Mechanical lysis and magnetic capture device

Abstract

The invention relates to a device (1) for the mechanical lysis and magnetic capture of nucleic acids in a sample, comprising at least: a rod (2) extending along a longitudinal axis X-X, the rod having a distal end (2a) and a proximal end (2b), an end piece (3) configured to be positioned at least partially on the distal end (2a) of the rod (2), the end piece (3) being intended to be dipped into a solution (20) containing at least the sample and one or more mechanical lysis elements (110), characterised in that the device (1) further comprises at least one rotation member for rotation about the axis X-X, the rotation member (4) being configured to co-operate with the end piece (3) and the end piece (3) having an outer surface on which at least one raised area (3a) is provided, and in that the rod (2) is at least partially magnetised.

Description

[0001] Title: Mechanical lysis and magnetic capture device

[0002] Technical field of the invention

[0003] The invention relates to the technical field of molecular biology and more particularly to systems for extracting nucleic acids from samples containing at least one analyte.

[0004] Technological background of the invention

[0005] In extraction systems, the cells of the sample are lysed to extract the DNA, and then the nucleic acids are captured to perform the tests.

[0006] Lysis can be mechanical, chemical, or a combination of both. Various techniques can be used for lysis purposes, for example, grinding with solid elements, high-pressure homogenization, ultrasonication, osmotic shock, freeze / thaw lysis, and the use of chemical compounds.

[0007] More specifically, lysis by grinding is a technique that destroys the cell wall using shear stress created by solid elements, preferably beads. These beads can be made of glass, silica, ceramic, zirconium, or metal, and may or may not be magnetic. They are agitated in a sealed container in the presence of the cells to be ground. The agitation can be internal or external to the container and generated by blades, magnetization, or a vortex, for example.

[0008] For nucleic acid capture, other types of beads are most often used. For example, silica-coated magnetic beads are used, which can be manipulated with a magnet. The magnetic particles are washed using discontinuous magnetization. This is followed by an elution phase, at the end of which the nucleic acids are detached.

[0009] In summary, in one case (lysis) the cell wall is fragmented and the DNA is released; in the other case (capture), the beads are designed to bind to nucleic acids and allow them to be isolated. With these conventional techniques, it is possible to extract nucleic acids repeatedly and reliably.

[0010] Object of the invention

[0011] The object of the invention is to improve these classical techniques in order to obtain faster and more efficient extraction without altering the nucleic acids.

[0012] To this end, the invention relates to a device for the mechanical lysis and magnetic capture of nucleic acids in a sample comprising at least:

[0013] A stem extending along a longitudinal axis XX, the stem having a distal end and a proximal end,

[0014] A tip configured to be positioned at least partially on the distal end of the rod, said tip being intended to be immersed in a solution containing at least the sample and one or more mechanical lysis elements, characterized in that the device further comprises at least one drive member rotating about the axis XX, said drive member being configured to cooperate with the tip, said tip having an external surface on which at least one relief is provided, and in that the rod is magnetized at least partially.

[0015] Advantageously, rotating the textured tip within the solution allows for more efficient agitation of the solution and lysis elements, thus shortening the lysis time. The magnetization of the rod enables accelerated capture of the lysis elements or, subsequently, the magnetic particles. Furthermore, the textured surface of the tip causes random movement of the lysis elements within the solution, improving lysis efficiency.

[0016] According to one feature of the invention, the tip includes a distal end called the tip, the relief extending from the tip over at least a part of the length of the tip between 20 and 30 mm, preferably 25 mm.

[0017] According to one feature of the invention, the relief is a rib.

[0018] According to one feature of the invention, the tip comprises a plurality of raised areas spaced apart from each other. According to another feature of the invention, the raised areas are spaced apart from each other and distributed radially, either randomly or symmetrically, around the circumference of the tip.

[0019] According to one feature of the invention, the relief(s) has a width greater than or equal to 0.6mm.

[0020] According to one feature of the invention, the relief(s) are continuous or discontinuous.

[0021] According to one feature of the invention, the relief(s) are rectilinear or helical.

[0022] According to one feature of the invention, the rotation speed of the nozzle is between 1000 and 4000 rpm and preferably between 3000 rpm.

[0023] According to one feature of the invention, the rod is translationally movable within the nozzle along the longitudinal axis XX. The movement of the rod within the nozzle allows, in particular, the variation of the magnetic field. Advantageously, the rod is inserted into the nozzle during the capture of the magnetic beads and is withdrawn before the beads are released.

[0024] In other words, the stem relative to the tip comprises at least two distinct positions, among which:

[0025] - a retracted position where the stem is positioned in the upper part of the tip and

[0026] - an operating position where the rod is positioned in the lower part of the nozzle.

[0027] In the retracted position, the balls are released and escape the magnetic field. In the operating position, the balls are subjected to the magnetic field: capture is activated.

[0028] According to one feature of the invention, in a first configuration, the magnetized part of the rod is entirely covered by the tip.

[0029] According to one feature of the invention, the magnetized portion of the rod is equal to or less than the length of the tip. According to another feature of the invention, in a second configuration, the magnetized portion of the rod is entirely outside the tip, thus allowing the release of the captured lysis elements.

[0030] According to one feature of the invention, the rod is partially magnetized along a portion of its length. Advantageously, the magnetized rod is arranged in such a way as to spread the lysis elements on the tip, thereby improving the washing of said lysis elements or the capture of nucleic acids.

[0031] Preferably, at least the distal end of the rod is magnetized.

[0032] According to one feature of the invention, the length of the magnetic portion of the rod is such that it prevents the lysis elements from coming into contact with the aluminum seal of the well containing the solution, and prevents the lysis elements from contacting the inner wall of the well when the tip and rod are outside the well. In fact, the length of the magnetic portion represents approximately 50% of the total length of the rod, and the length of the magnetic portion is between 10 mm and 25 mm.

[0033] Advantageously, the shape of the rod, its magnetic strength and its type of magnetization impact the speed and aggregation shape of the captured lysis elements.

[0034] According to one feature of the invention, the magnetization of the rod is diametrically oriented. Thus, the attraction surface is larger than with the use of an axially magnetized magnet, resulting in a significant reduction in capture time. Furthermore, the orientation of the magnetization allows for the homogeneous distribution of the magnetic lysis elements or magnetic particles across the entire surface of the tip where the rod is located. This distribution improves the washing efficiency of the beads or particles (provided the particles are not released in another washing method) and consequently reduces the time required for this step in nucleic acid extraction.

[0035] The invention also relates to a mechanical lysis and magnetic capture system comprising at least one device according to the invention and at least one lysis element. According to one feature of the invention, the system further comprises at least one well containing a solution to be lysed, including at least the sample.

[0036] Advantageously, the lysis elements are configured to be captured on the outer surface of the tip by the magnetic force of the rod positioned inside the tip.

[0037] According to one feature of the invention, the lysis elements comprise at least one magnetic ball. According to a first alternative, the lysis elements contain only magnetic balls.

[0038] According to one feature of the invention, the lysis elements comprise at least one non-magnetic bead. According to another feature of the invention, the lysis elements are a mixture of magnetic and non-magnetic beads.

[0039] According to one feature of the invention, the lysis elements can be zirconium beads, magnetic zirconium, glass, ferromagnetic, etc.

[0040] According to one feature of the invention, the lysis elements have a diameter between 100 µm and 1000 µm. Advantageously, the diameter of the lysis elements may differ from one lysis element to another, or at least one lysis element may have a diameter different from the others, or all the lysis elements may have the same diameter.

[0041] According to one feature of the invention, at least one well is equipped with a splash guard to prevent splashing during the solution lysis phase. Indeed, the rotation of the tip during mechanical lysis could generate spills causing cross-contamination of the other wells being treated nearby.

[0042] According to one feature of the invention, the nozzle has a slightly conical upper portion. During rotation, the upper portion of the nozzle is positioned within the upper portion of the lysis well. The clearance between the nozzle and the well is such that, during rotation of the nozzle, the liquid present in the well cannot escape.

[0043] Brief description of the figures

[0044] The invention will be better understood from the following description, which relates to an embodiment of the present invention, given by way of non-limiting example and explained with reference to the accompanying schematic figures. The accompanying schematic figures are listed below:

[0045] [Fig. 1] is a perspective view of the device according to the invention,

[0046] [Fig. 2] is a longitudinal cross-sectional view along the XX axis of the device illustrated in figure 1,

[0047] [Fig. 3] is a longitudinal cross-sectional view along the XX axis of the tip of the device according to the invention,

[0048] [Fig. 4] is a perspective view of the stem of the device according to the invention,

[0049] [Fig. 5] is a schematic view of the mechanical lysis using the device according to the invention,

[0050] [Fig. 6] is a schematic view of the magnetic capture using the device according to the invention,

[0051] [Fig. 7] is a succession of diagrams (a) to (i) illustrating the extraction algorithm,

[0052] [Fig. 8] is a perspective view of the system according to the invention,

[0053] [Fig. 9] is a perspective view of a detail of the system according to the invention.

[0054] Detailed description

[0055] The device according to the invention is a mechanical lysis and magnetic capture device 1 comprising at least one rod 2 extending along a longitudinal axis X-X, the rod 2 having a distal end 2a and a proximal end 2b, as illustrated in Figures 2 and 4.

[0056] According to the invention, the rod 2 is magnetized at least partially.

[0057] In a preferred embodiment, illustrated in Figure 4, the rod 2 is advantageously magnetized at the distal end 2a and on a portion of an intermediate part 2c extending between the two ends 2a, 2b of the rod 2.

[0058] In an alternative not shown, the rod 2 is magnetized only on the distal end 2a. In a preferred embodiment, the magnetization of the rod is oriented diametrically as can be seen in Figure 4. More specifically in Figure 4, the hatched area referenced N indicates magnetic North and the unhatched area referenced S indicates magnetic South.

[0059] According to the invention, and as illustrated in Figures 1, 2, and 3, the device 1 comprises a tip 3 configured to be positioned at least partially at the distal end 2a of the stem 2, as can be seen, for example, in Figures 1 and 2. The tip 3 of the device 1 advantageously has one or more ridges 3a. The ridges 3a extend, as illustrated in Figure 1, longitudinally over a portion of the tip 3, preferably over a distal end of the tip 3. The ridges 3a are in the form of fins or protrusions. In the example illustrated in Figure 1, the ridges 3a are fins distributed regularly around the circumference of the distal end of the tip 3. Other distributions are possible, and the number of ridges is not limited to the illustrated example.

[0060] Furthermore, according to the invention, the rod 2 is movable in translation along the longitudinal axis XX in the end piece 3.

[0061] The device 1 according to the invention further comprises at least one drive member 4 rotatable about the axis XX, said drive member 4 being configured to cooperate with the nozzle 3 as shown in Figures 1 and 2 (the nozzle 3 is preferably fixed to the drive member 4). The drive member 4 includes a through hole allowing the rod 2 to pass through said drive member 4. Thus, the rod 2 slides within the drive member 4 and consequently within the nozzle 3. Advantageously, the drive member 4 is mounted on a pipette 5 illustrated in Figures 8 and 9.

[0062] The drive element 4 can be mobile in rotation around the axis XX, which consequently drives the tip 3 in rotation.

[0063] The drive element 4 moves in translation along the X axis and consequently the tip 3 and the rod 2 move simultaneously in translation along the XX axis.

[0064] In Figure 7(a), for the purpose of mechanical lysis, the lysis buffer taken from well 109 is mixed with the sample to be lysed from well 107. Then, in Figure 7(b), device 1, and in particular tip 3, is immersed in the solution 20 obtained in Figure (a), and a first mechanical lysis is performed. Well 107 also contains at least one lysis element 110, and preferably a plurality. In Figure 7(c) and Figure 6, a magnetic field is applied, attracting the lysis elements 110 to tip 3 of device 1. The lysis elements 110 aggregate around tip 3, preferably towards the distal end of tip 3. Device 1 is then removed from well 108 and transferred (Figure 7(d)) ​​to extraction well 107 (Figure 7(e)). The lysis elements 110 are released into the extraction well 107 and the device 1 is rotated so as to agitate the lysis elements 110 present in the solution 20 as illustrated in Figure 7(f).Thanks to the ribs 3a of device 1, the lysis elements 110 have a more random trajectory and with more energy, which improves lysis. During lysis, the rod 2 is positioned at least partially in the tip 3, the magnetized part (2a and / or 2c) of the rod 2 being completely covered by the tip 3. In Figure 7(g), a magnetic field is applied to recover the lysis elements 110, which are then transported (translation of the rod 2 and the tip 3 with the lysis elements 110 on the tip 3) into a well 104 for one or more successive washes (Figure 7(i)).

[0065] The device 1 according to the invention is integrated into a mechanical lysis and magnetic capture system 100 according to the invention. The system 100 may comprise a plurality of devices 1 according to the invention.

[0066] Each device 1 of the system conforms to what has been described previously. If the system 100 comprises several devices 1, these are arranged to satisfy the configuration of the well support 105 shown in particular in Figure 8.

[0067] According to the invention, the system 100 also includes at least one lysis element 110 and preferably a plurality of lysis elements 110. In the illustrated example, the lysis elements 110 are balls. The lysis elements 110 are configured to be captured on the outer surface of the tip 3 by the magnetic force of the rod 2 positioned inside the tip 3 as illustrated in Figure 6.

[0068] Furthermore, the system 100 includes at least one well 104 in which the lysis of the solution 20 to be lysed and the magnetic capture of the nucleic acids from said solution 20 are carried out. More particularly, the well is part of a well holder 105 comprising a plurality of wells 104. Advantageously, at least one well 104 is equipped with a splash guard. Advantageously, the splash guard may be in the form of a plate adapted to the geometry of the well holder and the configuration of the wells within the well holder. Of course, this shape of the guard may be different without departing from the scope of the invention.

[0069] Of course, the invention is not limited to the embodiments described and shown in the accompanying figures. Modifications remain possible, particularly with regard to the composition of the various elements or by substitution of technical equivalents, without departing from the scope of protection of the invention.

Claims

DEMANDS 1. Device (1) for mechanical lysis and magnetic capture of nucleic acids in a sample comprising at least: a rod (2) extending along a longitudinal axis XX, the rod having a distal end (2a) and a proximal end (2b), a tip (3) configured to be positioned at least partially on the distal end (2a) of the rod (2), said tip (3) being intended to be immersed in a solution (20) containing at least the sample and one or more mechanical lysis elements (110), characterized in that the device (1) further comprises at least one drive member rotating about the axis XX, said drive member (4) being configured to cooperate with the tip (3), said tip (3) having an external surface on which is provided at least one relief (3a), and in that the rod (2) is magnetized at least partially.

2. Device according to claim 1, wherein the tip (3) comprises a distal end (2a) referred to as the tip, the relief (3a) extending from the tip (2a) over at least a portion of the length of the tip (3).

3. Device according to any one of claims 1 or 2, wherein the relief (3a) is a rib.

4. Device according to any one of claims 1 to 3, the tip (3) comprises a plurality of reliefs (3a) spaced apart from each other.

5. Device according to any one of claims 1 to 4, the rod (2) is movable in translation in the tip (3) along the longitudinal axis XX.

6. Device according to any one of claims 1 to 5, in a first position, the rod (2) is positioned partially in the tip (3), the magnetized part of the rod being entirely covered by the tip.

7. Device according to claim 6, in a second position, the magnetized part of the rod (2) is entirely out of the tip (3).

8. Device according to any one of claims 1 to 7, the magnetization of the rod (2) is oriented diametrically.

9. Mechanical lysis and magnetic capture system (100) comprising at least one device (1) according to any one of claims 1 to 8 and at least one lysis element (110).

10. System according to claim 9, comprising at least one well (104) in which is present a solution (20) to be lysed comprising at least the sample.

11. System according to claim 10, wherein at least one well (104) is equipped with an anti-splash seal.

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