anode 404 and cathode 406, each being individually connected to a voltage source 416 (e.g., a source of DC voltage). In embodiments, the voltage source 416 provides a voltage differential within a range from about 0.6 V to about 0.8 V. In embodiments of spacer 410, the entire flow of dialysis fluid 408 is directed to flow over the anode 404.

Anode 404 is configured to generate photo-electrons or holes when exposed to light. In embodiments, anode 404 has a substrate 418 that carries nanostructures 420 formed of a nanomaterial (e.g., TiCh nanowires). The anode 404 can be held in a substrate holder 422. In operation, the anode 404 is illuminated by at least one light source 424 that emits light (e.g., UV light) for the electrochemical reaction shown in Equation 1. At the anode 404, photo-excited nanostructures 420 provide holes for the oxidation of solution species on the surface, while electrons are collected on underlying conducting oxide (e.g., fluorine doped thin oxide or FTO), and then transported to the cathode electrode to split water into OH".

The light required for the photo-chemical decomposition of the urea can be provided by a light array 426 that includes one or more light sources 424 (e.g., light emitting diodes (LEDs), lasers, discharge lamps, etc.). The light sources 424 can be arranged in a 2-dimensional (2D) array, such as on a panel. In embodiments, the light sources 424 emit light at a 365 nm wavelength. In embodiments, the light sources 424 emit light at an ultraviolet (UV) or visible light wavelength. In embodiments, the light sources 424 generate light with the intensity of less than 4 mW/cm2 at the surface of the anode 404 (e.g., at the surface of the substrate 418). In embodiments, higher light intensities can be used, for example light with the intensity of 4 mW/cm2 or greater at the surface of the anode 404. In embodiments, a quantum efficiency of incident photons (incident photo-electric efficiency) is about 51%. In embodiments, the anode 404 can operate based on the incoming natural light in conjunction with or without dedicated light array 426.

Cathode 406 blocks liquids (e.g., water), and in embodiments is gas-permeable such that it passes gases (e.g., air or oxygen) through. In embodiments, the cathode 406 is made of conductive cloth. For example, the conductive cloth can be a platinum-coated (Pt-coated) cloth or carbon cloth, or Ti felt. In embodiments, the cathode 406 can be a conductive paper-based cathode. The cathode 406 can be mechanically held in place by spacers 428, 430 having supporting elements for the cathode 406, for example mesh supporting elements 432, mesh supporting elements 434 (or other gas-permeable structural elements). In embodiments, ambient air is pumped over cathode 406 toward anode 404. In still other embodiments, the cathode 406 is not formed of a gas permeable material (e.g., a stainless-steel plate). In such embodiments, air or oxygen is introduced into the system through air introduction means. In example embodiments, the air introduction means includes fluid conduits formed through the cathode 406 or fluid conduits formed through an end plate.

The electrochemical reaction that takes place in the photo-oxidation module 400 can be described as follows: Anode : CO(NH ₂ ) ₂ + GOH — > CO ₂ + N ₂ + 5H ₂ O + 6e Cathode : O ₂ + 2H ₂ O + 4e — > 4£)H~

Net : CO(NH ₂ ) ₂ + 3/2O ₂ — > CO ₂ + N ₂ + 2H ₂ O (Equation 1)

With at least some embodiments of the disclosure, significant and unexpected performance improvements are observed when compared to the performance of conventional technology. For example, matching a daily urea production to the 6e" oxidation process for 15 gram (0.25 moles) a day target uses electrical current of 1.7A over a 24 hour period. With a target 1 mA/cm ² photocurrent density on a TiCh nanostructured anode, the total device area becomes about 1700 cm ² , or 1.82 ft ² . With such total device area, it becomes feasible to deploy a relatively small, portable and/or wearable device that oxidizes about 15 g of urea per day. At least some embodiments of such a device would utilize about twelve 8000 mAh batteries for 8-hour operation without recharging and proportionally less batteries for shorter operations, which culminate to provide a significant technical advantage over previous existing efforts.

Furthermore, the high conversion efficiency of urea decomposition at low concentrations shows a high selectivity of TiCh to oxidize urea vs. generating oxochlorospecies that are generally undesirable. Additionally, photocurrent density is more than one order of magnitude higher than that achieved by the prior art without nanostructures or light arrays.

The photo-oxidation module 400 of FIG. 4 is representative and is not limiting. Other embodiments can utilize different photo-oxidation modules, such as described below with respect to FIG. 5C.

Referring to FIG. 5C, there is shown a perspective view of another example oxidation module according to the present disclosure. The shown oxidation module 500 can form part of any oxidation module of the present disclosure. Like photo-oxidation module 400 of FIG. 5B, photo-oxidation module 500 includes at least one cathode, anode, and light source which acts on dialysis fluid in a photo-oxidation fluid cell, as described below.

In use, dialysis input fluid stream 518 enters the fluid distribution means 512a, which distributes the dialysis fluid between the three photo-oxidation panels 502a, 502b, 502c. As dialysis fluid flows through the fluid channels 506 of each photo-oxidation panel, the light panels 504a, 504b illuminate the anodes of each photo-oxidation panel, thereby initiating oxidation of urea in the dialysis fluid into CO2, N2, and H2O. The oxidized dialysis output fluid stream 520 leaves the photo-oxidation panels 502a, 502b, 502c via fluid distribution means 512b. Gaseous components of the oxidized dialysis fluid (including CO2 and N2) are separated from the H2O as bubbles, which leave the fluid conduit through a membrane (e.g., in an ultrafiltration monitoring module as described above).

In particular, photo-oxidation module 500 can be formed as a stack of photooxidation panels 502a, 502b, 502c, and a plurality of light panels 504a, 504b. Each light panel 504a, 504b is disposed adjacent to at least one photo-oxidation panel, e.g., between two adjacent photo-oxidation panels.

Although the illustrated embodiment includes three photo-oxidation panels, other embodiments can include a different number of panels, e.g., one, two, four, five, or a greater number of panels. Similarly, although the illustrated embodiment includes two light panels, other embodiments can include a different number of panels, e.g., one, three, four, five, or greater number of panels, in order to increase urea removal capacity or to reduce size. In embodiments, photo-oxidation module 500 includes a same number of photo-oxidation panels as light panels, or one less light panel than photo-oxidation panels. In embodiments, the light array is formed integrally with the photo-oxidation panel, and therefore the photo-oxidation module 500 does not have any separate light panels.

Each photo- oxidation panel 502a, 502b, 502c includes a photo-oxidation fluid cell having a plurality of parallel fluid channels 506 which diverge from a fluidic inlet 508 and converge at a fluidic outlet 510. The photo-oxidation panels 502a, 502b, and 502c are fluidly connected to each other at the input and output sides, respectively, by fluid distribution means 512a and 512b. In example embodiments, fluid distribution means 512a and 512b includes manifolds and/or flexible tubing.

Each photo- oxidation panel includes an anode/cathode array 514 disposed in the fluid channels 506. In embodiments, a first side of the anode/cathode array 514 is a TiCh/FTO anode (TiCh hydrothermally grown on conductive fluorine-doped thin oxide glass). In embodiments, a second side of the anode/cathode array 514 is a Pt/C gas- permeable cathode catalyst (Pt-coated carbon paper side). According to certain embodiments, the anode/cathode array 514 each has an active surface area of approximately 0.25-2.0 square feet, in order to remove the 12-15 g of urea in 24 hours (a representative level of human urea production). Although TiCh/FTO anodes and Pt/C cathodes are used in the illustrated embodiment, other embodiments can utilize different anode and/or cathode compositions.

Light panels 504a, 504b each include a light array 516 (e.g., a plurality of LEDs) that faces the anode of at least one adjacent photo-oxidation panel and provides photoactivation to initiate the oxidation of urea in dialysis fluid flowing through the fluid channels 506. Although LEDs are used in the illustrated light panels 504a, 504b for their efficiency and output, other embodiments include other forms of illumination (such as lasers, discharge lamps, and the like).

DIALYSIS FLUID REGENERATION METHODS

Referring to FIG. 7, there is shown a schematic of an example method of processing dialysis fluid according to the present disclosure. An example method 600 of processing dialysis fluid can be implemented with any of the dialysis fluid processing systems described herein but is not limited to such dialysis fluid processing systems.

In step 602, a dialysis fluid is received from a hemodialysis machine, such as by any of the dialysis fluid processing systems described herein.

In optional step 604, a pH of the dialysis fluid is determined and optionally regulated. In embodiments, the determined pH is utilized in a feedback loop to regulate the flow of dialysis fluid between an anode and cathode. For example, a completion parameter of the hemodialysis treatment is determined based on the determined pH, and based on the determined pH, the flow of dialysis fluid is optionally slowed or stopped.

In step 606, the dialysis fluid is filtered, such as with a urea-selective osmotic membrane (forward or reverse osmosis membrane), nanofiltration membrane, or ion exchange membrane to separate the dialysis fluid into a urea-containing dialysis fluid stream and a byproduct excess fluid stream containing uremic toxins, sodium, and other byproducts. In step 608, the dialysis fluid is flowed between an anode and cathode while illuminating the anode with a light source, to oxidize urea in the dialysis fluid and to produce H2O. Optionally, oxygen is flowed across the cathode through the dialysis fluid and toward the anode while the anode is illuminated with the light source.

In optional step 612, one or more gases (e.g., CO2, N2) are removed from the dialysis fluid. In embodiments, a quantity of removed gas is determined, and optionally utilized to measure an efficiency 610 of the urea oxidation process and optionally to regulate one of a current draw, voltage, flow rate, or pressure of the dialysis fluid conversion process.

In step 614, the H ₂ O resulting from the oxidation of urea in the dialysis fluid is provided to a hemodialysis machine.

In optional step 616, a dialysis treatment is carried out using the H2O provided in step 614 as dialysis fluid.

CIRCUITRY, PROCESSOR, AND COMPUTER IMPLEMENTATIONS Embodiments disclosed herein, including embodiments that include or utilize a controller, a processor, and/or processor executable instructions, can utilize circuitry to implement those technologies and methodologies. Such circuitry can operatively connect two or more components, generate information, determine operation conditions, control an appliance, device, or method, and/or the like. Circuitry of any type can be used. In embodiments, circuitry includes dedicated hardware having electronic circuitry configured to perform operations or computations on a dedicated basis, without any use of microprocessors, central processing units, or software or firmware or processorexecutable instructions. However, in embodiments, circuitry includes, among other things, one or more computing devices such as one or more processors (e.g., microprocessor), one or more central processing units (CPU), one or more digital signal processors (DSP), one or more application-specific integrated circuits (ASIC), one or more field-programmable gate arrays (FPGA), or the like, or any variations or combinations thereof, and can include discrete digital and/or analog circuit elements or electronics, or combinations thereof. In embodiments, circuitry includes one or more ASICs having a plurality of predefined logic components. In embodiments, circuitry includes one or more FPGA having a plurality of programmable logic components. In embodiments, circuitry includes hardware circuit implementations (e.g., implementations in analog circuitry, implementations in digital circuitry, and the like, and combinations thereof). In embodiments, circuitry includes combinations of circuits and computer program products having software or firmware processor-executable instructions stored on one or more computer readable memories, e.g., non-transitory computer-readable storage mediums, that work together to cause a device or system to perform one or more methodologies or technologies described herein.

In embodiments, circuitry includes circuits, such as, for example, microprocessors or portions of microprocessors, that require software, firmware, and the like for operation. In embodiments, circuitry includes an implementation comprising one or more processors or portions thereof and accompanying software, firmware, hardware, and the like. In embodiments, circuitry includes a baseband integrated circuit or applications processor integrated circuit or a similar integrated circuit in a server, a cellular network device, other network device, or other computing device. In embodiments, circuitry includes one or more remotely located components. In embodiments, remotely located components (e.g., server, server cluster, server farm, virtual private network, etc.) are operatively connected via wired and/or wireless communication to non-remotely located components (e.g., desktop computer, workstation, mobile device, controller, etc.). In embodiments, remotely located components are operatively connected via one or more receivers, transmitters, transceivers, or the like.

Embodiments include one or more data stores that, for example, store instructions and/or data. Non-limiting examples of one or more data stores include volatile memory (e.g., Random Access memory (RAM), Dynamic Random Access memory (DRAM), or the like), non-volatile memory (e.g., Read-Only memory (ROM), Electrically Erasable Programmable Read-Only memory (EEPROM), Compact Disc Read-Only memory (CD- ROM), or the like), persistent memory, or the like. Further non-limiting examples of one or more data stores include Erasable Programmable Read-Only memory (EPROM), flash memory, or the like. The one or more data stores can be connected to, for example, one or more computing devices by one or more instructions, data, or power buses.

In embodiments, circuitry includes one or more computer-readable media drives, interface sockets, Universal Serial Bus (USB) ports, memory card slots, or the like, and one or more input/output components such as, for example, a graphical user interface, a display, a keyboard, a keypad, a trackball, a joystick, a touch-screen, a mouse, a switch, a dial, or the like, and any other peripheral device. In embodiments, circuitry includes one or more user input/output components that are operatively connected to at least one computing device to control (electrical, electromechanical, software-implemented, firmware-implemented, or other control, or combinations thereof) one or more aspects of the embodiment.

In embodiments, circuitry includes a computer-readable media drive or memory slot configured to accept signal -bearing medium (e.g., computer-readable memory media, computer-readable recording media, or the like). In embodiments, a program for causing a system to execute any of the disclosed methods can be stored on, for example, a computer-readable recording medium (CRMM), a signal -bearing medium, or the like. Non-limiting examples of signal-bearing media include a recordable type medium such as any form of flash memory, magnetic tape, floppy disk, a hard disk drive, a Compact Disc (CD), a Digital Video Disk (DVD), Blu-Ray Disc, a digital tape, a computer memory, or the like, as well as transmission type medium such as a digital and/or an analog communication medium (e.g., a fiber optic cable, a waveguide, a wired communications link, a wireless communication link (e.g., transmitter, receiver, transceiver, transmission logic, reception logic, etc.). Further non-limiting examples of signal-bearing media include, but are not limited to, DVD-ROM, DVD-RAM, DVD+RW, DVD-RW, DVD-R, DVD+R, CD-ROM, Super Audio CD, CD-R, CD+R, CD+RW, CD-RW, Video Compact Discs, Super Video Discs, flash memory, magnetic tape, magneto-optic disk, MINIDISC, non-volatile memory card, EEPROM, optical disk, optical storage, RAM, ROM, system memory, web server, or the like.

TERMS AND CONDITIONS The detailed description set forth above in connection with the appended drawings, where like numerals reference like elements, are intended as a description of various embodiments of the present disclosure and are not intended to represent the only embodiments. Each embodiment described in this disclosure is provided merely as an example or illustration and should not be construed as preferred or advantageous over other embodiments. The illustrative examples provided herein are not intended to be exhaustive or to limit the disclosure to the precise forms disclosed. Similarly, any steps described herein can be interchangeable with other steps, or combinations of steps, in any suitable combination and/or order to achieve the same or substantially similar result. Generally, the embodiments disclosed herein are non-limiting, and the inventors contemplate that other embodiments within the scope of this disclosure can include structures and functionalities from more than one specific embodiment shown in the figures and described in the specification.

In the foregoing description, specific details are set forth to provide a thorough understanding of example embodiments of the present disclosure. It will be apparent to one skilled in the art, however, that the embodiments disclosed herein can be practiced without embodying all the specific details. In some instances, well-known process steps have not been described in detail in order not to unnecessarily obscure various aspects of the present disclosure. Further, it will be appreciated that embodiments of the present disclosure can employ any combination of features described herein and/or alternatives thereof.

Although the term “hemodialysis” is used throughout this disclosure for consistency and to facilitate understanding, the dialysis fluid processing systems expressly or implicitly disclosed herein are not limited to use with hemodialysis machines.

As used herein, the terms “fluid” and “fluidly”, when used to refer to connections of certain structures such as channels, conduits, connections, and the like, refer to the property of such elements being in fluid or fluidic communication with each other, whether directly or indirectly, such that a fluid (e.g., a liquid), can flow from one such element to another such element via one or more connections therebetween. The present application can include references to directions, such as "vertical," "horizontal," "front," "rear," "left," "right," "top," and "bottom," etc. These references, and other similar references in the present application, are intended to assist in helping describe and understand the particular embodiment (such as when the embodiment is positioned for use) and are not intended to limit the present disclosure to these directions or locations.

The present application can also reference quantities and numbers. Unless specifically stated, such quantities and numbers are not to be considered restrictive, but examples of the possible quantities or numbers associated with the present application. Also in this regard, the present application can use the term "plurality" to reference a quantity or number. In this regard, the term "plurality" is meant to be any number that is more than one, for example, two, three, four, five, etc. The term "about," "approximately," "near," etc., includes the stated value as well as non-stated values that are near to or approximate the stated value according to practicable ranges as would be recognized by those skilled in the art. The term "based on" means "based at least partially on."

For the purposes of the present disclosure, the phrase "at least one of A, B, and C," means (A), (B), (C), (A and B), (A and C), (B and C), or (A, B, and C), including all further possible permutations when greater than three elements are listed. Likewise, as used herein, the term “A, B, and/or C” means (A), (B), (C), (A and B), (A and C), (B and C), or (A, B, and C), including all further possible permutations when greater than three elements are listed. Unless otherwise stated, the term “or” is an inclusive “or”, and the phrase “A or B” means (A), (B), or (A and B). Unless otherwise stated, the term “and” requires both elements; for example, the phrase “A and B” means (A and B).

In the claims and for purposes of the present disclosure, the terms “comprising,” “comprises,” “comprise,” and the like, are open ended and do not exclude any additional features, elements, materials, or steps from those recited or described.

The principles, representative embodiments, and modes of operation of the present disclosure have been described in the foregoing description. However, aspects of the present disclosure, which are intended to be protected, are not to be construed as limited to the particular embodiments disclosed. Further, the embodiments described herein are to be regarded as illustrative rather than restrictive. It will be appreciated that variations and changes can be made by others, and equivalents employed, without departing from the spirit of the present disclosure. Accordingly, it is expressly intended that all such variations, changes, and equivalents fall within the spirit and scope of the present disclosure as claimed.

While illustrative embodiments have been illustrated and described, it will be appreciated that various changes can be made therein without departing from the spirit and scope of the invention.