Patent Description:
Various fluid handling devices, including cassettes, are known for use in a multiplicity of technical fields (see, for example, <CIT>, <CIT>, <CIT> and <CIT>. These also include certain bio-processing related applications.

Bio-processing is generally a mature technology, with generally accepted and validated processing methodologies. Each process generally has specific associated equipment. However, the cost of that equipment and the inflexibility of those accepted practices are a barrier to entry in the industry. Additionally the usual route to a validated process is to start with a pilot scale process before scaling up to increased production. The conventional way of scaling up is increase the size (and cost) of the equipment used, which means that the then scaled up process needs to be revalidated, and the pilot scale equipment is then redundant.

Technically skilled operators are conventionally required at all stages of bio-processing, which adds to costs and is a barrier for developing economies to enter the industry. Conventionally bioprocessing equipment comprises discrete hardware components which are interconnected in use by fluid lines. Efforts to simplify individual elements of that hardware abound, but technical solutions to integrate substantially complete bioprocessing hardware at the pilot and up-scaled stages are rare, and would provide a significant technical and commercial advantage.

Most bio-processing is carried out in batches because some of the hardware used can process only a certain volume before it needs to be changed. Each time a batch is processed the equipment has to be sterilized, leading to additional cost.

Some attempts to integrate biological processes have been made at the microfluidic level, but the resultant apparatus is of no use in processing useful amounts of material in bio-processing, for example several ml or more, tens of ml, or liters.

Various aspects and embodiments of the present invention, as defined by the appended claims, are therefore provided.

The object of embodiments of the present invention is to provide a modular bioprocessing unit which has multiple hardware functions combined into a single generally sealed housing so that the unit can be used for multiple bioprocessing functions singly (a unit), or in multiples (a system) when interconnected with other identical or similar units. Thus, other than unavoidably large parts of a bio-processing system such as, fluid reservoirs, chromatography columns, bio-reactors, filters or membranes, all or most of the hardware associated with bio-processing can be formed into one modular unit, where the term 'modular unit' is intended to mean a unit which is adapted to operate with one or more like units, for example where each unit has complementary physical features to effect such a cooperative operation. In order to facilitate low cost manufacture and modularity, such units could have identical or similar external dimensions and form a whole by their common assembly, for example in an external frame or connected in abutting relationship at complementary sides or edges of the units, and/or where inlets and outlets of the units are arranged such that direct abutting contact between units provides a fluid passage between units. Alternatively, or in addition, fluidic interconnections may be made via intermediate tubes in some instances. The use of an external frame may provide for electrical and/or pneumatic power, and electrical signal communication to the units which form a system.

Where multiple units are used together, it is possible to form a continuous integrated bio-processing system where specific steps are undertaken in series and/or in parallel, as explained in more detail below. In particular one unit can be used whilst another is replenished, washed, or otherwise readied for further bio-processing whilst the one unit is processing.

Herein the term 'modular' is intended to encompass hardware capable of being connected directly to, or adjacent to, other similar hardware in a stack, row, column, array, or other pattern, preferably so that the combined hardware functions together, for example in series or parallel as a system, but where a single unconnected piece of hardware can function independently as a unit if needed. This invention is different to so called modular components of a system that comprise different hardware and carry out specific unique functions but that can be put together in numerous ways. Such known modular components cannot be used independently as a bio-processing unit, but rather need to be put together with multiple other different components to make such a system.

More further advantages and benefits of the present invention will become readily apparent to the person skilled in the art in view of the detailed description below.

The invention will now be described in more detail with reference to the appended drawings, wherein:.

<FIG> shows schematically a bio-processing unit <NUM> which includes a modular housing <NUM> in the form of a cassette which includes various inlets and outlets described in more detail below. In summary, the unit has integral components comprising or consisting of: a selection valve <NUM> used to select an input fluid (a liquid or gas) typically a buffer fluid; a fluid flow inducing component in this case a pump <NUM>; a flow meter <NUM>; a sample fluid inlet <NUM> used typically to introduce a sample fluid into a buffer fluid; various two way valves <NUM> which have a common construction and are described in more detail below, but have the function of allowing fluid flow entry or egress between the components listed here; a pH sensor <NUM>; a conductivity (Cond') sensor <NUM>; and a UV flow cell spectrophotometer <NUM> for determining light absorbance characteristics of fluid in the cassette, or an air trap (not referenced). The construction of each of these components is known generally but may be adapted to suit this application as described below. The components of the unit <NUM> are interconnected internally of the cassette by a fluid path or paths <NUM> to provide a substantially complete bio-processing unit which can be used for multiple applications. Whilst the order of the components as illustrated is preferred for practical reasons, the order could be changed without significant loss of utility.

In order to that plural units can be brought together to form a bio-processing system, a cassette holder <NUM> is illustrated in <FIG>, which can hold plural units <NUM> side by side such that their inlets and outlets can be connected either directly where possible, or can be connected by interconnecting fluid paths, such as tubes fitted to quick couplings or the like. If the units are connected directly, then side inlets and outlets e.g. <NUM>, <NUM>, <NUM>. <NUM>, where 'side' means the side in view in <FIG> and an opposing side not visible in <FIG>, may be brought together so that the units, with the help of valves and an external control <NUM>, can be selectably brought into use either one by one, serially together or in parallel to suit the bio-processing function required. Simple annular seals can be employed around the inlets/outlets which connect units together for example in a stack as shown in <FIG>. In that case the stack of units provides a three dimension arrangement of fluid paths <NUM>, and where the inlets and outlets are arranged on both sides of the cassette, the valves can be used to control flow into and out of adjacently stacked cassettes. Where supplementary inlets and outlets are needed, for example where a chromatography column is interposed in a fluid flow, then such inlets and outlets can be formed at edges of the units, e.g. the edges of the stacked units shown exposed in <FIG>. It will be apparent that edge to edge abutment would also be a practicable arrangement, providing more access for fluidic interconnections by means of interconnecting tubing. In that case intermediate tubing could be used for interconnections between plural units formed into a system, optionally using aseptic connections, for example provided commercially under the trade name INTACT Connectors, by Medinstill Development LLC.

<FIG> and <FIG> show one example of a construction which could be adopted to make a unit <NUM>, not falling under the scope of the claims.

<FIG> shows an exploded view of the three main parts used, and <FIG> shows the same parts exploded, but viewed from a different angle. The main parts are front plate <NUM>, a middle plate <NUM>, and a back plate <NUM>, each formed from plastics material such as polypropylene or polycarbonate. Each plate is, in use brought into a fluid tight sealing contact with its neighbor to form a fluid tight assembled unit <NUM>, by means of holes <NUM> which enable fasteners (not shown) to compress the plates into said sealing contact.

The front plate <NUM> has a front face 112f which includes various selectable inlets <NUM>,<NUM>,<NUM>,<NUM>,<NUM>, <NUM>,<NUM>, and further ports (inlets or outlets) formed by orifices <NUM>, <NUM>, <NUM>,<NUM>,<NUM>,<NUM>,<NUM>. These ports are illustrated as simple through-apertures, but in practice are likely to be terminated with a quick coupling of known construction, suitable for fluidic connections to external bio-process components, or to other units <NUM> in a system. In addition, the front face 112f of plate <NUM> has exposed stems <NUM> of values <NUM>, which stems include a slot <NUM> indicating the position of the valves <NUM>. The stem <NUM> of the selection valve <NUM> is also exposed in the face 112f and also includes indicia representing the routing position of the selection valve <NUM>. The remaining features shown on face 112f are indicia representing the internal interconnections between the inlets, outlets and valves, and the internal sensors employed.

The rear face 122r of the plate <NUM> (<FIG>) shows that the inlets and ports extend through the plate to the rear face, as do the valve stems <NUM>.

Middle plate <NUM> in use receives or expels liquid flow via the inlets/outlets which extend through front plate <NUM> to reach the middle plate front surface 114f. Channels <NUM> formed in a front surface 114f form one or more fluid paths from interconnecting the components of the unit <NUM> and the various ports <NUM>, <NUM>, <NUM>,<NUM>,<NUM>,<NUM>,<NUM>. Whilst the unit flow can be reversed, the preferred direction of flow is as illustrated by the arrows shown within the channels <NUM>. Valve stem <NUM> can be rotated to select one of the selection valve inlets <NUM> to <NUM> to import fluid. Pump <NUM>, in this case a flexible gear pump with one of the gears driven by an electric motor <NUM>, is operable to induce flow. Such a gear pump is described in a co-pending patent application PCT/ <CIT> which disclosure is incorporated herein by reference. The flow meter <NUM> is positioned immediately downstream of the pump <NUM>. The flow meter is of known construction for example an optical flow meter where light is scattered when a particle crosses the first beam and detecting optics collects the scattered light on a photodetector, which then generates a pulse signal. As the same particle crosses the second beam, the detecting optics collect scattered light on a second photodetector, which converts the incoming light into a second electrical pulse. By measuring the time interval between these pulses, the fluid velocity is calculated as V=D/t where D is the distance between the laser beams and t is the time interval. For a known cross sectional area of the flow path <NUM>, and a known density of fluid, a mass flow rate can be calculated.

The inlet <NUM> provides a route for additional sample fluid to be injected into the flow path <NUM>. Two one-way valves <NUM> provide for sample injection to be directed only downstream of the inlet <NUM>. In use fluid flow would next encounter a pressure sensor <NUM> of known construction, for example a resilient element strained by differential pressure in the fluid path and connected to an optical element deflectable with said resilient element and thereby used to quantify said pressure as the optical element's characteristics change. After the pressure sensor, fluid flowing will encounter one of the valves <NUM> shown in <FIG> with its stem <NUM> shown in section and thereby showing the arcuate path (<NUM> <FIG>) through the stem which path can be diverted by rotation of the valve stem, to reposition the path into one of three flowing positions. Thereby fluid can flow toward the remaining components of the cassette <NUM> as illustrated or out through the adjacent path leading to the orifice <NUM>. The same description applies to the two other valves immediately downstream of the valve described above. Pressurized flow could be brought in to the orifices <NUM>,<NUM>, and <NUM> of course, and then directed by the valves <NUM>.

Further downstream is another pressure sensor <NUM>, a pH sensor <NUM>, a conductivity sensor <NUM> and a UV light spectrophotometric flow cell for measuring light absorbance of fluids, all having known constructions. A further two valves <NUM> allow for fluid flows to be diverted in use, for example in response to the outputs of the sensors mentioned.

The back plate <NUM> has a front face 116f which carries electrical conductors <NUM> for carrying power and signals to respective sensors, and has an opening for holding the pump motor <NUM>. The plate <NUM> also carries a connector block <NUM> for connecting said conductors to an external control <NUM> (<FIG>) via complementary connectors (not shown) located in the holder <NUM>. The conductors make contract with complementary conducting elements on the rear face 114r of the middle plate <NUM> at assembly of the plates <NUM>, <NUM> and <NUM>. Also, the stem of motor <NUM> engages on assembly with the driven gear of pump <NUM>.

<FIG> show enlarged views of one of the valve stems <NUM>, wherein the slot <NUM> is shown more clearly which aligns with an arcuate duct <NUM> in the stem, each side of which is a seal <NUM> for sealing against a respective stem orifice in the front and middle plates.

<FIG> shows schematically an alternative pump construction <NUM>', wherein an actuator <NUM>' drives a piston <NUM>' within a chamber <NUM>' in a reciprocating manner, and two one-way valves <NUM>' restrict flow in in a flow path F to one direction indicated by arrow F. That construction provides a lower cost solution to the gear pump <NUM> described above. The actuator could be electrically or pneumatically driven for example.

<FIG> shows an enlarged view the selection valve stem <NUM>, wherein a rear face of the stem (viewable on face 112r in <FIG>) is uppermost, and includes a selection valve channel <NUM> for diverting fluid flow from the desired inlet to the internal fluid flow path formed in face 114f and positioned at the center of rotation of the stem <NUM> in this case. An annular seal <NUM> inhibits valve leakage.

It should be noted that one or more of the sensors <NUM>, <NUM>,<NUM> and <NUM> could be replaced by an inlet and an outlet, with or without a valve <NUM>, arranged to divert any fluid flow to a remote sensor with equivalent functionality to the sensor replaced. In that case, it could be possible to reuse such a remote sensor after disposal of the remainder of the unit <NUM>.

The invention is not to be seen as limited by the embodiments described herein, but can be varied within the scope of the appended claims as is readily apparent to the person skilled in the art. For instance, it is envisaged that other valve constructions could be used which are equally low cost and thereby suitable for disposable units. One such valve construction is a pneumatically operable diaphragm valve for example of the type described in co-pending <CIT> where pneumatic control is used to open and close valves whereby directing fluid flow in place of the valves <NUM>. That that case the pneumatic supply used to drive the valves could be used to drive the pump <NUM>' also. A connector block similar to the connector block <NUM>, would be used if pneumatic power and or valve signals were employed. Whilst it is possible to manually control the valve operations, as described above, automated control, for example via controller <NUM> is preferred. In that instance pneumatic valves or motorized valves could be used in place of the manually selectable valves <NUM> and <NUM> illustrated. In addition, it should be noted that the specific embodiments described herein could be constructed in various ways other than the construction shown. For example, the electrical power connections <NUM>, could be omitted and the sensors could be made internally powered for example by means of batteries and thereby need just signal connections. The sensors could be made RF activated, and would then need no power other than that provided by the RF energy used to induce a sensor response from the relevant sensor. Thereby both signal and power connections could be omitted, other than a power/pneumatic supply to the pump <NUM>. Since the units are formed wholly or predominantly from plastics material and can be supplied for use in substantially sterile hermetically sealed packaging, then they are suitable as single use devices.

For low cost a single generic cassette <NUM> could be made, but with different throughput capacity, for example different channel <NUM> cross sectional areas and different pump capacities. In that way, scale up of the system is possible without the need to revalidate the process. In another alternative the cassettes could be optimized to suit a predefined bio-processing function, for example cassettes designed specifically for chromatography, or filtration, or virus inactivation etc. and thereby such specialized cassettes may omit sensors or pumps not used for that particular application. However, the external configuration of the cassette can be kept universal so that all cassettes fit a common external holder, such as holder <NUM>.

<FIG> illustrates the unit <NUM> as a functional schematic representation, where the unit components are set out in a linear series. In this variant, the UV light absorbance meter is upstream of the conductivity and pH sensors but this merely illustrates that the exact order of the components could be different to the order which is illustrated in <FIG>.

<FIG> shows the unit of <FIG> employed with a chromatography column, filter, membrane or other external component <NUM>. The direction of flow in use is illustrated by the various arrows and in particular the flow is diverted through the external component <NUM> by valves <NUM>. Selection valve <NUM> can be used initially to take in fluids at inlet <NUM> for example from a cell culture vessel or the like (not shown), process those fluids and deliver them to outlet <NUM> for as long as the sensors indicate that a desired fluid is available at the outlet <NUM>. Before and/or after that period, unwanted fluids can be delivered to the outlet <NUM> as waste etc. Cleaning fluid or secondary fluids can then be taken in at inlet <NUM> and if necessary delivered to the waste outlet <NUM>.

<FIG> shows a second application of the unit <NUM>, in this instance used together with a second unit <NUM>' to form a bioprocessing system, along with a filtration device <NUM> and a holding tank <NUM>. With this arrangement, it is possible to perform conditioning steps e.g. filtration or liquid conditioning between chromatography steps. Sample treatment by means of ultrafiltration or diafiltration or cross flow filtration and/or liquid conditioning an also be performed selectively.

<FIG> shows the unit <NUM>, together with a second unit <NUM>' for viral inactivation, where a protein (called protein A in this case) can be introduced from a chromatography apparatus or culture volume into port <NUM> along with a base from port <NUM> and diverted to a holding tank <NUM> for viral inactivation. The pH of the tank can be adjusted with the addition of an acid from port <NUM>. The fluid in holding tank <NUM> can be processed in a second unit <NUM>' after a time in the tank <NUM>, by diverting flow into a cross flow filter <NUM>' and out via a valve 180c'. the viral inactivation step can be omitted by diverting fluids along path <NUM> to ward a valve 180c and into the second unit <NUM>' for filtration at filter <NUM>'.

<FIG> shows three units <NUM>, <NUM>' and <NUM>" used together for three stages of a chromatographic bio-processing of a sample S, for example a sample fluid containing a protein of interest which is to be concentrated, and including three chromatography columns <NUM>, <NUM>' and <NUM>". Operation could take place serially i.e. using one column after the other for greater concentration of the eluted product at output E, or sequentially, i.e. one unit is operable until its chromatography media is saturated or fully bound and the breakthrough is captured at the second column until then the flow is switched to the next unit and so on, or continuously i.e. in that sequential manner, but additional with a purifying step for a resting column to make it ready to further operation when needed. In each case the valves used can be switched accordingly and waste products can be diverted to a waste path W rather than to the output E.

<FIG> and <FIG> show a bio-processing unit <NUM> according to the invention, which can function in the same manner as the bio-processing units described above. Therein, two principal layers, a fluidic layer <NUM> and a pneumatic layer <NUM> are illustrated, separated by a support layer <NUM> and a flexible elastomeric layer <NUM>. The fluidic layer <NUM> has fluid conduits <NUM>, only some of which are referenced, providing inlets and outlets as described above only two of which <NUM>- <NUM> are referenced. The direction of flow at junctions <NUM> in said paths is controlled by go/no-go membrane valves <NUM>, only one of which is referenced, for example, one formed at each leg of the junction <NUM>. By opening a pair of valves in desired legs of the junction corresponding to the desired fluid flow path, then fluid can be directed correspondingly only along those open legs. Flow can be split by opening three or more membrane valves. Flow can be partially restricted by offering a fractional gas pressure or vacuum in a pneumatic channel. Pulsed pressure or vacuum could also be employed to partially restrict flow. Gas pressure /vacuum pulse width modulation can also be used to variably restrict flow. Pneumatic layer <NUM> and support layer <NUM> together direct gas pressure and/or vacuum via pneumatic channels <NUM>, to deflect an associated portion of the membrane <NUM> , and thereby to effect the opening or closing of respective fluid paths <NUM> for valving, as mentioned immediately above. Each pneumatic channel has a respective nipple <NUM>, for a suitable pressured gas supply and/or vacuum connection.

In order to induce fluid flow in the fluid channels <NUM> a pump <NUM> is provided, in this case formed from <NUM> chambers which are compressible or expandable. Preferably, each chamber has an inlet and outlet and a one-way valve at its respective inlet and outlet, and so the arrangement for each chamber is similar to the pump <NUM> shown in <FIG>. However, the pump will work with just a pair of one way valves serving one or more chambers. The pump may be powered electrically via solenoids, or pneumatically using the same pressurized gas supply that will operate the valves.

The above examples should not be seen as limiting. It is envisaged that any of the following bioprocessing steps could be performed with the unit described above, either operating singly or together with multiple units as system: cell removal by filtration of a liquid culture medium comprising a recombinant therapeutic protein or the like; chromatographic capture using additional apparatus such as a chromatographic column or separation membrane for capturing cells, viruses or recombinant therapeutic protein from a liquid culture medium; viral inactivation; solution conditioning; one or more polishing steps via chromatographic columns or membranes; ultrafiltration/diafiltration after chromatographic purification; sample/solution conditioning; and/or providing means for a column switching chromatography. Where multiple units are used to form a system, the controller <NUM> is operable to control the operating sequence of the valves and pumps used, in accordance with a predefined program, where necessary modified by data representative of sensor readings. It is further possible that each unit has its own control and that the units are connectable via a communication bus, so that the units communicate, for example, one unit being designated as a master unit, and the remaining unit(s) acting as slave units.

Claim 1:
A bio-processing system for use with at least one chromatography column (<NUM>, <NUM>', <NUM>") and including at least one modular bio-processing unit (<NUM>) operable with like units, the, or each, unit (<NUM>) comprising:
a housing (<NUM>) having one or more internal fluid paths (<NUM>), the housing (<NUM>) having plural inlets (<NUM>,<NUM>,<NUM>,<NUM>,<NUM>,<NUM>,<NUM>);
a selection valve (<NUM>) for selecting an inlet (<NUM>,<NUM>,<NUM>,<NUM>,<NUM>,<NUM>,<NUM>);
one or more fluid flow inducing components (<NUM>) operatively associated with the or each fluid path (<NUM>);
plural additional ports (<NUM>,<NUM>,<NUM>,<NUM>,<NUM>,<NUM>,<NUM>), downstream of the intended flow in the one or more internal fluid paths (<NUM>);
one or more sensor elements (<NUM>,<NUM>,<NUM>,<NUM>) operatively associated with the or each path (<NUM>), said sensor(s) elements (<NUM>,<NUM>,<NUM>,<NUM>) including one or more of: a flow sensor, a conductivity sensor, a pressure sensor, a pH sensor, and a light absorbance sensor such as a UV spectroscopic concentration sensor; and
plural valves (<NUM>) for preventing or reducing flow in the or each path (<NUM>) and for selectively diverting flow relative to the plural additional ports (<NUM>,<NUM>,<NUM>,<NUM>,<NUM>,<NUM>,<NUM>) and said one or more sensor elements (<NUM>,<NUM>,<NUM>,<NUM>), wherein:
the, or each, unit (<NUM>) comprises at least three layers (<NUM>, <NUM>, <NUM>, <NUM>) therein; and
wherein the at least three layers comprise a fluidic layer (<NUM>) and a pneumatic layer (<NUM>) separated by a support layer (<NUM>), and wherein a flexible elastomeric layer (<NUM>) is provided between said support layer (<NUM>) and said fluidic layer (<NUM>).