Bio-artificial liver

Abstract

A bio-artificial liver support system for continuous and discontinuous treatment providing liver support for a patient, the system comprising: a chamber comprising a biomass; a tubing system comprising a plurality of circuits adapted to provide for independent circuit operation with respect to an apheresis machine or patient; and monitoring apparatus comprising one or more sensors adapted to collect, record, analyse, download and / or store data from the system.

Description

[0001]Bio-artificial Liver The present invention relates to the field of extracorporeal liver perfusion and, more particularly, to a bio-artificial liver. At present, the main treatment for acute and chronic liver disease and liver failure is transplantation. However, such transplantation has the problem that it is restricted by the availability of donor organs. Thus, for a patient that has liver disease or liver failure, there is an urgent need for a device which can temporarily perform the function of a patient's liver, keeping the patient alive whilst a suitable donor organ is found, or which provides an environment to ensure that the patient can be supported whilst the patient's own liver recovers sufficient functionality for their survival. Two types of device have been produced to try to meet the above need, namely a purely artificial liver machine and a bio-artificial liver machine. Both types of machine rely on perfusion of a patient’s plasma or blood into an extracorporeal circuit for a period of six or more hours. Purely artificial liver machines are physical or chemical in nature, and typically provide a detoxification function by adsorption or exchange, for example, using resin, charcoal, ion exchange columns and / or albumin. Bio-artificial livers contain a biological component such as liver cells, either alone or in combination with an artificial device as a hybrid system. Such systems have typically used either human or animal (e.g. porcine) liver cells. Bio-artificial livers have been developed that used hollow fibre cartridges in which cells were separated from plasma or whole blood by a membrane. EP 2170429 relates to a system in which a biological chamber can be housed to form a bio- artificial liver. One of the problems associated with previous devices is the requirement for the bio-artificial liver device to be connected to a patient and / or an apheresis machine at all times otherwise having to restart. The present invention seeks to address this problem. According to a first aspect, there is provided a bio-artificial liver support system for continuous and discontinuous treatment providing liver support for a patient, the system comprising: a chamber comprising a biomass; a tubing system comprising a plurality of circuits adapted to provide for independent circuit operation with respect to an apheresis machine or patient; and monitoring apparatus comprising one or more sensors adapted to collect, record, analyse, download and / or store data from the system. Preferably, the monitoring apparatus further comprises a graphical user interface adapted to display the data. Preferably, the monitoring apparatus comprises one or more sensors and the graphical user interface. Advantageously, the system enables fluids, including but not limited to whole plasma, to perfuse a biomass constrained within a chamber in a fluidised bed configuration. Advantageously, the system may be operated for prolonged periods of several days. Preferably, the chamber is sterile and / or disposable. Preferably, the chamber comprises a baseplate and a cylindrical wall. In one embodiment, the chamber has a mean flow velocity (between 1 and 10 mm above the baseplate) of 3.67x10-4 m / s at 1 mm, decreasing with the height of the cross-sectional area to 2.58x10-4 m / s at 10 mm above the base plate, at a flow of 320 ml / min, according to the following equation: y = -0.00005ln(x) + 0.00036 with a correlation (R²value) of 0.97085. Advantageously, when the chamber has a mean flow velocity in accordance with the above parameters, this enables satisfactory fluidization of biomass in the chamber. Furthermore, the advantage of the above average flow velocity (i.e. obtained at 320ml / min fluid flow) is to ensure that there is homogenous distribution of flow through the chamber and the fluidized biomass which has an impact on both cell proliferation, both during biomass preparation and when in use in the system for patient treatment. If the above parameters are not used, the mass transfer will be compromised, and channels may appear within the biomass enabling the plasma flow to bypass the biomass such that the patient may not benefit from the full functional biomass treatment. In addition, if the above parameters are not used then the optimal fluidisation of the biomass is not achieved within the system. It is preferred that the fluid flow rate range within the chamber is between 250 and 450 ml / min. Preferably, the system is adapted to enable it to run independently of an apheresis machine and / or a patient. Advantageously, the system is operable independently of a patient and / or an apheresis machine. Advantageously, the system may be operated for periods of several days when not connected to a patient or apheresis machine. Preferably, the system is adapted to provide for oxygenation and / or filter exchange when connected or not connected to a patient and / or apheresis machine. Preferably, the system is adapted to provide for temperature management. Preferably, the system comprises a plurality of pumps. Preferably, the pumps run during operation of the system. Advantageously, the provision of the pumps that are adapted to run during operation of the system means that the biomass within the system remains viable. Preferably, the system comprises a bypass circuit design. Advantageously, the provision of pumps and one or more bypass circuits within the system means that the system can run independently of an apheresis machine (e.g. the system does not rely on a pump or pumps provided within the apheresis machine). Advantageously, the system of the present invention enables continuous and discontinuous treatment providing liver support, operating for prolonged periods of several days, whether or not connected to an apheresis machine or patient. Preferably, the system has three circuits, wherein each circuit runs at a different speed. Preferably, the system comprises a fast circuit, a slow circuit and a saline circuit. Preferably, the system has three colour coded circuits, and three bypass lines. Preferably, the system comprises a patient bypass circuit design to allow the system to run independently of an apheresis machine and / or patient. Preferably, the combination of the pumps and the patient bypass circuit design allows the system to operate independently of a patient and / or an apheresis machine. In one embodiment, the bypass design may be adapted to stop the slow circuit whilst keeping the fast circuit in operation. In one embodiment, the saline bypass design may be adapted to stop the slow circuit whilst keeping the fast circuit and saline circuit in operation. Advantageously, the provision of the pumps and bypass circuits means that the flow through the system does not stop, thus preventing coagulation from taking place. Preferably, two circuits are connected via a flow splitter circuit to provide a flow diversion that is dependent on set pump flow rates. Preferably, the chamber is disposable. Preferably, the chamber is sterile. Advantageously, the system delivers biological functionality via excellent mass transfer of chemical entities in a biomass contained between the chamber and a temperature-controllable circulating fluid within the tubing system. Preferably, the system comprises tubing. Preferably, the tubing within the system is sterile. Preferably, the tubing may be transparent. Preferably, the system is adapted to monitor the inline pressure, temperature, oxygen and level of fluid within the system. Preferably, the system is also adapted to measure one or more parameters such as pump speeds, dissolved oxygen and / or bubble trap state. Preferably, the system comprises a safety feature to prevent untreated fluids from re-entering the patient circulation. Preferably, the safety feature comprises a one way valve. Preferably, the system comprises a one way valve to ensure that there is no fluid path backflow or mixing of treated with untreated fluid. Advantageously, the one way valve prevents untreated plasma from returning to the patient. Advantageously, the chamber within the system can be rapidly replaced, either while connected to or disconnected from a patient or apheresis machine. Typically, the chamber is adapted to allow for entry and exit of biomass in an aseptic manner. Preferably, the system acts as a perfusion system mimicking the relationship between portal vein and peripheral venous flows. Preferably, the system comprises a plurality of ports to enable inflow and exit from the system in a sterile manner. Typically, the chamber comprises: (a) a plurality of biomass sampling ports; (b) an inlet; (c) an outlet; (d) a drain port; (e) an oxygen in and out port; (f) a biomass in and out port; (g) one or more filters; (h) a flow distributor; (i) an air inlet / outlet vent to allow for the release of pressure from the chamber; and / or (j) a thermo-pocket to house a temperature probe. It is preferred that the sample ports are provided at different heights with respect to the biomass within the chamber. In one embodiment, the chamber may be injection moulded. Preferably, the chamber is cryopreservable. Preferably, the system uses a fresh, cryopreserved and / or cryorecovered biomass, which enables rapid delivery of temporary liver support to patients using approximately 30-70% liver cell mass. It is preferred that the chamber is dimensioned such that it can hold hydrogel encapsulated biomass representing 30-70% of human liver cell number as biomass, where 30-70% is typically equivalent to 70 billion cells as organoids. Preferably, the chamber comprises a double coiled gas permeable oxygenation path connectable to an oxygen supply via external ports on the chamber. Preferably, the chamber comprises a vent to enable easy priming and emptying of fluid and equalization of pressure. Typically, the chamber is adapted to culture the biomass and recover the biomass after cryopreservation prior to use in the system. It is preferred that the chamber is used to provide a fluidized bed with a height to diameter ratio of up to 2:1. Preferably, the system housing is coated with an antibacterial material. Preferably, the system is adapted to allow for the equalisation of pressures within the system. Advantageously, this feature allows for the equalisation of pressures, for example, in the situation where there are pump speed mismatches (for example that may occur when the system is connected to an apheresis machine). Preferably, the system comprises an air-vent to enable dissipation of oxygen and other gases. Preferably, the system is adapted to allow for modular filter changes using a bypass circuit design without interruption of performance. Preferably, the system is adapted to be operated simultaneously when recirculating, priming or flushing a separate filter. Preferably, the system comprises one or more functional filters and / or one or more safety filters. Preferably the system comprises a functional filter bypass that enables bypassing of the functional filter if required, but not the safety filter. Preferably, the system enables sample collection and sample / fluid addition via injectable needleless fluid ports. Preferably, the system comprises a y-piece and splitter reservoirs, with inbuilt filters to trap escaped particles greater than approximately 270um in diameter, and to equalise pressure build up during a priming and / or treatment phase. Preferably, the system is adapted to provide for the removal of DNA and endotoxin from circulating fluids. Preferably, the graphical user interface allows the data to be saved, permanently stored and / or downloaded by a medical professional operator. Preferably, the graphical user interface comprises a display that provides the following information: the time of day; pump flow rates; the temperature within the chamber; fluid or air residing in the level detector; individual pressures and pressure trends across pressure transducers throughout the tubing circuit; pressure differentials across items positioned within the circuits; and / or the level of dissolved oxygen in the fast flow circuit. Preferably, the graphical user interface is adapted to show the temperature within the chamber as a function of time. Preferably, the graphical user interface is adapted to show the actual pressure differentials across the chamber and / or the filter sets, and as a trend with respect to time. Preferably, the graphical user interface comprises an alarm system to notify the user if a fault develops within the system. Preferably, the alarm may be an audible, visual or verbal alarm. Advantageously, the alarm may be activated if the temperature within the chamber falls outside of the required range during operation of the system, or if the level of dissolved oxygen in the fast flow circuit falls outside of the required range. In one embodiment, the graphical user interface alerts the user according to the alarm status. Preferably, the graphical user interface records the performance of the system using inline / online monitoring. Preferably, the monitoring apparatus comprising the sensors and graphical user interface is adapted to monitor parameters including, for example, temperature, pH, dissolved oxygen, glucose level and / or other metabolic levels. Preferably, the system comprises an air / liquid component that can be emptied or filled during operation of the system. In one embodiment, the air / liquid component may be monitored by an ultrasonic detection system. Preferably, the system comprises a light to illuminate the chamber. Advantageously, the light allows a user to observe and determine the level of the bed height of the biomass, for example, to optimise mass transfer. Preferably, the system comprises means to reduce or increase the level of ambient light within the system. In one embodiment, the means to reduce or increase the level of ambient light is a switch or button. Advantageously, the provision of a means to reduce or increase the level of ambient light within the system allows the system to accommodate the differences between day and night ambient background light, for example, to meet patient comfort expectations. Preferably, the alarm sound can be reduced to accommodate the differences between day and night ambient sounds. Preferably, the alarm sound can be reduced or muted. Preferably, the system comprises a button or switch to mute or reduce the alarm sound. In one embodiment, the alarm may only be muted for approximately one minute before being reactivated. Preferably, the alarm signal is reset once the alarm condition is resolved. Preferably, the system is provided in a unit which comprises four lockable wheels. Advantageously, the system is mobile and may be moved such that it can be positioned in a desired position. Advantageously, the system can be operated at the bedside of a patient. Preferably, the system comprises a handle or push rail. Preferably, the handle or push rail is provided at a height substantially adjacent to the waist of an individual. Advantageously, the handle or push rail is provided at mid height to allow for easy movement of the system (e.g. by pushing or pulling the system). Advantageously, the system is provided in a unit to protect the electronics and mechanics that are housed within the unit. Preferably, the unit comprises two doors that open to approximately 180 degrees. Preferably, the doors may be made from a transparent material. Preferably, the doors may be made from a glass or plastics material. Advantageously, the provision of transparent glass or plastics doors allows a user to monitor the components within the system. Preferably, the unit comprises a drawer to house consumable components and instructions for use. Preferably, the unit comprises one or more (typically three) access hatches to enable access to electric and electronic components of the system. Typically, the access hatches are provided at the rear of the unit. Preferably, the system comprises a surge protector and dipole switch. Advantageously, a dipole switch may be provided to ensure electrical connection to the mains can only lead to correct connection. Preferably, the surge protector and dipole switch are provided at the rear of the system. It is preferred that the surge protector and the dipole switch are placed between the mains power feed and the system. Preferably, the dipole switch and surge protector are the first items placed between the mains power feed and the system. Preferably the surge protector and dipole switch are the first items in the mains cable from the electrical mains supply. Preferably, the surge protector and dipole switch are medical grade approved. Preferably, the system comprises an 8-way mains power strip. Typically, the system comprises a 24 volt power supply to the graphical user interface. Preferably, the system comprises a 5 volt power supply to the ultrasonic detector. Preferably, the system comprises one or more holders for a power cable and for oxygenation tubing when not in use. Preferably, the system comprises a chamber holder. Advantageously, the chamber holder enables ease of chamber swap over and prevents the chamber from toppling over and / or movement during use. Preferably, the chamber holder allows the chamber to be held in an orientation that enables better fluidisation and therefore better mass transfer. Preferably, the system comprises at least one tube holder to prevent / reduce the risk of the tubes within the system becoming damaged during operation of the system. Preferably, at least one tube holder is configured to hold the tubes at different orientations depending on what is required. Preferably, the system comprises holders for plasma, saline and / or waste bags. Preferably, the system comprises electronic provision for six pressure transducer connections. Preferably, the system comprises one or more holders for filter attachment. Typically, the system comprises a tubing circuit diagram on the internal rear face of the system. Advantageously, the tubing circuit diagram allows a user to ensure that the tubing is placed correctly within the system. Preferably, the system comprises a blood warmer to maintain the circuit temperature within the system. Preferably, the system comprises coloured and white clamps on tubing to delineate function. Preferably, the system comprises a mobile workstation which enables continuous operation whether connected or disconnected from a patient, and for a prolonged period, that houses a disposable, cryopreservable, oxygenated fluidised bed bioreactor chamber containing cells and / or organoids, temperature probe, reservoirs for whole plasma or circulating fluids, multiple filters, tubing sets containing pressure transducers, integral filters, dissolved oxygen probe, tubing holders, pumps, a graphical user interface that enables performance monitoring, an ultrasonic air / level detector. Preferably, the system comprises a sensor cover. Advantageously, the sensor cover prevents interference from ambient light. Preferably, the normal operating range, warning range and action required range of the system are visually observed with green, amber and red colours. Preferably, a thermal cover is provided around the outside of the chamber which acts to maintain an even temperature within the chamber. According to a second aspect, there is also provided a method of providing for continuous and discontinuous treatment providing liver support for a patient using a system according to the first aspect. The invention will be further described by way of example and with reference to the following figures, wherein: Figure 1 shows a front view of a system according to an embodiment of the present invention; Figure 2 shows a front view of the internal components of a system according to an embodiment of the present invention; Figure 3 shows a rear view of a system according to an embodiment of the present invention; Figure 4 shows a schematic view of a system according to an embodiment of the present invention; Figure 5 shows a schematic view of the system according to an embodiment of the present invention; Figure 6a shows a side plan view of a chamber according to an embodiment of the present invention; Figure 6b shows a front perspective view of a chamber according to an embodiment of the present invention; Figure 6c shows a front view of a chamber according to an embodiment of the present invention; Figure 7 shows a schematic view of the fast circuit according to an embodiment of the present invention; Figure 8 shows a schematic view of the slow circuit according to an embodiment of the present invention; Figure 9 shows a schematic view of the saline circuit according to an embodiment of the present invention; Figure 10 shows a schematic view of the fast circuit according to an embodiment of the invention, showing sections 1 to 7; Figure 11 shows a schematic view of section 1 of the fast circuit from Figure 10 according to an embodiment of the present invention; Figure 12 shows a schematic view of section 2 of the fast circuit from Figure 10 according to an embodiment of the present invention; Figure 13 shows a schematic view of section 3 of the fast circuit from Figure 10 according to an embodiment of the present invention; Figure 14 shows a schematic view of section 4 of the fast circuit from Figure 10 according to an embodiment of the present invention; Figure 15 shows a schematic view of section 5 of the fast circuit from Figure 10 according to an embodiment of the present invention; Figure 16 shows a schematic view of section 6 of the fast circuit from Figure 10 according to an embodiment of the present invention; Figure 17 shows a schematic view of section 7 of the fast circuit from Figure 10 according to an embodiment of the present invention; Figure 18 shows a schematic view the slow circuit according to an embodiment of the present invention, showing sections 1 to 5; Figure 19 shows a schematic view of section 1 of the slow circuit from Figure 18 according to an embodiment of the present invention; Figure 20 shows a schematic view of section 2 of the slow circuit from Figure 18 according to an embodiment of the present invention; Figure 21 shows a schematic view of section 3 of the slow circuit from Figure 18 according to an embodiment of the present invention; Figure 22 shows a schematic view of section 4 of the slow circuit from Figure 18 according to an embodiment of the present invention; Figure 23 shows a schematic view of section 5 of the slow circuit from Figure 18 according to an embodiment of the present invention; Figure 24 shows a one way check valve that may be used according to an embodiment of the invention; Figure 25a and 25b show a tube holder that may be used according to an embodiment of the invention; Figure 26a is a peristaltic pump that may be used with the fast circuit according to an embodiment of the invention; Figure 26b is a peristaltic pump that may be used with the slow circuit according to an embodiment of the invention; Figure 26c is a peristaltic pump that may be used with the saline circuit according to an embodiment of the invention; Figure 27 is a graph showing the differential pressures measured within the system of the present invention; Figure 28 is a graph showing the temperature and oxygen level measurements within the system of the invention; Figure 29 is a graph showing the results from the fast and slow pumps and the bubble traps measured within the system of the present invention; Figure 30 is a graph showing the measurements of cell viability that were determined using the system of the present invention; Figure 31 is a graph showing the corrected glucose change measured within the system of the present invention; Figure 32 is a graph showing the lactate dehydrogenase change measured within the system of the present invention; Figure 33 is a graph showing the alkaline phosphatase change measured within the system of the present invention; Figure 34 is a schematic representation of the layout provided on the graphical user interface in accordance with an embodiment of the invention; Figure 35 shows a schematic overview of the electronics system according to an embodiment of the invention; Figure 36 provides a schematic overview of the functions of the system according to an embodiment of the invention; and Figure 37 shows a graph demonstrating the average flow velocities within the chamber in accordance with an embodiment of the invention. The reference numerals used in the description below relate to the following components: 2. Bio-artificial liver (BAL) support system 4. Chamber 6. Tubing system 8. Graphical user interface (GUI) 20. Wheels 24. Handle 26. One way valve 28. Peristaltic pump 40. Tube holders 50. Fast circuit 52. Slow circuit 54. Saline circuit 56. Bypass circuit 60. Safety filter 62. Pressure transducer 100. Filter 101. Hydrophobic filter 102. Clamp 104. Cap 106. Female Luer Lock (FLL) 107. Male Luer Lock (MLL) 108. Rotating Male Luer Lock (RMLL) 110. Air trap chamber 114. Pump tube 116. Blood warmer tubing With reference to the figures, there is provided a bio-artificial liver support system 2 for continuous and discontinuous treatment providing liver support for a patient, the system comprising: a chamber 4 comprising a biomass; a tubing system 6 comprising a plurality of circuits adapted to provide for (multiple) independent circuit operation; and monitoring apparatus comprising one or more sensors adapted to collect, record, analyse and store data from the system. With reference to the figures, the monitoring apparatus preferably further comprises a graphical user interface (GUI) 8 adapted to display the data. The monitoring apparatus preferably comprises one or more sensor and the graphical user interface, wherein the monitoring apparatus is adapted to collect, record, analyse, store and display data from the system. In one embodiment, the system of the present invention relates to a liver support system that may be used to treat patients suffering with liver failure. The chamber 4 is a disposable biocartridge as shown in Figure 6 that is adapted to hold alginate encapsulated liver-derived cells that are spheroids and creates a microgravity environment via its function as a fluidized bed bioreactor. It is used during three different stages, the first two of which are during production of the ATMP (advanced therapy medicinal product) biomass. The first stage is the biomass cell growth into microspheroids when the micro beads are fluidised in the chamber connected to a reservoir for recirculation (bioreactor reservoir). The second stage is the cell recovery after cryopreservation in cryobags, or in the chamber itself. In the third stage the chamber is used in the workstation providing part of the bio-artificial liver function via its connection to the giving set, and via an apheresis machine, the patient. The chamber is typically produced from medical grade materials: injection moulded cyclic olefin copolymer, 316 stainless steel and medical grade silicone that is used for gassing tubing (platinum cured USPClass VI) and silicone gaskets. The chamber design allows: sterile bead sampling, addition of the hydrogel beads and removal of the hydrogel beads preserving sterility, oxygenation, temperature monitoring and fluidization of the bead biomass. It is preferred that the chamber has a mean flow velocity (between 1 and 10 mm above the baseplate) of 3.67x10-4 m / s at 1 mm decreasing with the height of the cross-sectional area to 2.58x10-4 m / s at 10mm above the base plate, at a flow of 320 ml / min, according to the following equation: y = -0.00005ln(x) + 0.00036 with a correlation (R²value) of 0.97085. Figure 37 shows a graph demonstrating the average velocities within the chamber in accordance with an embodiment of the invention. Advantageously, when the chamber has a mean flow velocity in accordance with the above parameters, this enables satisfactory fluidization of biomass in the chamber. The advantage of the above average flow velocity (obtained at 320 ml / min fluid flow), is to ensure that there is an optimal level of homogenous distribution of flow through the chamber and the fluidized biomass which has an impact on both cell proliferation during biomass preparation, and when in use in the system for patient treatment. Preferably, the fluid flowrate range is between 250 and 450 ml / min A disadvantage of not operating within the above parameters is that if the best fluidization of the biomass is not achieved, the mass transfer will be compromised, and channels may appear enabling the plasma flow to bypass the biomass such that the patient may not benefit from the full functional biomass treatment. It would be understood that the average velocity would change at different flow rates of liquid through the chamber. Whilst the values of the average flow velocities would change, the relationship between values at 1 and 10 mm above the base plate would remain the same as defined above. In one embodiment, temperature stability in the chamber may be aided by the use of the chamber thermal cover that is provided within the system. In addition, the system may comprise one or more sensor covers to prevent interference from ambient light, The bio-artificial liver components are all connected via a “giving set” of tubing, which also connects to an apheresis machine that, in turn, connects to the patient. There are three flow circuits: a treatment (fast) circuit which is comprised of a fast circuit running at flow rates approximating that of blood flow through the liver; a slow circuit running at flow rates that match the plasma flow rates from the apheresis machine, which is in turn dependent on the whole blood flow from the patient, together with the patient’s haematocrit (e.g. the patient’s ratio of plasma and blood cells). There is also a saline circuit used for bypass and priming purposes. Each type of circuit has an element of peristaltic pump tubing which connects to a peristaltic pump 28 that is specific for the particular circuit to which it belongs. There is a fluid inlet path connection to enable attachment to an apheresis machine from the patient and an outlet line path connection (i.e. a line going back to the patient via an apheresis machine). A diagram of the transfer of fluid through the system is shown in Figure 4. The chamber 4 is located within the fast circuit. The fast circuit is where patient plasma is treated and it runs at approximately ten times faster than the slow circuit. Safety (60) and functional filters (100) are located within the slow circuit which returns plasma back to the patient. From the slow circuit the treated plasma is typically delivered to an apheresis machine where it is restored with the cellular components of blood and then returned to the patient. The saline circuit allows recirculation of the functional filters via a peristaltic pump in the event that the slow circuit has to be temporarily halted. The saline circuit also allows for heparinisation of the filters when required, particularly during filter change-over periods. The system typically comprises two sets of two filters (60 and 100) that may be used in parallel, thus allowing the filters to be changed or switched during treatment. In order to change filters, the primary filter may be clamped such that the flow may then be transferred to a secondary filter. Figure 5 shows a schematic representation of the fast circuit 50, slow circuit 52, saline circuit 54 and bypass circuit 56. The giving set typically comprises six pressure transducers for pressure monitoring to alert a user that filter changes may be required. The dissolved oxygen consumption of the biomass is monitored by the use of an inline oxygen sensor. The bio-artificial liver biomass requires oxygen to maintain viability and when the oxygen drops to a critical point it is supplemented directly to the inside of the biomass chamber using gas diffusion via a thin-walled silicone tubing. A one-way valve 26 is located at a patient bypass line which only allows treated plasma that has gone through the safety and functional filters to go back into the fast circuit when needed but blocks the opposite fluid flow. The one-way valve therefore prevents any untreated plasma going back to the patient. The “giving set” is therefore the disposable sterilized tubing set produced for connection to the biomass cartridge at the workstation and to the plasma exchange device for treatment in a clinical setting. Most of the tubing within the giving set is made of medical grade polyvinylchloride (PVC) material. PVC tubing is a transparent flexible tubing that is widely used as a medical product component due to its chemical compatibility and manufacturing from non-toxic resins, and smooth interior and exterior surface which prevents sediment accumulation and lowers the chances of bacterial infection. The PVC tubing is also placticiser free. Where peristaltic pumps are used, specific peristaltic pump tubing is used instead of PVC tubing. The peristaltic pump tubing allows the pump to create a flow around the giving set circuits by use of the pumps. It is preferred that the peristaltic pump tubing comprises Pharmed BPT material or an equivalent material. Advantageously, the system comprises a bypass circuit design to allow the system to run independently of an apheresis machine and / or patient. Preferably, the combination of the pumps and the bypass circuit design allows the system to operate independently of a patient and / or an apheresis machine. The system also comprises male and female luer connectors. These connectors are required in order to make connections in all the giving set non-continuous tubing sections. Preferably, to prevent incorrect positioning of tubing, connections can only be made from a male to female orientation. Additionally, other components within the system are connected via these connectors (e.g. pressure transducers, bags, and connection to and from the plasmapheresis device). The system also comprises a “rotating luer” connector which allows a more stable or permanent connection of the different parts, which makes it less likely for inadvertent disconnection of the tubing. The system also comprises a plurality of T connectors and / or adapters: There are T-shaped tubing fittings to connect different tubing loops. The joins are made by tubing insertion into the connector and solvent gluing. They are called adapters when the tubings to be connected are of different sizes. The system also comprises a plurality of Y connectors / adapters: There are two types of Y shaped tubing fittings to connect different tubing loops together. The first type is a luer free connector: the top two branches at the top are symmetrical and approximately 60 degrees apart. All of the joins are made by tubing insertion into the connector and gluing. The second type is similar; however the main part of the Y connector in this case is straight with a single branch on the side at an approximately 30 degree angle in which a join can be created by rotating the male luer in place. These connectors are known as adapters when the tubing to be connected has different sizes. The system also comprises a saline bag: this is a standard physiological saline bag for intravenous injection in patients. It is used for saline recirculation of the functional and safety filters and re-heparinising the functional filters. The waste bags are two three litre bags that are located in the slow circuit for the collection of the waste fluids during the priming and treatment phases. The waste liquid arises from the initial priming of the circuit, from functional recirculation and from re-heparinisation. Drip chambers are provided within the system and provide different functionalities to the giving set in different parts of the circuit. The giving set typically comprises an inverted drip chamber wherein two drip chambers are located between two Y connectors. The inverted drip chamber comprises a filter having a cover cap provided at the top, wherein the filter has a length of approximately 60 mm and a diameter of approximately 10-15 mm. In one embodiment, the inverted drip chambers are glued to the 6.8 mm outside diameter tubing (fast circuit tubing). The system also comprises a fast-slow circuit splitter chamber which is located within the fast circuit. There is a single flow inlet underneath coming from the inverted drip chambers and a double top outlet allowing the flow to split between the fast and slow circuit. The outlet ports are connected to a sensor in the fast circuit and to the slow circuit. The system also comprises an air trap / level sensor: a drip chamber located in the slow circuit to avoid air bubbles reaching the patient. There is no internal filter inside this drip chamber. The air trap / level sensor has a 0.2 µm sterile hydrophobic filter (101) at the top to enable air to be vented. The system also comprises a drip chamber for the saline bag: a simple spike flow-through chamber located at the saline circuit to observe the fluid drops. The pressure transducers 62 provided within the system convert a pressure waveform into an electrical signal. The six pressure transducers enable the operator to monitor the technical functioning of the bio-artificial liver circuit during a patient connected operation. In one embodiment, six pressure tranducers are located in the giving set and are used to monitor pressure increases, potentially indicating bloackages in the circuit. High pressure readings would be recorded when filters are blocked or clamps are left closed inadvertently. In one embodiment, the circuit uses TruWave PX600 Edwards Sciences pressure tranducers. The one way valve 26 allows fluid flow in only one direction but blocks the opposite fluid flow. In one embodiment, the one way valve (Figure 24) comprises polycarbonate and silicone. Typically, the one way valve is lipid resistant and displays stress-crack resistance when it makes contact with lipid emulsions. The one way valve has a female luer lock inlet and a male luer lock outlet. It is placed in the giving set at the patient bypass line to avoid any of the plasma in the fast circuit flowing back to the patient without going through the safety and functional filters. Table 1 below shows the tubing length tolerances that may be used with the giving set depending on the length of tube used. Table 1 Length Tolerance (+ / -) % Error 50-250mm 5mm 10-2 250-510mm 10mm 4-2 510-2000mm 20mm3.9-12000-4500mm 200mm10-4.4The fast circuit was split into seven sections. Figure 10 shows the fast circuit and the individual sections are shown in Figures 11 to 17. The slow circuit was split into five sections. Figure 18 shows the slow circuit and Figures 19 to 23 shows the individual sections of the slow circuit. The different sections of the fast and slow circuits are prepared in individual bags for sterilization. Each section will have the line drawing of that section on the printed label on the bag so that it can be matched with the instructions for use. The system further comprises a vent to ensure that any excess oxygen was removed from the workstation and did not build up. The position of this vent was chosen to be as close to the source of the oxygen as possible. The vent is comprised of 4 sections; a 3D printed grommet that is inserted into a cut in the workstation frame, a fine sponge-like membrane that sits inside the grommet and two fine meshes that close the opening. The system further comprises a drawer which can be opened easily irrespective of the main workstation doors. The sides of the drawer act as supports for the upper shelf on which the pumps sit and have been reinforced with extra material to prevent bowing. The workstation is required to have a dipole switch and surge protector as per safety requirements for use in hospitals and clinical areas. During operation of the system, data was collected and monitored. Such data included pressures, differentials, oxygen, temperature, bubble trap stateand pump speed.The pressure thresholds of the system are shown in Table 2 below: Table 2 Low out L High out of U ow out of Acceptable High out Parameter nit of of range - range - - operating of ran range - Measure action ge - wa action required rning range warning required BAL Differential mmHg 0 50 50 75 75 180 180 200 200 350 F1 Differential mmHg - 100 -50 -50 0 0 100 100 150 150 200 F2 Differential mmHg - 100 -50 -50 0 0 200 200 250 250 300 PT1 mmHg 0 75 75 125 125 200 200 225 225 300 PT2 mmHg 0 5 5 10 10 35 35 40 40 50 PT3 mmHg -20 -10 -10 0 0 300 300 400 400 500 PT4 mmHg -20 -10 -10 0 0 150 150 250 250 500 PT5 mmHg -20 -10 -10 0 0 150 150 250 250 500 PT6 mmHg -30 -25 -25 -20 -20 30 30 40 40 50 The system comprises functional and safety filters 60. In one embodiment, the functional filter was a 3M Zeta Plus encapsulated filter 60ZB05A 340cm2 surface. The Zeta plus filter is composed of cellulose and a positively charged resin that pulls negatively charged contaminants from the fluid. The positive charge is capable of reducing negatively charged DNA, endotoxins and some proteins. However, the filter does not bind proteins useful for the patient, such as albumin. The filter shape is lenticular and different surface sizes are available. The 340cm2 surface filter size was chosen due to the high capacity with a relatively low dead volume (~1L). It complies with USP 88 Class VI Biological reactivity test and it has an FDA drug master file. The filter may be a 1020cm2 filter. In one embodiment, the safety filter was Betafine 3M PPG series 0.6μm 5” filter capsule. The safety filter performs a size exclusion (0.6μm) fluid particle filtration. A graded porosity multi-layer filter design allows capture of larger sized particle contaminants on the outer media layer. Thus, there is a gradual particle filtration throughout the filter media. This provides an increased filter life (30-50% depending on application) compared to uniform porosity media filters. The Betafine filter is manufactured using a staggered pleat configuration providing more open space between the pleats (up to 50%). The advanced Pleat technology (APT) allows for greater contaminant loading between pleats at the inside diameter. The filter layer is based on polypropylene material, which is manufactured free of adhesives and surfactants and offering low extractable levels when used with compatible solvents. At flow rates of 9.1 litres per minute for water (2 imperial gallons per minute) the 5” Betafine filter differential pressure is 0.1bar (1.5psi, 77.5 mmHg). In terms of pressure capacity, the maximum forward differential pressure the filter could withstand is 4 bar (3000 mmHg at 25°C), and a maximum operating pressure of 4 bar at 40°C. The recommended filter replacement differential pressure is 2.4 bar (1800mmHg). There are three peristaltic pumps 28 provided inside the workstation, which contain a graphical interface with digital LCD to show pump performance. The pump located on the left is used for the fast circuit (Pump 1), the one on the middle for the slow circuit (Pump 2), and the one on the right for the saline circuit (Pump 3). The actual pumps and their location within the workstation can be seen in Figure 1. Pumps 1 and 2 and connected to the GUI controller for monitoring the flow rates applied during the treatment. They are fitted with open head sensors to stop the drive motor when the pump head is opened. Table 3 shows the maximum speed of the three pumps: Table 3 Pump Maximum speed (rpm) 1 (fast circuit) 1700 2 (slow circuit) 1097.2 3 (saline circuit) 600 The system typically comprises a plurality of optical sensors. The measuring principle of the optical sensors is the following: LED light transmitted through an optical fibre excites the optical oxygen sensor to emit fluorescence. The oxygen partial pressure is in dependent on the oxygen level. Optical sensors measure the partial pressure of oxygen either in either a dissolved or gaseous state. The optical sensor is integrated in the inner surface of a flow through cell (T shaped connector) which allows in-line measurement of partial pressure of oxygen. The optical sensor is typically pre-sterilized and pre-calibrated such that it is ready to use and offers a non-invasive contactless technology. The system may further comprise at least one sensor cover. The system typically comprises an access hatch that is provided at the back of the workstation. The graphical user interface 8 comprises a display that provides the following information: the time of day; pump flow rates; the temperature within the chamber; fluid or air residing in the level detector; individual pressures and pressure trends across pressure transducers throughout the tubing circuit; pressure differentials across items positioned within the circuits; and / or the level of dissolved oxygen in the fast flow circuit. During the treatment the graphical user interface is used to monitor the status of the treatment. This is typically completed in conjunction with controlling pump flow rates, pressures, temperatures and patient status during treatment. The graphical user interface may comprise a digital touch screen used to passively read inputs from sensors to alert the user to any problems (e.g. pressure build up, abnormal oxygen levels, etc) and to log data, for example, for post treatment analysis. An example of the display provided on the graphical user interface is shown in Figure 34. With reference to Figure 34, the following information may be provided on the graphical user interface: 1. Individual Pressure values 2. % Dissolved oxygen (DO) value 3. Temperature value 4. Bubble trap information 5. Fast pump speed value 6. Slow pump speed value 7. Differential pressure values The GUI may also provide the following information and / or controls: 1. Alarm mute control 2. Main light brightness control 3. System (BAL) light control 4. Day / night mode 5. Logging and download of data 6. Display trends (e.g. oxygen / temperature trends, differential trends, pressure transducer trends) 7. Alarm demos (e.g. allowing a user to test the alarm) 8. Patient / hospital ID data 9. Selection mode for set-up or treatment 10. User access level “Log in” control The graphical user interface comprises an alarm system to notify the user if a fault develops within the system. Preferably, the alarm may be an audible, visual or verbal alarm. Advantageously, the alarm may be activated if the temperature within the chamber falls outside of the required range during operation of the system, or if the level of dissolved oxygen in the fast flow circuit falls outside of the required range, or if the pressure or pressure differentials are outside of the required operating range. In one embodiment, the graphical user interface alerts the user according to the alarm status. The system comprises a light to illuminate the chamber. Advantageously, the light allows a user to observe and determine the level of the bed height of the biomass, for example, to optimise mass transfer. The system comprises means to reduce or increase the level of ambient light within the system. In one embodiment, the means to reduce or increase the level of ambient light is a switch or button. Advantageously, the provision of a means to reduce or increase the level of ambient light within the system allows the system to accommodate the differences between day and night ambient background light, for example, to meet patient comfort expectations. The alarm sound can be muted or reduced to accommodate the differences between day and night ambient sounds. Preferably, the system comprises a button or switch to mute or reduce the alarm sound. An overview of the system electronics according to an embodiment of the invention is shown in Figure 35. This overview shows an arrangement wherein data from pressure sensors 1 to 6, a temperature sensor and an oxygen probe is collected and is fed into a graphical user interface. In this embodiment, the inputs from various sensors are displayed on the graphical user interface. The data is processed by software within the system and then displayed on the graphical user interface. The data is used to determine whether a particular sensor is within a specified range and if it is not within the range, trigger an alarm. The converted sensor data is also sent to a data logger which is updated during the use of the system and can be used to show data trends. The information shown on the graphical user interface enables an operator to monitor and log multiple elements of the device’s function, including pressures, pump speeds, temperature, dissolved oxygen concentration and bubble trap state. These readings provide an indication of the device’s function. In the embodiment shown in Figure 35, some sensors are provided but not implemented. These sensors may be implemented in other embodiments of the invention. An overview of the functions of the system is shown in Figure 36. This figure shows how a sensor input is converted into a value (e.g. when measuring temperature, the unit is converted into a value in °C). The system assesses whether this value is within a specified range. The value is displayed on a graphical user interface. If the value is not within the range the alarm will trigger. Figure 36 also shows the feature whether the data is logged by the system and used, for example, for analysis at a later stage. Typically, the Graphical User Interface displays colour coded values: green is within acceptable operating range; amber is high, i.e. out of range - Warning; red is high, i.e. out of range - Action required, see Table 2. Thus, the amber colour presents a warning to the user and the red colour shows that action is needed. The system is provided in a unit which comprises four lockable wheels 20. Advantageously, the system is mobile and may be moved such that it can be positioned in a desired position. Advantageously, the system can be operated at the bedside of a patient. The system comprises a handle or push rail 24. Preferably, the handle or push rail is provided at a height substantially adjacent to the waist of an individual. Advantageously, the handle or push rail is provided at mid height to allow for easy movement of the system (e.g. by pushing or pulling the system). Advantageously, the system is provided in a unit to protect the electronics and mechanics that are housed within the unit. The unit comprises two doors that open to approximately 180 degrees. Preferably, the doors are glass or transparent plastic material. Advantageously, the provision of glass doors allows a user to monitor the components within the system. The unit comprises a drawer to house consumable components and instructions for use. The unit comprises three access hatches to enable access to electric and electronic components of the system. Typically, the access hatches are provided at the rear of the unit. The system comprises a surge protector and dipole switch to ensure electrical connection to mains can only lead to correct connection. Preferably, the surge protector and dipole switch are provided at the rear of the system. Preferably the surge protector and dipole switch are the first elements in the mains cable from the electrical mains supply. The system comprises an 8-way mains powerstrip and a 24 volt power supply to the graphical user interface. The system comprises a 5 volt power supply to the ultrasonic detector. The system comprises a holder for a power cable and / or for oxygenation tubing when not in use. The system comprises a chamber holder. Advantageously, the chamber holder enables ease of chamber swap over and prevents the chamber from toppling over during use. The system comprises tube holders 40 to prevent / reduce the risk of the tubes within the system becoming damaged during operation of the system (for example, see Figure 25). The system further comprises holders for plasma, saline and / or waste bags. The system comprises a holder for a filter attachment. The system comprises a tubing circuit diagram on the internal rear face of the system. Advantageously, the tubing circuit diagram allows a user to ensure that the tubing is placed correctly within the system. The system comprises a blood warmer to maintain the circuit temperature within the system. The system comprises coloured and white clamps on tubing to delineate function. The clamps are shown in the figures by reference numeral 102. The clamps used in the system have different sizes and are coloured in accordance with their particular function in this system. In addition, the system typically comprises coloured tubing (e.g. red, blue and green striped tubing) that may also be used to delineate function. During operation, the system monitors, collects and records data including pressure, differentials, oxygen, temperature, bubble trap state and pump speed. Some of the results of the parameters that were measured are shown in the following figures: Figure 27 is a graph showing the differential pressures measured within the system of the present invention; Figure 28 is a graph showing the temperature and oxygen level measurements within the system of the invention; Figure 29 is a graph showing the results from the fast and slow pumps and the bubble traps measured within the system of the present invention; Figure 30 is a graph showing the measurements of cell viability that were determined using the system of the present invention. In addition to cell number and viability data, samples were collected to assess cell functionality at several time points. Figure 31 is a graph showing the corrected glucose change measured within the system of the present invention; Figure 32 is a graph showing the lactate dehydrogenase change measured within the system of the present invention; and Figure 33 is a graph showing the alkaline phosphatase change measured within the system of the present invention. Thus, the system comprises a “giving set” of tubing which is connected to: a biomass chamber, a functional filter, a safety filter, all within a workstation. The giving set is connected to and from an apheresis machine.

Claims

Claims 1. A bio-artificial liver support system for continuous and discontinuous treatment providing liver support for a patient, the system comprising: a chamber comprising a biomass; a tubing system comprising a plurality of circuits adapted to provide for (multiple) independent circuit operation with respect to a patient and / or an apheresis machine; and monitoring apparatus comprising one or more sensors to measure adapted to collect, record, analyse, download and store data from the system.

2. A system according to claim 1, wherein the monitoring apparatus further comprises a graphical user interface adapted to display the data.

3. A system according to claim 1 or 2, wherein the system is adapted to enable it to run independently of an apheresis machine and / or a patient.

4. A system according to claim 1, 2 or 3, wherein the system comprises a bypass circuit design to allow the system to run independently of an apheresis machine and / or patient.

5. A system according to any preceding claim, wherein the system comprises three circuits, wherein each circuit is adapted to run at a different speed.

6. A system according to claim 5, wherein the system comprises a fast circuit, a slow circuit and a saline circuit.

7. A system according to any preceding claim, wherein each of the plurality of circuits and bypass lines are colour coded.

8. A system according to any preceding claim, wherein two circuits are connected via a flow splitter circuit to provide a flow diversion that is dependent on set pump flow rates.

9. A system according to any preceding claim, wherein the monitoring apparatus is adapted to monitor the inline pressure, temperature, oxygen and level of fluid within the system.

10. A system according to any preceding claim, wherein the system comprises a safety feature to prevent untreated fluids from re-entering the patient circulation.

11. A system according to claim 10, wherein the safety feature comprises a one way valve and / or bypass circuits.

12. A system according to any preceding claim, wherein the chamber can be rapidly exchanged.

13. A system according to any preceding claim, wherein the system has ports to enable inflow and exit from the system in a sterile manner.

14. A system according to any preceding claim, wherein the chamber comprises: (a) a plurality of biomass sampling ports; (b) an inlet; (c) an outlet; (d) a drain port; (e) an oxygen in and out port; (f) a biomass inlet and outlet for filling or emptying biomass (preferably hydrogel encapsulated spheroids); (g) one or more filters; (h) a flow distributor; and / or (i) an air inlet / outlet vent to allow for the release of pressure from the chamber, (j) thermo- pocket to house temperature probe.

15. A system according to claim 14, wherein the sample ports are provided at different heights with respect to the biomass within the chamber.

16. A system according to any preceding claim, wherein the chamber comprises a double coiled gas permeable oxygenation path connectable to an oxygen supply via external ports on the chamber.

17. A system according to any preceding claim, wherein the system comprises a y-piece and splitter reservoir, with inbuilt filters to trap escaped particles greater than 270um in diameter, equalise pressure build up during the priming and / or treatment phase.

18. A system according to any preceding claim, wherein the graphical user interface allows the data to be saved, permanently stored and / or downloaded by a medical professional or operator.

19. A system according to any preceding claim, wherein the graphical user interface comprises a display that provides the following information: the time of day; pump flow rates; the temperature within the chamber; fluid or air residing in the level detector; individual pressures and pressure trends across pressure transducers throughout the tubing circuit; pressure differentials across items positioned within the circuits; and / or the level of dissolved oxygen in the fast flow circuit.

20. A system according to any preceding claim, wherein the graphical user interface comprises an alarm system to notify the user if a fault develops within the system. Preferably, the alarm may be an audible, visual or verbal alarm.

21. A system according to any preceding claim, wherein the graphical user interface records the performance of the system using inline / online monitoring.

22. A system according to claim 21, wherein the graphical user interface can be adapted to monitor parameters including pH, glucose and / or other metabolic levels.

23. A system according to any preceding claim, wherein the system comprises an air / liquid component that can be emptied or filled during operation of the system.

24. A system according to claim 23, wherein the air / liquid component may be monitored by an ultrasonic detection system.

25. A system according to any preceding claim, wherein the system comprises a light to illuminate the chamber.

26. A system according to claim 25, wherein the system comprises means to reduce or increase the level of ambient light within the system 27. A system according to any one of claims 20 to 26, wherein an alarm sound can be reduced to accommodate the differences between day and night ambient sound.

28. A system according to any preceding claim, wherein the system is provided in a unit which comprises four lockable wheels, a handle or push rail and / or two doors that open to 180 degrees.

29. A system according to any preceding claim, wherein the system comprises a tubing circuit diagram on the internal rear face of the system.

30. A system according to any preceding claim, wherein the system comprises means to warm the fluid within the system to a desired temperature.

31. A system according to any preceding claim, wherein the system comprises two sets of filters that are adapted to be used in parallel.

32. A system according to claim 31, wherein the system comprises safety and functional filters.

33. A system according to any preceding claim, wherein the chamber has a mean flow velocity (between 1 and 10 mm above the baseplate) of 3.67x10-4 m / s at 1 mm decreasing with the height of the cross-sectional area to 2.58x10-4 m / s at 10mm above the base plate, at a flow of 320 ml / min, according to the following equation: y = -0.00005ln(x) + 0.00036 with a correlation (R²value) of R² = 0.97085.

34. A system according to any one of claims 2 to 33, wherein the normal operating range, warning range and action required range of the system are visually observed with green, amber and red colours.

35. A system according to claim 34, wherein the colours are provided on the graphical user interface within the system.

36. A system according to any preceding claim, wherein a thermal cover is provided around the outside of the chamber which acts to maintain an even temperature within the chamber.

37. A system according to any preceding claim, wherein the system comprises a sensor cover.

38. A method of providing for continuous and discontinuous treatment providing liver support for a patient using a system according to any one of claims 1 to 38.

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