Lid assembly for sample tubes, method for using same to collect magnetic beads, and sample processing kit - Patents.com

Abstract

A lid assembly for a sample tube for collecting magnetic beads from the sample tube and subsequently releasing the beads, the lid assembly comprising: a closure portion including means for removably attaching the closure portion to an opening of the sample tube to close the sample tube; a bead collection platform configured to be positioned within or above the opening of the sample tube when the closure portion is attached to the sample tube, the bead collection platform having a bead collection surface on one side for contacting liquid in the sample tube during use and a magnet storage cavity on the other side behind the bead collection surface; and a magnet holder portion comprising a magnet, the magnet being removably insertable into the magnet storage cavity toward the bead collection surface such that when the magnet is present in the magnet storage cavity, the magnet can hold the magnetic beads against the bead collection surface and when the magnet is not present in the magnet storage cavity, the lid assembly is unable to magnetically hold the magnetic beads against the bead collection surface. Methods of using such devices to collect magnetic beads from liquids in sample tubes, as well as related kits and accessories, are also provided.

Description

[Technical field]

[0001] This invention was made with United States Government support under Award No. R01AI128765 awarded by the National Institute of Allergy and Infectious Diseases of the National Institutes of Health. The United States Government has certain rights in the invention.

[0002] The present invention relates to a lid assembly for a sample tube adapted to collect magnetic beads from a liquid in the sample tube, and an associated method of using such an apparatus. The apparatus and method are particularly suited, but by no means limited to, performing extraction of target biomolecules from solid or liquid samples using magnetic separation. A sample processing kit including such an apparatus is also provided, together with some accessories.

[0003] The term "magnetic beads" as used herein should be broadly interpreted. First, the term "magnetic" should be broadly interpreted to include "paramagnetic". Furthermore, the term "beads" should also be broadly interpreted to include particles of various sizes, including nanoparticles (i.e., particles less than 1 μm in diameter), micron-sized particles (i.e., on the order of 1-500 μm in diameter), and larger particles (in some cases up to about 1 mm in diameter). As one of ordinary skill in the art will appreciate, the principles of the present disclosure are not limited to any particular size or composition of magnetic "beads", and for any given application, one of ordinary skill in the art will understand to use beads of appropriate size and composition. [Background technology]

[0004] Magnetic separation using magnetic beads is a well-established technique for extracting target biomolecules from a sample.

[0005] Magnetic beads typically consist of two components: a magnetic material (often iron, nickel or cobalt) and a chemical moiety that provides functionality to the beads, thereby allowing them to attach to biomolecules or other chemical or biological species. Such species can include, but are not limited to, polynucleotides such as nucleic acids (e.g., RNA or DNA), proteins, biological cells, and other chemical or biological molecules.

[0006] The principles of magnetic bead extraction are well established and outlined, for example, in US Pat. No. 4,554,088 and US Pat. No. 5,705,628, which themselves refer to further background art on this technology.

[0007] More recently, US Patent Application Publication No. 2015 / 0196905 A1 proposes a centrifugable liquid container with a magnet integrated into its lid for separating magnetic beads in suspension in liquid, comprising four removable components: a centrifugable liquid container, a small removable magnet, a hollow cylindrical connector cap, and an open lid adapter. In use, the components are attached together by a screw thread.

[0008] The fact that the vessel of US2015 / 0196905A1 is specifically centrifugable suggests that in practice centrifugation may often be necessary to adequately perform its intended function. However, the use of a centrifuge limits the use of the vessel to laboratories or at least locations where electrical power is available. This makes the vessel unsuitable for use in locations where there is no source of electrical power or where the use of a centrifuge is not possible.

[0009] Another potential drawback of the device disclosed in US 2015 / 0196905 A1 is that the use of threads between components makes the device somewhat cumbersome and believed to be time consuming to use. Indeed, the components do not appear to lend themselves to quick and easy use, which increases the risk of contamination of the magnetic beads, especially when transferring them between containers. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] U.S. Pat. No. 4,554,088 [Patent Document 2] U.S. Pat. No. 5,705,628 [Patent Document 3] US Patent Application Publication No. 2015 / 0196905A1 Summary of the Invention [Problem to be solved by the invention]

[0011] Therefore, there is a need for an apparatus that addresses at least some of the above problems to enable a rapid, simple, low-cost, power-free extraction process to be performed for target biomolecules from a sample using magnetic beads. [Means for solving the problem]

[0012] According to a first aspect of the present invention there is provided a lid assembly as set forth in claim 1 of the accompanying claims.

[0013] Thus, there is provided a lid assembly for a sample tube for collecting magnetic beads from the sample tube and subsequently releasing the beads, the lid assembly comprising a closure including means for removably attaching the closure to an opening of the sample tube to close the sample tube, a bead collection platform configured to be positioned in or over the opening of the sample tube when the closure is attached to the sample tube, the bead collection platform having a bead collection surface on one side for contacting liquid in the sample tube during use and a magnet storage cavity on the opposite side behind the bead collection surface, and a magnet holder comprising a magnet, the magnet being removably insertable into the magnet storage cavity towards the bead collection surface such that when the magnet is present in the magnet storage cavity the magnet can hold the magnetic beads against the bead collection surface and when the magnet is not present in the magnet storage cavity the lid assembly is unable to magnetically hold the magnetic beads against the bead collection surface.

[0014] As one of skill in the art would understand from this disclosure, the term "sample tube" as used herein should be interpreted broadly to encompass any suitable tube that may be used to contain or process a sample or a derivative of a sample.

[0015] By allowing the magnet to be removably insertable into the magnet receiving cavity, the state of the lid assembly can be quickly and easily changed from a state in which the magnetic beads are attracted to the bead collection surface to a state in which such beads are released, without requiring the use of electrical power, which also lends itself to good use of the device in remote locations without the need for specialist training.

[0016] Additionally, by being platform-like as described herein, the bead collection platform can advantageously hold the collected magnetic beads substantially exposed to the surrounding air when the lid assembly is removed from the sample tube, thus aiding in drying of the collected beads during use.

[0017] In a presently preferred embodiment, the magnet holder is completely separable from the closure, thereby making the device easy to use, simple and cheap to manufacture and therefore easily available to the end user.

[0018] However, in other variations, the magnet holder may be coupled to the closure, and the magnet may be movable within the magnet receiving cavity towards or away from the bead collection surface.

[0019] Preferably, the magnet holding portion further comprises a user-gripable portion to which the magnet is attached, thereby facilitating a user to manipulate and insert the magnet into the magnet receiving cavity and subsequently remove the magnet from the magnet receiving cavity.

[0020] The user-gripable portion may have a relatively thin and flat shape, allowing it to be easily grasped between a user's thumb and index finger, or it may have a cross-sectional profile such that it can act as a stand to support the magnet holder (optionally with the closure and sample tube attached) upside down. The magnet receiving cavity may be in the form of a socket shaped to receive at least the magnet of the magnet holder. Optionally, the magnet holder may be rotatable within the socket.

[0021] In certain embodiments, the magnet holder and the closure may be interengageable when the magnet is inserted into the magnet cavity. Thus, the magnet may be reversibly locked in place within the magnet cavity, thereby ensuring that the lid assembly maintains its bead-attaching state and preventing the magnet holder from accidentally falling off. This may be particularly beneficial when the sample tube is inverted with the lid assembly attached, or when the lid assembly is used to transport magnetic beads from one sample tube to another.

[0022] For example, the magnet retainer may optionally include one or more radial protrusions and the socket may include one or more complementary channels into which the one or more radial protrusions may engage, or the magnet retainer and socket may include threads that are engageable with one another. Alternatively, or additionally, the socket may be provided with gripping means (eg protrusions or ridges) for gripping the magnet holder.

[0023] Advantageously, for quick and easy use, the means for removably attaching the closure to the opening of the sample tube may comprise a press-fit fitting adapted to engage the opening of the sample tube, hi a currently preferred embodiment the press-fit fitting is a bead collection platform. In an alternative embodiment, the means for removably attaching the closure to the opening of the sample tube may comprise a snap-fit ​​mechanism.

[0024] In various embodiments, the closure may have an elongated shape when viewed from above, as this has been found to work well in combination with sample tubes having hinged caps.

[0025] The closure may include first and second finger tabs (optionally having recessed or textured outer surfaces) on either side of the closure for gripping by a user's thumb and finger during use.

[0026] In certain embodiments, the first and second finger tabs extend below the bead collection surface and can function as a stand to support the lid assembly in an upright orientation when separated from the closure.

[0027] Alternatively, or in addition, the first and second finger tabs may extend above the bead collection surface and can act as a stand to support the lid assembly (optionally with a sample tube attached) in an upside-down orientation.

[0028] The bead collection platform may extend parallel to and be separate from the first and second finger tabs. Among other things, such a configuration facilitates airflow around the bead collection platform when the lid assembly is removed from the sample tube, thus facilitating drying of any magnetic beads collected thereon (such beads being substantially exposed to air), while protecting the bead collection surface from accidental contact with a user's fingers.

[0029] Optionally, the bead collection surface may incorporate concave or recessed areas to facilitate collection of the magnetic beads. Alternatively, the bead collection surface may be convex to aid in drying of the collected magnetic beads.

[0030] Alternatively, or additionally, the bead collection surface can incorporate an array of indentations or depressions to promote uniform distribution of the magnetic beads across the bead collection surface. Optionally, the bead collecting surface incorporates fluid wicking members (eg, wicking spikes) to facilitate removal of liquid from the bead collecting surface.

[0031] According to a second aspect of the present invention there is provided a kit comprising a lid assembly according to the first aspect of the present invention, at least a first sample tube, optionally a pipette and / or a swab and / or a further sample collection tube.

[0032] In one embodiment, the kit may have multiple sample tubes connected to each other, for example side-by-side, to facilitate use of the tubes in the required order. Optionally, the last sample tube may be connected to its adjacent sample tubes by a frangible connection, which may allow subsequent processing of the contents of the last tube separate from the other tubes.

[0033] In certain embodiments, the kit may have a first, second and third sample tube. For example, the first sample tube may contain a lysis / binding buffer, the second sample tube may contain a washing solution, and the third sample tube may contain an elution solution. The tubes in the kit may be pre-filled with such liquids. Additionally or alternatively, the first sample tube may be pre-filled with magnetic beads. However, alternatively, the magnetic beads may be provided in a separate container, sachet, blister pack, molded co-fill tube, etc.

[0034] Advantageously, the packaging for the kit (including the sample tube(s), lid assembly, and optionally other components) may be configured to function as a stand / station for the contents of the kit during use, thereby replacing additional laboratory equipment such as a tube shelf. More specifically, the kit may comprise a tray incorporating one or more recesses or cavities for supporting the sample tube(s) and a recess in which the lid assembly is placed. The packaging may thus provide a dedicated area for placing each tube during / between processing steps and a dedicated space in which the lid assembly may be placed to allow liquid to evaporate from the magnetic beads held on the bead collection surface. The packaging may also provide a dedicated space in which the sample collection / swab tubes can remain during the extraction procedure, thus effectively coupling the sample with the extraction kit. The packaging may also include a cover that, once used, can function as a waste container or as a temporary staging area for the sample tubes and other contents of the kit.

[0035] According to a third aspect of the invention, a sample tube is provided having a closable cap, the cap including a compartment for containing a reagent, the compartment having a removable cover for sealing the reagent therein. In particular, the compartment may be inside the cap such that the compartment is located within the sample tube when the cap closes the sample tube. Due to this cap compartment, such a tube facilitates the introduction of a predetermined amount of a predetermined reagent into a liquid in the sample tube. The reagent may be wet and / or lyophilized and may be used, for example, for amplification, detection or biosensing of an extracted analyte present in the liquid in the sample tube. The cap may be attached to the tube by a flexible hinge.

[0036] In some embodiments, the reagents may be in the form of beads, which facilitates loading of the reagent into the compartment and allows the reagent to pass as a whole out of the compartment into the tube, for example by dripping out of the compartment, however in other embodiments the beads may be press-fit into the compartment to prevent them from accidentally falling out.

[0037] In certain embodiments, the reagent may be a lyophilized colorimetric detection reagent. As will be appreciated by those skilled in the art, in other embodiments the reagent may be lyophilized and non-colorimetric, while in yet other embodiments the reagent may not be lyophilized and non-colorimetric. Thus, more generally, the reagent may be any suitable detection reagent.

[0038] The kit of the second aspect above may comprise at least one sample tube according to the third aspect, in particular to function as the third sample tube above. According to a fourth aspect of the invention, there is provided a method for collecting magnetic beads from a liquid in a sample tube (in which the beads may be suspended), the method comprising the steps of: attaching a closure of the lid assembly to the opening of the sample tube; Agitating (e.g., gently shaking or inverting) the liquid with the magnet inserted into the magnet containing cavity such that the magnetic beads contact the bead collection surface and are held against the bead collection surface by the magnet. Such a process is quick and easy to carry out and does not require the use of electricity, centrifuges, or specialist training. The sample tube may be a first sample tube containing a first liquid, and the method may further comprise: removing the lid assembly from the first sample tube with the magnet inserted into the magnet cavity and the magnetic beads held by the magnet against the bead collection surface; attaching a closure of the lid assembly to an opening of a second sample tube containing a second liquid; removing the magnet from the magnet containing cavity such that the magnetic beads are no longer held against the bead collection surface by the magnet and are suspended in the second liquid.

[0039] This therefore allows the lid assembly to quickly and easily transfer magnetic beads from a first liquid in a first sample tube to a second liquid in a second sample tube. Additionally, to further transport the beads, the method further comprises: reinserting the magnet into the magnet receiving cavity (with the closure portion of the lid assembly still attached to the opening of the second sample tube); agitating the second liquid such that the magnetic beads contact the bead collection surface and are held by the magnet against the bead collection surface; removing the lid assembly from the second sample tube with the magnet inserted into the magnet cavity and the magnetic beads held by the magnet against the bead collection surface; attaching a closure of the lid assembly to an opening of a third sample tube containing a third liquid; removing the magnet from the magnet containing cavity such that the magnetic beads are no longer held against the bead collection surface by the magnet and are suspended in the third liquid. Optionally, to finally remove the magnetic beads from the third liquid, the method further comprises: reinserting the magnet into the magnet receiving cavity (with the closure portion of the lid assembly still attached to the opening of the third sample tube); agitating the third liquid such that the magnetic beads contact the bead collection surface and are held by the magnet against the bead collection surface; removing the lid assembly from the third sample tube with the magnet inserted into the magnet cavity and the magnetic beads held by the magnet against the bead collection surface; Then, optionally, positioning the lid assembly and / or magnetic beads.

[0040] In certain practical embodiments, the method may be for the extraction of a target biomolecule (e.g., a nucleic acid (e.g., RNA or DNA) characteristic of a particular virus, such as, but not limited to, SARS-CoV-2), wherein: The first liquid is a lysis / binding buffer for dissolving the target biomolecules, thereby releasing them into solution, and binding the biomolecules to the magnetic beads; The second liquid is a cleaning liquid, The third liquid is an elution liquid for eluting the biomolecules. Thus, the target biomolecule may include a nucleic acid.

[0041] The method may further comprise the steps of introducing a detection reagent (eg, a colorimetric detection reagent) into the eluate and, optionally, applying heat to determine the presence or absence of the target biomolecule.

[0042] The third sample tube (containing the elution liquid) may be a sample tube according to the third aspect described above, wherein the reagent retained in the cap compartment is a detection reagent, and the step of introducing the detection reagent into the elution liquid comprises the step of releasing it from the cap compartment of the sample tube.

[0043] It will be appreciated that methods based on the present principles may use a number of sample tubes other than three, and any number of processing steps required for extraction of a particular biomolecule.

[0044] According to a fifth aspect of the present invention, there is provided a handheld device capable of holding multiple sample tubes and manually stirring or inverting them simultaneously, the device comprising a handle portion and a plurality of sample tube holding clips, each for holding a respective sample tube.

[0045] The device may further comprise a plurality of restraining arms, each extending above a respective one of the retaining clips to prevent the sample tube from falling out of the retaining clips when the device is inverted. Each restraining arm may be offset to one side of a respective retaining clip.

[0046] According to a sixth aspect of the present invention, there is provided a method for manually stirring or inverting multiple sample tubes simultaneously, comprising the steps of inserting the sample tubes into an apparatus according to the fifth aspect and manipulating a handle portion.

[0047] Optionally, at least one of the sample tubes may be attached to a lid assembly according to the first aspect, and optionally, at least one of the sample tubes may be a sample tube according to the third aspect. Embodiments of the present invention will now be described, by way of example only, with reference to the drawings in which: [Brief description of the drawings]

[0048] [Figure 1](a) A perspective view of a lid assembly for a sample tube with a magnet holder that engages with the closure, (b) a perspective view of the magnet holder having a user-gripable portion with a magnet attached, (c) an exploded view of the magnet holder, and (d) a perspective view of a closure including first and second finger tabs, a bead collection platform, and a magnet receiving cavity in the form of a socket. [Diagram 2] 2 is a perspective view of the underside of the closure of FIG. 1 showing the underside bead collection surface of the bead collection platform and an optional wicking member (in this case a central wicking spike). [Diagram 3] FIG. 3 is a perspective view of the underside of a variation of the closure of FIG. 2 without the optional wicking member. [Figure 4] FIG. 2 is a view of the lid assembly of FIG. 1 placed on its side, without magnetic beads present on the bead collection surface. [Diagram 5] 5 is a view similar to FIG. 4 of the lid assembly of FIG. 1 placed on its side with magnetic beads present on the bead collection surface. [Figure 6] 2 is a side view of the lid assembly of FIG. 1 showing magnetic beads being held against the bead collection surface by magnets in the magnet holder. [Figure 7] 2A-2C illustrate a process for disengaging and separating the magnet holders of FIG. 1 from their respective closures. [Figure 8] 2A-2C show the lid assembly and sample tube of FIG. 1 and the process of attaching the closure to the opening of the sample tube. [Figure 9] FIG. 9 further illustrates the lid assembly of FIG. 1 being attached to the sample tube of FIG. 8. [Figure 10] 9A-9C illustrate a process for disengaging and separating the magnet holders of the lid assembly of FIG. 8 from their respective closures, with the closures attached to sample tubes. [Figure 11] 11A and 11B are cross-sectional side views of the disengagement process and the separation process of FIG. [Figure 12]FIG. 2 is a perspective view of a kit including the lid assembly of FIG. 1, three sample tubes, and a pipette (in this case, a precise volumetric pipette). [Figure 13] FIG. 13 is a perspective view of a variation of the kit of FIG. 12 including additional sample collection tubes. [Figure 14] FIG. 14 is a further perspective view of a kit such as that of FIG. 12 or FIG. 13, with a cover and backing panel. [Figure 15] FIG. 2 is a perspective view of three sample tubes connected together with the lid assembly of FIG. 1. [Figure 16] FIG. 2 shows steps (a)-(l) of a method for collecting magnetic beads from a first liquid in a first sample tube and subsequently transferring the beads to a second liquid in a second sample tube. [Figure 17] 2A-2C show a variation of the lid assembly of FIG. 1 in (a) a perspective view, (b) a cutaway view of the closure portion, and (c) a top view of the closure portion, where the magnet receiving cavity includes a gripping ridge for gripping the magnet holder. [Figure 18] 2A and 2B are (a) engaged cross-sectional and (b) disengaged perspective views of another variation of the lid assembly of FIG. 1, in which the magnet retainer and the socket are provided with threads that are engageable with each other. [Figure 19] FIG. 2 shows a variation of the lid assembly of FIG. 1 in which the first and second finger tabs of the closure are positioned to act as a stand for supporting the lid assembly upside down with a sample tube attached. [Figure 20] FIG. 2 shows another variation of the lid assembly of FIG. 1 attached to a sample tube, in which the user-gripable portion of the magnet holder is configured to act as a stand for supporting the lid assembly and attached sample tube in an upside-down orientation. [Figure 21] FIG. 1 shows a perspective view of a sample tube with a closable cap, the cap having a removable cover and including a compartment for containing reagent beads. [Figure 22]22A and 22B are a perspective cross-sectional view and a cross-sectional view of the sample tube in FIG. 21. [Diagram 23] FIG. 22 illustrates a method of using the sample tube of FIG. 21 in which reagent beads are released into the liquid in the sample tube to perform a colorimetric analysis to determine the presence or absence of a target species in the liquid. [Figure 24] FIG. 2 is a perspective view of a handheld device for holding multiple sample tubes and allowing them to be manually agitated or inverted simultaneously, with one such sample tube in place with the lid assembly of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0049] In the drawings, like elements are designated with like reference numbers throughout. This embodiment represents the best way known to the applicant to practice the invention, however, it is not the only way in which it can be accomplished.

[0050] overview In the present disclosure, a rapid, low-cost, power-free extraction process can be performed for target biomolecules from liquid (or solid) samples. The target biomolecule can be a polynucleotide, such as a nucleic acid (e.g., RNA or DNA). For example, the target biomolecule can be, but is not limited to, a characteristic RNA of a particular virus, such as SARS-CoV-2. The process does not require expensive laboratory equipment (such as a centrifuge, vortex mixer or micropipette), a power source, or detailed pre-training, and can be performed virtually anywhere, such as at the point of care (i.e., away from the laboratory). The entire process from the initial sample (such as a swab, saliva, tissue or blood) to the extracted biomolecule (e.g., protein, RNA or DNA) can be performed in less than 5 minutes by a not-well-trained user. The process is based on magnetic separation using magnetic beads (the term "magnetic beads" should be interpreted broadly, as outlined above). The principle of the present extraction process is similar to that of other magnetic bead extraction kits and is not limited to a particular size or composition of magnetic beads. Indeed, for any given application, one of skill in the art will understand to use beads of the appropriate size and composition.

[0051] Referring initially to FIG. 8, the present disclosure provides a lid assembly 100 for a sample tube 30. The sample tube 30 may be an existing sample tube, such as those manufactured by Eppendorf AG and commonly referred to as Eppendorf tubes (RTM), on which the illustrated tube has and is based. However, it should be noted that the principles of the present disclosure are in no way limited to use with Eppendorf tubes (RTM), but may be applied to sample tubes of different geometries and dimensions, including tubes that do not have hinged caps. That said, while the actual implementation of the present lid assembly 100 is designed to fit a particular diameter of a sample tube, there is no restriction (within reasonable limits) as to the diameter of the sample tube that the implementation of the lid assembly 100 may be molded to fit. Typically, such sample tubes are on the order of a few centimeters in length, about one centimeter in diameter, and have a volume on the order of 0.5 to 2 milliliters. In use, the sample tube 30 contains a liquid in which magnetic beads are suspended. The lid assembly 100 can be used to collect the magnetic beads from a liquid and subsequently release the beads into a different tube, typically containing a different liquid.

[0052] As will be described in detail below, the lid assembly 100 comprises two main parts, namely a closure part 20 and a magnet holder 10. The magnet holder 10 is reversibly removable from the closure part 20 and incorporates a magnet, which in our currently preferred embodiment is a neodymium magnet, although other magnetic materials may alternatively be used. The closure part 20 has a bead collection surface 26. In use, the magnet holder 10 is introduced into the magnet receiving cavity in the closure part 20, thereby positioning the magnet behind the bead collection surface 26, in order to extract magnetic beads from the liquid in the sample tube 30 and cause them to be captured by the bead collection surface 26. When the magnet is in this position (and in practice, typically following gentle inversion of the tube), the magnetic beads in the sample tube 30 are attracted by the magnet and held against the bead collection surface 26, under the influence of the magnet's magnetic field. The magnetic beads can then be released from the bead collection surface 26 by removing the magnet holder 10 from the closure part 20, thereby removing the magnetic field.

[0053] The lid assembly 100, when viewed from above, may typically have a footprint of about 2-3 centimeters by about 1-2 centimeters, and its overall height (when the magnet holder 10 is attached to the closure 20) may be about 2-4 centimeters, although these measurements are merely approximate and are merely examples. In any given case, the dimensions of the lid assembly 100 will depend on the dimensions of the sample tube 30 that it is designed to fit. The dimensions of the lid assembly 100 may also be designed to accommodate different hand sizes of users. Thus, the lid assembly 100 can be made in a range of different sizes to fit a variety of sample tubes and be convenient and comfortable for a variety of users.

[0054] In the following, the lid assembly 100 is first described in detail, including the mechanism and manner in which the magnet holder 10 is inserted and engaged with the closure 20. Next, the manner in which the lid assembly 100 can be attached to and used with a sample tube 30 is described. Then, several sample processing kits including the lid assembly 100 and sample tube 30 are presented, followed by a method of using the device, for example to perform extraction of target biomolecules from solid or liquid samples using magnetic separation. Finally, several variations of the device, and accessories, are described.

[0055] Lid Assembly Referring initially to FIG. 1, an example lid assembly 100 according to the present disclosure will now be described in detail. FIG. 1( a ) shows the lid assembly 100 with the magnet holder 10 engaged with the closure portion 20 .

[0056] -Magnet holder 10 Figure 1(b) shows the magnet holder 10 alone, for example removed (or not yet inserted) from the closure 20, and Figure 1(c) shows an exploded view of the same components. The magnet holder 10 comprises a magnet 18, which may advantageously be a neodymium magnet, although other magnetic materials may alternatively be used. In the example shown, the magnet 18 is cylindrical in shape, but different shapes are possible.

[0057] The magnet holder 10 further comprises a body portion 12, which may be made of a plastic material (e.g., by injection molding or three-dimensional printing). The magnet 18 is attached to the body portion 12, for example, by adhesive. A recess may be provided on the underside of the body portion 12 to receive the magnet 18 and precisely align the magnet for attachment. In other variations, the recess and magnet 18 may be configured to engage one another in a press-fit manner, thereby eliminating the need for adhesive to hold the magnet in place. Alternatively, the magnet 18 may have the body portion 12 overmolded therearound, such that the magnet is fused to the entire inside of the body portion 12.

[0058] The body portion 12 mainly comprises a user-graspable portion 13 which can be grasped by a user, typically between thumb and index finger, to manipulate the magnet holder 10 during use.

[0059] In the illustrated example of magnet holder 10, the lower region of body portion 12 between user-gripable portion 13 and magnet 18 is in the form of a cylindrical shaft 14 having first and second radial projections 16a, 16b. As will be explained further below, cylindrical shaft 14 and radial projections 16a, 16b enable magnet holder 10 to rotatably engage with closure portion 20.

[0060] -Closing part 20 1(d) and 2 show the closure 20 in isolation. The closure 20 may be made of a plastic material (e.g., by injection molding or three-dimensional printing) and comprises an upper portion 21 (flat or substantially flat), first and second finger tabs 24a, 24b by which the closure can be grasped and manipulated by a user during use, and a central bead collection platform 25 extending downwardly from the upper portion 21. Optionally, the finger tabs 24a, 24b may have a recessed or textured outer surface to improve grip by a user. It will be understood that the term "upper" (and similarly "upper") refers to the closure 20 in the orientation shown in Figs. 1 and 8, i.e., as the closure 20 is oriented when attached to a sample tube 30, whereas the "lower" (and similarly "lower") refers to the opposite orientation relative to "upper" and "upper".

[0061] The bead collection platform 25 has a bead collection surface 26 on one side and a magnet receiving cavity 22 on the other side, both aligned with the centre of the closure 20. The bead collection platform 25 is arranged to be located within (or potentially, in alternative embodiments, above) the opening of the sample tube 30 when the closure 20 is attached to the sample tube 30, so that the bead collection surface 26 is available for contact with liquid within the sample tube 30 during use. The magnet receiving cavity 22 extends behind the bead collection surface 26 (as shown in cross section in FIG. 11 ) in the form of a substantially cylindrical (axial) socket, the main function of which is to receive the magnet 18 of the magnet holder 10, if required.

[0062] Thus, the magnet holder 10, and in particular the magnet 18, is removably insertable into the magnet receiving cavity 22 toward the bead collection surface 26. The cylindrical shape (i.e., circular cross-section) of both the magnet 18 and the shaft 14 of the magnet holder 10 allows the magnet holder 10 to be inserted downwardly and rotated within the cavity 22.

[0063] In the illustrated example, the magnet receiving cavity 22 further includes a pair of opposing longitudinal channels 22' shaped to receive the radial protrusions 16a, 16b of the magnet holder 10, and a pair of circumferential channels 23 into which the radial protrusions 16a, 16b can rotate to broadly engage in a non-sprung bayonet-type mounting manner when the magnet 18 is fully inserted within the cavity 22.

[0064] Thus, the magnet holder 10 is first inserted linearly (non-rotationally) into the magnet receiving cavity 22 with the radial protrusions 16a, 16b aligned with the longitudinal channel 22'. Then, once the magnet 18 is fully inserted into the cavity 22, a user can engage the magnet holder 10 with the closure 20 by rotating the magnet holder 10 relative to the closure 20 such that the radial protrusions 16a, 16b move along the circumferential channel 23. In the illustrated example, the magnet holder 10 rotates clockwise relative to the closure 20 as viewed from above to perform the engagement process.

[0065] As shown, the circumferential channels 23 may each extend 90° around the cavity 22, such that the radial protrusions 16a, 16b reach a stop when the magnet holder 10 is rotated 90° relative to the closure 20. The circumferential channels 23 may incorporate small indentations or detents (or click) mechanisms to provide tactile feedback to the user when the radial protrusions 16a, 16b reach or approach the ends of their respective circumferential channels 23 and / or to lightly and reversibly lock the protrusions 16a, 16b at (or near) the ends of the circumferential channels 23. For example, in one embodiment, the mechanism may provide a "click" effect to the user that occurs when the magnet holder 10 is rotated 45° relative to the closure 20. Such a "click" effect may be caused by small protrusions (one on each radial protrusion 16a / 16b and one on each channel 23) passing each other and interfering momentarily as the magnet holder 10 is rotated.

[0066] Such operation of the magnet holding portion 10 and the closure portion 20 is performed by the user grasping the user-gripable portion 13 of the magnet holding portion 10 with one hand and the finger tabs 24a, 24b of the closure portion 20 with the other hand and moving the magnet holding portion 10 and the closure portion 20 relative to each other.

[0067] Figure 2 shows the underside of the closure 20 of Figure 1. The bead collection surface 26 on the underside of the bead collection platform 25 can be seen to have a raised outer rim 29 (the diameter of which is slightly larger than the remainder of the bead collection platform 25), a recessed or depressed area 28 for collecting magnetic beads during use, and an optional wicking member 27 (in this case in the form of a wicking spike) in the center.

[0068] The wicking spikes 27 help prevent fluid carryover and retention of liquid on the bead collection surface 26, particularly when the lid assembly 100 is being used to transfer magnetic beads from one sample tube to another (as in such cases it is generally undesirable for the beads to transfer any of the collected liquid). This effect is achieved by the wicking spikes 27 breaking the surface tension of any such liquid, forcing the liquid down onto the spikes 27 and encouraging the removal of the closure 20 and any beads retained thereon. No centrifugation is required to achieve this effect.

[0069] FIG. 3 shows an underside of variation 20' of the closure of FIG. 2. Variation 20' is the same as that of FIG. 2, but without the optional wicking member. Thus, closure 20' has a larger central concave or recessed area 28, potentially allowing for a greater amount of magnetic beads to be collected. Otherwise, closure 20' has the same features and functions as closure 20, and the two may in fact be used interchangeably. Thus, any subsequent references herein to closure 20 should be understood as encompassing the possibility of using closure 20' instead.

[0070] In an alternative variation to that shown in Figures 2 and 3, region 28 may have a convex (or dome-shaped) profile rather than a concave profile. Such a convex (or dome-shaped) profile may facilitate drying of the magnetic beads when collected on a surface by exposing the beads to more of the circulating ambient air.

[0071] 8 and 11, for example, the closure 20 includes means for removably attaching the closure 20 to the opening of the sample tube 30 to close the sample tube 30. In the illustrated embodiment, the means for removably attaching the closure 20 to the opening of the sample tube 30 is provided by a bead collection platform 25, which is shaped to fit snugly into the opening of the sample tube 30 in a broadly bung-like, press-fit manner, thereby allowing for quick and easy attachment (and subsequent removal) of the lid assembly 100 from the sample tube 30.

[0072] Sealing of the closure 20 with the opening in the sample tube 30 is also enhanced by a rim 29 of the bead collection surface 26 that has a slightly larger diameter than the remainder of the bead collection platform 25, forming a compression fit with the inner wall of the sample tube 30 in an essentially press-fit manner. The rim 29 therefore advantageously serves two functions: to retain the magnetic beads within the recessed area 28, and to form a compression fit with the inner wall of the sample tube 30.

[0073] Other variations of the closure 20 may provide alternative means for removably attaching the closure 20 to the opening of the sample tube 30. For example, the closure 20 may incorporate a snap-fit ​​feature or a thread arrangement for engaging with a complementary feature on the sample tube.

[0074] It will be appreciated that the bead collection platform 25 extending downward from the center of the top portion 21 has air all around it when the closure 20 is not attached to the sample tube 30. This allows the bead collection surface 26 to hold the magnetic beads 42 largely exposed to air upon removal from the sample tube (but still protected by the first and second finger tabs 24a, 24b that run parallel to the bead collection platform 25 but separate from it). This allows any liquid on the beads to evaporate quickly before resuspending the beads in the next liquid, thereby avoiding contamination of the next liquid with the previous liquid. Such evaporation typically takes only about 30 seconds and does not require additional drying equipment.

[0075] Furthermore, once the bead collection surface 26 is inserted into a subsequent sample tube 30, the unobstructed nature of the bead collection surface 26 allows the magnetic beads 42 to be easily removed from the lid assembly 10 and resuspended in the liquid contained within that subsequent tube 30 by gently shaking or inverting the tube in the absence of the magnet 18.

[0076] For example, with reference to Figures 4, 5, 8 and 10, the upper portion 21 of the closure portion 20 preferably has an elongated shape when viewed from above or below, allowing it to comfortably fit onto a sample tube 30 having a hinged cap 34 (see, e.g., Figure 8) without contaminating the hinge 36 or cap 34.

[0077] More specifically, as shown in Figures 4 and 5, the top 21 of the closure 20 may be in the shape of an elongated irregular hexagon when viewed from above or below, having two opposing sides formed by first and second finger tabs 24a, 24b, and four further sides 22a, 22b, 22c, 22d. Sides 22a and 22b, and similarly sides 22c and 22d, meet at an obtuse angle. This allows the closure 20, and indeed the entire lid assembly 100, to rest on its side on the surface 40 without rolling off, as shown in Figures 4 and 5. The illustrated elongated irregular hexagon is just one possible shape for the closure, although other shapes, such as a rectangle or semicircle, are also feasible.

[0078] 5 and 6 are views of the lid assembly 100 of FIGS. 1, 2 and 4, specifically with magnetic beads 42 present on the bead collection surface 26 within the recessed or welled area 28. The side view of FIG. 6 shows that the first and second finger tabs 24a, 24b can also be used as a stand to support the lid assembly 100 upright on the surface 40 on which it is standing. Thus, the first and second finger tabs 24a, 24b extend below the bead collection surface 26 (and beyond the wicking member 27) such that the magnetic beads 42 remain off the surface 40 and are not contaminated by the surface.

[0079] Thus, the first and second finger tabs 24a, 24b protect the magnetic beads 42 on the bead collection surface 26 from accidental contact with the surface 40 and (at least to some extent) the user's fingers.

[0080] When the magnet 18 is present (i.e., inserted into) the magnet receiving cavity 22, the magnet 18 can hold the magnetic beads against the bead collection surface 26. That is, the bead collection surface 26 can be used to collect the magnetic beads 42 suspended in the liquid in the sample tube 30. This is because under the influence of the magnetic field of the magnet, the magnetic beads 42 are attracted towards the magnet 18, resulting in the beads 42 being held against the bead collection surface 26.

[0081] Conversely, when the magnet 18 is not present within the magnet containing cavity 22 (i.e., not inserted therein or removed), the lid assembly 20 cannot magnetically hold the magnetic beads against the bead collecting surface 26 because there is no magnetic field as described above to attract the beads against the bead collecting surface 26. Thus, by removing the magnet 18 from the magnet containing cavity 22, the magnetic beads 42 held on the bead collecting surface 26 can be released from the bead collecting surface 26.

[0082] A strong magnet (i.e., one that generates a strong magnetic field), such as a neodymium magnet, is preferably used to maximize the pulling effect of magnet 18 (when inserted into cavity 22) on magnetic beads 42 and hold them against bead collection surface 26.

[0083] - Removal of the magnet holder 10 from the closure part 20 The magnet holder 10 can be disengaged and separated from the closure 20 by reversing the insertion and engagement process described above. Such a disengagement and separation process is illustrated in FIG. 7. First (a) the magnet holder 10 is rotated 90° counterclockwise relative to the closure 20 as indicated by arrow R to disengage the first and second radial projections 16a, 16b from the respective circumferential channels 23 and thus align the first and second radial projections 16a, 16b with the respective longitudinal channels 22′ (FIG. 1(d)). Next (b) the magnet holder 10 is lifted upwardly from the magnet receiving cavity 22 in the direction of arrow U. This results in (c) the magnet holder 10 being separated from the closure 20. As described above, the magnet holding portion 10 and the closure portion 20 are operated by the user grasping the user-gripable portion 13 of the magnet holding portion 10 with one hand and the finger tabs 24a, 24b of the closure portion 20 with the other hand, and moving the magnet holding portion 10 and the closure portion 20 relative to each other.

[0084] - attaching the lid assembly 100 to the sample tube 30 As shown in FIG. 8, the present lid assembly 100 can be attached to a sample tube 30, such as an Eppendorf tube (RTM). Such a tube 30 has a body including a straight region 31 and a tapered end region 32, with an opening 33 at the top surrounded by a rim 35. As shown, the sample tube 30 can have an openable cap 34 connected to the rim 35 of the tube by a flexible hinge 36. When in its closed position, the cap 34 seals the opening 33 of the tube. The cap 34 has a finger tab 37 that can prompt a user to open the cap, and an internal plug portion 38 that sits within the rim 35 of the tube when the cap is closed.

[0085] In use, to attach the lid assembly 100 to the tube 30, the cap 34 (if present) of the tube 30 is first opened, and then the lid assembly 100 is positioned in the direction of arrow D to engage the bead collection platform 25 in the opening 33 of the tube 30 in a press-fit manner, with the rim 29 of the bead collection surface 26 forming a compression fit with the inner wall of the tube 30. As shown in Figure 9, operation of the lid assembly 100 is accomplished by the user grasping the finger tabs 24a, 24b of the closure 20 with one hand and holding the tube 30 with the other hand, bringing the two together. It should be noted that this press-fit attachment method is quick and easy.

[0086] FIG. 10 illustrates the process of disengaging and separating the magnet holders 10 of the lid assembly 100 from their respective closures 20, while the closures 20 remain attached to the sample tubes 30. First (a) the magnet holder 10 is rotated 90° counterclockwise relative to the closures 20, as per arrow R, as described above in connection with FIG. 7. Then (b) the magnet holder 10 is retracted upwardly from the magnet receiving cavity 22, in the direction of arrow U, resulting in (c) the magnet holder 10 being separated from the closures 20. As described above, such manipulation of the magnet holders 10 and closures 20 is accomplished by a user grasping the user-graspable portion 13 of the magnet holder 10 with one hand and the finger tabs 24a, 24b of the closures 20 (with the closures 20 gripping the tubes 30) with the other hand, and moving the magnet holders 10 and closures 20 relative to one another.

[0087] Alternatively, the user can simply grasp the sample tube 30 (with the closure 20 attached) with one hand and rotate and retract the magnet holder 10 with the other. The reverse procedure can be employed when introducing and engaging the magnet holder 10 with the closure 20 on the sample tube 30 when in the field.

[0088] Figure 11 is a cross-sectional side view of (a) the disengagement process and (b) the separation process of Figure 10. Also noteworthy here are the cross-sectional shapes of magnet 18, bead collection platform 25, bead collection surface 26, and magnet receiving cavity 22.

[0089] It can be seen that the magnet 18 and magnet containing cavity 22 are sized such that when the magnet holder 10 is engaged with the closure 20, the magnet 18 touches (or is very close to) the bottom of the cavity 22. Furthermore, to allow the magnet 18 to be as close as possible to the bead collection surface 26, thereby maximizing the effect of the magnet's magnetic field on the magnetic beads 42 within the tube 30, it is preferred that the thickness of material between the bead collection surface 26 and the magnet containing cavity 22 be as thin as possible while at the same time maintaining a reliable level of strength and robustness.

[0090] Also visible is the cross-sectional profile of the bead collecting surface 26, with its raised outer rim 29, recessed or depression area 28 for collecting magnetic beads, and optional wicking member 27 in the center.

[0091] In alternative variations of the closure 20, the bead collecting surface 26 may have a flat profile or may be convex. Regardless of the overall profile of the bead collecting surface 26, yet another possibility is to incorporate therein an array of indentations or recesses where the magnetic beads 42 are attracted and held to the surface 26. This aims to achieve an even distribution of the beads across the bead collecting surface 26 so as to prevent the beads from clumping together, thereby improving their ability to dry and also facilitating their subsequent release from the surface 26 when the magnet 18 is removed.

[0092] kit 12-14, the present disclosure also provides a kit including a lid assembly 100 as described above, one or more sample tubes 30, and optionally a pipette 54 and / or a swab, and / or further sample collection tubes 55 (FIG. 13).

[0093] For example, FIG. 12 shows a kit 50 including a lid assembly 100, three sample tubes 30, and a pipette 54 (in this case, a precision volume pipette). The kit 50 includes an inexpensive but useful packaging tray 52 made of molded (e.g., thermoformed) plastic, which also serves as a stand for the sample tubes 30 and the lid assembly 100. More specifically, the tray 52 incorporates a number of dedicated recesses or cavities 51 (integrally formed into the tray molding) in which the sample tubes 30 are placed, and a dedicated recess 51' in which the lid assembly 100 is placed, thus holding the sample tubes 30 and the lid assembly 100 in an upright orientation, eliminating the need for additional laboratory equipment such as tube shelves. In fact, the kit does not even require a bench or table top, as it can in principle be used on any surface, including the user's lap when seated. The tray 52 also has an outwardly extending rim 53 which increases the overall rigidity of the tray 52 .

[0094] In this figure, the tubes 30 are subsequently labeled A, B and C, and these labels will be referenced when describing how such tubes can be used in conjunction with the lid assembly 100 to perform extraction of target biomolecules from a sample, for example using magnetic separation.

[0095] FIG. 13 is a perspective view of a variation 50′ of the kit of FIG. 12. As shown, the kit 50′ may further include (or be designed to accept) an additional sample collection tube 55, which may also function as a sample inactivation tube. An additional dedicated recess or cavity 51″ may be formed in the tray 52 to hold the tube 55 in an upright orientation. The tube 55 may be obtained externally rather than being provided as part of the kit 50′. By inserting the tube 55 into the dedicated recess or cavity 51″, the user can spatially correlate a given sample with the rest of the kit 50′, thus keeping all tubes of a given sample together and reducing the possibility of any mix-up with tubes from another nearby kit. It can also be seen that the kit 50' is shown with a removable backing sheet 58 (which may be cardboard or plastic) in place.

[0096] As shown in FIG. 14, such a kit may also include a removable cover 56, also made of molded (e.g., thermoformed) plastic, that extends over the tubes 30 and lid assembly 100 and other contents. The cover 56 has a rim 57 that is attached to a backing sheet 58 during manufacture and holds the rim 53 of the tray 52 against the backing sheet 58 for shipping purposes, keeping the components therein sterile and in place. The cover 56 also incorporates a molded feature 59 that fits around the magnet retaining portion 10 of the lid assembly 100 when the kit is closed and holds the lid assembly 100 in place during shipping. If removed during use, the cover 56 can function as a waste container or a temporary staging area for the sample tubes 30 and other contents of the kit once they have been used. As shown, the cover 56 incorporates a peel-off corner 57' that is part of the rim 57. Peel corner 57' is raised relative to the remainder of rim 57 to allow for easy opening and removal of cover 56 from backing sheet 58, thus opening the kit and releasing tray 52 for use. As will be appreciated by those skilled in the art, other means of removably attaching cover 56 to tray 52 are possible, such as by a snap-fit ​​mechanism between cover 56 and tray 52 that is integrally formed as part of the thermoforming process of cover 56 and tray 52.

[0097] As shown in FIG. 15, another kit 60 provided by the present disclosure includes a plurality of sample tubes 30 (in this case three) connected to each other side by side by connecting pieces 62. By connecting the tubes 30 to each other in this manner, stepwise processing of the magnetic beads from tube to tube can be facilitated. The kit 60 also includes a lid assembly 100 that can be used with any of the tubes 30 (conveniently by moving the lid assembly sequentially, i.e., from A to B, then to C, from tube to tube). Optionally, the last of the sample tubes 30 (in this case, tube C) may be connected to its adjacent tube (tube B) by a frangible connection 64 so that the last tube (C) can be easily detached from the other tubes and taken out separately for further processing. Of course, it will be understood that such frangible connections 64 can also be provided between any of the connected tubes 30, if necessary.

[0098] In all of the above kits (50, 50' and 60), the sample tubes 30 may be supplied already containing various liquids (examples of which are described below). Additionally, the liquid in the first sample tube 30 may be pre-loaded with magnetic beads 42.

[0099] However, if the long-term stability of the magnetic beads 42 in the liquid of the first sample tube 30 is an issue, only the magnetic beads 42 may be pre-filled in the first sample tube 30 and the liquid may be in a separate container. For example, the liquid may be provided in a separate tube (e.g., but not necessarily, a molded co-fill tube) or in a disposable tear-open sachet, capsule or blister pack from which the liquid may be transferred (e.g., squeezed) into the first sample tube 30 as needed. Such a blister pack may be provided pre-attached to the opening of the first sample tube 30, so that the user only needs to press the blister pack to rupture its underside (e.g., consisting of a film or foil) and release the liquid into the first sample tube 30 to mix with the magnetic beads 42. The blister pack can then be removed from the opening of the first sample tube 30.

[0100] Alternatively, the liquid in question may be provided in the first sample tube 30 and the magnetic beads 42 may be provided in a separate container, sachet, capsule, blister pack or molded co-fill tube, from which they may be transferred into the first sample tube 30 as required in a similar manner to the liquids described above. How to collect magnetic beads from liquid in a sample tube

[0101] 16, and initially referring to steps (a) through (f) thereof, the present disclosure provides a method of using the present lid assembly 100 to collect magnetic beads 42 from a liquid 44 in a sample tube 30 in which the beads 42 are suspended. For clarity, the reference numbers in FIG. 16 are not repeated for each step, but it should be understood that the same items are used for each step unless otherwise noted. Features of the lid assembly are referred to using the reference numbers assigned to the preceding drawings. The method will be described beginning with step (a) of FIG. 16, with respect to collecting magnetic beads 42 from liquid 44 in sample tube A.

[0102] As shown in step (a), the method first involves the user opening the sample tube 30 (if in fact the tube is closed by a cap; the method is equally applicable for use with tubes that do not have a cap and therefore are already open, in which case step (a) is omitted).

[0103] Next, as shown in step (b), the method includes attaching the closure portion 20 of the lid assembly 100 to the opening 33 of the sample tube 300, resulting in the configuration shown in step (c). As mentioned above, in a presently preferred embodiment, the attachment method is by engaging the bead collection platform 25 within the opening 33 of the tube 30 in a press-fit manner, with the rim 29 of the bead collection surface 26 forming a compression fit with the inner wall of the tube 30. It is noted that at this stage, the magnet holder 10, and more specifically the magnet 18, is inserted (and optionally locked, if a locking mechanism as described above is provided) into the magnet receiving cavity 22 of the closure portion 20.

[0104] Next, as shown in step (d), the method includes gently agitating the liquid 44, for example by gently inverting the sample tube 30 or gently shaking the liquid 44, so that the magnetic beads 44 come into contact with the bead collection surface 26 and are held against the bead collection surface 26 by the magnet 18. The illustration of step (d) shows the tilt of the magnetic beads 42 concentrating towards the bead collection surface 26. In practice, the process of collecting the magnetic beads 42 on the bead collection surface 26 takes several seconds.

[0105] Next, as shown in step (e), the magnetic beads 42 are collected on the bead collecting surface 26 of the lid assembly. As a result, the liquid in the tube is now clear (i.e., bead free).

[0106] Now referring to steps (f) onwards, the method may further include a step of the user removing the lid assembly 100 from the sample tube A with the magnet 18 still inserted into the magnet storage cavity 22 and the magnetic beads 42 held against the bead collection surface 26 by the magnet 18.

[0107] Sample tube A may be considered to be the first sample tube, and the liquid 44 contained therein may be considered to be the first liquid. There may be at least a second sample tube 30 (herein designated sample tube B) containing a second liquid 46 from which it is desired to release and resuspend the magnetic beads 42. Thus, the method may further comprise the step of opening sample tube B (if sample tube B is in fact closed, as shown in step (g)) and then attaching the closure 20 of the lid assembly 100 to the opening 33 of the second sample tube (tube B) containing the second liquid 46, as shown in step (h). At this stage, the magnetic beads 42 remain held against the bead collecting surface 26 of the lid assembly 100.

[0108] Then, as shown in steps (i) and (j), to release the magnetic beads 42 from the bead capture surface 26, the method further includes the user removing the magnet 18 from the magnet receiving cavity 22 such that the magnetic beads 42 are no longer held by the magnet 18 against the bead capture surface 26. As outlined above with reference to Figures 10 and 11, removing the magnet 18 may require the user to first rotate the magnet holder 10 (e.g., in a counterclockwise direction R) as shown in step (i), and then retract the magnet holder 10 upwards (in the U direction) to separate it from the closure 20. At this stage, since the magnet 18 is not present, the magnetic beads 42 are no longer magnetically held against the bead capture surface 26.

[0109] To resuspend the magnetic beads 42 in the second liquid 46, as shown in step (k), the user can gently agitate the liquid 46, for example by gently inverting the sample tube B or gently shaking the liquid 46, so that the magnetic beads 42 come into contact with the liquid 46, are swept away from the bead collection surface 26, and are resuspended in the liquid. At this stage, it is possible that at least some of the beads 42 will fall into the liquid 46 without such agitation of the liquid being required, but resuspension of the beads 42 in the liquid 46 will be more rapid and complete if such agitation is performed. This results in the configuration shown in step (l), where the magnetic beads 42 are suspended in the second liquid 46 in tube B.

[0110] It will be appreciated that the above method can be continued by extracting the magnetic beads 42 from tube B and transferring them to a third sample tube (e.g., tube C as exemplified in the kit) containing a third liquid, and so forth. Thus, following step (l) above, the method comprises: reinserting the magnet 18 into the magnet cavity 22; agitating the second liquid 46 such that the magnetic beads 42 contact the bead collection surface 26 and are held against the bead collection surface 26 by the magnet 18; removing the lid assembly 100 from the second sample tube (Tube B) with the magnet inserted 18 into the magnet receiving cavity 22 and the magnetic beads 42 held against the bead collection surface 26 by the magnet; attaching the closure portion 20 of the lid assembly 100 to the opening of a third sample tube (tube C) containing a third liquid; The method further includes a step of removing the magnet 18 from the magnet storage cavity 22 such that the magnetic beads 42 are no longer held against the bead capture surface 26 by the magnet 18 and are suspended in the third liquid (after the third liquid has been agitated against the bead capture surface 26, if necessary).

[0111] It will be appreciated that the above method can be quickly and easily performed, particularly considering the press-fit manner in which the lid assembly 100 is attached to a variety of sample tubes 30 and the corresponding ease with which the lid assembly 100 can be removed from the sample tubes, and further considering the simple manner in which the magnet holder 10 can be removed from or attached to the closure portion 20.

[0112] The ease of use of the device is further enhanced by the tray 52, which acts as a stand for the various components during use, thus facilitating a completely manual use of the components without the need for other tube shelves or stands, and eliminating the need for the user to place anything on an external surface. This is particularly important when the tubes are in the open state, during transfer of magnetic beads, as placing open tubes on an external surface increases the risk of contamination of the contents. The device, including the tray / stand 52, also advantageously facilitates one-handed use of the device, which can be beneficial at times.

[0113] Method for extracting target biomolecules from a sample using magnetic separation - Patents.com To illustrate the advantages of the lid assembly 100 of the present invention and the above method in a practical situation, a method for performing extraction of target biomolecules from a liquid (or solid) sample using magnetic separation is described using the present lid assembly 100 and magnetic beads 42 (in this case, particularly magnetic nanoparticles). The method is described again with reference to FIG.

[0114] To first summarize the method, target biomolecules such as DNA / RNA / proteins are first released from the sample via a lysis buffer and then bound to magnetic nanoparticles with a binding buffer. These beads are then washed using a washing solution to remove contaminants / chemicals from the previous step as well as undesired biological molecules. Once the beads are washed, the purified analytes are eluted (released) from the beads via an elution buffer (e.g., molecular grade water, or Tris-EDTA (TE) buffer). The eluted analytes (e.g., RNA) can then be used for downstream molecular applications such as polymerase chain reaction (PCR) processing, isothermal amplification, etc., according to the user's requirements. It will be understood that "Tris" is an abbreviation for tris(hydroxymethyl)aminomethane and EDTA is an abbreviation for ethylenediaminetetraacetic acid.

[0115] Thus, to carry out the method, a first, second and third sample tube (e.g., tubes A, B and C of the above kit) containing a first, second and third liquid, respectively, are used. In a general sense, the first liquid is a lysis / binding buffer for dissolving the target biomolecules, thereby releasing them into solution, and binding the biomolecules to the magnetic beads. The second liquid is a washing liquid. The third liquid is an elution liquid for eluting the biomolecules. In more detail, and referring to FIG. 16, the method includes the following steps.

[0116] Preliminary Step 1: A biological sample (e.g., nasal secretions suspected of containing viral particles such as SARS-CoV-2 particles) is collected using a nasopharyngeal swab and placed into a sample collection tube 55 (e.g., a so-called eNAT(RTM) tube) containing an inactivation buffer.

[0117] Preliminary Step 2: A pipette 54 (which may advantageously be a disposable pipette of precise volume) is used to transfer a volume of inactivation buffer containing the virus particles eluted from the swab from the sample collection tube 55 to the first sample tube 30, i.e., tube A in FIG. 16, and the mixture is gently shaken. Tube A is pre-filled with a lysis / binding buffer (e.g., based on guanidinium thiocyanate, optionally including a solvent such as isopropanol or ethanol), and magnetic beads 42, which now also contain the virus particles eluted from the swab. The magnetic beads 42 have a silica coating that binds to nucleic acid from the virus particles.

[0118] Now referring to FIG. Step (a): Open the lid of tube A. Step (b): Lift the lid assembly 100 (with the magnet holder 10 engaged with the closure 20) onto the tube A. Step (c): Attach the lid assembly 100 to the tube A. Step (d): Gently invert tube A with lid assembly 100 attached to collect magnetic beads 42 onto bead collection surface 26 via magnetic attraction. Step (e): The magnetic beads 42 are collected on the bead collecting surface 26 of the lid assembly 100. As a result, the liquid in the tube is now clear (bead free). Step (f): The lid assembly 100 holding the magnetic beads 42 is removed from tube A. Step (g): Open the second sample tube 30, i.e. tube B in Figure 16. Tube B contains a washing solution (e.g. a solution of 80% ethanol). Step (h): The lid assembly 100 holding the magnetic beads 42 is attached to tube B. Steps (i) and (j): The magnet retaining portion 10 is disengaged and removed from the closure portion 20 so that the magnetic beads 42 are no longer magnetically retained against the bead collection surface 26 . Step (k): The magnetic beads 42 are released from the bead collection surface 26 and resuspended in a wash solution by gently inverting or shaking tube B, thereby washing the beads and removing contaminants / chemicals from the previous step and undesired biological molecules, resulting in the configuration shown in step (l).

[0119] Following step (l), the method further comprises the steps of:

[0120] Step (m): The magnet holder 10 is reinserted into the magnet receiving cavity 22 of the closure part 20 (still attached to tube B). Step (n): Gently invert tube B with lid assembly 100 attached to collect magnetic beads 42 onto bead collection surface 26 via magnetic attraction. Step (o): The lid assembly 100 holding the magnetic beads 42 is removed from tube B. Step (p): The magnetic beads 42 on the removed lid assembly 100 are exposed to air for 30 seconds to allow the washing solution (in this case an ethanol solution) to evaporate. If a kit 50 as shown in Figure 12 is used, the lid assembly 100 is advantageously placed in a dedicated recess 51' at this stage to allow the magnetic beads 42 to dry whilst keeping the lid assembly 100 and the beads 42 away from potential sources of contamination. Step (q): The lid assembly 100 holding the magnetic beads 42 is attached to the opening of the third sample tube (tube C) containing the eluate. Step (r): The magnet holder 10 is disengaged and removed from the closure 20, so that the magnetic beads 42 are no longer magnetically held against the bead collection surface 26. Step (s): The magnetic beads 42 are detached from the bead collection surface 26 and resuspended in the elution solution by gently inverting tube C, causing elution of the analyte of interest (e.g., RNA characteristic of the viral particle) for subsequent processing.

[0121] Optionally, to remove the magnetic beads 42 from the eluate, the method may further comprise the following additional steps.

[0122] Step (t): Reinsert the magnet holder 10 into the magnet receiving cavity 22 of the closure 20 (still attached to the tube C) and extract the magnetic beads 42 from the eluate by gently inverting the tube C, thereby recovering the magnetic beads 42 on the bead collection surface 26 via magnetic adsorption. As a result, only the eluted analyte (e.g., the characteristic RNA of the virus particle) remains in the eluate for further processing. Step (u): The lid assembly 100 can now be removed from the tube C and discarded along with the used magnetic beads 42. The magnet holder 10 may be stored and reused if desired.

[0123] The entire process from sample (e.g., nasopharyngeal swab, saliva or blood) to extracted RNA can be performed in less than 5 minutes by a virtually untrained user at the point-of-care.

[0124] -Experimental verification of the above method The above technique was experimentally implemented and a comparative study was performed using the "gold standard" column-based extraction method from Qiagen: QIAamp viral RNA mini kit. 7 A total of six samples containing 1000 PFU / mL of IgG were analyzed by both methods, and the extracted RNA was quantified by E gene-targeted RT-qPCR. Recovery results averaged 3 × 100 for the Qiagen kit and our technique, respectively. 10 and 1.4 × 10 10 These promising results demonstrate that the frugal, fast and easy extraction method of the present invention can compete very favorably with traditional laboratory-based extraction techniques that require expensive equipment and electricity and incur delays of over 30 minutes.

[0125] Advantages of the above method and device Traditionally, sample preparation plays a key role in analytical science. The present method overcomes limitations associated with existing expensive, time-consuming, and complex molecular extraction kits by providing a new approach that allows for a rapid (less than 5 minutes) extraction process of different molecules from different sources of clinical samples (e.g., different types of swabs and biological samples). The presently disclosed method and device provide a cost-effective, robust, and safe kit suitable for disposable use, requiring minimal steps / time and reagents, no centrifugation or vortexing, no electricity, no expensive equipment, no detailed pre-training, and easily implementable in low-resource or remote settings. These and other advantages are obtained by:

[0126] Use of the above-described controllable, magnetizable lid assembly 100 for disposable (e.g., Eppendorf (RTM)) sample tubes to collect magnetic beads 42 and transport target particles attached to the magnetic beads through one or more subsequent sample preparation steps (e.g., lysis / binding, washing, elution). · Lid assembly that can fit any tube type (e.g., screw top, snap top, etc.) or size (e.g., 0.5ml, 1ml, 1.5ml, etc.). A removable magnet 18 from the closure 20 to allow easy resuspension of the beads at each step if necessary. · The ability to move magnetic beads 42 through multiple pre-filled tubes, rather than adding / removing chemicals or solutions to / from a single tube containing the beads. · Design of the lid assembly to protect the magnetic beads 42 from accidental surface or user contact (eg, as shown in Figures 5 and 6). Optional inclusion of wicking members (eg, wicking spikes) on the bead collection surface 26 to prevent liquid retention due to surface tension.

[0127] In comparison to existing technology, the use of the present lid assembly achieves or enables the following: Eliminates the need for electrical equipment (centrifuges, vortex mixers, mains heaters, safety cabinets, etc.). Eliminates the need for expensive micropipettes to transfer liquids. · No need to use silica-based membranes to purify the product. Reduce the minimum extraction time from at least 30 minutes required by commercially available kits to less than 5 minutes. Eliminates the need for a laboratory-based environment and mains power, and can therefore be used as a point-of-care extraction method in remote locations. With the kit as currently described (where the package / tray acts as the stand), no other tube shelves or stands are required and the user does not need to place anything on the external surface, thus reducing the risk of contamination of the testing equipment and liquids. In fact, the kit does not even require a bench or table top, as it can in principle be used on any surface, including the user's lap when seated. The kit is best stored at room temperature (no freezer required). - Extraction does not require highly skilled personnel. Extremely frugal, typically less than GBP 1 per sample.

[0128] Modifications, Alternatives and Accessories Detailed embodiments and several possible alternatives have been described above. As will be appreciated by those skilled in the art, several modifications and further alternatives can be made to the above embodiments and still benefit from the invention embodied therein.

[0129] In the above-described embodiment of the lid assembly 100, the magnet holder 10 is completely separable from the closure portion 20 and insertable into the magnet receiving cavity 22 of the closure portion 20, with the magnet 18 positioned closely behind the bead collection surface 26 to attract the magnetic beads 42 toward and onto the bead collection surface 26.

[0130] However, alternative configurations of the lid assembly may be envisaged that are still based on the principle of having a magnet close to the rear side of the bead collection surface to attract magnetic beads to the front (liquid-facing) side of the bead collection surface when required, and moving the magnet away from the rear side of the bead collection surface when there is no need to attract beads to the surface (i.e. when the magnetic beads are to be released).

[0131] For example, the magnet need not be part of a completely separable magnet holder. Instead, the magnet or magnet holder can remain coupled to the closure while being controllably movable toward or away from the rear side of the bead collection surface. In one such example, the magnet holder may be tethered to the closure. In another example, the detachability of the magnet holder from the closure may be limited by a constraint mechanism while still allowing the magnet holder to move toward or away from the rear side of the bead collection surface. Such movement may be (but need not be) linear. For example, in another variation, the magnet may be movable toward or away from the rear side of the bead collection surface by a rocker switch mechanism. Another arrangement for controllably advancing or retracting the magnet relative to the rear side of the bead collection surface can use a push button mechanism broadly similar to that of a retractable ballpoint pen.

[0132] In the above-described embodiment of the lid assembly 100, the engagement process between the magnet holder 10 and the closure portion 20 includes linearly inserting the magnet holder 10 into the cavity 22 of the closure portion 20 and then rotating the magnet holder 10 relative to the closure portion 20 (e.g., up to 90°) to engage the first and second radial protrusions 16a, 16b along their respective circumferential channels 23.

[0133] However, as shown in FIG. 17, a variation of the lid assembly 100a may omit the rotational engagement principle and related features and use only linear insertion to engage the magnet holder 10a with the closure part 20a (as indicated by the double arrow in FIG. 17(a)). Thus, the shaft 14 of the magnet holder 10a is smooth and lacks the radial protrusions 16a, 16b of FIG. 1. Similarly, as shown in FIG. 17(b) and FIG. 17(c), the magnet receiving cavity 22 of the closure part 20a lacks the circumferential channel 23 of FIG. 1. However, to provide a constant engagement, the closure part 20a may incorporate gripping means (in this case longitudinal protrusions / ridges 47) within the magnet receiving cavity 22 for gripping the magnet holder 10a. In all other material respects, the features of the lid assembly 100a are the same as those of the lid assembly 100 described above (e.g., as shown in FIG. 1).

[0134] For devices in which rotational engagement between the magnet holder 10 and the closure 20 is not required, the shaft 14 of the magnet holder 10 need not be cylindrical, but may instead have a cross-sectional shape that does not permit rotation (e.g., a square shape).

[0135] It should also be noted that even with the above-described lid assembly 100 providing for linear insertion and subsequent rotational engagement of the magnet holder 10 and closure 20, the rotation step can be omitted after the magnet 18 is inserted into the cavity 22 if the user so desires, e.g., to further expedite the process. However, under such circumstances, the user should be careful to avoid the magnet holder accidentally coming off the closure 20 at an inopportune moment, e.g., by applying gentle pressure on the magnet holder 10 to hold it in place.

[0136] 18 shows (a) an engaged cross-sectional view and (b) a disengaged perspective view of another variation 100b of the lid assembly of FIG. 1, in which the magnet holder 10b and the closure 20b include interengageable threads 48 (which may optionally be multi-start threads). In all other material respects, the features of the lid assembly 100b are the same as those of the lid assembly 100 described above (e.g., shown in FIG. 1).

[0137] With respect to the above-described embodiment of the lid assembly 100, it has been described that the first and second finger tabs 24a, 24b extend below the bead collecting surface 26 and thus can be used as a stand to support the lid assembly 100 in an upright orientation on the surface 40 (as shown in FIG. 6). However, under some circumstances, it may be advantageous to be able to support the lid assembly upside down, with a sample tube 30 attached, for example, to allow gravity to assist in the collection of the magnetic beads 42 on the bead collecting surface 26. To this end, FIG. 19 shows another variation 100c of the lid assembly of FIG. 1, in which the first and second finger tabs 24a′, 24b′ of the closure portion 20c extend both below and above the bead collecting surface 26 to an extent sufficient to act as a stand to support the lid assembly 100c upside down, with a sample tube 30 attached (as well as, alternatively, in an upright position without a sample tube attached). In all other material respects, the features of the lid assembly 100c are the same as those of the lid assembly 100 (eg, shown in FIG. 1) described above.

[0138] In yet another variation (not shown), the first and second finger tabs of the closure may extend only above the bead collection surface (i.e., the opposite side of FIG. 6 ) to an extent sufficient to function as a stand that can only support the lid assembly upside down (optionally with a sample tube attached).

[0139] Figure 20 shows another variation 100d of the lid assembly of Figure 1, where the user-gripable portion 13' of the magnet holder 10' has a wide cross-sectional profile (in this case, cross-shaped) such that it can act as a stand for supporting the magnet holder 10' upside down. This is instead of the user-gripable portion 13 of Figure 1, which has a relatively thin and flat shape and is not suitable for stably supporting the magnet holder 10 upside down and without assistance. Preferably, as shown in Figure 20, the cross-sectional profile of the illustrated variation of the user-gripable portion 13' provides a sufficiently stable stand so that it can also support the attached closure 20 and attached sample tube 30 upside down if required.

[0140] -Modified sample tubes and methods of use As shown in Figures 21 and 22, the present disclosure also provides a modified sample tube 30' that is a variation of the sample tube 30 described above.

[0141] Similar to conventional sample tubes as described above, modified sample tube 30' has a body including a straight region 31 and a tapered end region 32, with an opening 33 at the top surrounded by a rim 35. (It will be understood that other geometries of modified sample tube 30' are possible, i.e., it need not necessarily have a straight region 31 or a tapered end region 32 as shown.) Sample tube 30' further comprises an openable cap 34 connected to the tube's rim 35 by a flexible hinge 36. Cap 34 has a tab 37 that can prompt a user to open the cap.

[0142] However, in contrast to conventional sample tubes, the cap 34 of the modified sample tube 30' further comprises a compartment 38' housing a quantity of reagent (which may be in the form of beads 70 or tablets, as shown). The compartment 38' has a removable cover 39, for example made of foil or plastic film, which seals the contents of the compartment 38'. The cover 39 may be provided with an integral pull-out tab 39' which initially folds over the remainder of the cover 39 to allow quick and easy removal of the cover 39 when required. It will be appreciated that the compartment 38' is inside the cap 34 and is located within the rim 35 of the tube 30' when the cap is closed.

[0143] Reagents (e.g., beads 70) are inserted into compartment 38' at the manufacturing facility and cover 39 is attached. During manufacturing, compartment 38' may be sealed by cover 39, preferably in a low oxygen environment to maximize reagent longevity.

[0144] As shown, the reagent may advantageously be in the form of beads 70 or tablets, which facilitates loading of the reagent into compartment 38', allows for long-term room temperature storage, and allows the reagent to pass as a unit out of compartment 38' into the body of the tube. However, alternatively, the reagent may be in the form of a dry powder, or a liquid or gel.

[0145] The reagent may be loose within the compartment 38' such that in use, when the cover 39 is removed from the compartment 38' and the cap 34 is closed over the opening 33 of the tube 30', the reagent will simply fall into the body of the tube and into any liquid therein. Such falling of the reagent may be facilitated if the reagent is in the form of beads 70 or tablets, as outlined above.

[0146] Alternatively, if the reagent is in the form of beads 70 or tablets (or chunks), it can be securely mounted within the compartment 38', for example by press-fitting it into a molded recess in the compartment 38', thereby preventing the reagent beads 70 from inadvertently falling out of the compartment (e.g. onto the floor) when the cover 39 is removed and the cap 34 is moved to its closed position. Once the cover 39 is removed from the compartment 38' and the cap 34 is closed onto the body of the tube 30, the user may need to use such a press-fitted amount of reagent to flush / dissolve the reagent beads 70 from the compartment 38' using the liquid in the tube by inverting the tube 30'.

[0147] The reagent (e.g., beads 70) may be any chemical entity, although following the methods described above in which magnetic separation is used to extract a target biomolecule (such as RNA characteristic of a particular virus) from a sample, the reagent may usefully be a lyophilized colorimetric detection reagent that may be introduced into an eluate containing (or potentially containing) the eluted target biomolecule and determine the presence or absence of the target biomolecule via colorimetric analysis.

[0148] Thus, in the above method, tube C (containing the eluate) may be a modified sample tube 30' and the reagent beads 70 are freeze-dried colorimetric detection reagent, preferably in bead or tablet form. Such a tube C, pre-filled with eluate and pre-prepared with freeze-dried colorimetric detection reagent beads 70 in a sealed compartment 38' inside the cap 34 of the tube, may form part of one of the kits mentioned above (e.g., as shown in Figures 12-15).

[0149] FIG. 23 illustrates this colorimetric analysis process. As step (a), the reagent beads 70 are released from the cap compartment 38' of the sample tube 30', so that as step (b), the reagent beads 70 enter the elution fluid 72 in the body of the sample tube. At this stage, the reagent beads 70 rapidly dissolve and mix with the elution fluid 72. It will be appreciated that all the chemical species required to perform nucleic acid amplification (e.g., PCR or LAMP) of a target biomolecule (e.g., viral RNA) now exist and, with this work, can be provided in kit form suitable for use in remote locations by substantially untrained users.

[0150] To allow the colorimetric amplification process to occur, it may be necessary to heat the contents of sample tube 30', for example to about 63° C., and hold at such temperature for a period of time, such as about 20 minutes. This will amplify the target nucleic acid, if present, thereby causing the liquid to change color. This is shown as step (d) in FIG. 23. On the other hand, if the target nucleic acid is not present, no amplification occurs and, as a result, the color of the liquid does not change, as shown as step (c) in Figure 23.

[0151] When performed in a remote location away from a power source, the heating can be provided by a chemical heat pack (e.g., which is "snapped" to activate, causing an exothermic reaction and releasing heat) or by a small battery- or solar-powered heater block into which the sample tube 30' can be inserted. It will therefore be appreciated that all aspects of the present disclosure are suitable for use in remote locations.

[0152] -reagent More generally, the reagents described above (eg, beads 70) may include a variety of chemical or other species (eg, enzymes, primers, etc.) required for a variety of nucleic acid amplification methods, and mixtures thereof.

[0153] For example, nucleic acid amplification methods may include polymerase chain reaction (PCR), reverse transcription PCR (RT-PCR), quantitative PCR (qPCR), reverse transcription qPCR (RT-qPCR), nested PCR, multiplex PCR, asymmetric PCR, touchdown PCR, random primer PCR, hemi-nested PCR, polymerase cycling assembly (PCA), colony PCR, ligase chain reaction (LCR), digital PCR, methylation specific PCR (MSP), co-amplification PCR at low denaturation temperature (COLD-PCR), allele specific PCR, intersequence specific PCR (ISS-PCR), whole genome amplification (WGA), inverse PCR, or thermal asymmetric interlaced PCR (TAIL-PCR). In some embodiments, the nucleic acid amplification reaction can be a nucleic acid isothermal amplification method. Isothermal amplification is a form of nucleic acid amplification that does not rely on thermal denaturation of the target nucleic acid during the amplification reaction and therefore does not require multiple rapid temperature changes. Therefore, isothermal nucleic acid amplification methods can be performed inside or outside a laboratory environment. Many 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 amplification (RPA), rolling circle amplification (RCA), lamination 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-amplified sequence replication (3SR), genomic exponential amplification reaction (GEAR) and isothermal multiple displacement amplification (IMDA). Further examples of such amplification chemistries are described, for example, in "Isothermal Nucleic Acid Amplification Technologies for Point-of-Care Diagnostics: A Critical Review" (Pascal Craw and Wamadeva Balachandrana Lab Chip, 2012, 12, 2469-2486, DOI:10.1039 / C2LC40100b).

[0154] In certain currently preferred embodiments, the reagents (e.g., beads 70) may include components to make any of the amplification chemistries described above compatible with pH-based or colorimetric detection (e.g., pH-LAMP). This may be accomplished, for example, by reducing the buffer capacity (perhaps by the absence of Tris-HCl). The reagents (eg, beads 70) may include a wide range of chemistries for visual (or other) detection of the target species that provide an indication of amplification.

[0155] For example, in certain embodiments, an amplification indicator can be an organic or inorganic compound that is added to a nucleic acid amplification reaction mixture such that the content of the solution (such as, for example, the presence or absence of a particular nucleic acid) can be visually determined.

[0156] In certain embodiments, the amplified indicator material may be a metal ion indicator (also called a complexometric or metallochromic indicator), which is a metal ion indicator that is capable of reacting with an uncomplexed indicator (e.g., Ca 2+ , Mg 2+ , Zn 2+ The term "color change agent" refers to a material that changes color after forming a metal ion complex having a color different from the color of the metal ion (such as, but not limited to, other metal ions).

[0157] Other amplification indicator substances well known to those skilled in the art are possible, such as, but not limited to, Hydroxynaphthol Blue, Eriochrome Black t, Calmagite, Curcumin, Fast Sulfone Black, Hematoxylin, Murexide, Xylenone 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.

[0158] In other embodiments, the amplified indicator material may be a pH indicator. As one of ordinary skill in the art will appreciate, pH indicators react with hydronium ions (HO + ) or hydrogen ion (H + ) is a chemical detector for detecting the presence of a substance. Typically, indicators change the color of a solution depending on the pH. Indicators can also indicate a change in other physical properties. For example, olfactory indicators show a change in their smell.

[0159] Other possible amplification indicator substances include, but are not limited to, for example, 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, azolithin red, bromocresol purple, bromothymol blue, phenol red, neutral red, naphtholphthalein, cresol red, cresolphthalein, phenolphthalein, thymolphthalein, alizarin yellow R yellow, and indigo carmine.

[0160] In other embodiments, the amplified indicator material may be a redox indicator (also called an oxidation-reduction indicator), which is an indicator dye that undergoes a distinct color change at a specific electrode potential. There are two general types of redox indicators: pH-independent redox indicators and pH-dependent redox indicators.

[0161] pH-independent redox indicators include, but are not limited to, 2,2'-bipyridine, nitrophenanthroline, N-phenylanthranilic acid, 1,10-phenanthroline iron(II) sulfate complex, N-ethoxychrysoidine, 2,2'-bipyridine, 5,6-dimethylphenanthroline, o-dianisidine, sodium diphenylamine sulfonate, diphenylbenzidine, diphenylamine, and viologens.

[0162] pH-dependent redox indicators include, but are not limited to, sodium 2,6-dibromophenol-indophenol, sodium o-cresol indophenol, thionine, methylene blue, indigo tetrasulfonic acid, indigo trisulfonic acid, indigo carmine, indigo monosulfonic acid, phenosafranine, safranine and neutral red.

[0163] While in the above discussion the reagent is described as being in the form of beads 70 attached to the cap section 38' of the modified sample tube 30', it will be understood that a quantity of the reagent (e.g., in the form of beads 70) may be provided in other ways for introduction into the elution fluid at the appropriate time. For example, the reagent beads 70 (or a quantity of the reagent in another form) may be provided in a separate tube (e.g., but not necessarily, a molded-to-fill tube), container or tear-off packet / sachet, which may be opened at the appropriate time to allow the reagent to be transferred into the sample tube containing the elution fluid. Such a tube, container or tear-off packet / sachet containing the reagent may be provided as part of one of the kits described herein.

[0164] -Handheld device for manually stirring or inverting multiple sample tubes Finally, in practice, it may be desirable to manually agitate or invert multiple sample tubes 30 / 30' simultaneously (with or without the lid assembly 100 attached) to save time. To accomplish this, FIG. 24 shows a handheld device 80 for holding multiple sample tubes 30 / 30' and manually agitating or inverting them simultaneously without the need for electrical power. One such sample tube 30 is shown held in place with the lid assembly 100 attached.

[0165] More specifically, the device 80 comprises a handle portion 82 and a number of sample tube retaining clips 84 for holding respective sample tubes 30 / 30'. The number of retaining clips 84 are attached to cross members 86 that extend perpendicular to and on either side of the handle portion 82.

[0166] The device 80 further includes a plurality of restraining arms 88, each extending above a respective one of the retaining clips 84. The restraining arms 88 help prevent the sample tubes 80 / 80′ from falling out of the retaining clips 84 when the device 80 is inverted.

[0167] 24, it can be seen that each restraining arm 88 is offset to one side of a respective retaining clip 84 in order to accommodate the sample tube 80 / 80' to which the lid assembly 100 is attached. By being so offset (and referring back to FIG. 1, for example), each restraining arm 88 does not contaminate the magnet retaining portion 10 (specifically, the user-gripable portion 13) of the lid assembly 100, but instead acts on one side of the magnet retaining portion 10 against the top 21 of the closure portion 20.

[0168] The device 80, including the retaining clips 84 and restraining arms 88, can be formed as a unitary structure from a plastic material, for example by injection molding or three-dimensional printing. Although the illustrated device 80 is shown as having the capacity to support nine sample tubes 80 / 80', this is by way of example only and other numbers of retaining clips 84 and restraining arms 88 are of course possible.

[0169] Accordingly, the present disclosure also provides a manual method of simultaneously agitating or inverting multiple sample tubes 30 / 30' comprising inserting the sample tubes 30 / 30' into the apparatus 80 and manipulating the handle portion 82 to simultaneously agitate or invert the tubes. Optionally, at least one of the sample tubes may be attached to the lid assembly 100 described above. Also, optionally, at least one of the sample tubes may be the modified sample tube 30' described above. It will be appreciated that no power is required to perform this manual method of simultaneously agitating or inverting sample tubes 30 / 30' and thus is suitable for use in remote locations or low resource settings.

Claims

1. 1. A lid assembly for a sample tube for collecting magnetic beads from a sample tube and subsequently releasing said beads, comprising: The lid assembly includes: A closure, means for removably attaching said closure to the opening of said sample tube in use to close said sample tube; a bead collection platform arranged to be located within the opening of the sample tube when the closure is attached to the sample tube, the bead collection platform having a bead collection surface on one side for contacting liquid in the sample tube during use, and a magnet receiving cavity on the other side behind the bead collection surface; a closure portion including a magnet holder comprising a magnet, the magnet being removably insertable into the magnet containing cavity toward the bead collecting surface such that when the magnet is present in the magnet containing cavity, the magnet can hold magnetic beads against the bead collecting surface, and when the magnet is not present in the magnet containing cavity, the lid assembly cannot magnetically hold magnetic beads against the bead collecting surface; the means for removably attaching the closure to the opening of the sample tube comprises a press-fit fitting adapted to engage the opening of the sample tube in use; the press-fit fitting is the bead collection platform; Lid assembly for sample tubes.

2. The magnet holding portion is separable from the closing portion, Alternatively, the magnet holder is coupled to the closure while allowing the magnet to move within the magnet receiving cavity toward or away from the bead collecting surface.

3. The magnet holding portion further comprises a user-grippable portion to which the magnet is attached; 3. A lid assembly according to claim 1 or claim 2, optionally wherein the user-gripable portion has a cross-sectional profile configured to support the magnet retaining portion in an upside-down orientation.

4. The magnet storage cavity is in the form of a socket shaped to receive at least the magnet of the magnet holding portion; A lid assembly according to any one of claims 1 to 3, optionally wherein the magnet holder is rotatable within the socket.

5. When the magnet is inserted into the magnet storage cavity, the magnet holding portion and the closing portion are engageable with each other; Optionally, said magnet retaining portion comprises one or more radial protrusions, and said socket comprises one or more complementary channels with which said one or more radial protrusions are engageable; or Alternatively, the magnet retaining portion and the socket include threads engageable with each other.

6. A lid assembly as described in claim 4, wherein the socket is provided with a gripping means for gripping the magnet holding portion.

7. The closure portion includes first and second finger tabs on opposite sides of the closure portion for allowing the closure portion to be grasped by a user's thumb and finger during use; Optionally, the first and second finger tabs extend below the bead collection surface and can function as a stand to support the lid assembly in an upright orientation when separated from the closure; Optionally, the first and second finger tabs extend above the bead collection surface and can function as a stand for supporting the lid assembly in an upside-down orientation; 7. The lid assembly of claim 1, wherein optionally, the bead collection platform extends parallel to and separate from the first and second finger tabs.

8. The bead collection surface incorporates a concave or recessed area; Alternatively, the bead collection surface is convex, or Alternatively, the lid assembly of any one of claims 1 to 7, wherein the bead collection surface incorporates an array of indentations or recesses.

9. A lid assembly described in any one of claims 1 to 8, wherein the bead collection surface incorporates a fluid wicking member.

10. A kit comprising a lid assembly as described in any one of claims 1 to 9, at least a first sample tube, and optionally a pipette, and / or a swab, and / or a further sample collection tube.

11. A method for collecting magnetic beads from a liquid in a sample tube, the method comprising: - attaching the closure of a lid assembly according to any one of claims 1 to 9 or the closure of a lid assembly of a kit according to claim 10 to an opening of the sample tube; agitating the liquid while the magnet is inserted into the magnet cavity such that the magnetic beads contact the bead collection surface and are held against the bead collection surface by the magnet; 1. A method for collecting magnetic beads from a liquid in a sample tube, comprising:

12. The sample tube is a first sample tube containing a first liquid, and the method comprises: removing the lid assembly from the first sample tube with the magnet inserted into the magnet cavity and the magnetic beads held by the magnet against the bead collection surface; attaching the closure of the lid assembly to the opening of a second sample tube containing a second liquid; removing the magnet from the magnet receiving cavity such that the magnetic beads are no longer held against the bead collection surface by the magnet and are suspended in the second liquid; The method of claim 11 , comprising:

13. Reinserting the magnet into the magnet cavity; agitating the second liquid such that the magnetic beads contact the bead collection surface and are held by the magnet against the bead collection surface; removing the lid assembly from the second sample tube with the magnet inserted into the magnet cavity and the magnetic beads held by the magnet against the bead collection surface; attaching the closure portion of the lid assembly to the opening of a third sample tube containing a third liquid; removing the magnet from the magnet receiving cavity such that the magnetic beads are no longer held against the bead collection surface by the magnet and are suspended in the third liquid; The method of claim 12 further comprising:

14. Reinserting the magnet into the magnet cavity; agitating the third liquid such that the magnetic beads contact the bead collection surface and are held by the magnet against the bead collection surface; removing the lid assembly from the third sample tube with the magnet inserted into the magnet cavity and the magnetic beads held by the magnet against the bead collection surface; then, optionally, positioning the lid assembly and / or the magnetic beads; The method of claim 13 further comprising:

15. For the extraction of a target biomolecule, the first liquid is a lysis / binding buffer for binding the biomolecule to the magnetic beads; the second liquid is a cleaning liquid; and the third liquid is an elution liquid for eluting the biomolecule, Optionally, the target biomolecule comprises a nucleic acid; Optionally, the method further comprises introducing a detection reagent into the elution solution and applying heat, if necessary, to determine the presence or absence of the target biomolecule.

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