Apparatus for maintaining separation of liquids, and method of using the same to process a sample

Abstract

The present disclosure relates to apparatus for extracting a chemical or biological species from a sample, the apparatus comprising: a first liquid in a first region; a second liquid in a second region, wherein the second liquid is immiscible with the first liquid; and beads for transporting the chemical or biological species; wherein the apparatus is configurable between: a first configuration in which there is a path for transport of the beads from the first liquid in first region to the second liquid in the second region, and a second configuration in which a barrier is provided between the first region and the second region.

Description

[0001]APPARATUS FOR MAINTAINING SEPARATION OF LIQUIDS, AND METHODOF USING THE SAME TO PROCESS A SAMPLEField of the InventionThe invention relates to apparatus and methods for extracting biomolecules, or otherchemical or biological species, from a sample for subsequent testing or analysis.Merely by way of example, the invention may be used for, but is by no means limitedto, maintaining separation of liquids used to extract targeted biomolecules from a swab sample. The term “magnetic beads” as used herein should be interpreted broadly. Firstly, the term “magnetic” should be interpreted broadly, to encompass “paramagnetic”and “superparamagnetic”. Moreover, the term “beads” (or “particles”) should alsobe interpreted broadly, to encompass particles of a range of sizes, including nanoparticles (i.e. particles that are less than 1 µm in diameter), micron-sizedparticles (i.e. of the order of 1 to 500 µm in diameter), and larger particles (potentiallyup to around 1 mm or so in diameter). As those skilled in the art will appreciate, theprinciples of the present disclosure are not limited to any particular size, shape orcomposition of the magnetic “beads”, and for any given application it will beunderstood that the skilled person could use beads of a suitable size, shape,composition, coating and functionalisation. Background to the InventionMagnetic beads can be used in methods for extracting targeted biomolecules froma sample. Magnetic beads typically comprise two components: a magnetic material(often iron, an iron oxide such as magnetite, nickel, or cobalt) and a coating thatenables the beads to attach to biomolecules or other chemical or biological species.Such species may include, but are not limited to, polynucleotides such as nucleic acid (e.g. RNA or DNA), proteins, biological cells, and other chemical or biological molecules.Methods of extracting the target species from the biological sample often usemultiple different liquids or buffers to extract and prepare the species for downstream analysis. For example, a lysis buffer can be used to break down asample and release DNA, RNA or proteins from cells (or, for example, viral capsids),to then be bound to the coating of magnetic beads. A wash liquid may then be usedto remove the lysis buffer and any unwanted biological material from the beads (e.g.without affecting the DNA / RNA / proteins bound to the beads). An elution liquid is then used to elute (release) the target species from the beads into the elution liquid, for subsequent analysis or processing.Whilst magnetic beads are not the only tool that can be used in conjunction with theaforementioned buffers to extract, isolate, and purify targeted biomolecules, they offer a convenient solution due to their high surface area and ability to be manipulated with a magnetic field, thus enabling their selective separation from the buffers. Commonly, the magnetic beads and attached biomolecules are eithermoved through a series of vessels or tubes containing the buffers, or the buffers areadded to and removed from a single vessel or tube, with the magnetic beads beingselectively retained in the tube using a magnetic field that is often produced using astationary magnet.Due to the large number of different buffers and steps that is often needed to extracta target molecule from a sample using magnetic beads, such methods are typicallyused in a laboratory environment and involve the use of numerous tubes, micro- pipettes, mixing devices, and a significant level of training. However, it is often desirable, especially in the case of diagnostic testing, for this process to be performed either at the point-of-care or by untrained users. Therefore, there is aneed for a portable and automatable solution.Recent methods utilise immiscible fluids to separate the different buffers from oneanother, and utilise a magnet to transport magnetic beads through the buffers.Whilst this method has potential to simplify the extraction process by eliminating theneed to completely separate the magnetic beads from each buffer in turn, itpossesses a number of significant technical challenges for adaptation to point-of-care applications. For example, there is a problem that even when immiscible liquidsare used to maintain separation of the reagents, the liquids are nevertheless proneto inadvertent mixing. Such unwanted mixing can be caused by vibrations inducedby transport. Contamination of the elution liquid due to leakage of the lysis buffer or wash liquid (e.g. ethanol) can seriously disrupt any test or analysis performed onthe eluted species. Moreover, this sensitivity to inadvertent mixing can limit theoptions for introducing a sample, particularly for the case of a swabbed specimen,since agitation used to release biological material from the swab can disturb theseparation of the reagents. The use of surface tension to maintain separationbetween immiscible liquids also results in restrictions on the surface area at eachliquid-liquid interface in order to maintain the separation, which can limit the usablevolume of each buffer (or the sample input), potentially decreasing performance. This is particularly an issue when working with ‘dirty’ or complex sample types withlarge quantities of unwanted material.It will be appreciated, therefore, that there is a need for improved apparatus andmethods for mitigating against one or more of the above issues to provide a morereliable, automatable, portable and high performing solution for the extraction of abiomolecule, or other chemical or biological species, from a sample.Summary of the Invention Aspects of the present invention are set out in the appended independent claims, while details of certain embodiments are set out in the appended dependent claims.In a first aspect the invention provides apparatus for extracting a chemical orbiological species from a sample, the apparatus comprising: a first liquid in a firstregion; a second liquid in a second region, wherein the second liquid is immisciblewith the first liquid; and beads for transporting the chemical or biological species;wherein the apparatus is configurable between: a first configuration in which thereis a path for transport of the beads from the first liquid in first region to the secondliquid in the second region, and a second configuration in which a barrier is providedbetween the first region and the second region.Beneficially, when the apparatus is in the first configuration the beads can betransported from the first liquid and into the second liquid, and when the device is inthe second configuration the barrier between the first region and the second regionhelps to prevent the liquids in the apparatus from mixing (for example, due tovibrations during transport of the apparatus). The term barrier is to be interpretedbroadly. When the apparatus is in the second configuration there may be nointerface between the first liquid in the first region and the second liquid in thesecond region. When the apparatus is in the second configuration there may be nopath for transport of the beads from the first liquid in the first region and into thesecond liquid in the second region.The second region may be provided within a first rotating valve; the apparatus maybe operable for rotation of the first rotating valve between an open positioncorresponding to the first configuration and a closed position corresponding to the second configuration; when the first rotating valve is in the open position there maybe a path for transport of the beads from the first liquid in first region to the secondliquid in the second region; and when the first rotating valve is in the closed position,a wall of the first rotating valve may form the barrier. Beneficially, the rotating valvesare particularly leak resistant, and provide a particularly compact arrangement.The apparatus may further comprise a third liquid in a third region; wherein the thirdliquid is immiscible with the second liquid; wherein when the apparatus is in the firstconfiguration there is a path for transport of the beads from the second liquid in thesecond region to the third liquid in the third region; and wherein when the apparatusis in the second configuration a barrier is provided between the second region andthe third region.When the first rotating valve is in the open position, the beads may be transportedfrom the first liquid in the first region to the third liquid in the third region via thesecond liquid in the second region. The third liquid may comprise a wash buffer. The first rotating valve may comprise a fifth port provided on an upper surface of thefirst rotating valve; and the apparatus may be configured, when the first rotatingvalve is in the closed position, for flow of the third liquid into the fifth port to fill the third liquid in the third region.The apparatus may further comprise: a fourth liquid in a fourth region; and a fifthliquid in a fifth region; wherein the fourth region is provided within a second rotatingvalve; wherein the apparatus is operable for rotation of the second rotating valvebetween an open position corresponding to the first configuration and a closedposition corresponding to the second configuration; wherein when the secondrotating valve is in the open position there is a path for transport of the beads fromthe third liquid in third region to the fifth liquid in the fifth region via the fourth liquidin the fourth region; wherein when the second rotating valve is in the closed positiona wall of the second rotating valve forms a barrier between the third region and thefourth region; and wherein when the second rotating valve is in the closed positionthe wall of the second rotating valve forms a barrier between the fourth region andthe fifth region. The first rotating valve and the second rotating valve may be rotatedeither simultaneously or sequentially to configure the apparatus between the first configuration and the second configuration.The third liquid and the fourth liquid may be immiscible; and the fourth liquid and thefifth liquid may be immiscible. The fourth liquid may comprise oil and the fifth liquidmay comprise an elution buffer. The apparatus may be configured for sequential rotation of the first rotating valve and the second rotating valve to reconfigure the apparatus from the first configuration and into the second configuration, and to reconfigure the apparatus from the second configuration and into the first configuration.The second rotating valve may comprise a sixth port provided on an upper surfaceof the second rotating valve; and the apparatus may be configured, when the secondrotating valve is in the closed position, for flow of the third liquid out of the third region and out of the sixth port.The apparatus may be configured for flow of the third liquid out of the apparatus viathe sixth port as the third liquid flows into the third region via the fifth port.Advantageously, the flow of the third liquid (e.g. wash buffer) out of the apparatusas the third liquid flows into the third region via the fifth port beneficially reduces theoccurrence of air bubbles becoming trapped inside the third liquid in the apparatusthat could inhibit the transport of the beads along the apparatus.Alternatively, the fifth port may be provided on a side of the apparatus at a location other than the upper surface of the first rotating valve, and the sixth port may be provided on a side of the apparatus at a location other than the upper surface of the second rotating valve. The first liquid may comprise a lysis buffer and the second liquid may comprise oil.The beads may be magnetic beads.The apparatus may be configured for receiving the sample in the first region, wherein the sample is a liquid sample. The apparatus may be configured for receiving the sample in the first region; wherein receiving the sample in the first region comprises receiving a swab tip in the first region. The apparatus may comprise a swab-supporting member arranged for preventingthe swab tip from engaging with a base of the first region. By virtue of the swab- supporting member, the tip of the swab is beneficially prevented from being pushedagainst the base of the first region (or from being pushed too far into the cartridgetowards the second region) by a user, reducing the risk of mucous or other viscousmaterial from the swab (that could cause the beads to become stuck) from beingtransferred to the base of the region. Moreover, by virtue of the provision of theswab-supporting member, movement of the swab tip that could disturb the liquid- liquid interfaces between the immiscible fluids is reduced (or prevented). The apparatus may be configured such that, in use, the first liquid in the first regionmay cover the swab-supporting member when the apparatus is in a generallyvertical orientation, and the first liquid in the first region may not cover the swab-supporting member when the apparatus is in a generally horizontal orientation.Beneficially, therefore, the chemical or biological species can be eluted by coveringthe swab tip with the first liquid when the apparatus is in the vertical orientation, andthe beads can be transported along the apparatus (e.g. using a magnetic field) whenthe apparatus is in the generally horizontal orientation (and the level of the first liquidis below that of the swab-supporting member), reducing the risk that beads willencounter the swab-supporting member and become stuck to mucous or otherviscous material that was transferred to the swab-supporting member from the swab(or become stuck to the swab itself). It will be appreciated that the swab tip need notnecessarily remain inside the apparatus and could be removed before the apparatusis moved into the generally horizontal orientation. Alternatively, the swab tip couldremain in the apparatus. As will be described in more detail later, the swab tip may be broken away from the remainder of the swab and remain inside the apparatus. The apparatus may be configured such that, in use, when the swab tip is in the first region: the first liquid in the first region covers the swab tip when the apparatus is in a generally vertical orientation, and the first liquid in the first region does not cover the swab tip when the apparatus is in a generally horizontal orientation.The first region may have a tapered shape along the longitudinal length of theapparatus. By virtue of the tapered shape of the region that contains the first liquid (e.g. lysis buffer), the level of the first liquid is advantageously below the level of theswab tip when the apparatus is in the generally horizontal orientation, but covers theswab tip when the apparatus is in a generally vertical orientation. Moreover, as aresult of the tapered shape of the first region, the depth of the first liquid is relativelysmall when the apparatus is in the horizontal orientation, and therefore when amagnet below the first region is used to transport the beads, the beads in the firstliquid are beneficially located closer to the magnet, increasing the force exerted onthe beads by the magnet and reducing the strength of magnet needed. The taperedshape also enables improved mixing of the beads within the majority of the liquid,rather than the beads only mixing with a small percentage of the liquid if the floorsurface area is small relative to the depth / height of the liquid.The apparatus may further comprise: a first O-ring that is arranged at an interfacebetween the first region and the first rotating valve; a second O-ring arranged at aninterface between the first rotating valve and the third region; a third O-ring arrangedat an interface between the third region and the second rotating valve; and a fourthO-ring arranged at an interface between the second rotating valve and the fifth region.The first rotating valve may be arranged for rotation within a sixth region, and thesecond rotating valve may be arranged for rotation within a seventh region; whereinthe first O-ring and the second O-ring are arranged between the wall of the firstrotating valve and a wall of the sixth region; and wherein the third O-ring and thefourth O-ring are arranged between the wall of the second rotating valve and a wallof the seventh region.A region between the first rotating valve and a wall of the sixth region may containthe second liquid; and a region between the second rotating valve and a wall of theseventh region may contain the fourth liquid. By virtue of the region of second liquidbetween the first rotating valve and a wall of the sixth region (and the region of thefourth liquid between the second rotating valve and the wall of the seventh region),the risk of the other liquids leaking from the apparatus is reduced, and the evaporation of the other liquids from the cartridge is inhibited. The second and fourthliquids (which may be oil) may also provide lubrication, enabling the rotating valvesto be rotated more easily within their respective regions.The apparatus may further comprise a fifth O-ring arranged around the first rotating valve and a sixth O-ring arranged around the second rotating valve; wherein the fifth O-ring is arranged to seal the second liquid in the sixth region; and wherein the sixth O-ring is arranged to seal the fourth liquid in the seventh region. The first O-ring and the second O-ring may be engaged with a wall of the first rotating valve, and the third O-ring and the fourth O-ring may be engaged with a wallof the second rotating valve; wherein the wall of the first rotating valve and the wallof the second rotating valve are each angled such that a compressive force isapplied to each of the first O-ring, the second O-ring, the third O-ring and the fourth O-ring. Advantageously, by virtue of the angled orientation of the walls of the rotating valves, the force from the rotating valves pushing against the O-rings has ahorizontal component (along the longitudinal direction of the apparatus) that isadjustable based on an amount of downward force applied to the rotating valves, further improving the strength of the seals, and enabling the strength of the seals to be configurable based on an amount of downward force applied to the rotating valves. The first rotating valve and the second rotating valve may have a conical or wedge shape, thereby providing the angled walls that engage with the first O-ring, the second O-ring, the third O-ring and the fourth O-ring.The first rotating valve may comprise a first groove or first protrusion in an uppersurface of the first rotating valve for engaging with a first rotating member for rotating the first rotating valve; and the second rotating valve may comprise a second grooveor second protrusion in an upper surface of the second rotating valve for engagingwith a second rotating member for rotating the second rotating valve. When theapparatus is in the second configuration, the first groove or first protrusion may bealigned with the second groove or second protrusion. Advantageously, by virtue ofthe grooves being aligned when the rotating valves are in the closed positions, whenthe apparatus is inserted into an automated device for rotating the valves, membersor tabs of the automated device can slot into the grooves as the apparatus isinserted into the automated device. Alternatively, rather than grooves, tabs (or anyother suitable protrusion) may be provided on the upper surface of the rotatingvalves, and the tab of the first rotating valve may be aligned with the tab of the second rotating valve when the apparatus is in the second configuration.The apparatus may further comprise: a first port through which the second liquidcan flow into the apparatus to fill the second region; and a second port through whichthe second liquid can flow out of the apparatus. and the apparatus may furthercomprise a port cover that is moveable between a filling position for filling of thesecond liquid into the second region, and a closed position for sealing the secondliquid inside the apparatus; wherein when the port cover is in the filling position, afirst aperture of the port cover is aligned with the first port, and a second aperture of the port cover is aligned with the second port.The first aperture and the second aperture may be configured such that as the portcover is moved into the closed position, one of the first port or the second port is sealed closed by the port cover before the other of the first port or the second port is sealed closed by the port cover. Advantageously, by virtue of the port coversealing one of the ports closed before the other port is sealed closed, excesspressure build-up in the second liquid (e.g. oil, which is an incompressible liquid)that can occur as the ports are sealed closed is beneficially reduced, since theexcess pressure can be released via ejection of the second liquid out of the port thatis sealed last. One of the first aperture or the second aperture may be circular, andthe other of the of the first aperture or the second aperture may have an elongate shape. The first port may be further configured for flow of the second liquid into the sixth region.The apparatus may be configured to allow flow of the second liquid out of theapparatus via the second port as the second liquid flows into the second region viathe first port. Advantageously, the flow of the second liquid (e.g. oil) out of theapparatus as the second liquid flows into the second region via the first portbeneficially reduces the occurrence of air bubbles becoming trapped inside thesecond liquid inside the apparatus that could inhibit the transport of the beads alongthe apparatus. In other words, by virtue of the provision of the two ports for filling thesecond liquid, a flow of oil can be pushed into (and out of, via the other port) theapparatus, reducing the risk of air bubbles becoming trapped, since air is allowed to vent out of the second port. The apparatus may further comprise: a third port through which the fourth liquid can flow into the apparatus to fill the fourth region; a fourth port through which the fourth liquid can flow out of the apparatus; and a corresponding port cover that is moveable between a filling position for filling of the fourth liquid into the fourth region, and a closed position for sealing the fourth liquid inside the apparatus; wherein when the port cover is in the filling position, a first aperture of the port cover is aligned with the third port, and a second aperture of the port cover is aligned with the fourth port. The third port may be further configured for flow of the fourth liquid into the seventh region. The apparatus may be configured to allow flow of the fourth liquid out of the apparatus via the fourth port as the fourth liquid flows into the fourth region via thefirst port. The third aperture and the fourth aperture may be configured such that asthe corresponding port cover is moved into the closed position, one of the third portor the fourth port is sealed closed by the port cover before the other of the third portor the fourth port is sealed closed by the port cover.The apparatus may further comprise at least one gas region, and the gas regionmay be arranged such that gas inside the gas region compresses as the pressureof the second liquid inside the second region increases. The apparatus may furthercomprise at least one foam disc, and the foam disc may be arranged such that the foam disc compresses as the pressure of the second liquid inside the second regionincreases. Advantageously, increases in pressure of the second liquid causes gas(e.g. air) in the gas region (e.g. bubble trap), or the foam disc, to compress,beneficially relieving some of the pressure in the second liquid (e.g. oil) that canoccur as the second liquid is sealed inside the apparatus. Pressure in the secondliquid can also occur due to temperature fluctuations during storage or operation of the apparatus. Alternatively, or additionally, the apparatus may comprise a region of compressible liquid, adjacent to the second liquid, for relieving some of the pressure in the second liquid.A base of the apparatus (e.g. a base of the first region) may be configured to imparta vertical force component on the beads as the beads are transported longitudinally along the apparatus (e.g. through the first liquid in the first region towards the second liquid in the second region). The base of the first region may comprise an undulatingsurface. A base of the first region may comprise ridges, steps, ribs, or a wave-likesurface. The base of the first region may comprise ribs, a wave-like surface, or anundulating surface. The base of the first region may comprise a series of grooves orindentations. By virtue of the ridges, steps, ribs, grooves or indentations, mixing ofthe beads in the first liquid (e.g. lysis buffer) as the beads are transported along theapparatus is improved, reducing the amount of clumping and increasing the surfacearea of the beads exposed to the first liquid. The base of the first region may beconfigured such that horizontal forces on the beads (e.g. induced using a magneticfield) result in upward motion of the beads, improving mixing of the beads with upperregions of the first liquid further away from the base of the first region.The apparatus may further comprise a plunger for ejecting the fifth liquid from thefifth region via a corresponding aperture.The apparatus may be configured for receiving the sample in the first region via an opening into the first region; wherein the apparatus comprises a wall inside the first region that defines a sample receiving region that extends from the opening, for receiving the sample; and wherein the wall is configured for preventing the first liquid from flowing out of the opening when the apparatus is in a generally horizontalorientation. The wall may be configured for preventing the first liquid from flowingout of the opening when the apparatus is inverted (when the opening is facinggenerally downward). Advantageously, the wall helps to prevent the liquid fromspilling from the apparatus. In other words, the wall is an anti-spill wall.The apparatus may be a cartridge for insertion into an automated device forselectively configuring the cartridge into the first configuration or the secondconfiguration and for extracting the chemical or biological species from the cartridge.The automated device may configure the cartridge into the first configuration or the second configuration by rotating the first rotating valve and the second rotating valveeither simultaneously or sequentially. The automated device may engage with theplunger to eject the fifth liquid from the fifth region via the corresponding aperture.In a second aspect the invention provides a method of extracting a chemical orbiological species from a sample, the method comprising: receiving the sample inthe first region of the apparatus according to the first aspect; eluting the chemical orbiological species from the sample using the first liquid in the first region; configuringthe apparatus to be in the first configuration; and transporting the beads from thefirst liquid in the first region and into the second liquid in the second region.In a third aspect the invention provides a method of extracting a chemical orbiological species from a sample, the method comprising: receiving the apparatusof the first aspect into the automated device; reconfiguring the cartridge into the firstconfiguration from the second configuration using the automated device; andtransporting the beads from the first liquid in the first region and into the secondliquid in the second region using the automated device.The method may comprise ejecting the fifth liquid from the fifth region via thecorresponding aperture by using the automated device to actuate the plunger.In a fourth aspect the invention provides a method of filling the apparatus according to the first aspect with the second liquid, the method comprising: moving the port cover into the filling position; and providing a flow of the second liquid through the first port, for flow of the second liquid out of the second port via the second region. Advantageously, the flow of the second liquid into one of the ports and out of the other port provides a flow of the second liquid through the second region to fill the second region, which reduces the risk of air bubbles becoming trapped inside the second region during the fill process. The method may comprise using one or more syringes or pumps to drive the flow of the second liquid through the first port. The method may comprise providing a first flow configuration for flow of the second liquid through the first port, for flow of the second liquid out of the second port via the second region; and providing a second flow configuration for flow of the second liquid through the second port, for flow of the second liquid out of the first port via the second region; wherein the method further comprises alternating between the first flow configuration and the second flow configuration. Advantageously, by virtue of the alternating filling between the first flow configuration and the second flowconfiguration, the occurrence of air bubbles becoming trapped within the secondregion is further reduced. The method may further comprise moving the port cover into the closed position after the second region has been filled with the second liquid. Brief Description of the Drawings Embodiments of the invention will now be described by way of example only with reference to the attached figures in which:Figure 1a schematically illustrates a series of liquids used to extract a biomoleculefrom a sample for subsequent testing or analysis;Figure 1b illustrates transport of magnetic beads through the liquids in a tube,showing a magnet in a first position, and the magnet having been moved along the length of the tube to a second position; Figure 2a schematically illustrates an arrangement of valves use to maintain separation of the liquids; Figure 2b shows a modification of the arrangement of Figure 2a; Figure 3 shows a cross section of a cartridge according to one example;Figure 4a shows a perspective view of the cartridge;Figure 4b shows a further perspective view of the cartridge in which a lid of thecartridge is open; Figure 5 shows a cross section of a modified version of the cartridge in which a swab can be screwed into the cartridge; Figure 6 shows a further perspective view of the cartridge; Figure 7 shows a top-down view of the cartridge; Figure 8 shows a view of a side of the cartridge from which oil is filled; Figure 9 shows a view of the underside of the cartridge; Figure 10 illustrates a cutaway view of the cartridge showing the paths via which the device is filled with oil; Figure 11 illustrates a cutaway view of the cartridge showing ports via which the device is filled with oil;Figure 12 shows a further cross-sectional view of the cartridge;Figure 13 shows a further cross-sectional view of the cartridge;Figure 14 shows a cutaway view of the cartridge;Figure 15 shows a further cutaway view of the cartridge; Figure 16 shows a top-down cutaway view of the cartridge;Figure 17 shows a top-down view of a rotating valve of the cartridge;Figure 18 shows a perspective view of a rotating valve of the cartridge;Figure 19 shows a cutaway and exploded view of the cartridge;Figure 20 shows a further cutaway view of the cartridge;Figure 21a schematically illustrates a path of the beads through the lysis liquid;Figure 21b shows a modification in which the chamber that contains the lysis liquidhas a substantially flat base;Figure 22a shows the cartridge in an upright position in which the tip of a swab iscovered by the lysis liquid;Figure 22b shows the cartridge in a horizontal position in which the level of the lysis liquid is below the tip of the swab; Figure 23 shows an exploded cross-sectional view of the cartridge;Figure 24 shows a cross-sectional view of O-rings and a rotating valve of thecartridge;Figure 25 shows a cross-sectional view a rotating valve of the cartridge when therotating valve is in an open position;Figure 26 shows a cross-sectional view a rotating valve of the cartridge when therotating valve is in a closed position;Figure 27 shows a cross-sectional view of the cartridge, illustrating a path used to fill the device with the wash liquid;Figure 28 shows a cross-sectional view of the cartridge when the rotating valves arerotated by 45 degrees from the open position;Figure 29 shows a cross-sectional view of an end portion of the cartridge, showing a plunger; Figure 30 shows a further view of the plunger; Figure 31a shows a modified version of the cartridge in which air bubble traps are provided; Figure 31b shows a further view of the air bubble traps; Figure 31c shows a modified version of the cartridge in which a foam disc is provided; Figure 31d shows a further view of the foam disc;Figure 32 shows a cross-sectional view of apparatus for filling the cartridge with oil;Figure 33 shows a cross section of a modified cartridge in which linear sliding valves are used;Figure 34a shows a cross-cross sectional view of a modified cartridge in whichmembrane valves are used; Figure 34b shows a further cross-sectional view of the modified cartridge in which membrane valves are used; Figure 35 shows a further view of the modified cartridge in which membrane valves are used; Figure 36 shows a further view of the modified cartridge in which membrane valves are used; and Figure 37 shows a modified cartridge in which rotating valves are used. In the figures, like elements are indicated by like reference numerals throughout. Detailed Description of Preferred Embodiments The present embodiments represent the best ways known to the Applicant of putting the invention into practice. However, they are not the only ways in which this can be achieved. Liquid SeparationAn arrangement of liquids used to extract a biomolecule or other chemical orbiological species from a sample, and general concepts related to maintainingseparation of liquids, will now be described with reference to Figs. 1a and 1b.Fig.1a schematically illustrates a series of liquids used to extract a biomolecule froma sample. In this example three liquids, labelled ‘A’, ‘B’ and ‘C’, are arranged insidea tube 100. A group of magnetic beads 102 is illustrated inside liquid A. A separationliquid, labelled ‘D’, is arranged between liquids A and B, and between liquids B and C. The separation liquid is immiscible with each of liquids A, B and C. In other words, the separation liquid has a propensity to remain separated from, and not to mix with,liquids A, B and C. Therefore, by virtue of the provision of the separation liquid inbetween the other liquids, the other liquids are inhibited from mixing. A magnet 105 can be used to drive (push or pull) the magnetic beads along the tube 100, from liquid A to liquid C via the intermediate liquids B and D, as the magnet105 moves longitudinally along the length of the tube 100 in the direction indicatedby arrow A. The tube 100 provides a continuous transport path along which thebeads can move. Therefore, a biological or chemical species can be easily andefficiently transported, on the surface of the beads, through each of the liquids.Turning now to Fig. 1b, in this example the tube 100 has a corresponding baseportion 114, and the liquids comprise a lysis buffer 104, a wash buffer 106, and anelution buffer 108. Regions of oil 112 are provided in-between the other liquids foruse as a separation liquid. The oil 112 is immiscible with the other liquids, andtherefore inhibits mixing. A group of beads 102 is illustrated in a region of oil 112adjacent to the lysis buffer 104 (which may also be referred to as a lysis liquid). Inuse, the beads 102 can be transported into the lysis buffer 104 under the influenceof the magnet 105 that is positioned below the base portion 114 of the tube 100, bymoving the magnet 105 in the direction A. The beads 102 can then be transported to the wash buffer 106 via the intermediate region of oil 112, by moving the magnet 105 further in the direction A. Advantageously, the intermediate section of oil 112 displaces the lysis buffer 104 from the surface of the beads 102, preventingtransport of lysis buffer 104 into the wash buffer 106. The wash buffer 106 (whichmay also be referred to as a wash liquid) is for removing any remaining lysis bufferand / or unwanted biological or chemical material from the surface of the beads 102.The beads 102 are then transported from the wash buffer 106 and into the elutionbuffer 108 (which may also be referred to as an elution liquid) as shown in the figure,via the further intermediate region of oil 112, by moving the magnet 105 further in the direction A. The intermediate region of oil 112 displaces the wash buffer 112 from the beads 102 before the beads 102 pass into the elution buffer 108. This isparticularly beneficial since the presence of certain components commonly found inwash buffers 112 (e.g. ethanol or certain salts) in the elution buffer can seriouslydisrupt any test or analysis performed on the eluted species. Advantageously, theprovision of the oil 112 between the wash buffer 106 and the elution buffer 108 removes the need for a separate drying step (which is relatively time consuming) to remove the wash buffer 106 from the beads, improving the efficiency of the method. Whilst in the example of Fig. 1a two regions of separation liquid (D) and threeadditional liquids (A, B and C) are shown (and similarly in Fig. 1b), this need notnecessarily be the case. Alternatively, for example, there may be only two additionalliquids (e.g. liquids A and B) separated by a single region of the separation liquid (D). In a further alternative, the liquids may simply comprise two reagent liquids thatare immiscible, in which case an additional separation liquid need not necessarilybe provided between the reagent liquids. In a further alternative there may morethan three liquids separated by regions of the separation liquid. For example, whilsttwo regions of separation liquid (D) are used to separate three additional liquids (A,B and C) in Fig.1a, alternatively three regions of separation liquid (D) could be usedto separate four additional liquids (for example if there is an additional wash buffer).Whilst the separation liquid D is immiscible with each of liquids A, B and C andtherefore inhibits mixing, mixing of the liquids may nevertheless occur when theliquids are subject to vibrations (e.g. during transport) or other strong forces. Someof the liquids (e.g. a lysis buffer) may contain a surfactant or detergent, which alsodestabilises the liquid-liquid interfaces and can result in unwanted mixing. Fig. 2ashows an improved configuration in which valves 120 are provided between eachof the liquids, to mitigate against such mixing. As shown in Fig. 2a, a first valve 120ais provided between liquids A and D, a second valve 120b is provided between liquids D and B, a third valve 120c is provided between liquids B and D, and a fourthvalve 120d is provided between liquids D and C. Each of the valves 120 can beinitially set to a closed position in which liquids cannot pass through the valves 120,advantageously minimising the risk of the liquids mixing or leaking during transport.The valves 120 can then be opened to allow the magnetic beads 102 to passbetween the liquids. It will be appreciated that even when valves 120 are providedas shown in Fig. 2a, use of the separation liquid D is nevertheless advantageoussince it inhibits mixing of the other liquids when the valves 120 are in the open position, and helps to remove the previous liquid from the surface of the beads asthe beads progress along the tube 100.Whilst Fig.2a shows an example in which a valve 120 is provided at every interface between two different liquids, Fig.2b shows an alternative in which the separationliquid D itself can transition to a solid state, to perform the function of a valve 120e.For example, wax (or any other suitable material that can transition between a liquid state and a solid state) may be used. The wax may initially be in a solid state inwhich the wax acts as a closed valve 120e, preventing mixing between liquids Aand B, and between liquids B and C. The wax may then be heated to cause the waxto transition to a liquid state, enabling transport of the magnetic beads 102 fromliquid A to liquid C, via liquid B, and via the intermediate regions of liquid wax.In any of the examples of Fig. 1a to Fig. 2b, the separation liquid D need notnecessarily be oil 112 or liquid wax. Any other suitable liquid that is sufficientlyimmiscible with the other liquids could alternatively be used. Moreover, in someexamples the buffers themselves may be sufficiently immiscible such that anadditional separation liquid is not needed (however, the additional separation liquidmay still be provided, for example to help remove the previous liquid from thesurface of the beads 102 as the beads 102 progress along the tube 100).The liquids illustrated in Figs.1a to 2b may be for an extraction process to be carriedout in respect of targeted biomolecules from a liquid or solid sample. The targetedbiomolecules may be, for example, polynucleotides such as nucleic acid (e.g. RNAor DNA). For example, the targeted biomolecule may be the characteristic RNA ofa particular virus, such as, but not limited to, SARS-CoV-2.The method is not restricted to any particular size or composition of the magneticbeads 102. Indeed, for any given application it will be understood that the skilledperson will use beads 102 of a suitable size and composition. Moreover, any othersuitable method of transporting material from a sample through the liquids may beused (e.g. by pushing a sample on a swab tip through the liquids). However, use ofmagnetics beads 102 is particularly advantageous since the beads 102 provide alarge surface area to be exposed to each of the liquids, and the small size of thebeads 102 helps to avoid disturbing the liquid separation when the beads 102 aretransported through the liquid interfaces. It will also be appreciated that the particularcoating of the beads 102 used will depend on the specifics of the particular reactionsand the target biomolecules. For example, the magnetic beads 102 may have asilica coating which binds with nucleic acids under certain buffer conditions.A method in which targeted biomolecules such as DNA / RNA / proteins are released from a sample and transported to the elution buffer 108 will now be described. Thetargeted biomolecules are first released from a sample using the lysis buffer 104,and are bound to the surface of the beads 102 (e.g. magnetic nanoparticles) presentin the lysis buffer 104. The beads 102 need not necessarily be present in the lysisbuffer 104 when the sample is introduced into the lysis buffer 104. For example, thebeads 102 could initially be in the oil 112, and transported into the lysis buffer 104after the sample has been inserted into the apparatus 200. Alternatively, for example, the beads 102 could be added into the lysis buffer 104 after the sample has been inserted, via the same aperture through which the sample was introduced.The beads 102 are then washed using the washing liquid 106, to removecontaminants / chemicals from the previous step, as well as unwanted biological molecules. Once the beads 102 have been washed, the purified analyte is eluted(released) from the beads 102 using the elution buffer 108 (e.g. molecular gradewater, or Tris-EDTA (TE) buffer). The eluted analyte (e.g. RNA) may then be used for downstream molecular applications such as polymerase chain reaction (PCR) processing, isothermal amplifications, etc., according to the user’s particularrequirements. It will be appreciated that “Tris” is short fortris(hydroxymethyl)aminomethane, and EDTA is an abbreviation ofethylenediaminetetraacetic acid. Thus, to perform the method, first, second and thirdliquids are used. In this example, the first liquid is a lysis / binding buffer liquid 104,for lysing the targeted biomolecules and thereby releasing them into solution, and binding the biomolecules to the magnetic beads; the second liquid 106 is a washingliquid; and the third liquid 108 is an elution liquid, for eluting the biomolecules. Asshown in Figs. 1a to 2b, the first, second and third liquids may be separated by anadditional separation liquid 112 (e.g. oil), to inhibit mixing and to aid with the removalof each previous buffer from the surface of the beads 102.The lysis / binding buffer liquid 104 may be, for example, based on guanidiniumthiocyanate, and optionally includes a solvent such as isopropanol or ethanol.The washing liquid 106 for removing contaminants / chemicals from the previoussteps, as well as unwanted biological molecules, may be, for example, a solution of80% ethanol.The elution liquid 108 causes elution of the analyte in question (e.g. characteristicRNA of viral particles), for subsequent processing. In the present example, theelution corresponds to the separation of the target biomolecule from the surface ofthe beads 102. After the target biomolecules have been eluted, the magnetic beads102 may be transported out of the elution liquid 108 (e.g. in the direction oppositeto that indicated by arrow A), leaving only the eluted analyte in the elution liquid 108,for subsequent processing (e.g. nucleic acid amplification using PCR or LAMPmethods).It will be appreciated that the reagents may comprise any suitable chemicalsubstances, and are not limited to a lysis buffer 104, wash buffer 106, or elutionbuffer 108.Illustrative Example - CartridgeParticularly advantageous apparatus for maintaining separation of liquids used toprocess a sample will now be described, referring firstly to Figs. 3 to 4b.Figs. 3 to 4b show an example in which the liquids are housed within a cartridge200. It will be appreciated that whilst the device of Figs.3 to 4b will be referred toas a ‘cartridge’, the device 200 need not necessarily be for insertion into anotherdevice. The cartridge 200 may also simply be referred to as the ‘device’ 200 or‘apparatus’ 200.In this example, a lysis buffer 104, wash liquid 106, elution buffer 108 and oil 112are provided within the cartridge 200. However, as described above, the presentinvention is not limited to use of these particular liquids, and any other suitableliquids could alternatively be used. In use, magnetic beads 102 in the cartridge 200 can be transported from the lysis buffer 104 to the elution buffer 108 via the washliquid 106, and via the intermediate sections of oil 112, using a magnetic force (forexample, from a magnet or electromagnet). The present examples will be describedwith reference to the use of a magnet 105 to provide the magnetic force, but it will be appreciated that one or more electromagnets could alternatively be used (or a plurality of magnets 105 could be used rather than a single magnet 105).The lysis buffer 104 breaks open cells / tissues from the sample, and genetic materialfrom the sample comes out into the solution. The pH and salt concentration of thelysis buffer 104 is such that DNA / RNA sticks to a silica surface of the magneticbeads 102. The magnetic beads may be nanoparticles, which advantageously havea large surface area to which the DNA / RNA can attach.In use, the magnetic beads 102 are transported from the lysis buffer 104 to the washbuffer 106 (comprised, for example, substantially of ethanol or another suitablesolvent), via a region of oil 112, using a magnet 105. Beneficially, the oil 112removes the lysis buffer 104 from the beads 102 before the beads 102 pass into thewash buffer 106. The wash buffer 106 removes (or dilutes) any remaining lysisbuffer 104 from the beads 102, and can also remove other unwanted chemical orbiological material from the surface of the beads 102. The beads 102 are thentransported into the elution buffer 108 via a further region of oil 112. The oil 112 beneficially removes the wash buffer 106 from the surface of the beads 102 beforethe beads pass into the elution buffer 108. The pH and salt concentration of theelution buffer is such that the DNA / RNA separates (elutes) from the beads into theelution buffer 108. The elution buffer 108 containing the eluted species can then beoutput from the cartridge for subsequent processing (e.g. for performing asubsequent test or analysis on the elution buffer and the extracted / isolatedmolecules). The cartridge 200 comprises a first portion 202 and a second portion 204. The firstportion 202 comprises a hinged door 206. In this example, the hinge 208 of the door206 is located on the upper side of the cartridge 200, but it will be appreciated thatthis need not necessarily be the case and that any other suitable position for thehinge 208 could alternatively be used. The hinged door 206 is operable between theopen position illustrated in Fig. 4b, and the closed position illustrated in Fig. 4a. Inthe open position, a swab can be inserted into the cartridge 200 via a correspondingaperture 205. Alternatively, for example, rather than inserting a swab the samplecould be introduced into the cartridge 200 via the aperture 205 using a pipette. Whenthe door 206 is in the closed position, the aperture 205 is sealed by a plug 209provided on the door 206. The door 206 may be lockable in the closed position, ormay be difficult to open (e.g. by configuring the edges of the door 206 to besubstantially flush with the adjacent surface 207 when the door 206 is in the closedposition), to prevent or inhibit re-opening of the door 206. Beneficially, this reducesthe risk of contamination after a sample has been placed into the device 200, andalso reduces the risk of lysis buffer 104 spilling out of the aperture 205 due to thedoor 206 being inadvertently opened. The device 200 may also be provided with afoil seal (not shown in the figure) covering the aperture 205, to further reduce therisk of contamination or spills. The foil seal is removed by the user before the swabis inserted through the aperture 205 (or before the sample is pipetted into thecartridge 200). Whilst in the present example the cartridge 200 is provided with a hinged door 206, this need not necessarily be the case. Alternatively, for example, a removeablescrew cap could be used to provide access to the inside of the cartridge 200. Maleor female threads could be provided around the aperture 205 for receiving and securing the screw cap.When the door 206 is in the open position a user may insert a sample through theaperture 205 and into a sample receiving cavity 210, by inserting a swab throughthe aperture 205. The sample may be, for example, a nasal secretion that has beencollected using a nasopharyngeal swab.The sample receiving cavity 210 is defined by a cavity wall 211, and leads to a swabsupporting member 212 (which may also be referred to as a swab support 212, orswab guard 212). Throughout the description the term cavity is to be interpretedbroadly to encompass a corresponding ‘volume’ or ‘region’. For example, the sample receiving cavity 210 may also be referred to as the sample receiving volume 210 or sample receiving region 210.The first portion 202 of the cartridge 200 contains a lysis buffer 104 in acorresponding cavity 309. Advantageously, the cavity wall 211 of the sample receiving cavity 210 functions as a spill guard that protects against the lysis buffer104 spilling from the cartridge 200 when the door 206 is in the open position. Whenthe cartridge 200 is titled such that the aperture 205 is facing downwards, the lysisbuffer 104 fills the space around the outside of the cavity wall 211, but does notenter the sample receiving cavity 210 because the opening into the sample receivingcavity 210 (adjacent to the swab support 212) is positioned sufficiently high, therebypreventing spilling of the lysis buffer 104 out of the cartridge 200.One or more magnets 105 or electromagnets (or more generally, any suitablemagnetic force) can be used to transport magnetic beads 102 from the lysis buffer104 to the elution buffer 108 via the wash buffer 106 (and via intermediate sectionsof oil 112). However, viscous material such as mucous may be present on the swabtip, and the magnetic beads 102 can become stuck to such viscous material,preventing or inhibiting the beads from being transported further along the device200 towards the elution buffer 108 by the magnet 105. If the swab tip were to contactthe base 214 of the chamber 309 the mucous may be transferred, increasing thelikelihood that the beads 102 will encounter the mucous and become stuck.Advantageously, the cavity wall 211 and the swab support 212 prevent the swabfrom being pushed against the base 214 of the chamber 309 by a user, reducing therisk of mucous or other viscous material being transferred.As will be described in more detail later with reference to Figs. 22a and 22b, thelevel of the lysis buffer 104 is advantageously below the level of the swab support 212 when the device 200 is in a generally horizontal orientation (as illustrated in Fig.3). Beneficially, therefore, the beads 102 can be transported along the length of thedevice 200 using the magnet 105 when the device 200 is in the generally horizontalorientation and the level of the lysis buffer 104 is below that of the swab support 212(and therefore not covering the tip of the swab), reducing the risk that beads 102 willencounter the swab tip and become stuck to mucous or other viscous material. Theswab tip need not necessarily remain inside the device 200, and could be removedbefore the device 200 is moved into the generally horizontal orientation. In this case, the configuration of the device 200 is nevertheless advantageous since by virtue of the level of the lysis buffer 104 being below that of the swab support 212, the risk of beads 102 encountering mucous or other viscous material that was transferred tothe swab support 212 from the swab tip is reduced. When the sample is introducedinto the device 200 using a swab, a reagent that promotes binding (for example,isopropanol), may be withheld from the first cavity 309 until the swab is sufficientlymixed in the first liquid 104. This is because if the chemical binding forces are toostrong, the targeted molecules will be encouraged to bind to the high surface areaof the swab itself, rather than to the beads 102. Therefore, the method may comprisemixing the swab tip with the first liquid 104 in the chamber 309, either removing theswab entirely or breaking off the swab tip, and then adding a binding promotingagent into the first cavity 309. At this stage, if the swab tip remains inside the device200, it is further beneficial that the liquid level is below that of the swab support 212and swab tip when the device is in the generally horizontal orientation, to preventyet uncaptured target molecules from preferentially binding to the swab instead ofto the beads 102.One or more reagents or components (e.g. isopropanol, or the beads) may beintroduced into the first cavity 309 using a blister pack. The blister pack may bearranged over the opening 205 into the first cavity 309. In use, a user may pop or rupture the blister pack to deliver the reagents or components into the first cavity 309. The blister pack may then be peeled off from the opening 205 to allow thesample to be introduced into the first cavity 309. Alternatively, the blister pack maybe arranged at any other suitable position, to deliver the reagents or components into the first cavity.The second portion 204 of the cartridge 200 comprises a first rotating valve 216 anda second rotating valve 218. Each of the rotating valves 216, 218 comprises arespective cavity 300, 301 that is filled with oil 112. In use, when the first rotatingvalve 216 is in an open position in which the cavity 300 of the first rotating valve 216that contains the oil 112 is generally aligned with an opening into the cavity 309 thatcontains the lysis buffer 104, and is generally aligned with a cavity 303 that containsthe wash liquid 106, the magnetic beads 102 can be transported from the lysis buffer104 in the first portion 202 and into the oil 112 inside the first rotating valve 216using the magnet 105. The beads 102 can then be transported from the oil 112inside the first rotating valve 216 into the cavity 303 that contains the wash liquid106. The cross-sectional area of the liquid-liquid interface between the lysis buffer 104 and the oil 112 is relatively small (and similarly the cross-sectional area of the liquid-liquid interface between the oil 112 and the wash buffer 106 is relatively small), which improves the separation of the two liquids via the surface tension between the immiscible liquids.The cavity 303 that contains the wash liquid 106 is arranged between the tworotating valves 216, 218, as illustrated in Fig.3. When the second rotating valve 218is in an open position (in which the cavity 301 of the second rotating valve 218 thatcontains the oil 112 is aligned with an opening into the cavity 303 that contains thewash liquid 106, and is aligned with an opening into the cavity 305 that contains theelution buffer 108), the beads can be transported from the wash liquid 106 and intothe elution buffer 108, via the oil 112 in the second rotating valve 218, using themagnet 105. It will be appreciated, therefore, that when the rotating valves 216, 218are in the open position the beads 102 can be transported along the length of thedevice 200 to pass through the sequence of liquids (e.g. as illustrated schematicallyin Figs. 1a). It will also be appreciated that when the rotating valves 216, 218 are inthe open position, the cavities 300, 301 that contain the oil 112 need not necessarilybe perfectly aligned with the cavities that contain the other liquids. For example,there may be a partial overlap between the openings into the cavities, through whichthe beads 102 can nevertheless still be transported.Each of the rotating valves 216, 218 is arranged in a respective cavity in the secondportion 204 having a corresponding cavity wall 222, 224. A set of O-rings 220 areprovided to form seals between the outer surface of the rotating valves 216, 218and the cavity walls 222, 224. A pair of angled O-rings 220a, 220b (see also Fig.19,for example) are provided adjacent to the first rotating valve 216, and a further pairof angled O-rings 220d, 220e are provided adjacent to the second rotating valve218. A first of the angled O-rings 220a is provided at the interface between thechamber 309 that contains the lysis buffer 104 and the first rotating valve 216. Asecond of the angled O-rings 220b is provided at the interface between the firstrotating valve 216 and the chamber 303 that contains the wash buffer 106. A thirdof the angled O-rings 220d is provided at the interface between the chamber 303that contains the wash buffer 106 and the second rotating valve 218. A fourth of theangled O-rings 220e is provided at the interface between the second rotating valve218 and the chamber 305 that contains the elution buffer 108. When the rotatingvalves 216, 218 are in the closed configuration, the openings of the cavities of therotating valves 216, 218 that contains the oil 112 are not aligned with the openingsof the cavities that contain the other liquids. In other words, a barrier is formed suchthat there is no interface between the liquid in the cavity inside the rotating valves and the other liquids. The outer surface of the rotating valves 216, 218 pushes against the angled O-rings 220 to form the sequence of barriers. For example, a surface of the first rotating valve 216 pushes against the second angled O-ring 220b, and a surface of the second rotating valve 218 pushes against the third angled O-ring 220d, thereby sealing the wash liquid 106 inside the corresponding cavity 303when the rotating valves 216, 218 are in the closed configuration. Advantageously,therefore, the provision of the angled O-rings 220 and the barriers that are formedbetween the liquids help to prevent the liquids in the cartridge 200 from mixing (e.g.due to vibrations during transport of the device 200) when the rotating valves 216,218 are in the closed position, and also help to prevent the liquids from leaking fromthe cartridge 200. Generally horizontal O-rings 220c, 200f are also provided around each rotatingvalve 216, 218, above the angled O-rings 220. These O-rings 220c, 200f provideadditional protection against liquids leaking from the cartridge 200 by preventing theoil 112 from leaking from the space around the rotating valves 216, 218. These O-rings 220c, 220f also act as a bearing surface for the valves 216, 218 to rotateagainst, and circumferentially support each rotating valve 216, 218 during rotation.The rotating valves 216, 218 thus only make contact with the three O-rings in eachcavity (the two angled O-rings 220a, 220b, 220d, 220e and the generally horizontalO-ring 220c, 220f). The cavities in which the rotating valves 216, 218 are situatedeach have only three openings, each gasketed with an O-ring, and allowing thevalve 216, 218 itself to seal off that portion of the device 200 (by engaging with thethree O-rings). Advantageously, in addition to the oil 112 provided inside the rotating valves 216,218, that forms part of the path for the beads 102 to travel from the lysis buffer 104to the elution buffer 108, additional oil 112 is also provided between the rotatingvalves 216, 218 and the cavity walls 222, 224 of the cavities in which the rotatingvalves 216, 218 are situated. Beneficially, therefore, even if some of the liquid (e.g.the lysis buffer 104) breaches an O-ring 220 seal, the oil 112 between the rotatingvalves 216, 218 and the cavity walls 222, 224 helps to prevent the liquid fromprogressing further along the cartridge 200, or from leaking out of the cartridge 200. The oil 112 between the rotating valves 216, 218 and the cavity walls 222, 224 also helps to provide lubrication to aid in the rotation of the valves 216, 218, and reducesthe risk of air bubbles becoming trapped when filling the apparatus with oil (since agap around the rotating valves, even if small, results in the trapping of air inside theapparatus). The generally horizontal O-rings 220c, 220f help to prevent the oil 112that is between the rotating valves 216, 218 and the cavity walls 222, 224 of the cavities in which the rotating valves 216, 218 are situated from leaking from thedevice 200. The generally horizontal O-rings 220c, 200f also aid in centring therotating valves 216, 218 within the respective cavities, to maintain a more even gap(between the rotating valves 216, 218 and the cavity walls 222, 224) for the oil 112.As shown in Fig. 3, the angled O-rings 220 are angled with respect to the directionof gravity when the device is in a horizontal orientation (and are angled with respectto the orientation of the path for transport of the beads 102 through the rotatingvalves 216, 218, and through the wash liquid 106). The outer surface of eachrotating valve 216, 218 exerts a force on the angled O-rings 220, improving thestrength of the seals. Advantageously, by virtue of the angled orientation of theangled O-rings 220, the force from the rotating valves 216, 218 pushing against theangled O-rings 220 has a horizontal component (along the longitudinal direction ofthe device 200), further improving the strength of the seals, and enabling the strength of the seals to be configurable based on an amount of downward force applied to the rotating valves 216, 218. In the present examples the angled O-rings220 are arranged at an angle of approximately 45 degrees, as illustrated in Fig. 3.However, it will be appreciated that any other suitable angle could be used (forexample, an angle between 20 degrees and 70 degrees, e.g. 30 degrees or 50degrees). It will also be appreciated that in the present example each angled O-ring220 opposes the other in its pair in a symmetrical manner, i.e. at mirroring angles (although this need not necessarily be the case).Whilst in the present examples angled O-rings 220 are used to improve the sealsbetween the chambers that contain the rotating valves 216, 218 and the otherchambers, this need not necessarily be the case. For example, only the generallyhorizontal O-rings 220c, 220f may be provided. Alternatively, no O-rings may beprovided, and the seals may be achieved, for example, using regions of overmoldedgasket material formed using an injection moulding method. The overmoldedregions could form part of the main body of the cartridge 200, or could be part of therotating valves 216, 218.Each of the rotating valves 216, 218 is provided with a respective groove 230, 232in an upper surface of the valve. The valves 216, 218 can be moved between theopen and closed configurations by inserting a rotatable member (e.g. a motor-drivenor manually-driven rotatable tab) into the grooves 230, 232, and rotating themembers to rotate the valves 216, 218 between the open and closed configurations.The first rotating valve 216 and the second rotating valve 218 may be rotatedsimultaneously, but could alternatively be rotated sequentially (with either the firstrotating valve 216 or the second rotating valve 218 being rotated before the otherrotating valve). Whilst in the present example each of the rotating valves 216, 218is provided with a respective groove 230, 232, this need not necessarily be the case. Alternatively, for example, a hex key could be used to rotate the valves 216, 218, by engaging with a corresponding recess provided on the upper surface of each valve 216, 218. It will be appreciated that the valves 216, 218 could also be rotated in any other suitable manner.When the rotating valves 216, 218 are in the open position, the grooves 230, 232are arranged generally perpendicularly to the longitudinal direction of the cartridge200 as shown in Figs. 4a and 4b (the grooves are arranged generallyperpendicularly to the path of the magnetic beads 102 along the length of thecartridge 200). When the rotating valves 216, 218 are in the closed position, thegrooves 230, 232 are rotated by 90 degrees to be generally aligned with thelongitudinal direction of the cartridge 200. Advantageously, by virtue of the grooves230, 232 being aligned with the longitudinal direction of the cartridge 200 when therotating valves 216, 218 are in the closed position, when the cartridge 200 is insertedinto a device for rotating the valves 216, 218 a member or tab of the device can slotinto the grooves 230, 232 as the cartridge 200 is inserted into the device. The devicefor rotating the valves 216, 218 may be the same device that moves a magnet (or otherwise uses a magnetic force) to drive the beads 102 along the length of thecartridge 200. An additional groove 229 is provided adjacent to the second rotatingvalve 218, and a further groove 228 is provided between the first rotating valve 216and the second rotating valve 218, to enable a first member or tab to pass along thelength of the device 200 and into the groove 230 of the first rotating valve 216, andto allow a second member or tab to pass into the groove 232 of the second rotatingvalve 216, as the cartridge 200 is inserted. In a particularly advantageous example,the cartridge 200 is configured for insertion into a device that rotates the rotating valves 216, 218, and moves the magnet 105 along the length of the cartridge 200 to transport the beads 102 from the lysis buffer 104 and into the elution buffer 108(via the wash buffer 106 and the regions of oil 112) after the valves 216, 218 havebeen opened. The configuration of the cartridge 200 therefore enables the processof opening the valves 216, 218 and transporting the beads 102 to be automated,and reduces the risk of user error in the operation of the valves 216, 218. Whilst in the present examples the rotating valves 216, 218 rotate by 90 degrees between the open and closed positions, this need not necessarily be the case. Alternatively, for example, the angular difference between the open and closed positions may be 45 degrees, or any other suitable angle.In the present examples, the ratio of the diameter (and similarly, the radius andcross-sectional area) of the chambers 300, 301 inside the rotating valves 216, 218that contain the oil 112 to the longitudinal length of the chambers 300, 301 (relatedto the ‘aspect ratio’ of the chambers 300, 301) is relatively small. Similarly, the cross-sectional area of the cavity 309 that contains the lysis buffer 104 at the interfacewith the oil 112 is relatively small, the cross sectional areas of the cavity 303 thatcontains the wash buffer 107 at the interfaces with the oil 112 is relatively small, andthe cross section area of the cavity 305 that contains the elution buffer 108 at theinterface with the oil 112 is relatively small. Advantageously, this reduces thepropensity for the oil 112 to mix with neighbouring liquids (the lysis buffer 104, wash buffer 106 and elution buffer 106) when the valves 216, 218 are in the open configuration. However, depending on the immiscibility of the particular liquids used, this need not necessarily be the case. Fill ports are also provided within the recesses 230, 232, for filling the wash buffer106 in the cartridge 200. A method of injecting wash buffer 106 into the cartridge willbe described in more detail later with reference to Fig.27. Whilst in the present example the rotating valves 216, 218 can be rotated byinserting members or tabs into the corresponding grooves 230, 232, this need notnecessarily be the case. Alternatively, for example, upwardly extending tabs may be provided on the upper surface of the rotating valves 216, 218. The tabs couldthen be gripped and rotated by a user (or by a mechanical device) to rotate thevalves 216, 218 between the open and closed configurations. However, the use ofgrooves 230, 232 is particularly advantageous since they reduce the risk of thevalves 216, 218 being inadvertently rotated. The volume of oil 112 provided inside the corresponding cavity 300, 301 of each rotating valve 216, 218 may be, for example, between approximately 50 µl and 150 µl (e.g.100 µl). The first compartment may contain, for example, between 0.5 mland 2.5 ml of lysis buffer 104 (e.g. 1 ml of lysis buffer). The capacity of the chamberthat contains the lysis buffer 104 may be, for example, between 3 ml and 6 ml. Thevolume of wash buffer in the cartridge 200 in the chamber 303 between the rotatingvalves 216, 218 may be, for example, between 25 µl and 150 µl (e.g. 50 µl). As willbe described later with reference to Fig. 27, the cartridge 200 may also containadditional wash buffer 106 inside conduits that are used to fill the wash buffer 106into the chamber 303 between the rotating valves 216, 218. The amount of elutionbuffer 108 inside the corresponding chamber 305 of the cartridge 200 may be, forexample, between 50 µl and 150 µl (e.g.110 µl). However, it will be appreciated that any other suitable amounts of the liquids could be used, and that the amountsof each liquid may depend on the particular reaction and reagents used. Forexample, some methods may use a smaller volume of elution buffer 108 in order toobtain a more concentrated eluted sample (or a larger volume of elution buffer 108to obtain a more dilute eluted sample).Whilst in the present examples, a magnet 105 is used to transport material from thesample along the length of the cartridge 200, this need not necessarily be the case. For example, the beads 102 could simply fall through the liquids by rotating thevalves 216, 218 into the open configuration and rotating the cartridge 200 into avertical configuration (so that the path for the beads 102 through the liquids isgenerally aligned with the gravitational force). However, use of a magnet 105enables the beads 102 to be more reliably and efficiently driven through the liquids,potentially in an automated manner. In particular, use of the magnet 105 enables the beads 102 to be driven through the interfaces between the different liquids, at which there may be significant surface tension (due to the use of immiscible liquidsto prevent mixing) that inhibits the movement of the beads 102. Moreover, whilst inthe present example a magnet 105 may be moved longitudinally along the length of the cartridge 200 to drive the beads 102 through the liquids, the magnet 105 couldalternatively, for example, be a fixed magnet 105 positioned adjacent to the part of the cartridge 200 that contains the elution buffer 108, and may simply pull the beadsalong the cartridge 200 towards the fixed magnet 105.In the example shown in Figs.3 to 4b the cartridge 200 is provided with a door 206used to seal the first part 202 of the cartridge 200. Fig. 5 shows a modified cartridge200’ in which a swab may screw into the first portion 202 of the cartridge 200’. Thescrew fitting of the swab helps to seal the cartridge 200’ and reduce the risk of leaksor contamination. As shown in Fig. 5, a swab 240 can be screwed into the firstportion 202 of the cartridge 200’. In this example the lysis buffer 104 covers the tip242 of the swab 240 when the device 200’ is in the generally horizonal orientation,but this need not necessarily be the case (alternatively, the lysis buffer 104 may cover the swab tip 242 only when the device 200’ is in a generally verticalorientation, as described above). The opening into the cartridge 200’ comprises afemale threaded portion 249 into which a male threaded portion 248 of the swab240 can be screwed, to seal the chamber using a corresponding cap 246 of theswab 240. Whilst in the example shown in Fig. 5 the swab support 212 is notprovided, and the base 250 of the chamber that contains the lysis buffer 104 has aflat and sloping configuration, this need not necessarily be the case. Alternativelythe first portion 202 of the cartridge may be as illustrated in the example shown inFig. 3, but having the door 206 replaced with the female threaded region 249 of Fig.5 for received the threaded swab 240 (although the door 206 could additionally beprovided, to seal the opening into cartridge 200’ whilst the swab is in use forcollecting a sample). In the example of Fig. 5 the conduits 323-326 used to fill thecartridge with oil 112 and wash buffer 106 have also been modified, but it will beappreciated that any suitable arrangement of fill conduits could be used. However, a particularly advantageous configuration for the fill conduits and correspondingmethods will be described in more detail later. In the example of Fig. 5, dowel pins221a, 221b are also provided, for retaining the rotating valves within the cartridge200.Returning now to the cartridge 200 illustrated in Figs. 3 to 4b, Fig. 6 shows a furtherperspective view of the cartridge 200. As shown in the figure, an aperture 307 isprovided to enable the elution buffer 108 to be extracted from the cartridge 200 forsubsequent analysis or testing (or to be moved to another region of the cartridge200 not shown in the figures). The aperture 307 could, for example, be providedwith a removable cap that can be opened to provide access to the chamber thatcontains the elution buffer 108 and the eluted species from the sample. Alternatively,for example, the aperture 307 could be covered with a foil seal that could bepunctured or removed to extract the elution buffer 108. The aperture 307 couldalternatively be provided with means for attaching to a syringe tip (e.g. a luer-lockfitting) for extraction of the elution buffer using a syringe. A plunger 318 that can beused to extract the elution buffer 108 will be described in more detail later with reference to Figs.29 and 30.Fill ports used to fill the oil 112 and wash buffer (wash liquid) 106 into thecorresponding cavities of the cartridge 200 will now be described, with reference toFigs. 7 to 11. The filling process will be described in more detail later with referenceto Figs. 23 to 32. Fig. 7 shows a top-down view of the cartridge 200. As shown inthe figure the first rotating valve 216 comprises a first wash liquid fill port cover 226, and the second rotating valve 218 comprises a second wash liquid fill port cover 227. The first wash liquid fill port cover 226 is shown in an open position, in which an opening 262 into the cartridge for filling the wash liquid is exposed via an opening in the cover 226. The second wash liquid fill port cover 226 is illustrated in a closedposition in which an opening 262 into the cartridge for filling the wash liquid 106 iscovered by the fill port cover 227. O-rings 298 (see e.g. Figs.15, 16 and 19) areprovided at the openings, and the wash liquid fill port covers 226, 227 engage withthe O-rings 298 when in the closed position to seal the wash liquid within thecartridge 200. Each of the wash liquid fill port covers 226, 227 is moveable betweenthe open and closed positions by sliding the fill port cover 226, 227 within acorresponding groove provided on the upper surface of the rotating valves. Alsoshown in Fig.7 are two recesses 266a, 226b provided adjacently to the first rotating valve 216, and two recesses 268a, 268b provided adjacently to the second rotating valve 218. As will be described in more detail later with reference to Figs.16 to 18, these recesses are associated with corresponding tabs (or ‘fins’) provided on the rotating valves 216, 218, and enable the rotating valves 216, 218 to be inserted into the respective cavities of the cartridge 200 when assembling the device. Whilst in the examples illustrated in Figs. 7 to 11 the wash buffer is filled via corresponding fill ports provided on the upper surface of the rotating valves, this need not necessarily by the case. Alternatively, for example, the wash buffer region could be filled with the wash buffer via ports provided in the main body of the cartridge, or via any other suitable opening. Fig.8 shows a view of a side of the cartridge from which oil is filled. A first pair of oil fill ports 270, 272 are provided for filling the oil chamber 300 of the first rotating valve 216 with oil 112 (and for filling the space between the first rotating valve 216 and the cavity walls 222 with oil 112). A second pair of oil fill ports 274, 276 are provided for filling the oil chamber 301 of the second rotating valve 218 with oil 112 (and for filling the space between the second rotating valve 218 and the cavity walls 222 withoil 112). A first oil fill port cover 278 and a second oil fill port cover 280 are providedfor the first rotating valve 216 and the second rotating valve 218, respectively. Theoil fill port covers 278, 280 are shown in the open position (or ‘filling position’) in Fig.8, in which the oil fill ports are accessible via corresponding openings in the oil fillport covers 278, 280. The oil fill port covers 278, 280 can be moved into a closedposition by sliding (towards the left-hand side of Fig. 8) the covers 278, 280 withincorresponding recesses 282, 284 such that the openings in the fill port covers 278,280 are no longer aligned with the oil fill ports, and the oil fill ports are sealed closedby the fill port covers. The first oil fill port cover 278 is provided with a pair ofalignment points 265a, 265b that help to maintain alignment of the fill port cover 278with the cartridge 200. The second oil fill port cover 280 is also provided with acorresponding pair of alignment points 265a, 265b. The alignment points 265, 267may also be used for sliding the oil fill port covers 278, 280 between the open and closed positions.As shown in Fig.8, the opening in the oil fill port cover 278, 280 that provides accessto one of the oil fill ports 270, 274 (in this example, the lower oil fill port) is circular,whereas the opening in the oil fill port cover 278, 280 that provides access to theother oil fill port 272, 276 has an elongate shape (in this example, an oval).Advantageously, the combination of the circular opening and the elongate openingmeans that when the fill port cover 278, 280 is slid into the closed position, one ofthe oil fill ports 270 will be sealed closed before the other oil fill port 272 is sealedclosed. When the oil fill port cover 278, 280 is slid into the closed position, anincrease in the fluid pressure of the oil 112 can occur. This can increase the risk ofthe liquids inside the cartridge 200 mixing or leaking, or result in liquid being ejectedinto the cavity 309 that contains the lysis buffer 104 (since the cavity 309 thatcontains the lysis buffer 104 is only partially filled with lysis buffer 104 and thereforeacts as a compressible volume). Advantageously, by virtue of the fill port covers278, 280 sealing one of the oil fill ports before the other oil fill port, as the oil fill portsare closed, excess pressure build-up in the oil 112 is beneficially avoided, since theexcess pressure is released via the fill port that is sealed last (the fill port that isaccessed via the asymmetrical or elongate opening in the oil fill port cover plate 278, 280). Whilst in the example illustrated in Fig. 8 the fill port covers 278, 280 are provided with a circular opening and an elongate opening to access the oil fill ports,any other suitable shapes for the openings that results in either the upper or lowerfill port being sealed closed before the other of the fill ports could be used (e.g. asquare opening and a rectangular opening). Moreover, whilst the configuration ofthe openings in the fill port covers 278, 280 illustrated in Fig. 8 that result in astaggered closing of the fill ports is particularly advantageous, staggered closing of the fill ports need not necessarily be used.Fig. 9 shows a view of the underside of the cartridge 200, in which the recesses282, 284 into which the oil fill port covers 278, 280 can be slid into to seal the oil fill ports can be seen.Figs. 10 and 11 show cutaway views of the cartridge 200, showing the oil fill portcover 278 and the conduits 286, 288 via which the cartridge 200 is filled with oil 112.As shown in the figures, the oil fill port cover 278 is provided within a corresponding casing 296, within which the oil fill port cover 278 can be slid between the open andclosed positions. As shown in Fig. 11, there is space provided within the casing 296for the oil fill port covers 278 to slide (towards the left hand side of Fig.11) into the closed position, to seal closed the oil fill ports. Each of the oil fill ports is coupled to a corresponding conduit 286, 288 that leads to the cavity in which the rotating valve216 is situated. As will be described in more detail later, oil 112 is filled into thecartridge 200 via one of the oil fill ports and the corresponding conduit, and exits viathe other conduit and the corresponding oil fill port. This method of filling the oil 112beneficially reduces the occurrence of air bubbles forming inside the oil 112, whichwould inhibit the transport of the beads 102 through the oil 112 using the magnet105. O-rings (not visible in Figs. 10 or 11) are provided at the oil fill ports, inside acorresponding O-ring casing 292. As the oil fill port cover 278, 280 is slid into the closed position, the cover 278, 280 engages with the O-rings to seal the oil fill ports closed. Whilst in the examples illustrated in Figs. 7 to 11 sliding fill port covers and corresponding O-rings are used to close and seal and fill ports, this need not necessarily be the case. Alternatively, each of the fill ports could be closed and sealed using any other suitable means. For example, the fill ports could be closed using an adhesive or heat-seal foil, using a rubber stopper or plug, using a UV cure adhesive, using an ultrasonically welded plug or cap, or using a press-fit plastic plug. In a further alternative the fill ports could be closed using a bolt, screw or threaded cap, where each fill port is threaded for receiving the bolt or screw to seal the fill port closed.Figs. 12 to 15 show further cross-sectional and cutaway views of the cartridge 200,in which the tapered shape of the cavity 309 that contains the lysis buffer 104 canbe seen. As illustrated in Fig. 12, the width of the cavity 309 decreases, in thetransverse direction, along the longitudinal length of the cartridge 200 towards thesecond portion 204 of the cartridge 200. As illustrated in Fig. 13, the height of thecavity 309 also decreases towards the second portion 204 of the cartridge. As willbe described in more detail later with reference to Figs.22a and 22b, by virtue ofthe tapered shape of the cavity 309 that contains the lysis buffer 104, the level of the lysis buffer 104 is advantageously below the level of the swab support 212 when the cartridge 200 is in a generally horizontal orientation, but covers the swab tip 312 when the cartridge 200 is in a generally vertical orientation.Fig. 16 shows a top-down cutaway view of the cartridge 200 in which the tabs 279a,279b of the first rotating valve 216 and the tabs 285a, 285b of the second rotatingvalve 218 can be seen. The rotating valves 216, 218 are illustrated in the openconfiguration in Fig. 16, in which the beads 192 can be moved along the length ofthe cartridge 200 from the lysis buffer 104 to the elution buffer 108. The tabs 279,285 engage with the main body of the second portion 204 of the cartridge 200, exerting a generally downward force on the rotating valves 216, 218. This forcepushes each rotating valve 216, 218 against the respective angled O-rings 220 (andagainst the generally horizontal O-rings 220c, 220f), improving the strength of theseals. In order to move the rotating valves 216, 218 into the open configuration, therotating valves 216, 218 are rotated by 90 degrees in a counterclockwise direction(when the cartridge is viewed top-down as in Fig. 16). The tabs 285, 279 remainengaged with the main body of the second portion 204 of the cartridge 200 when the rotating valves 216, 218 are in the closed configuration (rather than the tabs 279, 285 being aligned with the recesses 266, 268 provided adjacently to each rotating valve 216, 218). The recesses 266, 268 adjacent to each rotating valve216, 218 are provided so that the tabs 279, 285 can pass through the recessesduring assembly, to enable the rotating valves 216, 218 to be inserted into thecartridge 200 during manufacture. However, it will be appreciated that theserecesses 266, 268 need not necessarily be provided. For example, the rotatingvalves 216, 218 could be placed inside the cartridge 200 before the uppermost partsof the cartridge 200 are assembled. Whilst the rotating valves 216, 218 of thepresent example are provided with tabs (or ‘fins’) for engaging with the main body of the cartridge 200 to push the rotating valves 216, 218 against the angled O-rings, it will be appreciated that these members need not necessarily be tab or fin shaped. Any other suitable member for engaging with the main body of the cartridge 200 topush the rotating valves 216, 218 against the O-rings 220 could alternatively beused. Alternatively, for example, an arrangement of springs could be used to push the rotating valves 216, 218 against the angled O-rings to improve the strength of the seals. In a further alternative a c-clip, spring pins or dowel pins could be used to push the rotating valves 216, 218 against the angled O-ringsFig. 19 shows a cutaway and exploded view of the cartridge 200, showing some ofthe components of the cartridge 200 in more detail. In particular, the O-rings 270, 272 that are arranged between the oil fill plate 278 and the oil fill conduits 286, 288 are shown. The O-ring 298 that is provided between the wash liquid fill port and the wash liquid fill port cover 226 is also shown. The cavity 302 inside which the first rotating valve 216 is arranged can also be seen. As shown in Fig.19, regions of the wall of the cavity 302 are shaped for receiving the corresponding O-rings.Fig. 20 shows a cutaway view of the cartridge. The arrangement of the swabsupport 212 above the tapered part of the chamber 309 that contains the lysis buffer104 can be seen. The slot 213 in the swab support 212 can also be seen in Fig.20.The slot 213 helps to allow the lysis buffer to flow around the swab tip when thedevice 200 is in the generally vertical orientation, and to drain back into the cavity 309 when the device 200 is in the generally horizontal orientation. The slot 213 beneficially helps to prevent pooling of the lysis buffer on the swab support 212. In Fig.20 the upper surface of the first rotating valve 216 has been hidden to illustrate the location of the oil fill conduits 286, 288 and the O-rings. Movement of the beads 102 within the lysis buffer 104 will now be described with reference to Figs. 21a and 21b. Fig. 21a shows an example in which a rotating magnet 306 is used to drive the magnetic beads 102 along the length of the cartridge200. As the magnet 306 moves along the length of the cartridge 200, the magnet306 exerts a force on the magnetic beads 102, causing them to move through thelysis buffer 104. The combination of the rotational and translational movement of themagnet 306 results in the beads 102 moving through the liquid in a cloud-likemanner. The translational movement of the magnet enables bulk movement of thebeads in their dispersed state, as translational movement along the cartridge 200.The rotational movement of the magnet 306 creates an oscillating magnetic fieldthat results in dispersion of the beads within a localized area in all directions, andalso assists in the translational movement along the cartridge 200. Beneficially,movement of the beads through the liquid in a cloud-like manner increases themixing of the beads 102 in the lysis buffer, and reduces the downward componentof force on the beads and the corresponding frictional forces (and reduces the riskof beads being dragged along the floor of the cartridge and becoming trapped bydiscontinuities in the surface). Moreover, the cloud-like formation of the beadsenables the use of smaller cross-sectional areas along the path for the beads from the lysis buffer 104 to the elution buffer 108. This is because clumped beads requirea larger cross-sectional area for the path, for reliable transportation along thecartridge 200. Advantageously, the use of smaller cross-sectional areas at theliquid-liquid interfaces helps to maintain separation of the liquids. The movement of the beads in the cloud-like manner also occurs as the beads are moved through theother liquids, such as the wash buffer 106 and the elution buffer 108. Whilst one ormore non-rotating magnets could alternatively be moved along the length of the cartridge 200 to drive the beads 102 along the cartridge 200, this may result in the beads clumping and dragging along the base 214 of the chamber, decreasing themixing and exposed surface area of the beads 102 in the lysis buffer 104 and in theelution buffer 108. For the case of the beads moving through the wash buffer 106,clumping of the beads can result in lysis liquid being trapped between the beadsand making its way into the elution chamber. In the example shown in Fig.21a, the base 214 of the chamber 309 comprises aseries of ridges or steps (or ‘ribs’, or ‘waves’), which beneficially further increasesthe mixing of the beads 102 with the lysis buffer 104. As the beads 102 are drivenalong the length of the chamber 309, the ridges of the base 214 of the chamber 309 result in the beads 102 being pushed upwards away from the base 214, and resultin the beads 102 moving turbulently in the lysis buffer 104 as they are transportedalong the length of the chamber 309, as illustrated schematically by the curly arrow.Therefore, by virtue of the ridged base 214, mixing of the beads in the lysis buffer104 is improved, reducing the amount of clumping and increasing the surface areaof the beads 102 exposed to the lysis buffer 104. Notably, in this example, theupward slope of the ridges (that causes the beads 102 to be pushed upwards to mixwith the lysis buffer 102) is angled, rather than being exactly vertical, reducing therisk of beads 102 becoming stuck against the ridges when being driven along thechamber 309 by the magnet 306. As illustrated in Fig.21a, the amount of lysis buffer104 inside the chamber 309 is selected so that the level of the lysis buffer 104 (andtherefore the maximum height reachable by the magnetic beads 102 in the lysisbuffer 104) does not extend past the swab support 212 when the device is in thegenerally horizontal orientation, reducing the risk of the beads encountering mucous or other viscous material that has been transferred to the swab support 212 from the swab. Whilst the provision of the ridges improves the mixing of the beads 102 with the lysis buffer 104, the base of the chamber 309 need not necessarily be provided with the series of ridges. For example, Fig.21b shows a modified version of the cartridge 200 in which the chamber 309 is provided with a flat base 308. The liquid level of the lysis buffer 104 when the cartridge 200 is in the generally vertical and horizontal orientations will now be described with reference to Figs.22a and 22b. Fig.22a shows the cartridge 200 in a generally vertical orientation. In the example shown in Fig.22a, the cartridge 200 is held by a user who has inserted a swab into the cartridge 200. By virtue of the tapered shape of the chamber 309 that contains the lysis buffer 104, the lysis buffer 104 covers the tip 312 of the swab 310 when the cartridge 200 is in the generally vertical orientation, enabling the lysisbuffer 104 to cause species from the sample to be released into the liquid. The swabsupport 212 may be provided with ribbing or dimpling, or any other suitable texture,to aid in the mechanical removal of material from the swab tip after it is inserted intothe cartridge 200. A wall of the cavity 309 may also comprise a textured region toaid in the mechanical removal of material from the swab tip. Fig. 22b shows a viewof the cartridge 200 after the cartridge 200 has been rotated into the generally horizontal orientation. By virtue of the tapered shape of the chamber 309 that contains the lysis buffer 104, the lysis buffer 104 does not cover the tip 312 of theswab 310 when the cartridge 200 is in the horizontal orientation (as described above, the tip of the swab engages with the swab support 212, and the level of thelysis buffer 104 is below the level of the swab support 212). The magnet 105 canthen be moved along the length of the chamber 309 when the cartridge 200 is in thehorizontal orientation, in order to mix the beads in the lysis buffer 104. Advantageously, since the lysis buffer 104 does not cover the swab tip 312 in Fig. 22b, the risk of the beads 102 becoming stuck to mucous or other viscous materialon the swab tip 312 as the beads 102 are driven through the liquid by the magnet105 is beneficially reduced. Moreover, as a result of the tapered shape of thechamber 309, the depth of the lysis buffer 104 is relatively small when the cartridge200 is in the horizontal orientation. This relatively low liquid level enables the cloudof beads 102 to more easily be mixed within the full cross-sectional area of the lysisbuffer 104, helping to ensure that no target molecules are unreachable.Fig. 23 shows a further exploded cross-sectional view of the cartridge 200 showingthe cavity 302 within which the first rotating valve 216 is rotated to transition betweenthe open and closed configurations. Fig. 24 shows a further cross-sectional view ofthe cartridge 200, showing the arrangement of O-rings 220 and the first rotatingvalve 216 within the cavity 302 in more detail. As descried above, the first rotatingvalve 216 pushes against the O-rings 220, improving the strength of the seals insidethe cartridge 200, reducing the risk of the liquids mixing or leaking from the cartridge 200. As described above, a chamber 300 inside the first rotating valve 216 is filledwith oil 112, and beads 102 pass from the lysis buffer 104 to the wash buffer 106via that region of oil 112 inside the first rotating valve 216. However, additional oil 112 is provided between the first rotating valve 216 and the wall of the cavity 302 in which the first rotating valve 218 is situated (and oil 112 is similarly provided between the second rotating valve 218 and the wall of the cavity in which the secondrotating valve 218 is situated). For example, oil 112 is provided in a gap 314 betweenthe base of the first rotating valve 216 and the base of the cavity 302, and in the regions 316a, 316b between the angled O-rings 220a, 220b and the generallyhorizontal O-ring 220c, as illustrated in Fig. 24 (and these regions 314, 316a, 316bare fluidically connected to provide a region of oil 112 around the rotating valve 216). Advantageously, the additional layer of oil 112 further reduces the risk of the liquids leaking from the cartridge 200, and also inhibits the other liquids from evaporating from the cartridge 200. The generally horizontal O-ring 220c helps to seal theadditional oil 112 within the cavity 302. In addition to the layer of additional oil 112provided around the rotating valves 216, 218 beneficially reducing the risk ofleakage or mixing of the other liquids, the additional oil 112 can also providelubrication, enabling the rotating valves 216, 218 to be rotated more easily withinthe cavities 302 (although this need not necessarily be the case, depending on theparticular liquid used). It will be appreciated that the liquid provided around each rotating valve 216, 218 need not necessarily be the same as the liquid provided inside the rotating valves 216, 218 (through which the beads 102 pass). Indeed, the substance provided between the rotating valves 216, 218 and the wall of the cavities302 in which the rotating valves 216, 218 are situated need not necessarily be aliquid. For example, a paste (e.g. grease) could be used to fill the gap between the rotating valves 216, 218 and the wall of the cavity 302, reducing the risk of liquids leaking from the cartridge 200. However, use of a liquid (e.g. oil 112) may be preferred, as this can be more easily injected into the cartridge 200. Filling of Liquids Filling of the oil 112 and wash buffer 106 into the cartridge 200 will now be describedin more detail, with reference to Figs.25 to 27. Fig.25 shows a cross-sectional viewof the first rotating valve 216 when the first rotating valve 216 is in the open position.As shown in Fig.26, when the first rotating valve 216 is in the open position 300, the chamber 300 inside the first rotating valve 216 to be filled with oil 112 is aligned along the longitudinal length of the cartridge 200. The oil fill conduits 286, 288 are therefore not aligned with the chamber 300 inside the first rotating valve 216. The conduit 252 for filling the wash buffer 106 can also be seen. In the example shown in Fig.25 the wash fill port cover 226 is in the closed position, sealing closed theopening into the wash buffer fill conduit 252 (by engaging with the corresponding O-ring 298). Similarly, the oil fill conduits 286, 288 can be sealed closed by thecorresponding oil fill port cover plate 278 (by engaging with the corresponding O-rings 270, 272). Therefore, both the oil fill conduits 286, 288 and the wash buffer fill conduit 252 are sealed closed, and this configuration may be used, for example, after the liquids have been filled into the cartridge, and the beads are to be transported through the liquids.Fig. 26 shows the cross section of Fig. 25, but when the first rotating valve 216 is inthe closed configuration. When the first rotating valve 216 is in the closed configuration, the chamber 300 inside the first rotating valve 216 to be filled with oil 112 is arranged along the transverse direction across the cartridge 200. One of theoil fill conduits 286, 288 is partially aligned with the chamber 300 inside the firstrotating valve 216 (in this example, the lower oil fill conduit 286 partially overlapswith the opening into the oil chamber 300 inside the rotating valve 216, but alternatively the oil fill conduit 286 could fully overlap with the opening into the oil chamber 300). Therefore, the chamber 300 inside the first rotating valve 216 can be filled with oil 112, via the corresponding oil fill conduits 286, 288, when the first rotating valve 216 is in the closed position. Oil 112 can be injected into the cartridge 200 via the lower oil fill conduit 286 (through the corresponding opening in the oil fillport cover plate 278 when the oil fill port cover plate 278 is in the open position).The oil 112 will then flow through the conduit 286 and into the chamber 300 inside the rotating valve 300. Advantageously, the oil 112 will also flow into the cartridge 200 to fill the space in between the first rotating valve 216 and the wall of the cavity302 in which the first rotating valve 216 is situated. As described above, thisadditional oil 112 provided around the outside of the rotating valves 216, 218 beneficially reduces the risk of the liquids inside the cartridge 200 mixing or leaking(and also reduces the amount of evaporation). During the fill process, oil flows outof the cartridge 200 via the upper oil fill conduit 288. In other words, oil flows into thecartridge 200 via the lower fill conduit 286, and out of the cartridge 200 via the upperfill conduit 288. Alternatively, the oil 112 could be injected into the upper oil fillconduit 288 and flow out of the cartridge 200 via the lower oil fill conduit 286, but filling using the lower oil fill conduit 286 as the inlet, i.e. from the bottom up, may bepreferable, to reduce the likelihood of air bubbles forming in the oil 112.Advantageously, by virtue of the provision of the two oil fill conduits 286, 288, a flowof oil 112 can be pushed through the corresponding cavities inside the cartridge200, reducing the risk of air bubbles being formed inside the chamber 300 (or beingformed in the space between the first rotating valve 216 and the cavity in which thefirst rotating valve 216 is situated) inside the first rotating valve 216, which wouldinhibit movement of the beads 102 along the chamber 300. In contrast, if only oneoil fill conduit 286 were used to fill the oil 112, air inside the chamber 300 maybecome trapped and compressed. Whilst the use of a pair of oil fill conduits 286,288 is preferred to reduce the risk of the trapping of air bubbles, alternatively one oilfill conduit could nevertheless be used (for example, the strength of the magnet 105may be such that the magnetic beads 102 can be driven through any air bubbles that form). Whilst in the present example the two oil fill conduits 286, 288 are located on the same side of the cartridge 200, this need not necessarily be the case, and each of the oil fill conduits 286, 288 could alternatively be arranged at any other suitablelocation on the cartridge 200 (e.g. on opposing sides of the cartridge, such that oilflows into the cartridge 200 in one side, and out of the cartridge 200 on the otherside). It will be appreciated the configuration of the cartridge 200 for filling the second rotating valve 218 with oil 112 (via a corresponding second pair of oil fill conduits) isthe same as the configuration used for the first rotating valve 216 that has beendescribed above with reference to Figs. 25 and 26.Fig. 27 shows a cross-sectional view of the cartridge 200, illustrating the paththrough which the wash buffer 106 flows to fill the cartridge 200 with the wash buffer106. As shown in the figure, the rotating valves 216, 218 are in the closedconfiguration, and a path is formed from the wash buffer fill port of the first rotating valve 216 to the wash buffer fill port of the second rotating valve 218. The wash buffer fill port covers 226, 227 are in the open positions, in which wash buffer 106can flow into (and out of) the cartridge 200. In order to fill the wash buffer cavity 303between the two rotating valves 216, 218 with the wash buffer 106, the wash buffer106 is injected into the opening in the upper surface of the first rotating valve 216 toflow along the corresponding wash buffer fill conduit 252, along the wash buffer cavity 303, and out of the cartridge 200 via the wash buffer fill conduit 254 provided in the second rotating valve 218. In other words, wash buffer 106 flows into the cartridge 200 via the opening in the first rotating valve 216 and flows out of the cartridge 200 via the opening in the second rotating valve 218 (alternatively the flow direction may be reversed, such that the wash buffer 106 flows into the cartridge 200 via the opening in the upper surface of the second rotating valve 218 and flows out of the cartridge 200 via the opening in the upper surface of the first rotating valve216). By virtue of the two wash buffer fill conduits 252, 254 forming a path for a flowof the wash buffer 106 into and out of the cartridge 200 during the fill process, therisk of air bubbles forming inside the cavity 303 during the fill process is beneficiallyreduced. In contrast, if the wash buffer 106 was filled into the wash buffer cavity 303using a single conduit, the flow of the wash buffer 106 into the cavity wouldcompress the air in the cavity 303, forming an air bubble (which could inhibit themovement of the magnetic beads 102 along the cavity 303). Nevertheless, whilstthe use of two wash buffer fill conduits 252, 254 is preferred to reduce the risk of thetrapping of air bubbles, one wash buffer fill conduit could alternatively be used.Moreover, whilst in the present example the wash buffer fill conduits 252, 254 are provided inside the rotating valves 216, 218, this need not necessarily be the case. Alternatively, for example, wash buffer fill ports could be provided on the side of the cartridge 200 (e.g. on the same side of the cartridge 200 on which the oil fill ports are provided). However, the present inventors have found that the configuration illustrated in Fig.27 is particularly advantageous, as the path for flow of the washbuffer 106 into and out of the cartridge 200 during the fill process reduces the riskof air bubbles becoming trapped. In contrast, when the wash buffer cavity 303 isfilled from the side of the cartridge, the present inventors have found that air bubbles are more prone to forming near the interfaces between the wash buffer fill conduits 252, 254 and the wash buffer cavity 303, as well as in the regions of the cavity 303 proximal to each of the rotating valves 216 and 218.When the filing of the wash buffer 106 into the wash buffer cavity 303 is complete,the wash buffer fill port covers 226, 228 are moved into the closed position. Washbuffer 106 remains in the wash buffer fill conduits 252, 254 after the filling processis complete. Advantageously, by virtue of the additional oil 112 provided around theoutside of the rotating valves 216, 218, the risk of the wash buffer 106 leaking outof the wash buffer fill conduits 252, 254 (e.g. after the rotating valves 216, 218 havebeen rotated into the open configuration) is beneficially reduced.Fig. 28 shows a further cross-sectional view of the cartridge 200 when the rotatingvalves are rotated by approximately 45 degrees from the open position.Elution buffer extractionExtraction of the elution buffer 108 from the cartridge 200 (or into a further region ofthe cartridge 200 not shown in the figures) will now be described, with reference toFigs. 29 and 30. Figs.29 and 30 show cross-sectional views of the cartridge 200, inwhich a plunger 318 can be seen. In use, the plunger 318 is pushed into acorresponding plunger cavity 322 that is filled with the elution buffer 108, to pushthe elution buffer 108 out of the cavity and out of the end of the cartridge 200 via thecorresponding aperture 307 (the aperture can be seen in Fig. 6).The elution buffer chamber 305, that is full of elution buffer 108, provides a path from the oil 112 inside the second rotating valve 218 to the elution buffer 108 in the plunger cavity 322. It will be appreciated, therefore, that when the second rotating valve 218 is in the open position, the beads 102 can be transported by the magnet 105 from the oil 112 inside the second rotating valve 218 and into the elution buffer108 inside the plunger cavity 322. The elution buffer 108 causes the chemical orbiological species from the sample to separate (elute) from the beads 102, into theelution buffer 108, ready for extraction from the cartridge 200 (or into a further regionof the cartridge 200 not shown in the figures). Advantageously, as illustrated in Fig.27, the curved walls of the elution buffer chamber 305 encourage mixing of thebeads 102 in the elution buffer 108. As shown in the Figure, when a magnet 306 is positioned generally adjacent to the elution buffer chamber 305 and rotated, thebeads 102 follow a path generally along the curved walls of the chamber 305 asindicated by the arrow 311, improving the mixing of the beads 102 within the liquid. The beads 102 may be removed from the elution buffer 108 before the elution buffer 108 is extracted. For example, the beads 102 may be transported back to the cavity309 that contains the lysis buffer 104. The second rotating valve 218 can then berotated into the closed position (the first rotating valve 216 may also be rotated intothe closed position, but this is not necessary for extracting the elution buffer 108).The plunger 318 is then pushed into the corresponding plunger cavity 322, therebycausing the elution buffer 108 to be ejected out of the cavity 305 that contains theelution buffer 108 (e.g. into a further region of the cartridge 200 not shown in thefigures, or from the cartridge 200 itself). As shown in Fig.30, a plunger face 322 of the plunger 318 is shaped to fit against the wall of the cavity 305 that contains the elution buffer 108 when the plunger 318 has been pushed into the cavity, maximising the amount of elution buffer 108 thatis ejected. An O-ring 320 is also provided around the plunger 318, to reduce the riskof elution buffer 108 leaking around the edges of the plunger 318 and out of the cartridge 200.The plunger 318 may be pushed into the cartridge 200 to eject the elution buffer 108by a user manually pushing against the exterior surface 234 of the plunger 318, butcould alternatively be pushed using a mechanical device, for example a linearactuator. As shown in Fig. 4b, the exterior surface 234 of the plunger 318 may havean asymmetrical shape, to ensure that the plunger 318 is correctly orientated insidethe cartridge 200 during manufacture, so that the plunger face 322 is correctlyorientated to fit against the wall of the cavity 305 that contains the elution buffer 108.Advantageously, the exterior surface 234 of the plunger 318 is substantially flush with the outer surface of the device 200, reducing the risk of a user inadvertently depressing the plunger. In a particularly advantageous embodiment, the cartridge 200 is inserted into a device that rotates the rotating valves 216, 218 between the open and closed positions, moves the magnet 105 along the length of the cartridge, and operates theplunger 318. Advantageously, therefore, the process of extracting the chemical orbiological species from the sample, moving the beads 102 through the liquids andinto the elution buffer 108, moving the beads out of the elution buffer 108, and thenextracting the elution buffer 108 can be automated, beneficially reducing the risk ofuser error in the operation of the valves 216, 218, magnet 105 or plunger 318. Forexample, by virtue of providing a device to control the operation of the plunger 318and the rotating valves 216, 218, a situation in which a user inadvertently pushes in the plunger whilst the rotating valves 216, 218 are in the open configuration (whichmay result in the elution buffer 108 being pushed back through the cartridge 200,and ejection of liquid into the chamber that contains the lysis buffer 104) canadvantageously be avoided. Similarly, a situation in which the user inadvertentlyejects the elution buffer 108 before the magnetic beads 102 have been removedfrom the elution buffer 108 using the magnet 105 can be avoided. Whilst the use of a plunger 318 provides a particularly efficient method for extracting the elution buffer 108, it will be appreciated that the plunger 318 need not necessarily be provided. Alternatively, for example, the aperture 307 into the cavity305 that contains the elution buffer 108 could be provided with a foil seal or plug,which could be punctured or opened to allow the elution buffer 108 to drain out ofthe cavity 305, or for it to be removed with an instrument such as a pipette.Oil PressureAs described above, during the filling of oil 112 into the cartridge 200, the pressureof the oil 112 may increase when the oil fill port cover plates 278, 280 are closed toseal the oil 112 within the cartridge 200. This increase in pressure can disrupt theseparation of the oil 112 from the other liquids, and may result in liquid being ejectedinto the chamber that contains the lysis buffer 104 (when the rotating valves 216,218 are subsequently rotated into the open configuration). Whilst in the examples described above this effect is mitigated by providing the oil fill port cover plates 278,280 having an elongated opening into one of the oil fill conduits, Figs. 31a to 31dshow a modified version of the cartridge 200 that further mitigates against the build-up of excess pressure in the oil 112.As illustrated in Figs. 31a and 31b, the cavities in which the rotating valves 216, 218are situated may be provided with air bubble traps 328 (which may also be referredto ‘gas cavities’ or ‘air cavities’). In the example shown in Figs. 31a and 31b, aplurality of air bubble traps 328 are provided, but alternatively only one air bubbletrap 328 could be provided per rotating valve. The air bubble traps 328 are relativelysmall cavities configured for trapping gas (e.g. air) during the filling process. As theoil fill port cover plates 278, 280 are closed, the increase in pressure causes the air in the air bubble traps 328 to compress, beneficially relieving some of the pressurein the oil 112 (or dampening the spike in the oil pressure that can occur as the oil issealed inside the cartridge 200). In other words, one or more regions of gas areprovided, and the gas compresses when the pressure in the oil 112 increases. Advantageously, the air bubble traps 328 are provided away from the oil cavities300, 301 inside the rotating valve 216, 218, so that the regions of air do not inhibitthe transport of the beads 102 through the oil 112 using the magnet 105.Figs. 31c and 31d show an alternative in which foam discs 332 are provided in thebase of the cavities in which the rotating valves 216, 218 are situated. The foam discs 332 function in a manner similar to that of the air bubble traps 328 describedabove. As the pressure in the oil 112 increases due to the oil fill port cover plates278, 280 being closed, the foam discs 332 are compressed, beneficially helping toequalise the pressure in the oil 112 with the pressure of the adjacent liquids.Filling ApparatusExemplary oil filling apparatus that could be used to inject the oil 112 into thecartridge 200 will now be described with reference to Fig.32. The filling apparatusmay also be referred to as a ‘filling jig’ or ‘oil injector’. As shown in Fig. 32, the fillingapparatus can be mounted to the side of the cartridge 200. A first syringe 338 canbe used to inject oil 112 into the cartridge 200 via one of the oil fill conduits 286, andoil is pushed out of the cartridge 200 and into a second syringe 340 via the other ofthe oil fill conduits 288. It will be appreciated that the filling apparatus need not necessarily comprise a syringe, and that any other suitable type of filling apparatus could alternatively be used, for example one or more pumps. Advantageously, by virtue of the provision of the second syringe 340, the oilpressure is increased during the fill process due to the pressure needed to force theoil 112 into the second syringe 340. This temporary increase in pressure (which canbe controlled by selecting an appropriately sized second syringe 340) helps tomitigate against the trapping of air bubbles inside the oil 112 during the fill process.Since the rotating valves 216, 218 are in the closed position when the oil is filled112, the risk of the oil 112 mixing with the other liquids in the cartridge 200 duringthe temporary increase in oil pressure is reduced. Nevertheless, it will beappreciated that the second syringe 340 need not necessarily be provided. In use,the tips of the syringes may be arranged to engage with the O-rings 270, 272 that are arranged between the oil fill plate 278 and the oil fill conduits 286, 288, to provide a particularly good seal with the syringes during the filling process. In a particularly advantageous example, the flow of liquid into the cartridge 200 from the syringe 338 is pulsed, which helps to remove air bubbles from within the liquid inside the cartridge 200. In other words, the flow rate and pressure of the liquid flowing into the cartridge 200 from the syringe 338 is varied during the filling process, which was beneficially found to encourage air bubbles to evacuate the cavity. Whilst the filling apparatus illustrated in Fig.32 is used for filling the cartridge 200 with oil 112, it will be appreciated that corresponding filling apparatus can be used to fill the cavity that contains the wash liquid 106, as described above with reference to Fig.27. Method of extracting a chemical or biological speciesA method of using the cartridge 200 to extract a chemical or biological species froma sample will now be described.In a first step, the rotating valves 216, 218 are initially in the closed orientation, anda user inserts a swab (or alternatively, pipettes a liquid sample) into the aperture205 of the first portion 202 of the cartridge 200. Any other additional buffers or components (e.g. the beads 102) could also be introduced into the cartridge via theaperture 205 at this stage. The cartridge 200 is in the vertical orientation (asillustrated in Fig. 22a) so that the lysis buffer 104 contacts the tip of the swab (butthe cartridge 200 need not necessarily be in the vertical orientation when the swabis inserted). The lysis buffer 104 causes release of DNA, RNA or proteins from thesample, to be bound to the coating of magnetic beads 102 that are in the lysis bufferchamber 309. The swab is then removed from the cartridge 200 by the user, the cap206 of the device is closed, and the device is rotated into the generally horizontalorientation (as illustrated in Fig. 22b). Alternatively, the swab tip may be broken offand remain inside the cartridge 200 when the cap 206 is closed. In a furtheralternative, the sample may be introduced into the cartridge 200 using a pipette rather than a swab.In an optional second step, the cartridge 200 is inserted into a machine for rotatingthe rotating valves 216, 218, moving the magnet 105, and operating the plunger318. Alternatively, the rotating valves 216, 218, magnet 105 and plunger 318 maybe operated manually by a user. In a further alternative, when one or moreelectromagnets are used to manipulate the beads within the cartridge 200, themachine controls the magnetic field generated by the electromagnets, to manipulatethe beads within the cartridge 200. More generally, the machine may be used toprovide a magnetic field source to manipulate the beads within the cartridge 200.In an optional third step, the magnet 105 is used to move the beads 102 within thelysis buffer 104, to mix the beads with the lysis buffer 104. Advantageously, thisincreases the amount of the target biological or chemical species that binds to thesurface of the beads 102.In a fourth step, the rotating valves 216, 218 are rotated into the open position,thereby removing the barriers between the liquids in the cartridge 200, and forminga path for the beads 102 to be transported from the lysis buffer 104 to the elution buffer 108, via the wash buffer 106 and the intermediate sections of oil 112 inside the rotating valves 216, 218. The rotating valves 216, 218 could be rotated either simultaneously or sequentially.In a fifth step, the beads are transported from the lysis buffer 104 into the washbuffer 106, via the oil 112 inside the first rotating valve 216. The oil 112 in the first rotating valve 216 helps to remove the lysis buffer 106 from the surface of the beads102. The wash buffer 106 removes the remaining lysis buffer 104 from the surfaceof the beads 102, and also helps to remove any unwanted biological or chemical species from the surface of the beads 102. In a sixth step, the beads 102 are transported from the wash buffer 106 to the elution buffer 108, via the oil 112 inside the second rotating valve 218. The oil inside the second rotating valve 218 helps to remove the wash buffer 106 from the surface of the beads 102, before the beads 102 pass into the elution buffer 108. The elution buffer causes the target chemical or biological species to be released from the surface of the beads 102 into the elution buffer. In a seventh step, the beads 102 are transported out of the elution buffer 108. Forexample, the beads 102 may be transported back to the lysis buffer 104 or washbuffer 106.In an eighth step, the second rotating valve 218 is rotated into the closed position.Optionally, the first rotating valve 216 may also be rotated into the closed position.In a ninth step, the plunger 318 is pushed into the cavity 322 (e.g. manually by auser, or using a linear actuator) that contains the elution buffer 108, causing theelution buffer 108 to be ejected from the cavity 305 that contains the elution buffer108. The ejected elution buffer 108 could be ejected into a test tube or well forstorage, for testing at a later time. Alternatively, the elution buffer 108 could beejected to a testing device for performing a suitable test or analysis on the ejectedliquid. For example, the elution buffer 108 could be ejected to a device (which maybe connected to the cartridge 200) for performing an amplification based (e.g. PCRor LAMP) DNA test. Whilst in this example both the first and second rotating valves 216, 218 are rotated into the open position in the fourth step, alternatively only the first rotating valve 216could be rotated into the open position at this stage and the second rotating valve218 may remain in the closed position. The first rotating valve 216 could be rotatedback into the closed position after the beads have been transported into the washbuffer in the fifth step. The second rotating valve 218 could be opened between thefifth step and the sixth step, to allow the beads to be moved into the elution buffer108 via the oil 112 inside the second rotating valve. The first rotating valve 216 andthe second rotating valve 218 may both be closed when the beads are in the wash buffer in the fifth step, to enable mixing of the beads within the wash buffer whilst preventing inadvertent mixing of the liquids inside the cartridge. Whilst in this example the beads 102 are transported out of the elution buffer 108 before the elution buffer 108 is ejected, this need not necessarily be in the case. Alternatively, for example, a magnetic field could be used to retain the beads withinthe cartridge 200 as the elution buffer 108 is ejected. Moreover, even when thebeads 102 are transported out of the elution buffer 108 before the elution buffer 108is ejected, the magnetic field could nevertheless be used to ensure that beads 102are not ejected with the elution buffer 108, in case not all of the beads weretransported out of the elution buffer 108 before the ejection.Whilst in this example the beads 102 are driven through the cartridge 200 by moving a magnet, this need not necessarily be the case. Alternatively, for example, the beads 102 could be transported through the cartridge 200 using a magnetic field from an electromagnet. As described above, the liquids used in the cartridge 200 are not limited to a lysis buffer 104, wash buffer 106, elution buffer 108 or oil 112, and any other suitableliquids could alternatively be used. Moreover, any suitable number of chambers andvalves could be included. For example, there may be a second wash chambercontaining either a different or the same wash liquid, and a third separating valveand corresponding oil chamber.Comparative Example: Sliding ValvesWhilst the rotating valves 216, 218 of the cartridge and the use of the O-rings 220 provides particularly good seals between the liquids, and provides a reliable mechanism for introducing or removing barriers between the liquids, rotating valves 216, 218 need not necessarily be used. For example, Fig.33 shows a cross sectionof a modified cartridge 400 in which linear sliding valves 335 are used, rather thanrotating valves 216, 218. As illustrated in Fig. 33, each sliding valve 335 includes a region of oil 112, andadjacent barrier regions 338. A first sliding valve 335a is illustrated in a closedposition, in which the barrier region 338a is arranged in between the lysis buffer 104and a region of oil 112. A second sliding valve 335b is illustrated in an open position, in which a region of oil 112 inside the sliding valve 335b is aligned with the oil 112 in the path for the beads 101 along the cartridge 400, and is aligned with a region of wash buffer 106 inside the cartridge 400. Third 335c and fourth 335d sliding valves are illustrated in the closed position, in which the barrier regions 338 of the sliding valves prevent mixing between the adjacent liquids.Each of the sliding valves 335 may be moved between the open and closedpositions using a respective handle 337. For example, a user may manually push or pull the handle 337 to operate the sliding valve 336, or the handle could be grippedand operated by a mechanical device (e.g. comprising a linear actuator or cam). Itwill be appreciated that that when the sliding valves are in the open position, there is a path for the beads to be transported in the longitudinal direction along the cartridge 400, from the lysis buffer 104 to the elution buffer 108 via the wash buffer 106, and via the intermediate regions of oil 112. When the sliding valves 335 are in the closed position, the barrier region 338 of each sliding valve 335 prevents the adjacent liquids from mixing. Whilst in the example illustrated in Fig.33 the barrier region 338 is schematically illustrated as a block of solid material inside the sliding valve, this need not necessarily be the case. Alternatively, the barrier 338 may be the wall of the sliding valve, and an aperture may be provided in the wall of the sliding valve 335 adjacentto the region of oil 112 inside the valve 335. The sliding valves may also compriseovermolded gasket regions. Advantageously, the sliding valves 335 are mechanically simple and intuitive to operate. In a further alternative, rather than providing the cartridge 400 with sliding valves 335, melted wax could be used, as described above. For example, the wax could initially be in a solid state, forming the barriers between each of the liquids in the cartridge. The wax could then be heated, to cause the wax to melt into a liquid statefor transport of the beads 102 through the wax.Whilst in the present example regions of oil 112 are provided between the first 335a and second 335b sliding valves, and between the third 335c and fourth 335d slidingvalves, this need not necessarily be the case. Alternatively, these separate regionsof oil 112 could be omitted. In this case, only two sliding valves are needed tomaintain separation of the lysis buffer 104, wash buffer 106 and elution buffer 108: a first sliding valve containing oil 112 arranged between the lysis buffer 104 and the wash buffer 106, and a second sliding valve containing oil 112 arranged between the wash buffer 106 and the elution buffer 108. In this case, the width of the sliding valves may be wider than illustrated in Fig. 33 to increase the width of the oil between the other liquids (but this need not necessarily be the case).Comparative Example: Membrane ValvesFigs. 34a to 36 illustrate a further alternative in which membrane valves are used toseparate the liquids.Fig. 34a shows a cross-cross sectional view of the modified cartridge 500 in whichmembrane valves are used. As shown in the figure, a membrane 508 is provided above a base portion 509 of the cartridge 500. The liquids (e.g. the lysis buffer 104, wash buffer 106, elution buffer 108 and oil 112) are provided in a channel 510between the membrane 508 and the base portion 509. In use, the membrane 508can be pressed against the base portion 509 to form barriers between the liquids. In this example, the cartridge 500 is provided with a thread 501 for receiving athreaded swab (e.g. as described above with reference to Fig. 5) or a threaded cap,but this need not necessarily be the case. A swab tip 242 is illustrated inside a chamber that contains lysis buffer 104. Each of the membrane valves 502 is illustrated in the open position in Fig.34a, in which there is a path for the beads to be transported from the lysis buffer 104 to the elution buffer 108, via the wash buffer 106 and the intermediate regions of oil 112. As illustrated in Figs 34a and 34b, four membrane valves 502 are provided, at positions B, C, D and E shown in the figure. In order to move the membrane valves 502 into the closed position, the user (or a mechanical device) grips a handle 506 of the cartridge 500, and slides the handle along the longitudinal direction of the cartridge 500 (towards the right-hand side of Fig. 34a). This causes a slidingmember 504 to move along the length of the cartridge 500. As illustrated in Fig.34a,the sliding member 504 has a sloped surface provided adjacently to each membrane valve 502. As the sliding member 504 is moved into the closed position, each sloped surface pushes against the respective membrane valve 502, to push the membrane valve 502 against the membrane 508. This causes the membrane 508 to become pinched between the base 509 of the cartridge 500 and the membrane valves 502,to form the barriers 512 illustrated in Fig. 34b. It will be appreciated that the handle506 or the sliding member 504 may be provided with a lock or latch, to lock the sliding member 504 (and therefore the membrane valves 502) in the open positionor the closed position. Whilst in the example illustrated in Fig. 34a the cam-likeengagement between the valves and the sliding member 504 is configured suchthat all of the valves are opened and closed simultaneously, this need notnecessarily be the case. Alternatively, one or more valves may open sequentially by varying the profile and position of each cam surface of the sliding member.Moreover, rather than the state of each of the valves being controlled by a singlesliding member 504, alternatively each of the valves 502 may be individually actuatable. For example, a threaded bolt or cylinder may be provided above eachvalve 502, and rotation of each bolt or cylinder could be used to open and closeeach valve 502 independently. Each valve 502 could also be controlled to open andclose using electromagnetic actuation (e.g. using a solenoid or linear actuator).In the example illustrated in Fig.34b, the regions of the channel 510 that contain the wash buffer 106 and the elution buffer 108 are relatively wide compared to the other regions of the channel that contain the other liquids. However, this need not necessarily be the case. Also illustrated in Fig.34b are oil injection locations 514, 518 at which oil 112 could be injected into the cartridge 500 to fill the corresponding sections of the channel 510. Similarly, a wash buffer injection location 516 and an elution buffer injection location 520 are also illustrated. However, it will be appreciated that the liquids could be filled into the cartridge 500 in any other suitable manner. In use, the membrane valves 502 can be moved into the closed position by sliding the sliding member 504 in the direction indicated by the arrow in Fig.34b, causing the sliding member 504 to press the membrane valves 502 against the membrane 508, resulting in the membrane pinching against the base portion 509 and forming the barriers. Advantageously, this helps to prevent the liquids in the cartridge 500 from mixing (e.g. mixing caused by vibration during transport). The user then inserts the swab tip 242 into the lysis buffer 104, causing the target chemical or biological species to be released into the lysis buffer 104. The membrane valves can then be moved into the open position, removing the barriers between the liquids, and enabling the magnetic beads 102 to be transported from the lysis buffer 104 to the elution buffer 108, via the intermediate regions of oil 112. As illustrated in Figs. 35 and 36, in this example a plurality of screws 521 are provided around the edge of the cartridge 500. The screws 521 are tightened to push an upper portion 503 of the cartridge 500 against the base portion 509 of the cartridge 500, compressing the membrane 508 between the upper portion 503 and the base portion 509. This compression of the membrane 508 (generally around the perimeter of the cartridge 500) reduces the risk of the liquids leaking from thecartridge 500. Alternatively, any other suitable means for securing the upper portion503, the base portion 509 and the membrane 508 could be used, for example asnap fit, ultrasonic welding, or an adhesive.As shown in Figs. 34a and 35, the cartridge 500 may be provided with a plunger511 for ejecting the elution buffer 108 (e.g. by pushing the plunger 511 against themembrane 508 to push the membrane into the channel 510 when the membranevalves 502 are in the closed position).Comparative Example: Quarter-Turn ValvesWhilst in some of the examples described above O-rings 220 are provided adjacent to the rotating valves 216, 218, to improve the strength of the seals and reduce the risk of the liquids mixing or leaking from the cartridge 200, this need not necessarily be the case. For example, Fig.37 shows a view of a modified cartridge 600 in whichO-rings are not provided. In this example, the first region of oil 112 is provided insidea first quarter-turn valve 602a, and the second region of oil 112 is provided inside a second quarter-turn valve 602a. The quarter-turn valves 602 can be moved betweenthe open and closed positions in the same manner as the rotating valves 216, 218described above. Whilst the provision of O-rings 220 is preferred to reduce the risk of the liquids mixing or leaking, the cartridge of 600 of Fig.37 in which no O-rings 220 are provided is particularly simple and straightforward to manufacture. Modifications and Alternatives Detailed embodiments and some possible alternatives have been described above. As those skilled in the art will appreciate, a number of modifications and further alternatives can be made to the above embodiments whilst still benefiting from the inventions embodied therein. It will therefore be understood that the invention is not limited to the described embodiments and encompasses modifications apparent to those skilled in the art lying within the scope of the claims appended hereto. Whilst in some examples described above the cavities containing the oil and the wash buffer have a constant cross-sectional shape along the longitudinal length of the cartridge, this need not necessarily be the case. Alternatively, each of the cavities for all or any of the lysis buffer, oil , wash buffer of elution buffer may have a cross-sectional shape that varies along the longitudinal length of the cartridge. For example, Fig. 34b shows an example in which a region of larger cross-sectional area is provided, and a similar region could be provided for any of the other cavities described above. In the example of Fig.34b, the change in cross-sectional area is achieved by varying the width of the cavity, which is particularly advantageous since it allows the cross-section area of the cavity to be varied without varying the vertical height of the cavity (and therefore when the magnet is arranged generally below the apparatus, the height of liquid above the magnet remains constant, helping toachieve consistent mixing through the liquids along the longitudinal length of thecartridge). Nevertheless, the cross-sectional area of any of the cavities couldalternatively be varied by varying the vertical height of the cavity along thelongitudinal length of the cartridge. Advantageously, varying the vertical height ofthe cavity provides a region at the top of the cavity into which air bubbles can migrate, reducing the risk that the beads will encounter the air bubbles as the beads are transported along the cartridge. Any of the cavities described above need not necessarily be linear, and could for example have a serpentine or circular shape. Any of the cavities described above may have cavity walls formed of fluorinated plastic to help reduce evaporation of the liquids from the cartridge. Any of the cavities described above may have cavity walls comprising a hydrophobic or hydrophilic coating. Whilst in the above examples the device 200 is illustrated as comprising two rotating valves 216, 216, the number of rotating valves is not limited to two. More generally, the device 200 may comprises as many cavities and valves as needed for the particular use case. For example, some sample types or molecules may require an additional wash liquid, in which case there may be four buffers / reagents and threerotating valves. Moreover, each rotating valve may have more than two positions,and may be, for example, a rotary three-way valve. In this case, the rotating valve may selectively provide a path for the beads into two or more regions.It will be appreciated that the reagents (e.g. the liquids, substances provided in theliquids, or coatings of the beads 102) in any of the above-described examples maycomprise any suitable chemical substances, and are not limited to a lysis buffer 104,wash buffer 106, or elution buffer 108. One of the reagents may be a lyophilizedcolorimetric detection reagent for determining the presence or absence of thetargeted biomolecules via colorimetric analysis. The lysis buffer may be similarlylyophilized, wherein the method includes the addition of liquid prior to the samplebeing introduced, or alternatively the liquid sample itself could provide therehydration. The reagents may comprise various chemicals or other species (e.g.enzymes, primers, etc.), and mixtures thereof, e.g. for use in nucleic acidamplification methods. For example, a nucleic acid amplification method maycomprise polymerase chain reaction (PCR), reverse transcription PCR (RT-PCR), quantitative PCR (qPCR), reverse transcription qPCR (RT-qPCR), nested PCR, multiplex PCR, asymmetric PCR, touchdown PCR, random primer PCR, hemi- nested PCR, polymerase cycling assembly (PCA), colony PCR, ligase chainreaction (LCR), digital PCR, methylation specific-PCR (MSP), co-amplification atlower denaturation temperature-PCR (COLD-PCR), allele-specific PCR, intersequence-specific PCR (ISS-PCR), whole genome amplification (WGA), inverse PCR, or thermal asymmetric interlaced PCR (TAIL-PCR). The nucleic acid amplification reaction may be a nucleic acid isothermal amplification method. Isothermal amplification is a form of nucleic acid amplification which does not rely on the thermal denaturation of the target nucleic acid during theamplification reaction and hence does not require multiple rapid changes intemperature. Isothermal nucleic acid amplification methods can therefore be carried out inside or outside of a laboratory environment. A number of isothermal nucleic acid amplification methods have been developed, including but not limited to Strand Displacement Amplification (SDA), Transcription Mediated Amplification (TMA), Nucleic Acid Sequence Based Amplification (NASBA), Recombinase PolymeraseAmplification (RPA), Rolling Circle Amplification (RCA), Ramification Amplification(RAM), Helicase-Dependent Isothermal DNA Amplification (HDA), Circular Helicase-Dependent Amplification (cHDA), Loop-Mediated Isothermal Amplification (LAMP), Single Primer Isothermal Amplification (SPIA), Signal Mediated Amplification of RNA Technology (SMART), Self-Sustained Sequence Replication (3SR), Genome Exponential Amplification Reaction (GEAR) and Isothermal Multiple Displacement Amplification (IMDA).One or more of the reagents may comprise components for making any of theaforementioned amplification chemistries compatible with pH-based or colorimetric detection (e.g. pH-LAMP). This may be accomplished, for example, by reducing buffer capacity (possibly through the absence of tris-HCL).The liquids may comprise an amplification indicator substance, which may be anorganic or inorganic compound that is added to a nucleic acid amplification reaction mix so that the content of the solution (such us, for example, the presence orabsence of specific nucleic acids) can be determined visually. The amplificationindicator substance may be a metal ion indicator (also called a complexometric indicator or metallochromic indicator), which is a substance that changes colour after forming a metal ion complex with a colour different from that of theuncomplexed indicator (such as, for example, but not limited to, Ca2+, Mg2+, Zn2+,and other metal ions). Other amplification indicator substances are possible, thatwill be familiar to those skilled in the art, such as, for example, but not limited to, hydroxynaphthol blue, eriochrome black t, calmagite, curcumin, fast sulphon black, hematoxylin, murexide, xylenon orange, BAPTA, BAPTA AM, BTC, BTC AM,Calcein, Calcein AM, Calcein Blue, Calcium Green 1, Calcium Green 2, CalciumGreen 5N, Coelenterazine, Coelenterazine cp, Coelenterazine f, Coelenterazine h, Coelenterazine hcp, Coelenterazine n, CoroNa Green, Corona Green AM, CoroNa Red, DAF FM, Fluo 3, Fluo 3 AM, PBFI AM, Phen Green SK, Quin 2, Quin 2 AM, and RhodZin 3. The amplification indicator substance may be a pH indicator. As those skilled in the art will appreciate, a pH indicator is a chemical detector for hydronium ions (H3O+)or hydrogen ions (H+). Indicators often cause the colour of the solution to changedepending on the pH. However, it will be appreciated that indicators can alsoindicate change via changes in other properties. For example, olfactory indicatorsindicate change via changes in their odour.Other possible amplification indicator substances include for example, but are not limited to: gentian violet, malachite green, thymol blue, methyl yellow, bromophenol blue , congo red, methyl orange, screened methyl orange (first transition), screened methyl orange (second transition), Bromocresol green, methyl red, methyl purple, azolitmin red, bromocresol purple, bromothymol blue, phenol red, neutral red, naphtholphthalein, Cresol red, Cresolphthalein, Phenolphthalein, Thymolphthalein, Alizarine Yellow R yellow, and Indigo carmine. The amplification indicator substance may be a redox indicator (also called an oxidation-reduction indicator), which is an indicator dye that undergoes a definite colour change at a specific electrode potential. Two common types of redoxindicators are pH independent redox indicators and pH dependent redox indicators.pH independent redox indicators include, but are not limited to, 2,2'-bipyridine, Nitrophenanthroline, N-Phenylanthranilic acid, 1,10-Phenanthroline iron(II) sulfate complex, N-Ethoxychrysoidine, 2,2'-Bipyridine, 5,6-Dimethylphenanthroline, o- Dianisidine, Sodium diphenylamine sulfonate, Diphenylbenzidine, Diphenylamine,and Viologen. pH dependent redox indicators include, but are not limited to, Sodium2,6-Dibromophenol-indophenol, Sodium o-Cresol indophenol, Thionine, Methylene blue, Indigotetrasulfonic acid, Indigotrisulfonic acid, Indigo carmine, Indigomono sulfonic acid, Phenosafranin, Safranin, and Neutral red.

Claims

CLAIMS1. Apparatus for extracting a chemical or biological species from a sample, theapparatus comprising: a first liquid in a first region; a second liquid in a second region, wherein the second liquid is immiscible with the first liquid; and beads for transporting the chemical or biological species; wherein the apparatus is configurable between: afirst configuration in which there is a path for transport of the beads fromthe first liquid in first region to the second liquid in the second region, anda second configuration in which a barrier is provided between the first region and the second region.

2. The apparatus according to claim 1,wherein the second region is provided within a first rotating valve;wherein the apparatus is operable for rotation of the first rotating valvebetween an open position corresponding to the first configuration and a closedposition corresponding to the second configuration;wherein when the first rotating valve is in the open position there is a path fortransport of the beads from the first liquid in first region to the second liquid in thesecond region; and wherein when the first rotating valve is in the closed position, a wall of thefirst rotating valve forms the barrier.

3. The apparatus according to claim 1 or 2,wherein the apparatus further comprises a third liquid in a third region;wherein the third liquid is immiscible with the second liquid; wherein when the apparatus is in the first configuration there is a path fortransport of the beads from the second liquid in the second region to the third liquidin the third region; andwherein when the apparatus is in the second configuration a barrier isprovided between the second region and the third region.

4. The apparatus according to claim 3 when dependent on claim 2, whereinwhen the first rotating valve is in the open position the beads can be transportedfrom the first liquid in the first region to the third liquid in the third region via thesecond liquid in the second region.

5. The apparatus according to claim 4, wherein the third liquid comprises awash buffer.

6. The apparatus according to any one of claims 3 to 5;wherein the first rotating valve comprises a fifth port provided on an upper surface of the first rotating valve; and wherein the apparatus is configured, when the first rotating valve is in the closed position, for flow of the third liquid into the fifth port to fill the third liquid in the third region.

7. The apparatus according to any one of claims 4 to 6, wherein the apparatusfurther comprises: a fourth liquid in a fourth region; and a fifth liquid in a fifth region; wherein the fourth region is provided within a second rotating valve;wherein the apparatus is operable for rotation of the second rotating valve between an open position corresponding to the first configuration and a closed position corresponding to the second configuration; wherein when the second rotating valve is in the open position there is a pathfor transport of the beads from the third liquid in third region to the fifth liquid in thefifth region via the fourth liquid in the fourth region;wherein when the second rotating valve is in the closed position a wall of thesecond rotating valve forms a barrier between the third region and the fourth region;andwherein when the second rotating valve is in the closed position the wall ofthe second rotating valve forms a barrier between the fourth region and the fifthregion.

8. The apparatus according to claim 7, wherein the third liquid and the fourthliquid are immiscible; and wherein the fourth liquid and the fifth liquid are immiscible.

9. The apparatus according to claim 7 or 8, wherein the fourth liquid comprisesoil and the fifth liquid comprises an elution buffer.

10. The apparatus according to any one of claims 7 to 9, wherein the apparatusis configured for sequential rotation of the first rotating valve and the second rotating valve to reconfigure the apparatus from the first configuration and into the secondconfiguration, and to reconfigure the apparatus from the second configuration andinto the first configuration.

11. The apparatus according to any one of claims 7 to 10, when dependent onclaim 6, wherein the second rotating valve comprises a sixth port provided on anupper surface of the second rotating valve; and wherein the apparatus is configured, when the second rotating valve is in the closed position, for flow of the third liquid out of the third region and out of the sixth port.

12. The apparatus according to claim 11, wherein the apparatus is configured forflow of the third liquid out of the apparatus via the sixth port as the third liquid flowsinto the third region via the fifth port.

13. The apparatus according to any preceding claim, wherein the first liquidcomprises a lysis buffer and the second liquid comprises oil.

14. The apparatus according to any preceding claim, wherein the beads aremagnetic beads.

15. The apparatus according to any preceding claim, wherein the apparatus isconfigured for receiving the sample in the first region, wherein the sample is a liquid sample.

16. The apparatus according to any one of claims 1 to 14,wherein the apparatus is configured for receiving the sample in the first region; and wherein receiving the sample in the first region comprises receiving a swab tip in the first region.

17. The apparatus according to claim 16, wherein the apparatus comprises aswab-supporting member arranged for preventing the swab tip from engaging witha base of the first region.

18. The apparatus according to claim 17, wherein the apparatus is configuredsuch that, in use: the first liquid in the first region covers the swab-supporting member whenthe apparatus is in a generally vertical orientation, and the first liquid in the first region does not cover the swab-supporting memberwhen the apparatus is in a generally horizontal orientation.

19. The apparatus according to any one of claims 16 to 18,wherein the apparatus is configured such that, in use, when the swab tip isin the first region: the first liquid in the first region covers the swab tip when the apparatus is in a generally vertical orientation, and the first liquid in the first region does not cover the swab tip when the apparatus is in a generally horizontal orientation.

20. The apparatus according to any preceding claim, wherein the first region hasa tapered shape along the longitudinal length of the apparatus.

21. The apparatus according to any one of claims 7 to 20, wherein the apparatusfurther comprises: afirst O-ring that is arranged at an interface between the first region and thefirst rotating valve; a second O-ring arranged at an interface between the first rotating valve and the third region; athird O-ring arranged at an interface between the third region and thesecond rotating valve; and a fourth O-ring arranged at an interface between the second rotating valve and the fifth region.

22. The apparatus according to claim 21,wherein the first rotating valve is arranged for rotation within a sixth region,and the second rotating valve is arranged for rotation within a seventh region;wherein the first O-ring and the second O-ring are arranged between the wall of the first rotating valve and a wall of the sixth region; and wherein the third O-ring and the fourth O-ring are arranged between the wallof the second rotating valve and a wall of the seventh region.

23. The apparatus according to claim 22,wherein the sixth region contains the second liquid; andwherein the seventh region contains the fourth liquid.

24. The apparatus according to claim 23,wherein the apparatus further comprises a fifth O-ring arranged around the first rotating valve and a sixth O-ring arranged around the second rotating valve; wherein the fifth O-ring is arranged to seal the second liquid in the sixth region; andwherein the sixth O-ring is arranged to seal the fourth liquid in the seventh region.

25. The apparatus according to any one of claims 19 to 24,wherein the first O-ring and the second O-ring are engaged with a wall of thefirst rotating valve, and the third O-ring and the fourth O-ring are engaged with a wall of the second rotating valve; wherein the wall of the first rotating valve is angled such that a compressiveforce is applied to each of the first O-ring and the second O-ring; andwherein the wall of the second rotating valve is angled such that acompressive force is applied to the third O-ring and the fourth O-ring.

26. The apparatus according to any one of claims 7 to 25,wherein the first rotating valve comprises a first groove or first protrusion inan upper surface of the first rotating valve for engaging with a first rotating memberfor rotating the first rotating valve; andwherein the second rotating valve comprises a second groove or secondprotrusion in an upper surface of the second rotating valve for engaging with asecond rotating member for rotating the second rotating valve.

27. The apparatus according to claim 26, wherein when the apparatus is in thesecond configuration the first groove or first protrusion is aligned with the secondgroove or second protrusion.

28. The apparatus according to any preceding claim, wherein the apparatusfurther comprises: afirst port through which the second liquid can flow into the apparatus to fillthe second region; anda second port through which the second liquid can flow out of the apparatus.

29. The apparatus according to claim 28, wherein the apparatus furthercomprises:a port cover that is moveable between a filling position for filling of the secondliquid into the second region, and a closed position for sealing the second liquidinside the apparatus; wherein when the port cover is in the filling position, a first aperture of theport cover is aligned with the first port, and a second aperture of the port cover isaligned with the second port.

30. The apparatus according to claim 29, wherein the first aperture and thesecond aperture are configured such that as the port cover is moved into the closed position, one of the first port or the second port is sealed closed by the port cover before the other of the first port or the second port is sealed closed by the port cover.

31. The apparatus according to any one of claims 28 to 30, when dependent onclaim 23, wherein the first port is further configured for flow of the second liquid into the sixth region.

32. The apparatus according to any one of claims 28 to 31, wherein theapparatus is configured to allow flow of the second liquid out of the apparatus viathe second port as the second liquid flows into the second region via the first port.

33. The apparatus according to any preceding claim,wherein the apparatus further comprises at least one gas region, and the gasregion is arranged such that gas inside the gas region compresses as the pressureof the second liquid inside the second region increases; orwherein the apparatus further comprises at least one foam disc, and the foamdisc is arranged such that the foam disc compresses as the pressure of the secondliquid inside the second region increases.

34. The apparatus according to any preceding claim, wherein a base of theapparatus is configured to impart a vertical force component on the beads as thebeads are transported longitudinally along the apparatus.

35. The apparatus according to claim 34, wherein the base comprises anundulating surface.

36. The apparatus according to claim 34 or 35, wherein the base comprisesridges, steps, ribs, a wave-like surface, indentations, or a series of grooves.

37. The apparatus according to any one of claims 7 to 36, wherein the apparatusfurther comprises a plunger for ejecting the fifth liquid from the fifth region via acorresponding aperture.

38. The apparatus according to any preceding claim,wherein the apparatus is configured for receiving the sample in the first region via an opening into the first region; wherein the apparatus comprises a wall inside the first region that defines a sample receiving region that extends from the opening, for receiving the sample; and wherein the wall is configured for preventing the first liquid from flowing outof the opening when the apparatus is in a generally horizontal orientation or whenthe apparatus is inverted.

39. The apparatus according to any preceding claim, wherein the apparatus is acartridge for insertion into an automated device for selectively configuring thecartridge into the first configuration or the second configuration.

40. A method of extracting a chemical or biological species from a sample, themethod comprising: receiving the sample in the first region of the apparatus according to any ofclaims 1 to 39; eluting the chemical or biological species from the sample using the first liquidin the first region; configuring the apparatus to be in the first configuration; andtransporting the beads from the first liquid in the first region and into thesecond liquid in the second region.

41. A method of extracting a chemical or biological species from a sample, themethod comprising: receiving the apparatus of claim 39 in the automated device;reconfiguring the cartridge into the first configuration from the second configuration using the automated device; and transporting the beads from the first liquid in the first region and into thesecond liquid in the second region using the automated device.

42. The method according to claim 41, wherein the method comprises:receiving the apparatus of claim 39 when dependent on claim 37 in the automated device; and ejecting the fifth liquid from the fifth region via the corresponding aperture byusing the automated device to actuate the plunger.

43. A method of filling the apparatus according to claim 29, or any claimdependent thereon, with the second liquid, the method comprising:moving the port cover into the filling position; and providing a flow of the second liquid through the first port, for flow of thesecond liquid out of the second port via the second region.

44. The method according to claim 43, wherein the method comprises using oneor more syringes or pumps to drive the flow of the second liquid through the firstport.

45. The method according to claim 43 or 44,wherein the method comprises providing a first flow configuration for flow ofthe second liquid through the first port, for flow of the second liquid out of the secondport via the second region; andproviding a second flow configuration for flow of the second liquid through thesecond port, for flow of the second liquid out of the first port via the second region; wherein the method further comprises alternating between the first flow configuration and the second flow configuration.

46. The method according to any one of claims 43 to 45, wherein the methodfurther comprises moving the port cover into the closed position after the second region has been filled with the second liquid.

Images