GB2643681A

GB2643681A - Apparatus and methods for transporting a chemical or biological species through liquids

Info

Publication number: GB2643681A
Application number: GB2412194.9A
Authority: GB
Inventors: Luke Cavuto Matthew; Wilkinson Gratiot Daniel; Evan Sproat Keith; Zimmerman Sharpe Nathaniel; Harrison Nguyen David; Zimmerman Sharpe Julia
Original assignee: Protondx Ltd
Current assignee: Protondx Ltd
Priority date: 2024-08-19
Filing date: 2024-08-19
Publication date: 2026-03-04
Also published as: WO2026041861A1

Abstract

A method of manipulating magnetic beads in a liquid inside a conduit, wherein the method comprises generating a variable magnetic field using at least one magnet or electromagnet to mix the magnetic beads in the liquid; and wherein a biological or chemical species is attached to the surface of the magnetic beads. The variable magnetic field may be created by rotating at least one magnet, moving the at least one magnet parallel to the conduit, or creating a phase difference in a plurality of magnets. The magnets may be positioned either side of the conduit such that the beads are spread across the cross-section of the conduit, in a cloud formation. An apparatus for processing a chemical or biological species comprising a cartridge with a first region containing a first liquid and a second region containing a second liquid, magnetic beads, and a device for receiving the cartridge and generating a variable magnetic field using at least one magnet or electromagnet.

Description

[0001] APPARATUS AND METHODS FOR TRANSPORTING A CHEMICAL OR BIOLOGICAL SPECIES THROUGH LIQUIDS

[0002] Field of the Invention

[0003] The invention relates to apparatus and methods for transporting a chemical or biological species through liquids. Merely by way of example, the invention may be used for, but is by no means limited to, driving magnetic beads through a series of liquids as part of a method for extracting a chemical or biological species from a sample. Associated apparatus and methods are provided.

[0004] 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" should also be interpreted broadly, to encompass particles of a range of sizes, including nanoparticles particles that are less than 1 pm in diameter), micron-sized particles (i.e. of the order of 1-500 pm in diameter), and larger particles (potentially up to around 1 mm or so in diameter). As those skilled in the art will appreciate, the principles of the present disclosure are not limited to any particular size or composition of the magnetic "beads", and for any given application it will be understood that the skilled person will use beads of a suitable size, composition, coating and functionalisation.

[0005] Background to the Invention

[0006] Magnetic beads can be used in methods for extracting targeted biomolecules from a sample. Magnetic beads typically consist of two components: a magnetic material (often iron, an iron oxide such as magnetite, nickel or cobalt) and a chemical component that provides functionality to the beads, thereby enabling the beads to attach to biornolecules 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.

[0007] Methods of extracting the target species from the sample often use multiple different liquids or buffers to extract and prepare the species for downstream analysis. For example, a lysis buffer can be used to break down a sample and release DNA. RNA or proteins from cells (or, for example, viral caosids), to be bound to the coating of magnetic beads. A wash liquid may then be used to remove the lysis buffer and any unwanted biological material from the beads. An elution liquid can then be used to elute (release) the target species from the beads into the elution liquid, for subsequent analysis or processing.

[0008] Whilst magnetic beads are not the only tool that can be used in conjunction with the aforementioned buffers to extract, isolate, and purify targeted biornolecules, 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 either moved through a series of vessels or tubes containing the buffers, or the buffers are added to and removed from a single vessel or tube, with the magnetic beads being selectively retained in the tube using a magnetic field that is often produced using a stationary magnet.

[0009] Due to the large number of different buffers and steps that are often needed to extract a target molecule from a sample using magnetic beads, such methods are typically used in a laboratory environment and involve the use of numerous tubes, micro-pipettes, mixing devices, and a significant level of training. Alternative methods for extraction include the use of a single vessel having multiple chambers, wherein the various buffers are separated via physical means and the beads are transported between the chambers using a magnet. Similarly, liquids might be co-located within a single chamber, so long as they are immiscible. Transporting the magnetic beads between these immiscible fluids can be achieved using a moveable magnet that enters each fluid separately, or using an external magnetic field source arranged outside of the chamber. However, there is a problem that it can be difficult to transport the beads between each of the liquids used for extracting or processing a target species due to the surface tension that Occurs at the liquid-liquid interfaces of immiscible liquids. Moreover, as the beads are transported through the liquids, for example using a static magnet that pulls the beads through the liquids towards the magnet, the beads tend to clump together or drag along the walls of the cavity that contains the liquids; reducing the effective surface area of the beads (and therefore degrading the capability of the beads to attract the target biomolecules). It will be appreciated, therefore, that there is a need for improved apparatus and methods for mitigating against these issues.

[0010] Summary of the Invention

[0011] 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.

[0012] In a first aspect the invention provides a method of manipulating magnetic beads in a first liquid inside a conduit, wherein the method comprises generating a variable magnetic field using at least one magnet or electromagnet to mix the magnetic beads in the first liquid; and wherein the surface of the magnetic beads is for attachment to a biological or chemical species.

[0013] It will be appreciated that the term 'variable magnetic field' is to be interpreted broadly, and includes the case in which a magnet is translated or rotated to generate the variable magnetic field. Whilst in this case the magnetic field is constant in the reference frame of the magnet, it is nevertheless variable in the reference frame of the beads.

[0014] Advantageously, by virtue of the variable magnetic field, the tendency of the beads to drag along the walls of the conduit as they are driven by the magnetic field is reduced, beneficially reducing the frictional force on the beads, and improving the reliability of manipulating the beads.

[0015] The use of the magnetic field to drive the beads through the liquid also removes the need to move the liquid with respect to the magnetic beads (for example as the beads are held in place by a static magnet). This beneficially simplifies the mechanical complexity of the apparatus, since the need for a pump to move the liquids around the beads is eliminated.

[0016] Manipulating the magnetic beads may comprise driving the beads along a path in a first direction using the variable magnetic field.

[0017] Generating the variable magnetic field may comprise rotating at least one magnet.

[0018] Generating the variable magnetic field may comprise simultaneously rotating and translating the at least one magnet. Advantageously, by virtue of the rotational and translational movement of the magnet, the tendency of the beads to drag along the 113 walls of the conduit as they are driven by the magnet is reduced, beneficially reducing the frictional force on the beads. The inventors have found that by virtue of the rotational movement of the magnet, the beads tend to separate from each other to create a cloud-like formation, improving the mixing of the beads within the liquid. The cloud-like formation reduces clumping of the beads, enables more consistent mixing of the beads within the liquid, and avoids the beads being pulled against the surface or wall closest to the magnetic field source (therefore reducing the frictional forces on the beads). The reduction in clumping of the beads also helps to avoid the trapping of residual liquid between the beads, which could otherwise lead to cross-contamination between the liquids as the beads are transported.

[0019] Moreover, the inventors have found that the use of the magnet having both rotational and translational movement enables the beads to be more reliably driven through liquid-liquid interfaces, and even around air bubbles present in the liquids. Therefore, the use of a magnet having both rotational and translational movement provides a particularly reliable method of driving the beads through liquid-liquid interfaces (or through viscous liquids), whilst also providing good mixing of the beads in the liquids. The inventors have also found that the power needed to reliably transport the beads using the magnet having both rotational and translational movement is particularly low (e.g., compared to use of an electromagnet, or compared to use of a pneumatic pump to move the liquids relative to the beads).

[0020] Therefore, the use of the magnet having both rotational and translational movement to drive the beads results in improved energy efficiency.

[0021] Translating the magnet may comprise moving the magnet in a direction that is generally parallel to the path in the first direction.

[0022] Generating the variable magnetic field may comprise translating an electromagnet in a direction that is generally parallel to the path in the first direction.

[0023] Generating the variable magnetic field may comprise rotating each of a plurality of magnets. Advantageously, use of a plurality of rotating magnets avoids the need for 113 a magnet to be translated along the length of the path for the beads, helping to reduce the mechanical complexity and to reduce the footprint of the device.

[0024] The magnets may be arranged sequentially along the path in the first direction.

[0025] The rotation of each of the plurality of magnets may be independently controllable.

[0026] The position of each of the plurality of magnets may also be independently controllable (e.g. by controlling the translational movement of each of the magnets).

[0027] The at least one magnet or electromagnet may comprise a plurality of electromagnets; wherein the plurality of electromagnets are arranged along the path in the first direction; and wherein generating the variable magnetic field comprises passing a current through each of the electromagnets.

[0028] By virtue of the arrangement of the electromagnets, the beads form a cloud structure. As will be described in more detail later, the inventors have found that this cloud structure formed by the beads improves the mixing of the beads with the liquid, and enables the beads to be driven more easily and reliably through the surface tension at liquid-liquid interfaces. Moreover, use of the electromagnets means that magnets do not have to be moved (translated or rotated) reducing the mechanical complexity of the apparatus.

[0029] The current passed through each of the electromagnets may be an alternating current, and the alternating current passed through neighbouring electromagnets may be out of phase.

[0030] The variable magnetic field may have an alternating polarity in the time domain at a particular location on the path.

[0031] The variable magnetic field may have an alternating polarity in the spatial domain along the path.

[0032] The method may further comprise transporting the magnetic beads from a first region containing the first liquid and into a second region containing a second liquid, wherein the first liquid and the second liquid are immiscible and adjacent to each other, such that there is a liquid-liquid interface between the first liquid and the second liquid; and wherein manipulating the magnetic beads comprises driving the beads from the first liquid in the first region and into the second liquid in the second region, across the interface.

[0033] The method may comprise generating the variable magnetic field by passing a current through a coil of wire that is arranged in a helical configuration around the path. Advantageously, by virtue of the coil arranged around the path, the beads can be driven through the liquid (and around air bubbles inside the liquids) particularly reliably.

[0034] The method may comprise generating the variable magnetic field by moving each of a plurality of magnets away from and towards the path; wherein the plurality of magnets are arranged along the length of the path in the first direction.

[0035] The movement of the magnets may be periodic, and the periodic motion of 30 neighbouring magnets away from and towards the path may be out of phase.

[0036] In a second aspect the invention provides apparatus for generating the alternating magnetic field according to the first aspect.

[0037] In a third aspect the invention provides apparatus for processing a chemical or biological species from a sample, the apparatus comprising: a cartridge comprising a first region containing a first liquid, and a second region containing a second liquid, wherein the first liquid and the second liquid are immiscible and adjacent to each other, such that there is a liquid-liquid interface between the first liquid and the second liquid; magnetic beads for transporting the chemical or biological species; 113 and device configured for receiving the cartridge, and for generating a variable magnetic field using at least one magnet or electromagnet, to drive the magnetic beads along a path from the first liquid in the first region and into the second liquid in the second region, across the interface.

[0038] The device may comprises at least one magnet, and the device may be operable to rotate the at least one magnet to generate the variable magnetic field.

[0039] The device may be operable to simultaneously rotate and translate the magnet.

[0040] The device may be configured for moving the magnet in a direction that is generally parallel to the path from the first liquid in the first region and into the second liquid in the second region The device may comprise a plurality of magnets, and the device may be operable to rotate each of the plurality of magnets to generate the variable magnetic field.

[0041] The device may be configured for independently controlling the rotation of each of the plurality of magnets.

[0042] When the cartridge has been received at the device, the magnets may be arranged along the length of the path from the first liquid in the first region and into the second liquid in the second region, adjacent to the first and second regions.

[0043] The device may comprise a plurality of electromagnets; wherein, when the cartridge has been received at the device, the plurality of electromagnets are arranged along the length of the path from the first liquid in the first region and into the second liquid in the second region, adjacent to the first and second regions; and wherein the device is operable to pass an alternating current through each of the electromagnets to generate the variable magnetic field.

[0044] The current passed through each of the electromagnets may be an alternating to current, and the alternating current passed through neighbouring electromagnets may be out of phase.

[0045] When the cartridge has been received at the device, the alternating magnetic field may have an alternating polarity in the time domain at a particular location on the path from the first liquid in the first region and into the second liquid in the second region.

[0046] When the cartridge has been received at the device, the magnetic field may have an alternating polarity in the spatial domain along the path from the first liquid in the first region and into the second liquid in the second region.

[0047] In a fourth aspect the invention provides the device configured to receive the cartridge of the apparatus according to the third aspect.

[0048] The device may be an automated device for automatically controlling the generation of the magnetic field to drive the magnetic beads along the path from the first liquid in the first region and into the second liquid in the second region.

[0049] In a fifth aspect the invention provides apparatus for generating the magnetic field according to the first aspect, the apparatus comprising: the plurality of magnets; a camshaft; and a plurality of cams arranged on the camshaft; wherein each of the plurality of magnets is mounted to a respective cam of the plurality of cams; and wherein the apparatus is operable to move each of the plurality of magnets away from and towards the path by rotating the camshaft.

[0050] In a sixth aspect the invention provides apparatus for generating the alternating magnetic field according to the first aspect, the apparatus comprising: a magnet; a motor that is coupled to the magnet for driving rotation of the magnet; and a moveable carriage that is configured for translational movement; wherein the magnet is arranged on the moveable carriage; and wherein the apparatus is operable to simultaneously rotate the magnet and translate the carriage. The translational movement need not necessarily be a linear movement (for example, the translation movement could be along a curved path). The apparatus may also be configured to control the distance between the magnet and the path for the beads. In other words, the apparatus may be configured to control the movement of the magnet in direction that is generally parallel to the path in the first direction, and additionally (e.g. simultaneously) control a variable spacing of the magnet away from the path. For example, the magnet may be moveably mounted to the carriage for control of the variable spacing, or the carriage itself may move away from and towards the path.

[0051] Brief Description of the Drawings

[0052] Embodiments of the invention will now be described by way of example only with reference to the attached figures in which: Figure la schematically illustrates a series of liquid used to extract a b olecuie from a sample for subsequent testing or analysis; Figure lb 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 perspective view of a cartridge according to one example; Figure 4 shows a further perspective view of the cartridge in which a lid of the cartridge is open; Figure 5 shows a further perspective view of the cartridge; Figure 6 shows a cross-sectional view of the cartridge Figure 7 shows a further cross-sectional view of the cartridge, iilustrating the driving of beads through the lysis buffer by a magnet; Figure 8 shows the magnet according to one example; Figure 9 shows a cross section of a modified cartridge in which linear sliding valves are used; Figure 10a shows a cross-cross sectional view of a modified cartridge in which membrane valves are used; Figure 10b shows a further cross-sectional view of the modified cartridge in which membrane valves are used; Figure 11a illustrates movement of a magnet for driving the beads along a conduit; Figure 11 b illustrates movement of a pair of magnets for driving the beads along a conduit; Figure 1 lc illustrates a set of three eiectromagnets for driving the beads along a conduit; Figure '11 d illustrates a magnet having rotational and translational movement for driving the beads along a conduit; Figure 11 e illustrates a set of three rotating magnets for driving the beads along a conduit; Figure I if illustrates a helical wire arranged for driving the beads along a conduit when an electrical current is passed through the wire; Figures lig to 11: schematically illustrate examples of driving the beads inside the conduit using a rotating magnet; Figure 12 shows a perspective view of apparatus for moving a magnet to drive beads along the cartridge; Figure 13 shows a cross-sectional view of the apparatus for moving the magnet; 30 Figure 14 shows a top-down view of the apparatus for moving the magnet; Figure 15 shows an example of apparatus comprising a plurality of magnets that are moved using a crankshaft, to drive the beads along the cartridge; and Figure 16 shows a crosssectionS view of the apparatus comprising a plurality of magnets.

[0053] In the figures, like elements are indicated by like reference numerals throughout.

[0054] Detailed Description of Preferred Embodiments

[0055] 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.

[0056] Liquid Separation An arrangement of liquids used to extract a biomolecule or other chemical or biological species from a sample, and general concepts related to maintaining separation of liquids, will now be described with reference to Figs. la and 1 b.

[0057] Fig. la schematically illustrates a series of liquids used to extract a biomolecule from a sample. In this example three liquids, labelled 'A', 'B' and 'C', are arranged inside a tube 100. A group of magnetic beads 102 is illustrated inside liquid A. A separation liquid, 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 in between the other liquids, the other liquids are inhibited from mixing.

[0058] A magnetic field (in this example a magnet 105, but alternatively any other suitable magnetic field source such as an electromagnet) can be used to drive (push or pull) the magnetic beads along the tube (or 'conduit') 100, from liquid A to liquid C via the intermediate liquids B and D, as the magnet 105 moves longitudinally along the length of the tube 100 in the direction indicated by arrow A. The tube 100 provides a continuous transport path along which the beads can move. Therefore, a biological or chemical species can be easily and efficiently transported, on the surface of the beads, through each of the liquids.

[0059] Turning now to Fig. 1 b, in this example the tube 100 has a corresponding base portion 114, and the liquids comprise a lysis buffer 104, a wash buffer 106, and an elution buffer 108. Regions of oil 112 are provided in-between the other liquids for use as a separation liquid. The oil 112 is immiscible with the other liquids, and therefore inhibits mixing. A group of beads 102 is illustrated in a region of oil 112 adjacent to the lysis buffer 104 (which may also be referred to as a lysis liquid). In use, the beads 102 can be transported into the lysis buffer 104 under the influence of the magnet 105 that is positioned below the base portion 114 of the tube 100, by moving 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, preventing transport of lysis buffer 104 into the wash buffer 106. The wash buffer 106 (which may also be referred to as a wash liquid) is for removing any remaining lysis buffer and/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 elution buffer 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 is particularly beneficial since the presence of certain components commonly found in wash buffers 112 (e.g. ethanol or certain salts) in the elution buffer can seriously disrupt any test or analysis performed on the eluted species. Advantageously, the provision 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.

[0060] Whilst in the example of Fig. la two regions of separation liquid (D) and three additional liquids (A, B and C) are shown (and similarly in Fig. 1b), this need not necessarily be the case. Alternatively, for example, there may be only two additional liquids (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 that are immiscible, in which case an additional separation liquid need not necessarily be provided between the reagent liquids. In a further alternative there may more than three liquids separated by regions of the separation liquid. For example, whilst two regions of separation liquid (D) are used to separate three additional liquids (A, B and C) in Fig. la, alternatively three regions of separation liquid (D) could be used to separate four additional liquids (for example if there is an additional wash buffer).

[0061] Whilst the separation liquid D is immiscible with each of liquids A, B and C and therefore inhibits mixing, mixing of the liquids may nevertheless occur when the liquids are subject to vibrations (e.g. during transport) or other strong forces. Some of the liquids (e.g. a lysis buffer) may contain a surfactant or detergent, which also destabilises the liquid-liquid interfaces and can result in unwanted mixing. Fig. 2a shows an improved configuration in which valves 120 are provided between each of the liquids, to mitigate against such mixing. As shown in Fig. 2a, a first valve 120a is 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 fourth valve 120d is provided between liquids D and C. Each of the valves 120 can be initially 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 pass between the liquids. It will be appreciated that even when valves 120 are provided as shown in Fig. 2a, use of the separation liquid D is nevertheless advantageous since 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 as the beads progress along the tube 100.

[0062] 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 separation liquid D itself can transition to a solid state, to perform the function of a valve 120e.

[0063] 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 in which the wax acts as a closed valve 120e, preventing mixing between liquids A and B, and between liquids B and C. The wax may then be heated to cause the wax to transition to a liquid state, enabling transport of the magnetic beads 102 from liquid A to liquid C, via liquid B, and via the intermediate regions of liquid wax.

[0064] In a further alternative, as will be described in more detail later, in the examples illustrated in Figs. 2a and 2b the separation liquid D may also be provided within the valves 120 (e.g. inside rotating valves as described later with reference to Figs. 3 to 7, or inside sliding valves as described later with reference to Fig. 9).

[0065] In any of the examples of Fig. la to Fig. 2b, the separation liquid D need not necessarily be oil 112 or liquid wax. Any other suitable liquid that is sufficiently immiscible with the other liquids could alternatively be used. Moreover, in some examples the buffers themselves may be sufficiently immiscible such that an additional separation liquid is not needed (however, the additional separation liquid may still be provided, for example to help remove the previous liquid from the surface of the beads 102 as the beads 102 progress along the tube 100).

[0066] The liquids illustrated in Figs. la to 2b may be for an extraction process to be carried out in respect of targeted biomolecules from a liquid or solid sample. The targeted biomolecules may be, for example, polynucleotides such as nucleic acid (e.g. RNA or DNA). For example, the targeted biomolecule may be the characteristic RNA of a particular virus, such as, but not limited to, SARS-CoV-2.

[0067] The method is not restricted to any particular size or composition of the magnetic beads 102. Indeed, for any given application it will be understood that the skilled person will use beads 102 of a suitable size and composition. Particularly advantageous methods of driving the magnetic beads 102 through the liquids will be described in more detail later. The use of magnetics beads 102 is advantageous since the beads 102 provide a large surface area to be exposed to each of the liquids, and the small size of the beads 102 helps to avoid disturbing the liquid separation when the beads 102 are transported through the liquid interfaces. It will be appreciated that the particular coating of the beads 102 used will depend on the specifics of the particular reactions and the target biomolecules. For example, the magnetic beads 102 may have a silica coating which binds with nucleic acids under certain buffer conditions.

[0068] 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. The targeted 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) present in the lysis buffer 104. The beads 102 need not necessarily be present in the lysis buffer 104 when the sample is introduced into the lysis buffer 104. For example, the beads 102 could initially be in the oil 112, and transported into the lysis buffer 104 after 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.

[0069] The beads 102 are then washed using the wash liquid 106, to remove contaminants/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 grade water, 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 particular requirements. It will be appreciated that "Tris" is short for tris(hydroxymethyl)aminomethane, and EDTA is an abbreviation of ethylenediaminetetraacetic acid. Thus, to perform the method, first, second and third liquids 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 washing liquid; and the third liquid 108 is an elution liquid, for eluting the biomolecules. As shown in Figs. la to 2b, the first second and third liquids may be separated by an additional separation liquid 112 (e.g. oil), to inhibit mixing and to aid with the removal of each previous buffer from the surface of the beads 102.

[0070] The lysis/binding buffer liquid 104 may be, for example, based on guanidinium thiocyanate, and optionally includes a solvent such as isopropanol or ethanol.

[0071] The washing liquid 106 for removing contaminants/chemicals from the previous steps, as well as unwanted biological molecules, may be, for example, a solution of 113 80% ethanol.

[0072] The elution liquid 108 causes elution of the analyte in question (e.g. characteristic RNA of viral particles), for subsequent processing. After the target biomolecules have been eluted, the magnetic beads 102 may be transported out of the elution liquid 108 (e.g. in the direction opposite to 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 LAMP methods).

[0073] It will be appreciated that the reagents may comprise any suitable chemical substances, and are not limited to a lysis buffer 104, wash buffer 106, or elution buffer 108.

[0074] Illustrative Example -Cartridge Exemplary apparatus containing the liquids used to extract a species from a sample will now be described, referring firstly to Figs. 3 to 7. In this example, the apparatus comprises cartridge 200 containing the liquids. Particularly advantageous methods for driving the magnetic beads 102 along the length of the cartridge 200 will be described in more detail later.

[0075] Figs. 3 to 7 show an example in which the liquids are housed within a cartridge 200.

[0076] It will be appreciated that whilst the device of Figs. 3 to 7 will be referred to as a 'cartridge', the device 200 need not necessarily be for insertion into another device.

[0077] The cartridge 200 may also simply be referred to as the 'device' 200 or 'apparatus' 200.

[0078] In this example, regions of lysis buffer 104, wash liquid 106, elution buffer 108 and Oil 112 are provided within the cartridge 200. However, as described above, the present invention is not limited to use of these particular liquids, and any other suitable liquids 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 wash liquid 106, and via the intermediate sections of oil 112, using a magnetic force (for example, the magnet 105 is not shown in Figs. 3 to 6). An example of a magnet 306 that could be used to drive the beads 102 along the cartridge 200 using translational and rotational movement of the magnet 306 is illustrated in Figs. 7 and 8. Alternative methods that could be used to drive the magnetic beads 102 through the liquids will be described later.

[0079] The lysis buffer 104 breaks open cells/tissues from the sample, and genetic material from the sample comes out into the solution. The pH and salt concentration of the lysis buffer 104 is such that DNA/RNA sticks to a silica surface of the magnetic beads 102. The magnetic beads may be nanoparticles, which advantageously have a large surface area to which the DNA/RNA can attach.

[0080] In use, the magnetic beads 102 are transported from the lysis buffer 104 to the wash buffer 106 (comprised, for example, substantially of ethanol or another suitable solvent), via a region of oil 112, using the magnet 105. The magnet 105 could be a magnet 306 of the type illustrated in Figs. 7 and 8, but as will be described in more detail later, a magnetic field from one or more electromagnets could alternatively be used. Beneficially, the oil 112 removes the lysis buffer 104 from the beads 102 before the beads 102 pass into the wash buffer 106. The wash buffer 106 removes (or dilutes) any remaining lysis buffer 104 from the beads 102, and can also remove other unwanted chemical or biological material from the surface of the beads 102.

[0081] The beads 102 are then transported 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 before the beads pass into the elution buffer 108. The pH and salt concentration of the elution buffer is such that the DNA/RNA separates (elutes) from the beads into the elution buffer 108. The elution buffer 108 containing the eluted species can then be output from the cartridge (or to another region of the cartridge not illustrated in the figures) for subsequent processing (e.g. for performing a subsequent test or analysis on the elution buffer and the extracted/isolated molecules), or output to a further analysis chamber of the cartridge (e.g. for amplification).

[0082] The cartridge 200 comprises a first portion 202 and a second portion 204. The first portion 202 comprises a hinged door 206. In this example the hinge 208 of the door 206 is located on the upper side of the cartridge 200, but it will be appreciated that this need not necessarily be the case and that any other suitable position for the hinge 208 could alternatively be used. The hinged door 206 is operable between the closed position illustrated in Fig. 3, and the open position illustrated in Fig. 4. In the open position, a swab can be inserted into the cartridge 200 via a corresponding aperture 205. Alternatively, for example, rather than inserting a swab the sample could be introduced into the cartridge 200 via the aperture 205 using a pipette. When the door 206 is in the closed position, the aperture 205 is sealed by a plug 209 provided on the door 206. The door 206 may be lockable in the closed position, or may be difficult to open (e.g. by configuring the edges of the door 206 to be substantially flush with the adjacent surface 207 when the door 206 is in the closed position), to prevent or inhibit re-opening of the door 206. Beneficially, this reduces the risk of contamination after a sample has been placed into the device 200, and also reduces the risk of lysis buffer 104 spilling out of the aperture 205 due to the door 206 being inadvertently opened. The device 200 may also be provided with a foil seal (not shown in the figure) covering the aperture 205, to further reduce the risk of contamination or spills. The foil seal is removed by the user before the swab is inserted through the aperture 205 (or before the sample is pipetted into the cartridge 200).

[0083] 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 removeable screw cap could be used to provide access to the inside of the cartridge 200. Male or female threads could be provided around the aperture 205 for receiving and securing the screw cap.

[0084] When the door 206 is in the open position, a user may insert a sample through the aperture 205 by inserting a swab through the aperture 205 and into a sample receiving cavity 210. The sample may be, for example, a nasal secretion that has 113 been collected using a nasopharyngeal swab Throughout the description the term cavity is to be interpreted broadly 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.

[0085] The first portion 202 of the cartridge 200 contains a lysis buffer 104 in a corresponding cavity 309. One or more magnets 306 or electromagnets (or more generally, any suitable magnetic force) is used to transport magnetic beads 102 from the lysis buffer 104 to the elution buffer 108 via the wash buffer 106 (and via intermediate sections of oil 112). Whilst a magnet 306 having rotational and translational movement is illustrated in Fig. 7, as will be described in more detail later the magnet 306 need not necessarily have both rotational and translational movement (and could alternatively be one or more electromagnets, or a plurality of rotating magnets having no movement along the longitudinal length of the cartridge 200) In this example the second portion 204 of the cartridge 200 comprises a first rotating valve 216 and a second rotating valve 218. Each of the rotating valves 216, 218 comprises a respective cavity 300, 301 that is filled with oil 112. In use, when the first rotating valve 216 is in an open position in which the cavity 300 of the first rotating valve 216 that contains the oil 112 is generally aligned with an opening into the cavity 309 that contains the lysis buffer 104, and is generally aligned with a cavity 303 that contains the wash liquid 106, the magnetic beads 102 can be transported from the lysis buffer 104 in the first portion 202 and into the oil 112 inside the first rotating valve 216 using the magnet 306. The beads 102 can then be transported from the oil 112 inside the first rotating valve 216 into the cavity 303 that contains the wash liquid 106. 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 113 surface tension between the immiscible liquids.

[0086] The cavity 303 that contains the wash liquid 106 is arranged between the two rotating valves 216, 218, as illustrated in Fig. 6. When the second rotating valve 218 is in an open position (in which the cavity 301 of the second rotating valve 218 that contains the oil 112 is aligned with an opening into the cavity 303 that contains the wash liquid 106, and is aligned with an opening into the cavity 305 that contains the elution buffer 106), the beads can be transported from the wash liquid 106 and into the elution buffer 108, via the oil 112 in the second rotating valve 218, using the magnet 306. It will be appreciated, therefore, that when the rotating valves 216, 218 are in the open position the beads 102 can be transported along the length of the device 200 to pass through the sequence of liquids (e.g. as illustrated schematically in Fig. la). It will also be appreciated that when the rotating valves 216, 218 are in the open position, the cavities 300, 301 that contain the oil 112 need not necessarily be 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 which the beads 102 can nevertheless still be transported.

[0087] Each of the rotating valves 216, 218 is arranged in a respective cavity in the second portion 204 having a corresponding cavity wall 222, 224. A set of 0-rings 220 are provided to form seals between the outer surface of the rotating valves 216, 218 and the cavity walls 222, 224. A pair of angled 0-rings 220a, 220b are provided adjacent to the first rotating valve 216, and a further pair of angled 0-rings 220d, 220e are provided adjacent to the second rotating valve 218. A first of the angled 0-rings 220a is provided at the interface between the chamber 309 that contains the lysis buffer 104 and the first rotating valve 216. A second of the angled 0-rings 220b is provided at the interface between the first rotating valve 216 and the chamber 303 that contains the wash buffer 106. A third of the angled 0-rings 220d is provided at the interface between the chamber 303 that contains the wash buffer 106 and the second rotating valve 218. A fourth of the angled 0-rings 220e is provided at the interface between the second rotating valve 218 and the chamber 305 that contains the elution buffer 108. When the rotating valves 216, 218 are in the closed configuration, the openings of the cavities of the rotating valves 216, 218 that contain the oil 112 are not aligned with the openings of the cavities that contain the other liquids. In other words, a barrier is formed such that 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 0-rings 220 to form the sequence of barriers. For example, a surface of the first rotating valve 216 pushes against the second angled 0-ring 220b, and a surface of the second rotating valve 218 pushes against the third angled 0-ring 220d, thereby sealing the wash liquid 106 inside the corresponding cavity 303 when the rotating valves 216, 218 are in the closed configuration. The provision of the angled 0-rings 220 and the barriers that are formed between 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 from the cartridge 200.

[0088] In this example, generally horizontal 0-rings 220c, 200f are also provided around each rotating valve 216, 218, above the angled 0-rings 220. These 0-rings 220d, 200e provide additional protection against liquids leaking from the cartridge 200 by preventing the oil 112 from leaking from the space around the rotating valves 216, 218. These 0-rings 220c, 220f also act as a bearing surface for the valves 216, 218 to rotate against, and circumferentially support each rotating valve 216, 218 during rotation. The rotating valves 216, 218 thus only make contact with the three 0-rings in each cavity (the two angled 0-rings 220a, 220b, 220d, 220e and the generally horizontal 0-ring 220c, 220f). The cavities in which the rotating valves 216, 218 are situated each have only three openings, each gasketed with an 0-ring, and allowing the valve 216, 218 itself to seal off that portion of the device 200 (by engaging with the three 0-rings). However, the generally horizontal 0-rings 220c, 200f need not necessarily be provided.

[0089] 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 104 to the elution buffer 108, additional oil 112 is also provided between the rotating to valves 216, 218 and the cavity walls 222, 224 of the cavities in which the rotating valves 216, 218 are situated. Beneficially, therefore, even if some of the liquid (e.g. the lysis buffer 104) breaches an 0-ring 220 seal, the oil 112 between the rotating valves 216, 218 and the cavity walls 222, 224 helps to prevent the liquid from progressing further along the cartridge 200, or from leaking out of the cartridge 200.

[0090] The generally horizontal 0-rings 220c, 220f help to prevent the oil 112 that 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 the device 200. The generally horizontal 0-rings 220c, 200f also aid in centring the rotating 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.

[0091] The angled 0-rings 220 are angled with respect to the direction of gravity when the device is in a horizontal orientation (and are angled with respect to the orientation of the path for transport of the beads 102 through the rotating valves 216, 218, and through the wash liquid 106). The outer surface of each rotating valve 216, 218 exerts a force on the angled 0-rings 220, improving the strength of the seals. Advantageously, by virtue of the angled orientation of the angled 0-rings 220, the force from the rotating valves 216, 218 pushing against the angled 0-rings 220 has a horizontal component (along the longitudinal direction of the 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 0-rings 220 are arranged at an angle of approximately 45 degrees. However, it will be appreciated that any other suitable angle could be used (for example, an angle between 20 degrees and 70 degrees, e.g. 30 degrees or 50 degrees). It will also be appreciated that in the present example, each angled 0-ring 220 opposes the other in its pair in a symmetrical manner, i.e. at mirroring angles (although this need not necessarily be the case).

[0092] Whilst in the present example angled 0-rings 220 are used to improve the seals between the chambers that contain the rotating valves 216, 218 and the other chambers, this need not necessarily be the case. For example, only the generally horizontal 0-rings 220c, 220f may be provided. Alternatively, no 0-rings may be provided, and the seals may be achieved, for example, using regions of overmolded gasket material formed using an injection moulding method. The overmolded regions could form part of the main body of the cartridge 200, or could be part of the rotating valves 216, 218.

[0093] Each of the rotating valves 216, 218 is provided with a respective groove 230, 232 in an upper surface of the valve. The valves 216, 218 can be moved between the open and closed configurations by inserting a rotatable member (e.g. a motor-driven or manually-driven rotatable tab) into the grooves 230, 232, and rotating the members 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 rotated simultaneously, but could alternatively be rotated sequentially (with either the first rotating valve 216 or the second rotating valve 218 being rotated before the other rotating valve).

[0094] When the rotating valves 216, 218 are in the open position, the grooves 230, 232 are arranged generally perpendicularly to the longitudinal direction of the cartridge 200 as shown in Figs. 3 to 5 (the grooves are arranged generally perpendicularly to the path of the magnetic beads 102 along the length of the cartridge 200). When the rotating valves 216, 218 are in the closed position, the grooves 230, 232 are rotated by 90 degrees to be generally aligned with the longitudinal direction of the cartridge 200 Advantageously, by virtue of the grooves 230, 232 being aligned with the longitudinal direction of the cartridge 200 when the rotating valves 216, 218 are in the closed position, when the cartridge 200 is inserted into a device for rotating the valves 216, 218 a member or tab of the device can slot into the grooves 230, 232 as the cartridge 200 is inserted into the device. The device for 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 the cartridge 200. An additional groove 229 is provided adjacent to the second rotating valve 218, and a further groove 228 is provided between the first rotating valve 216 and the second rotating valve 218, to enable a first member or tab to pass along the length of the device 200 and into the groove 230 of the first rotating valve 216, and to allow a second member or tab to pass into the groove 232 of the second rotating valve 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 drives the beads 102 through the cartridge 200 using a magnetic field, 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 have been opened. The configuration of the cartridge 200 therefore enables the process of opening the valves 216, 218 and driving the beads 102 along the cartridge using the magnet 306 to be automated, and reduces the risk of user error in the operation of the valves 216, 218.

[0095] Whilst in the present example 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.

[0096] In the present example, the ratio of the diameter (and similarly, the radius and cross-sectional area) of the chambers 300, 301 inside the rotating valves 216, 218 that contain the oil 112 to the longitudinal length of the chambers 300, 301 (related to 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 interface with the oil 112 is relatively small, the cross sectional areas of the cavity 303 that contains the wash buffer 107 at the interfaces with the oil 112 is relatively small, and the cross sectional area of the cavity 305 that contains the elution buffer 108 at the interface with the oil 112 is relatively small. Advantageously, this reduces the propensity 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.

[0097] Fill ports (not shown in the figures) are also provided within the recesses 230, 232, for filling the wash buffer 106 into the cartridge 200.

[0098] Whilst in the present example the rotating valves 216, 218 can be rotated by inserting members or tabs into the corresponding grooves 230, 232, this need not necessarily be the case. Alternatively, for example, upwardly extending tabs may be provided on the upper surface of the rotating valves 216, 218. The tabs could then be gripped and rotated by a user (or by a mechanical device) to rotate the valves 216, 218 between the open and closed configurations. However, the use of grooves 230, 232 is particularly advantageous since they reduce the risk of the valves 216, 218 being inadvertently rotated.

[0099] 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 pl and 150 pl (e.g. 100 pl). The first compartment may contain, for example, between 0.5 ml and 2.5 ml of lysis buffer 104 (e.g. 1 ml of lysis buffer). The capacity of the chamber that contains the lysis buffer 104 may be, for example, between 3 ml and 6 ml. The volume of wash buffer in the cartridge 200 in the chamber 303 between the rotating valves 216, 218 may be, for example, between 25 pl and 150 pl (e.g. 50 pl). The cartridge 200 may also contain additional wash buffer 106 inside conduits that are used to fill the wash buffer 106 into the chamber 303 between the rotating valves 216, 218. The amount of elution buffer 108 inside the corresponding chamber 305 of the cartridge 200 may be, for example, between 50 pl and 150 pl (e.g. 110 pl). However, it will be appreciated that any other suitable amounts of the liquids could be used, and that the amounts of each liquid may depend on the particular reaction and reagents used. For example, some methods may use a smaller volume of elution buffer 108 in order to obtain a more concentrated eluted sample (or a larger volume of elution buffer 108 to obtain a more dilute eluted sample).

[0100] In the present examples, a magnet 306 is used to transport material from the sample along the length of the cartridge 200, by driving the magnetic beads 102 through the liquids inside the cartridge 200. The magnet is shown in more detail in Fig. 8, which illustrates the polarity of the magnet 306. In the example shown of Fig. 7 the magnet to 306 has both translational and rotational movement that is used to drive the magnetic beads 102 through the liquids. However, as will be described in more detail later, whilst the combination of translational and rotational movement beneficially drives the beads 102 through the liquids in a cloud-like manner and with sufficient force to drive the beads through the liquid-liquid interfaces, the magnet 306 need not necessarily have both rotational and translational movement.

[0101] Use of the magnet 306 enables the beads 102 to be reliably and efficiently driven through the liquids, potentially in an automated manner. In particular, use of the magnet 306 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 liquids to prevent mixing) that inhibits the movement of the beads 102.

[0102] As shown in Fig. 5, an aperture 307 is provided to enable the elution buffer 108 to be extracted from the cartridge 200 (or moved into another region of the cartridge 200 not shown in the figures) for subsequent analysis or testing. The aperture 307 could, for example, be provided with a removable cap that can be opened to provide access to the chamber that contains 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 be punctured or removed to extract the elution buffer 108. The aperture 307 could alternatively be provided with means for attaching to a syringe tip (e.g. a luer-lock fitting) for extraction of the elution buffer using a syringe. A plunger can be used to extract the elution buffer 108 from the cartridge 200 (or to eject the elution buffer 108 into another region of the cartridge 200 not shown in the figures). The exterior surface 234 of the plunger is illustrated in Fig. 4, and a user (or device) may press against the exterior surface 234 of the plunger to eject the elution buffer 108 via the corresponding aperture 307.

[0103] Fill ports used to fill the oil 112 and wash buffer (wash liquid) 106 into the corresponding cavities of the cartridge 200 can be seen in Fig. 3. 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 to 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 with oil 112). A first oil fill port cover 278 and a second oil fill port cover 280, shown for example in Fig. 6, are provided for the first rotating valve 216 and the second rotating valve 218, respectively. The oil fill port covers 278, 280 have an open position (or filling position') in which the oil fill ports are accessible via corresponding openings in the oil fill port covers 278, 280. The oil fill port covers 278, 280 can be moved into a closed position by sliding (towards the left-hand side of Fig. 6) the covers 278, 280 within corresponding 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 closed by the fill port covers. The first oil fill port cover 278 is provided with a pair of mounting points 265a, 265b that enable filling apparatus to be mounted to the cartridge 200. The second oil fill port cover 280 is also provided with a pair of mounting points 265a, 265b that enable filling apparatus to be mounted to the cartridge 200. The mounting points 265, 267 may also be used for sliding the oil fill port covers 278, 280 between the open and closed positions.

[0104] Whilst in this example sliding fill port covers and corresponding 0-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.

[0105] 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.

[0106] The opening in the oil fiil port cover 278, 280 that provides access to one of the oil fill ports 270, 274 (in this example, the lower oil fill port) may be circular, whereas the opening in the oil fill port cover 278, 280 that provides access to the other oil fill port 272, 276 may have an elongate shape (in this example, an oval). Advantageously, the combination of the circular opening and the elongate opening to means that when the fill port cover 278, 280 is slid into the closed position, one of the oil fill ports 270 will be sealed closed before the other oil fill port 272 is sealed closed. When the oil fill port cover 278, 280 is slid into the closed position, an increase in the fluid pressure of the oil 112 can occur. This can increase the risk of the liquids inside the cartridge 200 mixing or leaking, or result in liquid being ejected into the cavity 309 that contains the lysis buffer 104 (since the cavity 309 that contains the lysis buffer 104 is only partially filled with lysis buffer 104 arid therefore acts as a compressible volume). Advantageously, by virtue of the fill port Covers 278, 280 sealing one of the oil fill ports before the other oil fill port, as the oil fill ports are closed, excess pressure build-up in the oil 112 is beneficially avoided, since the excess pressure is released via the fill port that is sealed last (the fill port that is accessed via the asymmetrical or elongate opening in the oil fill port cover plate 278, 280). Whilst the fill port covers 278,280 may be 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 lower fill port being sealed closed before the other of the fill ports could be used (e.g. a square opening and a rectangular opening). Moreover, staggered closing of the fill ports need not necessarily be used.

[0107] Each of the oil fill ports is coupled to a corresponding conduit that leads to the cavity in which the rotating valve 216 is situated. Oil 112 is filled into the cartridge 200 via one of the oil fill ports and the corresponding conduit, and exits via the other conduit and the corresponding oil fill port. This method of filling the oil 112 beneficially reduces the occurrence of air bubbles forming inside the oil 112, which would inhibit the transport of the beads 102 through the oil 112 using the magnet 306. 0-rings may be provided at the oil fill ports, inside a corresponding 0-ring casing. As the oil fill port cover 278, 280 is slid into the closed position, the cover 278, 280 may engage with the 0-rings to seal the oil fill ports closed.

[0108] As shown in Fig. 6, the cavity 309 that contains the lysis buffer 104 may have a tapered shape. In this example the width of the cavity 309 decreases, in the transverse direction, along the longitudinal length of the cartridge 200 towards the second portion 204 of the cartridge 200. The height of the cavity 309 may also decrease in the vertical direction, along the longitudinal length of the cartridge 200. By virtue of the tapered shape of the cavity 309 that contains the lysis buffer 104, when a swab is inserted into the cartridge the level of the lysis buffer 104 is advantageously below the level of the swab tip 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.

[0109] Movement of the beads 102 within the lysis buffer 104 will now be described with reference to Fig 7. Fig. 7 shows an example in which a rotating magnet 306 is used to drive the magnetic beads 102 along the length of the cartridge 200. As the magnet 306 moves along the length of the cartridge 200, the magnet 306 exerts a force on the magnetic beads 102, causing them to move through the lysis buffer 104. The combination of the rotational and translational movement of the magnet 306, results in the beads 102 moving through the liquid in a cloud-like manner. The translational movement of the magnet enables bulk movement of the beads in their dispersed state, as translational movement along the cartridge 200. The rotational movement of the magnet 306 creates an oscillating magnetic field that results in dispersion of the beads within a localized area in all directions, and also assists in the translational movement along the cartridge 200. Beneficially, movement of the beads through the liquid in a cloud-like manner increases the mixing of the beads 102 in the lysis buffer, and reduces the downward component of force on the beads and the corresponding frictional forces (and reduces the risk of beads being dragged along the floor of the cartridge and becoming trapped by discontinuities in the surface). Moreover, the cloud-like formation of the beads enables 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 require a larger cross-sectional area for the path, for reliable transportation along the cartridge 200. Advantageously, the use of smaller cross-sectional areas at the liquid-liquid interfaces helps to maintain separation of the liquids. The movement of the beads 102 in the cloud-like manner also occurs as the beads 102 are moved through the other liquids, such as the wash buffer 106 and the elution buffer 108. Whilst one or more non-rotating magnets could 113 alternatively be moved along the length of the cartridge 200 to drive the beads 102 along the cartridge 200, this can result in the beads clumping and dragging along the base 214 of the chamber, decreasing the mixing and exposed surface area of the beads 102 in the lysis buffer 104 and in the elution buffer 108 (and reducing the proportion of the beads that are successfully driven through liquid-liquid interfaces).

[0110] 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 beads and making its way into the elution chamber. The inventors have also found that the combination of the rotational and translational movement of the magnet 306 causes the beads to move through the liquid as a relatively dense cloud of beads, beneficially enabling the beads to be more easily driven through the liquid-liquid interfaces (e.g. the interface between the elution buffer 104 and the oil 112).

[0111] In the example shown in Fig. 7, the base 214 of the chamber 309 comprises a series of ridges or steps (or 'ribs', or waves), which beneficially further increases the mixing of the beads 102 with the lysis buffer 104. As the beads 102 are driven along 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 result in the beads 102 moving turbulently in the lysis buffer 104 as they are transported along the length of the chamber 309, as illustrated schematically by the curly arrow.

[0112] Therefore, by virtue of the ridged base 214, mixing of the beads in the lysis buffer 104 is further improved. Notably, in this example, the upward slope of the ridges (that causes the beads 102 to be pushed upwards to mix with the lysis buffer 102) is angled, rather than being exactly vertical, reducing the risk of beads 102 becoming stuck against the ridges when being driven along the chamber 309 by the magnet 306. As illustrated in Fig. 7, the amount of lysis buffer 104 inside the chamber 309 can be selected so that the level of the lysis buffer 104 (and therefore the maximum height reachable by the magnetic beads 102 in the lysis buffer 104) does not extend past the swab support 212 when the device is in the generally 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. The amount of lysis buffer 104 inside the chamber 309 can additionally be selected such that the beads 102 can reach the full height of the liquid when being mixed in the liquid using the magnet 306. This is because the maximum distance that the cloud of beads 102 can extend away from the magnet 306 is limited by the magnitude of the applied magnetic field (at the location of the beads) and the gravitational forces on the beads. When a rotating magnet 306 is used, the maximum distance that the cloud of beads 102 can extend away from the magnet 306 also depends on the rotational speed of the magnet. Mixing of the beads within the full volume of the lysis buffer 104 is desirable to ensure that no target molecules are unreachable by the beads 102.

[0113] 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, the chamber 309 could alternatively be provided with a flat base 308.

[0114] The swab support 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 into the cartridge 200. A wall of the cavity 309 may also comprise a textured region to aid in the mechanical removal of material from the swab tip.

[0115] 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 a swab 310 that is engaged with the swab support 212 when the cartridge 200 is in the generally vertical orientation (enabling the lysis buffer 104 to cause species from the sample to be released into the liquid), and the lysis buffer 104 does not cover the tip 312 of the swab 310 when the cartridge 200 is in the horizontal orientation. The magnet 306 can then be moved along the length of the chamber 309 when the cartridge 200 is in the horizontal orientation, in order to mix (or 'agitate') the beads in the lysis buffer 104.

[0116] Advantageously, since the lysis buffer 104 does not cover the swab tip 312 when the device is in the horizontal orientation, the risk of the beads 102 becoming stuck to mucous or other viscous material on the swab tip 312 as the beads 102 are driven through the liquid by the magnet 306 is beneficially reduced. Moreover, as a result 113 of the tapered shape of the chamber 309, the depth of the lysis buffer 104 is relatively small when the cartridge 200 is in the horizontal orientation. This relatively low liquid level enables the cloud of beads 102 to more easily be mixed within the full cross-sectional area of the lysis buffer 104, helping to ensure that no target molecules are unreachable.

[0117] Method of extractina a chemical or biological species A method of using the cartridge 200 to extract a chemical or biological species from a sample will now be described.

[0118] In a first step, the rotating valves 216, 218 are initially in the closed orientation, and a user inserts a swab (or alternatively, pipettes a liquid sample) into the aperture 205 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 the aperture 205 at this stage. The cartridge 200 is in the vertical orientation so that the lysis buffer 104 contacts the tip of the swab. The lysis buffer 104 causes release of DNA, RNA or proteins from the sample, to be bound to the coating of magnetic beads 102 that are in the lysis buffer chamber 309. The swab is then removed from the cartridge 200 by the user, the cap 206 of the device is closed, and the device is rotated into the generally horizontal orientation. Alternatively, the swab tip may be broken off and remain inside the cartridge 200 when the cap 206 is closed. In a further alternative, the sample may be introduced into the cartridge 200 using a pipette rather than a swab.

[0119] In an optional second step, the cartridge 200 is inserted into a machine for rotating the rotating valves 216, 218, driving the beads 102 through the cartridge using a magnetic field, and operating the elution chamber plunger. Alternatively, the rotating valves 216, 218, application of the magnetic field, and plunger could be operated manually by a user.

[0120] A magnetic field (e.g. from the magnet having rotational and translation movement in the example show in Fig. 7) is used to move the beads 102 within the lysis buffer 113 104, and to mix the beads with the lysis buffer 104. Advantageously, the beads form the cloud-like structure as they are driven through the liquid, which increases the amount of the target biological or chemical species that binds to the surface of the beads 102 (as well as reducing the frictional forces between the beads and the floor of the cartridge, as described above).

[0121] 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 forming a 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.

[0122] In a fifth step, the beads 102 are transported (by driving the beads 102 through the liquids using the magnetic field) from the lysis buffer 104 and into the wash buffer 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 beads 102. The wash buffer 106 removes the remaining lysis buffer 104 from the surface of the beads 102, and also helps to remove any unwanted biological or chemical species from the surface of the beads 102.

[0123] In a sixth step, the beads 102 are transported (by driving the beads 102 through the liquids using the magnetic field) 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.

[0124] In a seventh step, the beads 102 are transported (by driving the beads 102 through the liquids using the magnetic field) out of the elution buffer 108. For example, the beads 102 may be transported back to the lysis buffer 104 or wash buffer 106.

[0125] 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.

[0126] In a ninth step, the plunger 318 is pushed into the cavity 305 (e.g. manually by a user, or using a linear actuator) that contains the elution buffer 108, causing the elution buffer 108 to be ejected from the cartridge 200 (or into another region of the cartridge not shown in the figures). The ejected elution buffer 108 could be ejected into a test tube or well for storage, for testing at a later time. Alternatively, the elution buffer 108 could be ejected to a testing device for performing a suitable test or analysis on the ejected liquid. For example, the elution buffer 108 could be ejected to a device (which may be connected to the cartridge 200) for performing an amplification based (e.g. PCR or LAMP) DNA/RNA test.

[0127] 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 216 could be rotated into the open position at this stage and the second rotating valve 218 may remain in the closed position. The first rotating valve 216 could be rotated back into the closed position after the beads have been transported into the wash buffer in the fifth step. The second rotating valve 218 could be opened between the fifth step and the sixth step, to allow the beads to be moved into the elution buffer 108 via the oil 112 inside the second rotating valve. The first rotating valve 216 and the 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.

[0128] 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.

[0129] Alternatively, for example, a magnetic field could be used to retain the beads within the cartridge 200 as the elution buffer 108 is ejected. Moreover, even when the beads 102 are transported out of the elution buffer 108 before the elution buffer 108 is ejected, the magnetic field could nevertheless be used to ensure that beads 102 are not ejected with the elution buffer 108, in case not all of the beads were transported out of the elution buffer 108 before the ejection.

[0130] 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. Methods of driving magnetic beads through a liquid will be described in more detail later.

[0131] 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 suitable liquids could alternatively be used. Moreover, any suitable number of chambers and valves could be included. For example, there may be a second wash chamber containing either a different or the same wash liquid, and a third separating valve and corresponding oil chamber.

[0132] Comparative Example: Sliding Valves Whilst the rotating valves 216, 218 of the cartridge and the use of the 0-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. 9 shows a cross section of an alternative device 400 through which the beads 102 could be driven using the magnet 306. Fig. 9 shows an example in which the device 400 is provided with linear sliding valves 335 rather than rotating valves 216, 218. In the example of Fig. 9 the magnet 306 is moved below the cartridge and along length of the cartridge, and the axis of rotation of the magnet runs from the top of the figure to the bottom. A side-on view of the magnet 306 is also illustrated below the magnet 306.

[0133] As illustrated in Fig. 9, each sliding valve 335 includes a region of oil 112, and adjacent barrier regions 338. A first sliding valve 335a is illustrated in a closed position, in which the barrier region 338a is arranged in between the lysis buffer 104 and a region of oil 112. A second sliding valve 335b is illustrated in an open position, to in which a region of oil 112 inside the sliding valve 335b is aligned with the oil 112 in the path for the beads 102 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.

[0134] Each of the sliding valves 335 may be moved between the open and closed positions 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 gripped and operated by a mechanical device (e.g. comprising a linear actuator or cam). It will be appreciated that that when the sliding valves are in the open position, there is a path for the beads to be transported (by driving the beads 102 along the cartridge using the magnet 306) 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.

[0135] Whilst in the example illustrated in Fig. 9 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 adjacent to the region of oil 112 inside the valve 335. The sliding valves may also comprise overmolded gasket regions. Advantageously, the sliding valves 335 are mechanically simple and intuitive to operate.

[0136] 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 state for transport of the beads 102 through the wax.

[0137] Comparative Example: Membrane Valves Figs. 10a and 10b illustrate a further alternative in which membrane valves are used to separate the liquids.

[0138] Fig. 10a shows a cross-cross sectional view of the modified cartridge 500 in which membrane 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 510 between the membrane 508 arid the base portion 509. In use, the membrane 508 can be pressed against the base portion 509 to form barriers between the liquids.

[0139] The beads 102 can be driven through the cartridge 500 using the magnet 306 when the barriers are not present (when the membrane 508 is not pressed against the base portion 509 to form barriers between the liquids).

[0140] In this example, the cartridge 500 is provided with a thread 501 for receiving a 25 threaded swab 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.

[0141] Each of the membrane valves 502 is illustrated in the open position in Fig. 10a, in which there is a path for the beads to be transported (by driving the beads along the cartridge 500 using the magnet 306) 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 10a and 10b, 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. 10a). This causes a sliding member 504 to move along the length of the cartridge 500. As illustrated in Fig. 10a, 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. 10b. It will be appreciated that the handle 506 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 position or the closed position. Whilst in this example the cam-like engagement between the valves and the sliding member 504 is configured such that all of the valves are opened and closed simultaneously, this need not necessarily 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.

[0142] In the example illustrated in Fig. 10b, 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. 10b 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.

[0143] 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. 10b, 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.

[0144] fip A plurality of screws may be provided around the edge of the cartridge 500 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 the cartridge 500. Alternatively, any other suitable means for securing the upper portion 503, the base portion 509 and the membrane 508 could be used, for example a snap fit, ultrasonic welding, or an adhesive.

[0145] The cartridge 500 may be provided with a plunger 511 for ejecting the elution buffer 108 from the cartridge 500 (or into a further region of the cartridge 200 not shown in the figures) by pushing the plunger 511 against the membrane 508 to push the membrane 508 into the channel 510 when the membrane valves 502 are in the closed position, to eject liquid via an aperture (not shown in the figure).

[0146] Transporting Magnetic Beads Methods and apparatus that can be used to drive magnetic beads 102 through liquids (including through liquid-liquid interfaces between the liquids) will now be described. For example, the methods and apparatus could be used to drive the beads 102 through the apparatus illustrated in any of Figs. 3 to 10b, or through liquids in any other suitable cartridge or other suitable type of device (or in a biological vessel, such as the human body) containing the liquids.

[0147] Translational Movement Fig. 11a illustrates an example in which translational movement of a magnet 604 is used to drive 102 the beads along the conduit 100. As shown in the figure, in this example a single magnet 604 is moved along the longitudinal length of the conduit 100, to drive the magnetic beads 102 through liquids inside the conduit 100 (the beads 102 and the liquids are not illustrated in the figure). The magnet 604 may be moved along the length of the conduit 100 using any suitable apparatus. For example, the magnet 604 could be mounted to a rail and moved along the length of the conduit 100 in an automated manner. Alternatively, for example, the magnet 604 could be pushed along a rail by a user. Whilst in the example illustrated in Fig. 11a (and in Fig. 11b) the north pole of the magnet 604 is arranged towards the conduit 100, this need not necessarily be the case. Alternatively the magnet 604 may be arranged such that the south pole is facing the conduit, or the magnet 604 could be arranged at an angle relatively to the conduit 100.

[0148] The translational movement of the magnet 604 along the longitudinal length of the conduit 100 need not necessarily be a single direct movement from one end of the conduit to the other 100. For example, the magnet 604 may be moved backwards and forwards (along the longitudinal length of the conduit 100) adjacent to a particular region of the conduit 100, in order to mix the beads 102 with the liquid in that region of the conduit 100. Moreover, the distance between the magnet 604 and the conduit 100 as the magnet 604 moves along the longitudinal length of the conduit 100 need not necessarily be constant. More generally, the magnet 604 may follow any suitable path along the length of the conduit 100 (for example, an S-shaped path).

[0149] Advantageously, the use of a magnet 604 to drive the beads 102 along the conduit 100 removes the need for a pump for moving the liquids relative to the beads 102, simplifying the mechanical complexity and improving the reliability of the apparatus.

[0150] Fig. 11b shows a modification of the example illustrated in Fig. 11a in which a plurality of magnets 604a, 604b are used to drive the beads 102 along the conduit (a pair of magnets in the example shown in Fig. 11b). Beneficially, the inventors have found that use of a plurality of magnets 604a, 604b rather than a single magnet 604 to drive the beads 102 along the conduit 100 reduces the tendency of the beads 102 to drag along the walls of the conduit 100. This advantageously reduces the frictional force on the beads 102, and also improves the mixing of the beads 102 with the liquids inside the conduits.

[0151] Whilst in the example of Fig. 11b two magnets 604a, 604b are used to drive the beads 102 along the conduit, the number of magnets 604 need not necessarily be 113 two. For example, three or more magnets 604 could be used to drive the beads 102 along the conduit 100. Each of the magnets 604a, 604b may be driven independently along the conduit 100.

[0152] Electromagnets Fig. 11c shows an example in which electromagnets 606a, 606b, 606c are used to drive the beads 102 along the conduit 100. In the example shown in Fig. 11c three electromagnets 606 are used, but the number of electromagnets 606 need not necessarily be three. For example, four or more electromagnets 606 could be used to drive the beads 102 along the conduit 100 (or two electromagnets 606, or one electromagnet 606). In use, an alternating magnetic field is generated by passing an alternating current through each of the electromagnets 606. Optionally, one or more of the electromagnets 606 may also be translated along the length of the conduit 100. The alternating current passed through neighbouring electromagnets 606 is out of phase. For example, a 90 degree phase difference in the current passed through neighbouring electromagnets can be used to drive the beads along a path in a first direction, or a 180 degree phase difference between the current passed through neighbouring electromagnets can be used to cause the beads to cluster and mix in the liquid.

[0153] In use, alternating current is passed through each of the electromagnets 606, causing the beads 102 to be driven along the conduit by the corresponding variable magnetic fields. As shown in Fig. 11c, the current through each electromagnet is configured such that the electromagnets 606 have an alternating polarity in the spatial domain along the length of the conduit 100 (and so the magnetic field inside the conduit 100 has an alternating polarity, along the length of the conduit). Since an alternating current is used, the magnetic field also has an alternating (or 'oscillating', or 'periodic') polarity in the time domain at each point along the conduit 100. This results in a 'wave of magnetic field that drives the beads 102 along the conduit 100. In other words, the method comprises generating an alternating magnetic field using electromagnets, to drive the beads. The frequency of the alternating current that is passed through each of the electromagnets 606 may be, for example, between 5 Hz and 12 kHz (e.g., 12 Hz, 1 kHz or 10 kHz).

[0154] Whilst in the example illustrated in Fig. 11c all of the electromagnets 606 are provided on the same side of the conduit 100 (for example, on the underside of one of the cartridges illustrated in Figs. 3 to 10b), this need not necessarily by the case.

[0155] For example, an additional set of electromagnets 606 could be provided on the opposing side of the conduit 100 to provide additional control of the movement of the beads 102.

[0156] Advantageously, the inventors have found that the arrangement of electromagnets 606 and the use of the alternating current results in the beads 102 forming a cloud that is driven along the conduit 100. The inventors have found that this cloud structure formed by the beads 102 improves the mixing of the beads 102 with the liquids inside the conduit 100, and enables the beads 102 to be driven more easily and reliably through the surface tension at liquid-liquid interfaces within the conduit 100 (e.g. the liquid-liquid interface between the elution buffer 104 and the oil 112 in the example shown in Fig. 7). Moreover, use of the electromagnets 606 means that magnets 604 do not have to be moved (translated) along the length of the conduit 100 (as shown in Fig. 11b), reducing the mechanical complexity of the apparatus.

[0157] It will be appreciated that since the current passed through each of the electromagnets 606 is out of phase (e.g. 90 degrees out of phase, or four coils each 90 degrees out of phase), the magnetic field has an alternating polarity in the spatial domain along the conduit 100. Moreover, since the current passed through each electromagnet 606 is alternating, the alternating magnetic field has an alternating polarity in the time domain at a particular location in the conduit 100.

[0158] Rotational and Translational Movement Fig. 11d shows an example in which a magnet 608 having both translational and rotational movement is used to drive the beads 102 along the conduit 100 (for example, as shown in the examples of Figs. 7, 9 and 10a). A variable magnetic field for driving the beads is generated by rotating the magnet.

[0159] As shown in Fig. 11d, the translational movement of the magnet 608 is along the longitudinal length of the conduit 100, and the magnet 608 rotates as it is moved along the length of the conduit 100. Translating the magnet may comprise moving the magnet in a direction that is generally parallel to a path for magnetic beads along the conduit 100 (e.g. from a first liquid in a first cavity and into a second liquid in a second cavity). However, the path of the magnet 608 along the conduit need not necessarily be linear, and the distance between the magnet 608 and the conduit 100 as the magnet 608 moves along the longitudinal length of the conduit 100 need not necessarily be constant.

[0160] The inventors have found that the use of the magnet having both rotational and translational movement enables the beads to be more reliably driven through liquid-liquid interfaces (or through a viscous liquid. The movement of the magnet illustrated in Fig. 11d also results in a particularly unified and well-defined cloud, whose position can be more easily controlled.

[0161] In this example the rotation of the magnet 608 is around an axis through the centre of a cylindrical magnet 608, although it will be appreciated that the magnet 608 could have any other suitable shape. An example of a magnet 608 that could be used is illustrated in Fig. 8. The axis of rotation is generally perpendicular to the direction of polarization of the magnet 608. Therefore, as the magnet rotates, the 'north and 'south' sides of the magnet 608 alternate between being the closest to the conduit 100. This results in an oscillating magnetic field being applied to the beads 102 (similar to the magnetic field applied to the beads in the example of Fig. 11c). Advantageously, by virtue of the rotational and translational movement of the magnet 608, the tendency of the beads 102 to drag along the walls of the conduit 100 as they are driven by the magnet 608 is reduced, beneficially reducing the frictional force on the beads 102. The inventors have found that the beads 102 form a cloud that is transported along the conduit 100, improving the mixing of the beads 102 within the liquids inside the conduit 100. Moreover, the inventors have found that the use of the magnet 608 having both rotational and translational movement enables the beads 102 to be more reliably driven through liquid-liquid interfaces inside the conduit 100 (or through viscous liquids), and even past air bubbles present in the liquids inside the conduit 100 (or around/over other obstacles in the conduit 100, such as over gaps in the base of the conduit). Therefore, the use of a magnet 608 having both rotational and translational movement provides a particularly reliable method of driving the beads 102 along the conduit 100, whilst also providing good mixing of the beads 102 in the liquids.

[0162] The inventors have also found that the power needed to reliably drive the beads 102 along the conduit 100 using the method illustrated in Fig. 11d is particularly low (e.g., compared to use of an electromagnet). Therefore, the use of the magnet 608 having both rotational and translational movement to drive the beads 102 along the conduit 100 results in improved energy efficiency.

[0163] Whilst Fig. 11d shows a single magnet 608 having rotational and translational movement, alternatively two or more of the magnets 608 could be used (for example, one arranged generally above the conduit and another arranged generally below the conduit). However, use of a single magnet 608 having rotational and translational movement advantageously reduces the amount of space around the conduit 100 that need be provided for the movement of the magnet 608.

[0164] It will be appreciated that whilst the magnet 608 could be moved directly from one end of the conduit 100 to the other, this need not necessarily be the case. For example, the magnet 608 could be moved back and forth along a region of the conduit 100 to improve the mixing the beads 102 in a liquid in that region of the conduit 100 (e.g., in the lysis buffer 104, wash buffer 106 or elution buffer 106 in the example illustrated in Fig 7). It will also be appreciated that the magnets or electromagnets need not necessarily be arranged below the conduit 100, and could alternatively be arranged adjacent to another side of the conduit 100, or circumferentially around the conduit 100. Moreover, whilst in the examples illustrated in Figs. 11a, 11b, lid and 11e the magnet(s) is illustrated as moving with respect to the conduit 100, alternatively the conduit 100 could be moved with respect to to the magnet to achieve the same relative motion.

[0165] Apparatus for moving the magnet 608 in the manner illustrated in Fig. 11d will be described in more detail later.

[0166] Rotating Magnets Fig. 11e shows an example in which a set of rotating magnets 610 are used to drive the beads 102 along the conduit 100. Each of a plurality of magnets are rotated to generate an alternating magnetic field.

[0167] In this example, different from the example described above with reference to Fig. 11d, the magnets 610 have rotational movement but no translational movement along the length of the conduit 100. As shown in Fig. 11e, each of the magnets 610 rotates in the same direction, and the magnets 610 are configured such that the magnetic field inside the conduit 100 has an alternating polarity in the spatial domain along the length of the conduit 100. At each point inside the conduit 100 the magnetic field also has an alternating polarity in the time domain due to the rotation of the magnets 610. However, the magnets 610 need not necessarily all rotate in the same direction at all times, and could be rotated independently in different directions and/or at different speeds to provide finer control of the driving of the magnetic beads along the conduit 100. For example, a first magnet could rotate at a first speed to drive the beads along the conduit 100, and a second magnet could be rotating in the opposite direction at a second speed lower than the first speed, to compress the cloud of beads whilst nevertheless allowing the cloud of beads to be driven along the conduit.

[0168] As shown in Fig. lie, the magnets 610 are arranged along the length of the path for the beads along the conduit 100 (e.g. along a path from a first liquid in a first cavity and into a second liquid in a second cavity, adjacent to the first and second cavities). Whilst in the example illustrated in Fig. lie the magnets 610 are arranged on only one side of the conduit, this need not necessarily be the case. For example, a group of the magnets 601 could be arranged below the conduit, and an additional 113 group of the magnets 6W could be arranged above the conduit.

[0169] Beneficially, the inventors have found that when the set of rotating magnets 610 is used to drive the beads 102 along the conduit, the beads 102 form a cloud that improves the mixing of the beads 102 in the liquids inside the conduit 100. Whilst the inventors have found that the beads 102 are more reliably driven through liquid-liquid interfaces (or air bubbles) in the example described above with reference to Fig. 11d, in which the magnet 608 has both rotational and translational movement, in some implementations the configuration of Fig. lie in which magnets 610 having only rotational movement are provided may be preferable. For example, the arrangement of magnets 610 illustrated in Fig. lie advantageously avoids the need for a magnet 608 to be translated along the length of the conduit, reducing the mechanical complexity.

[0170] In the examples illustrated in Figs. 11a, 11 b, lld and 11 e the magnets may be neodymium magnetics. However, it will be appreciated that any other suitable type of magnet could alternatively be used. Coil

[0171] Fig. llf shows an example in which a coil of wire 612 is arranged around the conduit 100 (arranged around the path for the beads 102). In other words, the conduit 100 is arranged inside the coil 612. In use, an electric current is passed through the coil 612, generating a magnetic field inside the conduit 100 that drives the beads 102 along the longitudinal length of the conduit 100.

[0172] Advantageously, the use of the coil 612 arranged around the conduit 100 enables the beads 102 to be driven through liquid-liquid interfaces or air bubbles inside the conduit 100 particularly reliably.

[0173] Moreover, since the electric current passing through the coil 612 can be easily reversed, the use of the coil 612 provides a mechanically simple arrangement for to switching the direction in which the beads 102 are being driven along the conduit 100. For example, an alternating current can be passed through the coil 612, for driving the beads 102 backwards and forwards along the conduit 100 in a particular region, to improve mixing of the beads 102 with the liquid in that region.

[0174] Whilst in the example illustrated in Fig. llf one coil of wire is arranged around the conduit 100, it will be appreciated that alternatively a plurality of coils of wire may be arranged sequentially along the length of the conduit, and each of the coils of wire may be controlled independently to provide finer control of the driving of the beads along the conduit 100.

[0175] An automated device may be used to generate the magnetic field according to any of the examples described above with reference to Figs. 11a to 11 f.

[0176] The automated device may be configured for receiving a cartridge (for example, but not restricted to, any of the cartridges described above with reference to Figs. 3 to 10b), and for generating a magnetic field (e.g. an alternating magnetic field) for driving the beads inside the cartridge (e.g. along a path from a first liquid in a first cavity and into a second liquid in a second cavity, across a liquid-liquid interface between the first and second liquids). The automated device may be configured for automatically controlling the generation of the magnetic field to drive the beads 102.

[0177] Rotational Movement and Mixing of Beads Rotational movement of the magnet 608 used to drive the beads along the conduit 100 in a cloud-like manner (for example, as illustrated in Fig. 11d) will now be described in more detail.

[0178] Fig. 11g schematically illustrates a magnet 608 being rotated in an anti-clockwise direction, causing the cloud of beads 102 to be driven towards the right-hand side of the figure in the direction indicated by the arrow. The size of the beads in Figs. 11g, 11h and 11i has been exaggerated for clarity. Fig. 11h schematically illustrates the magnet 608 being rotated in a clockwise direction, causing the cloud of beads 102 to be driven towards the left-hand side of the figure in the direction indicated by the arrow. It is noted that in the examples of Fig. llg and 11h, the relative position of the beads 102 with respect to the magnet 608 does not affect the longitudinal direction in which the cloud of beads is driven 102. For example, if the cloud of beads 102 in Fig. 11g was arranged to the left of the magnet 608 (rather than to the right of the magnet 608, as illustrated in the figure), the beads 102 would nevertheless be driven towards the right-hand side of the figure. Similarly, if the cloud of beads 102 in Fig. 11h was located to the left of the magnet 608, the beads 102 would nevertheless be driven towards the left-hand side of the figure.

[0179] Fig. iii shows an example of how the geometry of the conduit 100 (or a liquid-liquid interface) can be used to enhance the mixing of the beads 102 in the liquid 100. In this example, the conduit 100 has a curved end, and the rotation of the magnet 608 causes the beads 102 to be driven towards the curved end to induce mixing of the beads 102 in the liquid. A similar example of how the geometry of the conduit 100 can be used to enhance the mixing of the beads 102 in the liquid 100 is illustrated in Fig. 7, in which the cavity 305 that contains the elution buffer 108 comprises a curved surface. A liquid-liquid interface can also be used to achieve the same effect, by driving the beads along the conduit 100 to the liquid-liquid interface, and then allowing the beads to mix in the liquid as illustrated in Fig. 11i without driving the beads through the liquid-liquid interface.

[0180] Apparatus for Rotational and Translational Movement of the Magnet Apparatus 700 for moving a magnet 608 as described above with reference to Fig. 11d will now be described with reference to Figs. 12 to 14. The apparatus 700 is operable to move the magnet 608 such that the movement of the magnet 608 has both translational and rotational components. The apparatus 700 can be used to drive the beads 102 through the liquids inside the cartridge 200 described above with reference to Figs. 3 to 7 (in other words, the magnet 608 could be the magnet 306 illustrated in Fig. 7), or one of the alternative devices illustrated in Figs. 9 to 10b. However, it will be appreciated that the apparatus 700 could alternatively be used to drive magnetic beads 102 through liquids in any other suitable type of device.

[0181] As shown in Figs. 12 to 14, the magnet 608 is mounted on a rod 702 that passes through the centre of the magnet 608. The rod 702 and magnet 608 assembly are mounted on a base portion 705, which can be transported by a moveable carriage 702 along the longitudinal length of the apparatus 700. The carriage 707 is moveable along a pair of guide rods 708a, 708b that pass through the carriage 702. As shown in Fig. 13, the carriage 707 comprises means for engaging with a central rod 702, to pull the carriage along the length of the rod 702. In this example, the rod 710 is male threaded and inserted into a corresponding female threaded socket of the carriage 707, and a powered rotation of the rod 710 using the motor 709 is used to pull the carriage 707 along the rod 710. However, any other suitable means of transporting the carriage 707 along the rod 710 could alternatively be used.

[0182] As the carriage 707 is transported along the longitudinal length of the guide rods 708a, 708b, a motor 703 rotates the rod 702 that passes through the magnet 608, causing the magnet 608 to rotate. In the example of Fig. 12, the electrical connection to the motor is provided inside a chain 706 that is connected to the motor, to protect the electrical connection as the carriage 707 is moved along the guide rods 708a, 708b.

[0183] It will be appreciated, therefore, that as the carriage 707 is moved along the guide rods 708a, 708b and the magnet 608 is rotated the magnet has both translational and rotational components to its movement, which is particularly advantageous for driving magnetic beads through liquids as described above.

[0184] Any suitable apparatus could be used to translate the magnet 608 along the conduit.

[0185] For example, a belt driven system, a rack and pinion system, a linear actuator, a lead screw, a ball screw or cam follower could be used. Moreover, the apparatus need not be restricted to linear translation of the magnet, and could move the magnet in three dimensions in addition to the rotational of the magnet. The apparatus may also be configured to provide the magnet with a variable tilt with respect to the conduit.

[0186] Comparative Example: Oscillating Vertical Movement of Magnets Apparatus 800 for moving a plurality of magnets, that could be used to drive the beads along any of the cartridges described above (or along any other suitable conduit), will now be described with reference to Figs. 15 and 16.

[0187] In the example illustrated in Figs. 15 and 16, the apparatus 800 is used to drive the beads through the liquids inside the cartridge 500 described above with reference to Figs. 10a and 10b. However, it will be appreciated that the apparatus 800 could alternatively be used to drive the beads 102 along any other suitable device containing the liquids.

[0188] As shown in Fig. 15, the apparatus 800 comprises a plurality of cams 804 arranged on a corresponding camshaft 813. In use, the camshaft 813 is rotated, causing each of the cams 804 to be moved up and down in the vertical direction. The ends of the cams 804 pass through apertures in two plates 812, 813 that constrain the horizontal movements of the cams 804, and ensure that the cams 804 remain correctly seated on the camshaft 813. In order to rotate the camshaft 813, the camshaft 813 can be connected to a driveshaft at mounting points 816 provided on the camshaft. The driveshaft can pass through apertures 806 in the apparatus 800 to connect to the mounting points 816. It will be appreciated that a driveshaft need not necessarily be connected to both ends of the camshaft 813. In other words, whilst two mounting points 816a, 816b are illustrated in the figures, only one mounting point might be used.

[0189] A magnet 814 is provided at one end of each of the cams 804, adjacent to the 5 cartridge 500. The cartridge 500 is arranged generally below the magnets 814 on a base portion 802 of the apparatus 800. Therefore, as the camshaft 813 is rotated, the movements of the cams 804 causes each magnet 814 to be moved up and down, towards and away from the cartridge 500. In other words, a magnetic field for driving the beads 102 along the cartridge is generated by moving each of a 10 plurality of magnets away from and towards a path for the beads, wherein the plurality of magnets are arranged along the length of the path. In this example the movement of the magnets 808 is periodic, and the periodic motion of neighbouring magnets 808 away from and towards the path (away from and towards the cartridge) is out of phase.

[0190] As shown in the figures, for a given position of the camshaft 813 the magnets 814 are not aligned in the vertical direction. In contrast, by virtue of the configuration of the camshaft, neighbouring magnets 814 are offset from each other in the vertical direction. Therefore, as the camshaft 813 is rotated, the vertical motion of the offset magnets 814 causes a wave of magnetic field to move along the longitudinal length of the cartridge 500, as each magnet is moved towards and away from the cartridge 500 in turn. This wave of magnetic field causes the magnetic beads 102 in the cartridge 500 to be driven along the longitudinal length of the cartridge. As the magnets are sequentially brought close to the conduit, the magnetic beads are attracted to that location. The beads are driven from point to point along the conduit, as they are attracted to each sequential magnet. A corresponding effect could alternatively be achieved using a sequence of electromagnets. The electromagnets could be powered sequentially using a non-alternating current, attracting the beads sequentially to each electromagnet along the conduit.

[0191] 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.

[0192] VAiiist 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 OF 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. 10b 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. lob, 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 to achieve consistent mixing through the liquids along the longitudinal length of the cartridge). Nevertheless, the cross-sectional area of any of the cavities could alternatively be varied by varying the vertical height of the cavity along the longitudinal length of the cartridge. Advantageously, varying the vertical height of the 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.

[0193] 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 les described above may have cavity waUs comprising a hydrophobic or hydrophilic coating.

[0194] 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 three rotating 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.

[0195] It will be appreciated that the reagents (e.g. the liquids, substances provided in the liquids, or coatings of the beads 102) in any of the above-described examples may comprise 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 lyophilized colorimetric detection reagent for determining the presence or absence of the targeted biomolecules via colorimetric analysis. The lysis buffer may be similarly lyophilized, wherein the method includes the addition of liquid prior to the sample being introduced, or alternatively the liquid sample itself could provide the rehydration. The reagents may comprise various chemicals or other species (e.g. enzymes, primers, etc.), and mixtures thereof, e.g. for use in nucleic acid amplification methods. For example, a nucleic acid amplification method may comprise 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, heminested PCR, polymerase cycling assembly (RCA), colony PCR, ligase chain reaction (LCR), digital PCR, methylation specific-PCR (MSP), co-amplification at lower 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-FOR).

[0196] 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 the amplification reaction and hence does not require multiple rapid changes in temperature. 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 Polymerase 113 Amplification (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).

[0197] One or more of the reagents may comprise components for making any of the aforementioned 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).

[0198] The liquids may comprise an amplification indicator substance, which may be an organic 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 or absence of specific nucleic acids) can be determined visually. The amplification indicator 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 the uncomplexed indicator (such as, for example, but not limited to, Ca2+, Mg2+, Zn2+, and other metal ions). Other amplification indicator substances are possible, that will 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, Calcium Green 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.

[0199] 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 (H30+) or hydrogen ions (H+). Indicators often cause the colour of the solution to change depending on the pH. However, it will be appreciated that indicators can also indicate change via changes in other properties. For example, olfactory indicators indicate change via changes in their odour.

[0200] 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.

[0201] 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 redox indicators 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, 2,21-Bipyridine, 5,6-Dimethylphenanthroline, oDianisidine, Sodium diphenylamine sulfonate, Diphenylbenzidine, Diphenylamine, and Viologen. pH dependent redox indicators include, but are not limited to, Sodium 2,6-Dibromophenol-indophenol, Sodium o-Cresol indophenol, Thionine, Methylene blue, Indigotetrasulfonic acid, Indigotrisulfonic acid, Indigo carmine, Indigomono sulfonic acid, Phenosafranin, Safranin, and Neutral red.

Claims

1. CLAIMS1. A method of manipulating magnetic beads in a first liquid inside a conduit, wherein the method comprises generating a variable magnetic field using at least one magnet or electromagnet to mix the magnetic beads in the first liquid; and wherein the surface of the magnetic beads is for attachment to a biological or chemical species.

2. The method according to claim 1, wherein manipulating the magnetic beads 113 comprises driving the beads along a path in a first direction using the variablemagnetic field.

3. The method according to claim 1 or 2, wherein generating the variable magnetic field comprises rotating at least one magnet.

4. The method according to claim 2, wherein generating the variable magnetic field comprises simultaneously rotating and translating at least one magnet.

5. The method according to claim 4, wherein translating the magnet comprises moving the magnet in a direction that is generally parallel to the path in the first direction.

6. The method according to claim 2, wherein generating the variable magnetic field comprises translating one or more electromagnets in a direction that is generally parallel to the path in the first direction.

7. The method according to any preceding claim, wherein generating the variable magnetic field comprises rotating each of a plurality of magnets.

8. The method according to claim 7 when dependent on claim 2, wherein the magnets are arranged sequentially along the path in the first direction.

9. The method according to claim 7 or 8, wherein the rotation of each of the plurality of magnets is independently controllable.

10. The method according to claim 2, wherein the at least one magnet or electromagnet comprises a plurality of electromagnets; wherein the plurality of electromagnets are arranged along the path in the first direction; and wherein generating the variable magnetic field comprises passing a current to through each of the electromagnets.

11. The method according to claim 10, wherein the current passed through each of the electromagnets is an alternating current, and wherein the alternating current passed through neighbouring electromagnets is out of phase.

12. The method according to any one of claims 2 to 11, wherein the variable magnetic field has an alternating polarity in the time domain at a particular location on the path.

13. The method according to any one of claims 2 to 12, wherein the variable magnetic field has an alternating polarity in the spatial domain along the path.

14. The method according to any preceding claim, wherein the method comprises transporting the magnetic beads from a first region containing the first liquid and into a second region containing a second liquid, wherein the first liquid and the second liquid are immiscible and adjacent to each other, such that there is a liquid-liquid interface between the first liquid and the second liquid; and wherein manipulating the magnetic beads comprises driving the beads from the first liquid in the first region and into the second liquid in the second region, across the interface.

15. The method according to any one of claims 2 to 14, wherein the method comprises generating the variable magnetic field by passing a current through a coil of wire that is arranged in a helical configuration around the path.

16. The method according to any one of claims 2 to 14, wherein the method comprises generating the variable magnetic field by moving each of a plurality of magnets away from and towards the path; wherein the plurality of magnets are arranged along the length of the path in the first direction.

17. The method according to claim 16, wherein the movement of the magnets is periodic, and the periodic motion of neighbouring magnets away from and towards the path is out of phase.

18. Apparatus for generating the variable magnetic field according to any one of claims 1 to 17.

19. Apparatus for processing a chemical or biological species from a sample, the apparatus comprising: a cartridge comprising a first region containing a first liquid, and a second region containing a second liquid, wherein the first liquid and the second liquid are immiscible and adjacent to each other, such that there is a liquid-liquid interface between the first liquid and the second liquid; magnetic beads for transporting the chemical or biological species; and a device configured for receiving the cartridge, and for generating a variable magnetic field using at least one magnet or electromagnet, to drive the magnetic beads along a path from the first liquid in the first region and into the second liquid in the second region, across the interface.

20. The apparatus according to claim 19, wherein the device comprises at least one magnet, and the device is operable to rotate the at least one magnet to generate the variable magnetic field.

21. The apparatus according to claim 20, wherein the device is operable to simultaneously rotate and translate the magnet.

22. The apparatus according to claim 21, wherein the device is configured for moving the magnet in a direction that is generally parallel to the path from the first liquid in the first region and into the second liquid in the second region.

23. The apparatus according to claim 19 or 20, wherein the device comprises a plurality of magnets, and the device is operable to rotate each of the plurality ofmagnets to generate the variable magnetic field.

24. The apparatus according to claim 23, wherein the device is configured for independently controlling the rotation of each of the plurality of magnets.

25. The apparatus according to claim 23 or 24, wherein when the cartridge has been received at the device, the magnets are arranged along the length of the path from the first liquid in the first region and into the second liquid in the second region, adjacent to the first and second regions.

26. The apparatus according to claim 19, wherein the device comprises a plurality of electromagnets; wherein, when the cartridge has been received at the device, the plurality of electromagnets are arranged along the length of the path from the first liquid in the first region and into the second liquid in the second region, adjacent to the first and second regions; and wherein the device is operable to pass a current through each of the electromagnets to generate the variable magnetic field.

27. The apparatus according to claim 26, wherein the current passed through each of the electromagnets is an alternating current, and wherein the alternating current passed through neighbouring electromagnets is out of phase.

28. The apparatus according to any one of claims 19 to 27, wherein when the cartridge has been received at the device, the alternating magnetic field has an alternating polarity in the time domain at a particular location on the path from the first liquid in the first region and into the second liquid in the second region.

29. The apparatus according to any one of claims 19 to 28, wherein when the cartridge has been received at the device, the magnetic field has an alternating polarity in the spatial domain along the path from the first liquid in the first region and into the second liquid in the second region.

30. The device configured to receive the cartridge of the apparatus according to any one of claims 19 to 29.

31. The device according to claim 30, wherein the device is an automated device for automatically controlling the generation of the magnetic field to drive the magnetic beads along the path from the first liquid in the first region and into the second liquid in the second region.

32. Apparatus for generating the magnetic field according to claim 16 or 17, the apparatus comprising: the plurality of magnets; a camshaft; and a plurality of cams arranged on the camshaft; wherein each of the plurality of magnets is mounted to a respective cam of the plurality of cams; and wherein the apparatus is operable to move each of the plurality of magnets away from and towards the path by rotating the camshaft.

33. Apparatus for generating the alternating magnetic field according to claim 4 or 5, the apparatus comprising: a magnet; a motor that is coupled to the magnet for driving rotation of the magnet; and a moveable carriage that is configured for translational movement; wherein the magnet is arranged on the moveable carriage; and wherein the apparatus is operable to simultaneously rotate the magnet and translate the carriage.

34. The apparatus according to claim 33, wherein the apparatus is further configured to control the distance between the magnet and the path.to

35. The apparatus according to claim 34, wherein the moveable carriage is configured for movement towards and away from the path.