Biological sample processing device

Abstract

The purpose of this invention is to provide a biological sample processing device capable of recovering the eluent as the final product with a high recovery rate. In the biological sample processing device of this invention, a pipette performs a suction operation while the tip of the pipette is in contact with the magnetic microbeads. After the pipette has aspirated the biological sample, there is a waiting time sufficient for the magnetic microbeads to be discharged from the pipette using a magnet (see Figure 6).

Description

Technical Field

[0001] This invention relates to a technique for processing biological samples containing nucleic acids and magnetic particles. Background Technology

[0002] In recent years, information obtained from nucleic acid analysis, such as cancer genome screening using next-generation sequencing (NGS) systems, has been applied in various fields including medical treatment, clinical testing, pharmaceuticals, and the food industry. In this nucleic acid analysis, nucleic acids must be extracted from various biological samples, such as blood, tissues, and cultured cells, as a pretreatment step.

[0003] Methods for nucleic acid extraction are generally based on the property of nucleic acids binding to silica in the presence of a dissociative agent or in the presence of an organic solvent, rather than using harmful organic solvents such as phenol or chloroform. Using the above methods, we report a nucleic acid extraction method using a nucleic acid capture pipette tip with a silica-containing solid phase built in as a nucleic acid capture carrier, and a method using magnetic microbeads (nucleic acid capture carriers) with a surface covered by silica. These methods include a binding step where nucleic acids bind to the nucleic acid capture carrier, and an elution step where nucleic acids are eluted from the nucleic acid capture carrier using an elution buffer.

[0004] The method using magnetic microbeads involves recovering the magnetic microbeads from the eluent using a magnet after the elution process. As an example, one method involves drawing the eluent containing magnetic microbeads into a dispensing pipette tip, using a magnet to retain the magnetic microbeads within the tip, and then ejecting only the eluent from the tip. Another example is the recovery of magnetic microbeads from the eluent by inserting a covered rod-shaped magnet into the eluent containing the magnetic microbeads.

[0005] Patent Document 1 describes a method for efficiently collecting magnetic microbeads by temporarily collecting them on the wall of a container and then recovering them using a magnetic rod. Patent Document 2 describes an example of extracting nucleic acids from a large volume (2 mL) of sample using a coarser magnetic comb and a finer magnetic comb, following the steps shown in Figure 23. Patent Document 3 describes the collection of magnetic particles from a liquid containing magnetic particles using a dispensing machine that aspirates and sprays the liquid, rather than performing the collection on the side of the container holding the sample.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: US6020211

[0009] Patent Document 2: US2022 / 0176369A1

[0010] Patent Document 3: Japanese Patent No. 3115501 Summary of the Invention

[0011] The problem that the invention aims to solve

[0012] As an example of a biological sample processing device, a nucleic acid extraction device is envisioned. For this device, especially in the examination using liquid biological samples, it is also envisioned that it may be necessary to extract genes from a relatively large volume of sample (several mL to tens of mL). Furthermore, considering subsequent examination procedures, the volume of the extracted sample is preferably concentrated to at least a small amount (tens of μL).

[0013] When the sample volume is large, the corresponding volume of reagents, including magnetic microbeads, also increases. After capturing nucleic acids from the sample, the magnetic microbeads undergo a washing process and are then placed in an eluent, where they are removed after nucleic acid extraction. When removing the magnetic microbeads from the eluent, if a magnetic rod is used, the rod is placed in the eluent, and the magnetic microbeads are attracted by the magnet at the tip of the rod. The rod is then pulled out. However, because the eluent is being recovered while the magnetic microbeads are still adsorbed with eluent, a significant amount of eluent is lost during recovery.

[0014] To address this issue, for example, as shown in Figure 23 of Patent Document 2, there is a method for elution treatment involving two nucleic acid extractions. This method involves, for example, temporarily eluting the nucleic acid in a medium volume (several hundred μL) of elution buffer, binding it again with a small amount of magnetic microbeads, and then eluting the nucleic acid in a small volume (several hundred μL) of elution buffer. This method involves two separate adsorption (magnetic collection) and elution processes for nucleic acid and magnetic particles, which may result in losses during intermediate steps, raising concerns about reduced nucleic acid recovery rates. Furthermore, the processing time is also increased.

[0015] The present invention was made in view of the above-mentioned problems, and its object is to provide a biological sample processing device that can recover the eluent as the final product with a high recovery rate.

[0016] Solution for solving the problem

[0017] In the biological sample processing apparatus of the present invention, the pipette performs a suction action while the tip of the pipette is in contact with the magnetic microbeads, and after the pipette has aspirated the biological sample, there is a waiting time sufficient for the magnetic microbeads in the pipette to be discharged out of the pipette by the magnet.

[0018] The effects of the invention are as follows.

[0019] According to the biological sample processing apparatus of the present invention, a biological sample processing apparatus is provided that can recover the eluent as the final product in high yield. As a result, the recovery rate of the eluent final product (nucleic acid, etc.) is also increased, and for example, improved accuracy of post-processing testing can be expected. Attached Figure Description

[0020] Figure 1 This is a perspective view of the biological sample processing device 1 according to Embodiment 1.

[0021] Figure 2 This is a diagram showing the detailed structure of each element of the biological sample processing device 1.

[0022] Figure 3 It is a diagram illustrating the stirring action.

[0023] Figure 4 It is a diagram illustrating the action of a magnetizer.

[0024] Figure 5 This is a flowchart of the recovery process of the washing solution after the washing and extraction process.

[0025] Figure 6 This diagram illustrates the suction action of the eluent during the recovery process.

[0026] Figure 7 This is a graph showing the pressure shift measured by the pressure sensor on the pipette during eluent recovery.

[0027] Figure 8 This diagram illustrates the loss of recovered eluent in existing biological sample processing devices.

[0028] Figure 9 This is a side view illustrating the set position used during the recovery operation of the eluent in Embodiment 2.

[0029] Figure 10 This is a flowchart of the recovery process of the eluent after the washing and extraction process in Implementation Method 2.

[0030] Figure 11 This diagram illustrates the suction action of the eluent during the recovery process.

[0031] Figure 12 This is a diagram showing the pipette unit 200 of the biological sample processing device 1 according to Embodiment 3. Detailed Implementation

[0032] <Implementation Method 1>

[0033] Figure 1This is a perspective view of the biological sample processing apparatus 1 according to Embodiment 1 of the present invention. In Embodiment 1, the present invention is applied to a nucleic acid extraction apparatus as a biological sample processing apparatus. The biological sample processing apparatus 1 is an apparatus for extracting nucleic acids from samples containing nucleic acids and magnetic particles. The biological sample processing apparatus 1 consists of a magnetic rod unit 100, a pipette unit 200, a container delivery unit 300, and a bottom magnet unit 400. The horizontal movement motor 206, the pipette up-and-down movement motor 204, and the container movement motor 305 will be described below.

[0034] Figure 2 This diagram shows the detailed structure of each element of the biological sample processing device 1. The magnetic rod unit 100 is a unit that moves the magnetic rod 101 and magnetic rod cover 102 vertically (Z-axis direction in the diagram) to stir the sample within the container and recover the magnetic microspheres contained within the sample. The front end or the entire magnetic rod 101 is made of neodymium magnet, and the magnetic force acts in the vertical direction (Z-axis direction in the diagram), enabling the collection of magnetic microspheres from the liquid. The magnetic rod cover 102 is hollow in shape, allowing the magnetic rod 101 to be inserted inside, and is made of resin (such as polypropylene). The inner diameter of the magnetic rod cover 102 is the same as the outer diameter of the magnetic rod 101.

[0035] The magnetic rod unit 100 includes a magnetic rod 101, a magnetic rod cover 102, a magnetic rod drive motor 103 for driving the above components, and a magnetic rod cover drive motor 104. Thus, since the magnetic rod 101 and the magnetic rod cover 102 are each equipped with a drive motor, the magnetic rod 101 and the magnetic rod cover 102 can be driven independently.

[0036] The pipette unit 200 is a unit equipped with a pipette for aspirating and dispensing samples. This unit includes a plunger 201 for generating aspiration pressure and a plunger drive motor 202 for actuating the plunger 201. The plunger drive motor 202 is controlled by a controller (not shown), whose speed can be arbitrarily set and changed, allowing for adjustments to the pipette's aspiration speed according to the situation.

[0037] The pipette unit 200 also includes a pressure sensor 203 for measuring the aspiration pressure of the pipette. The pressure sensor 203 can measure the internal pressure of the pipette, enabling real-time measurement of the aspiration pressure during aspiration. Furthermore, the measured pressure data is sent to a processing unit (not shown) for use in controlling the various motors. The pipette unit 200 also includes a pipette up-and-down movement motor 204 for moving the pipette up and down along the Z direction in the figure.

[0038] In this embodiment, the pipette unit 200 includes a pipette that can be moved along the Y direction by the horizontal movement motor 206, enabling it to access all containers. The number of pipettes is arbitrary, and multiple pipettes may also be provided.

[0039] The container conveying unit 300 is a unit for moving the container holding the sample in the horizontal direction (X-axis direction) according to each process. The container conveying unit 300 includes a container support 304 for supporting the container and a container moving motor 305 for moving the container support 304 and each container.

[0040] The biological sample processing device 1 has three types of containers for processing: a large container 301, a medium container 302, and a small container 303. These containers are arranged at certain intervals in the X and Y directions in the figure.

[0041] The bottom magnet unit 400 is a unit used to bring the magnet into contact with and separate it from the bottom of the container holding the sample. In this embodiment, the bottom magnet unit 400 is provided in two locations. Each bottom magnet unit 400 is constructed, for example, using a bottom magnet 401 made of neodymium magnet and an actuator 402 for moving it up and down in the vertical direction (Z-axis direction in the figure). When the bottom magnet 401 approaches the bottom surface of the container, the bottom magnet 401 can magnetize the magnetic beads onto the bottom surface of the container.

[0042] One of the two bottom magnet units 400 is located directly below the magnetic rod 101 and magnetic rod cover 102 of the magnetic rod unit 100, and can be used when the magnetic rod unit 100 processes samples. The other is located directly below the pipette tip 205 of the pipette unit 200, and can be used when the pipette unit 200 processes samples.

[0043] In the biological sample processing device 1, the stirring action of the liquid in the stirring container is performed by moving the magnetic rod unit 100 up and down, the magnetic collection action of collecting and recovering the magnetic microspheres present in the liquid is performed by using the magnetic rod 101, and the release action of releasing the recovered magnetic microspheres back into the liquid is performed.

[0044] The processing of the magnetic rod unit 100 is carried out by moving the container, which is the object of processing, in the horizontal direction (X direction in the figure) directly below the magnetic rod 101 and the magnetic rod cover 102, and by moving the magnetic rod 101 or the magnetic rod cover 102 up and down.

[0045] Figure 3 This is a diagram illustrating the action of stirring. Stirring is the action of agitating a solution within a container, such as... Figure 3 As shown, this is done by simply inserting the magnetic rod cover 102 into the container and moving it up and down.

[0046] Figure 4 This diagram illustrates the magnetic collecting action. The magnetic collecting action involves using the magnetic rod 101 to collect and retrieve the magnetic microspheres. At this time, as... Figure 4As shown, with the magnetic rod 101 inserted into the magnetic rod cover 102 in a manner where the solution and magnetic microbeads do not directly contact the magnetic rod 101, the magnetic rod cover 102 and the magnetic rod 101 move up and down simultaneously in the container liquid to stir the sample solution and capture the magnetic microbeads. More preferably, the magnetic rod 101 is moved up and down while the bottom magnet 401 is brought close to the wall (bottom) of the container, thereby capturing the magnetic microbeads at both the container wall (bottom) and the magnetic rod 101, thus improving the capture efficiency.

[0047] The release action is the action of releasing the magnetic microspheres captured by the magnetic rod 101 into the solution. This action is performed when magnetic microspheres, magnetized by the container of the moving source, are placed into the container of the moving destination during the transfer of magnetic microspheres between containers. With the magnetic microspheres magnetized by the magnetic rod 101, the magnetic rod 101 and the magnetic rod cover 102 are placed into the solution, and then only the magnetic rod 101 is removed. Thus, the magnetic force does not act on the front end of the magnetic rod cover 102, and the magnetized magnetic microspheres are released into the liquid. Furthermore, in this state, the magnetic rod cover 102 can be moved up and down in the liquid to shake off the magnetic microspheres attached to its front end. Alternatively, the bottom magnet 401 can be used to attract the magnetic microspheres to the bottom of the container, causing the magnetic microspheres to separate from the magnetic rod cover 102.

[0048] In order to extract nucleic acids from the sample, the biological sample processing device 1 performs the following three steps (1) to (3).

[0049] (1) Binding process: The process of binding nucleic acids present in the sample with magnetic microbeads. Magnetic microbeads are added to a large quantity of liquid sample (whole blood, plasma, serum, etc.) in a large container 301. The amount of magnetic microbeads added depends on the amount of liquid sample, but generally, the amount added increases when the sample quantity is large. Furthermore, reagents that promote the binding of the nucleic acids to the magnetic microbeads are added as needed. Then, the sample solution is stirred using a magnetic rod cover 102 to bind the magnetic microbeads with the biological material. After the magnetic microbeads have fully bound to the nucleic acids, the magnetic microbeads in the liquid are collected and recovered.

[0050] (2) Cleaning step: This step involves cleaning the magnetic beads bound to nucleic acids and removing non-specific contaminants from the magnetic beads. The magnetic beads bound to nucleic acids are added to a container 302 containing cleaning reagents and stirred. There are no particular limitations on the cleaning reagents; for example, any reagent that can maintain the binding of nucleic acids to the nucleic acid capture carrier and remove the reagents and impurities added in step 1 from the nucleic acid capture carrier is acceptable. For example, low-molecular-weight alcohols, low-molecular-weight ketones, or other organic compounds can be used. Alternatively, ethanol, isopropanol, etc., can be used as cleaning reagents; ethanol with a concentration of 70% or higher is particularly preferred. After cleaning the magnetic rod cover 102 and the magnetic beads, the alcohol components are dried to prevent the cleaning solution from contaminating the nucleic acid eluent in the next step. There are no restrictions on the drying method; the alcohol components are evaporated by leaving the magnetic rod cover 102, with the magnetic rod 101 inserted, above the cleaning container.

[0051] (3) Eluting process: The process of eluting and washing the nucleic acid, which has been captured and bound to the magnetic microbeads, from the sample into the elution buffer. The elution buffer is sent to the subsequent testing process, so a small amount is generally preferred, which is assumed to be about 30 μL to 50 μL here. After the washing process, the magnetic microbeads that have been magnetized are released into a small container 303, which is then immersed in a container containing the nucleic acid elution buffer and stirred in this state. Thus, the nucleic acid is eluted into the nucleic acid elution buffer.

[0052] After elution, the sample liquid contains the nucleic acid to be tested, and the eluent is recovered. At this point, since the unwanted magnetic beads are immersed in the eluent, they need to be removed. The magnetic beads in the solution are bound in a large volume of liquid and are present in large quantities. The following describes the operation for recovering a small amount of eluent containing the aforementioned large number of magnetic beads. The recovery of the eluent is performed using a pipette unit 200.

[0053] Figure 5 This is a flowchart of the recovery process of the washing solution after the washing and extraction process. Figure 6 This diagram illustrates the aspiration action of the eluent during the recovery process. To recover the eluent adsorbed onto the magnetic microbeads, the biological sample processing device 1 performs an aspiration action with the tip of the pipette tip 205 in contact with the surface of the magnetic microbeads 303B collected and deposited at the bottom of the small container 303 by the bottom magnet 401. The recovery process will be explained below with reference to the above-described diagram.

[0054] Figure 6(1): Immediately after the washing and extraction process is completed, the magnetic microspheres are in a state of floating and dispersing in the washing liquid. Therefore, before the suction of the washing liquid begins, the bottom magnet 401 is brought into contact with the bottom of the small container 303 and left for a predetermined time. Thus, the magnetic microspheres 303B are magnetized at the bottom of the small container 303 (bottom magnet placed ~ waiting for predetermined time).

[0055] Figure 6 (2): Lower the pipette and check that the eluent 303L at the tip of the pipette tip 205 contacts the liquid surface (pipettes descent ~ liquid surface detection). After detection, begin aspiration of the eluent (start aspiration (aspiration speed v1)). The volume of liquid to be recovered is preset, but the count of the aspirated volume of the eluent begins when aspiration starts (start aspiration volume counting). This aspiration volume count can also be specified, for example, by the amount of plunger movement. In this case, the plunger is generally driven by a stepper motor, and the drive pulse of the stepper motor can be preset according to the aspiration volume.

[0056] While continuously aspirating the eluent, the pipette tip 205 continues to descend. The descent speed is determined by the aspiration speed and the shape of the container, and is set to be greater than the speed at which the liquid level drops due to aspiration. In this way, the pipette tip 205 descends in accordance with the drop in liquid level caused by aspiration, thereby preventing the tip from being exposed to air and accidentally aspirating air due to the drop in liquid level.

[0057] Figure 6 (3): Then, detect the contact between the tip of the pipette tip 205 and the upper surface of the magnetic microbeads 303B that are magnetized by the bottom magnet 401 and accumulated at the bottom of the small container 303. When the detection occurs, stop the descent of the pipette (microbead detection ~ stop pipette descent).

[0058] At this moment, the tip of the pipette tip 205 contacts the upper surface of the magnetic microspheres 303B. At this position, the plunger speed is reduced, decreasing the aspiration speed (here, the aspiration speed is set to v2 (v1 > v2)). Then, the aspiration action continues until the pre-set amount of eluent to be recovered is completely aspirated. The aspiration speed at this point is set such that the aspiration force is lower than the magnetic force of the bottom magnet. That is, the aspiration force, based on the material, shape, and plunger diameter of the pipette tip 205, is set to be lower than the magnetic force, based on the type and size of the bottom magnet and the physical properties (permeability, particle size, etc.) of the magnetic microspheres. By continuously aspirating under these conditions, the eluent contained between the magnetic microspheres can be recovered with a high recovery rate without aspirating the magnetic microspheres themselves.

[0059] Figure 6(4): After completing the predetermined amount of aspiration, stop the plunger operation and stop aspiration (absorb the predetermined amount ~ stop aspiration). Then, move the pipette to spray the recovered eluent into other containers. While moving the pipette, it is possible to aspirate a small amount of magnetic microbeads at the tip of the pipette tip 205. Therefore, it is preferable to use the magnetic force of the bottom magnet 401 to attract the magnetic microbeads inside the pipette tip 205 and remove them from the pipette tip 205. Considering the movement time of the magnetic microbeads, it is preferable to wait for a predetermined time after aspiration stops (wait for the predetermined time) and then move the pipette (pipettes rise). It should be noted that in this step, the liquid near the bottom of the container is aspirated into the pipette along the surface of the microbeads.

[0060] In the above process, the contact detection between the tip of the pipette tip 205 and the eluent surface and the contact detection of the upper surface of the magnetic microbeads 303B can be implemented by using the pressure sensor of the pipette to detect changes in the pipette's aspiration pressure.

[0061] Figure 7 This is a graph showing the pressure shift measured by the pressure sensor on the pipette during eluent recovery. The pipette tip 205 descends from its initial position, and when its tip contacts the surface of the eluent 303L (let's call the tip movement z1 at this point), 303L of eluent is aspirated, and the pressure changes (…). Figure 7 (Part A in the middle). Furthermore, when the tip of the pipette tip 205 contacts the upper surface of the magnetic microbeads 303B that are being magnetized and accumulated (let the descent amount at this time be z2), the magnetic microbeads 303B are drawn in, and the pressure changes ( Figure 7 (Part B in the middle). By detecting the above pressure changes, it is possible to detect the contact between the pipette tip 205 and the liquid surface of the eluent 303L, as well as the contact between the pipette tip 205 and the upper surface of the magnetic microbeads 303B.

[0062] exist Figure 7 During pressure testing, if a small amount of magnetic microbeads 303B enters the pipette tip 205, the bottom magnet 401 can attract the magnetic microbeads 303B back to the bottom of the container and discharge them from the pipette tip 205.

[0063] Figure 8 This diagram illustrates the loss of recovered eluent in existing biological sample processing devices. When removing magnetic microspheres from the eluent, as... Figure 8 As shown, a magnetic rod 101 is immersed in the eluent, and magnetic microspheres 303B are attracted by the magnet at the tip of the magnetic rod 101. The magnetic rod 101 is then removed from this state. However, since the recovery is performed with the eluent adsorbed onto the magnetic microspheres, a significant amount of loss occurs in the recovered eluent. This embodiment can suppress such loss.

[0064] <Implementation Method 1: Summary>

[0065] In the biological sample processing apparatus 1 of Embodiment 1, magnetic microbeads 303B are attracted using a bottom magnet 401 while eluent 303L is aspirated using a pipette. When the tip of the pipette 205 contacts the magnetic microbeads 303B, the pipette descent is stopped and the aspiration force is reduced. Therefore, during eluent recovery, the liquid adsorbed on the magnetic microbeads 303B can also be recovered, achieving a high recovery rate of the nucleic acid eluent as the final product.

[0066] <Implementation Method 2>

[0067] The structure of the biological sample processing device 1 in Embodiment 2 of the present invention is substantially the same as that in Embodiment 1, and it performs the same operation. Therefore, in the following description, the description of the structure that is common in both embodiments will be omitted, and the description will focus on the differences between the two.

[0068] In Embodiment 2, similar to Embodiment 1, during eluent recovery, the surface of the magnetic microbeads 303B is brought into contact with the tip of the pipette tip 205 for aspiration. However, unlike Embodiment 1, the surface position of the magnetic microbeads 303B is set to a predetermined value. Due to deviations in the amount of microbeads and the container's placement, an error arises between the predetermined value and the actual position of the magnetic microbead surface. This error can lead to accidental aspiration of microbeads and pipette tip clogging. Embodiment 2 addresses this problem.

[0069] Figure 9 This is a side view illustrating the set position used during the eluent recovery operation in Embodiment 2. In Embodiment 2, the set position is... Figure 9 The values ​​shown are the first set position (Za) and the second set position (Zb). The first set position (Za) is the position where the pipette tip will not contact the surface of the magnetic microbeads 303B even with various deviations; it is the position between the liquid surface of the eluent and the upper surface of the magnetic microbeads 303B that have been magnetized and accumulated. The second set position (Zb) is the position where the magnetic microbeads 303B contact the pipette tip 205.

[0070] Figure 10 This is a flowchart of the recovery process of the eluent after the washing and extraction process in Implementation Method 2. Figure 11 This diagram illustrates the suction action of the eluent during the recovery process. Hereinafter, the recovery operation of the eluent in Embodiment 2 will be described with reference to the aforementioned diagram.

[0071] Immediately after the washing and extraction process is completed, the magnetic microspheres are in a state of floating and dispersing in the washing solution. Therefore, before the extraction of the washing solution begins, the bottom magnet 401 is brought into contact with the bottom of the small container 303 for a predetermined waiting time. This causes the magnetic microspheres 303B to be magnetized at the bottom of the small container 303 (bottom magnet placed ~ waiting for predetermined time).

[0072] Figure 11 (1): Then, lower the pipette and begin pipetting (pipettes lower ~ begin aspiration (aspiration speed v1)), and continue aspiration until the first set position (Za) is reached (start movement count ~ whether the first set position (Za) has been reached). The descent speed and aspiration speed at this time are determined by the shape of the container, and the descent speed of the pipette is set to be greater than the speed at which the liquid level drops due to aspiration. In this way, the pipette tip 205 is lowered in accordance with the drop in liquid level caused by aspiration, thereby preventing the tip from being exposed to air due to the drop in liquid level and the accidental aspiration of air.

[0073] Figure 11 (2) to (5): After descending to the first set position (Za), perform phased aspiration and movement (low speed / phased aspiration (aspiration speed v2) ~ whether to move to the second set position (Zb)). That is, reduce the aspiration speed of the pipette (here the aspiration speed is set to v2), repeatedly perform predetermined aspiration, descent and standby for a predetermined time until the pipette tip 205 reaches the second set position (Zb). The standby time is set to be sufficient time required for the magnetic beads to return to their original position by magnetic force when they are mixed into the pipette.

[0074] Figure 11 (6): After the pipette tip 205 comes into contact with the magnetic microbeads 303B, when a predetermined amount of elution solution is aspirated, aspiration is performed while some magnetic microbeads are mixed in. For the aspirated magnetic microbeads, during the standby time, the magnetic microbeads inside the pipette tip 205 are attracted by the bottom magnet 401 and discharged from the pipette tip 205 (waiting for the predetermined time). After the magnetic microbeads are discharged, the pipette is raised (pipettes rise).

[0075] In this way, during the recovery of the eluent, the surface of the magnetic microbeads is brought into contact with the tip of the pipette tip for aspiration, but the magnetic microbeads mixed into the pipette tip 205 are discharged from the pipette by the bottom magnet 401. Thus, similar to Embodiment 1, the liquid adsorbed on the magnetic microbeads 303B can also be recovered during the recovery of the eluent, achieving a high recovery rate of the nucleic acid eluent as the final product.

[0076] In Embodiment 2, the information from the pressure sensor is not used; instead, the first set position Za and the second set position Zb are used. However, it can also be used in conjunction with the pressure sensor described in Embodiment 1.

[0077] <Implementation Method 3>

[0078] The structure of the biological sample processing device 1 in Embodiment 3 of the present invention is substantially the same as that in Embodiment 1, and it performs the same operation. Therefore, in the following description, the description of the structure that is common in both embodiments will be omitted, and the description will focus on the differences between the two.

[0079] Figure 12 This is a diagram showing the pipette unit 200 of the biological sample processing apparatus 1 according to Embodiment 3. In Embodiment 3, an image capture machine 500 is used to capture images of the surface of the eluent and the interface between the magnetic microbeads and the eluent after magnetization.

[0080] The arithmetic unit 501 pre-obtains a threshold related to the color difference between the color of the eluent 303L and the color of the magnetic microbeads 303B (RGB data or their binarized data). Using this threshold, the arithmetic unit 501 calculates the position of the interface between the two based on image data acquired by the image capture device 500. The arithmetic unit 501 lowers the pipette relative to this interface position. Alternatively, the arithmetic unit 501 can also determine the tip position of the pipette tip 205 in the Z direction based on image data acquired by the image capture device 500 and its color information, etc. The arithmetic unit 501 can also determine the contact state between the determined tip of the pipette tip 205 and the magnetic microbead interface.

[0081] The arithmetic unit 501 can also use image data acquired by the image capture device 500 to detect the liquid level of the eluent 303L. The arithmetic unit 501 lowers the pipette tip 205 according to this height, initiating aspiration from this liquid level. Then, it lowers the tip at a predetermined speed to the calculated interface height of the magnetic microbeads 303B and aspirates (aspiration speed v1). The pipette tip 205 descends, and stops when its tip contacts the interface of the magnetic microbeads 303B. At this position, the aspiration speed is reduced (here, the aspiration speed is set to v2, v1 > v2), and a predetermined volume is aspirated.

[0082] In Embodiment 3, the control method used in Embodiment 2 to move the pipette in stages can also be used. Furthermore, the pressure sensor from Embodiment 1 can also be used.

[0083] <Regarding variations of the present invention>

[0084] In the above embodiments, as a detection in Figure 7The pressure change mechanism described herein can be, for example, the arithmetic unit 501 described in Embodiment 3. The arithmetic unit 501 can determine contact by comparing the pressure value or pressure change rate (time derivative) with a preset threshold. Alternatively, the arithmetic unit 501 can determine contact by matching it to a standardized pressure change pattern. Other arbitrary methods or combinations thereof may also be used.

[0085] In the above embodiments, Figures 5-6 The actions described in the text and in Figures 10-11 The actions described herein can be controlled by the arithmetic unit 501, for example.

[0086] The arithmetic unit 501 can be constructed from hardware such as circuit devices with its functions installed, or it can be constructed by executing software with its functions installed through arithmetic devices such as a CPU (Central Processing Unit).

[0087] In the above embodiments, v1 is, for example, 5 times, 10 times, or more than v2, but is not limited thereto. As long as v1 is at least greater than v2, the effects of the present invention can be achieved. In other words, the larger v1 is, the higher the speed of liquid suction.

[0088] In the above embodiments, the suction force of v1 for drawing in the magnetic microbeads can be weaker than the attractive force of the bottom magnet 401. If the suction force based on v1 is weaker, the likelihood of drawing the magnetic microbeads into the pipette midway through its descent decreases, thus offering an advantage within this range. Furthermore, since the liquid aspiration rate also decreases, a larger v1 is preferable if liquid aspiration efficiency is a priority.

[0089] Symbol Explanation

[0090] 1—Biological sample processing device; 100—Magnetic rod unit; 101—Magnetic rod; 102—Magnetic rod cover; 103—Magnetic rod drive motor; 104—Magnetic rod cover drive motor; 200—Pipette unit; 201—Plunger; 202—Plunger drive motor; 203—Pressure sensor; 204—Pipette up-and-down movement motor; 205—Pipette tip; 206—Horizontal movement motor; 300—Container delivery unit; 301—Large container; 302—Medium container; 303—Small container; 304—Container support; 305—Container movement motor; 400—Bottom magnet unit; 401—Bottom magnet; 500—Image capture device.

Claims

1. A biological sample processing device for processing biological samples containing magnetic microbeads, characterized in that, have: A magnet, which can be configured to contact the bottom surface of the container holding the aforementioned biological sample; and A pipette for aspirating the biological sample from the container or spraying the biological sample into the container. The aforementioned pipette performs a suction action while its tip is in contact with the aforementioned magnetic microbeads. After the aforementioned pipette aspirates the aforementioned biological sample, there is sufficient time for the aforementioned magnetic microbeads to be expelled from the aforementioned pipette using the aforementioned magnet.

2. The biological sample processing device according to claim 1, characterized in that, The pipette descends while its tip is immersed in the biological sample, and aspiration is performed at a first aspiration rate. With the tip of the pipette in contact with the magnetic microbeads, the pipette performs a suction action at a second suction speed that is lower than the first suction speed. After the pipette performs the aspiration action at the second aspiration speed, there is a waiting time sufficient for the magnetic microbeads inside the pipette to be expelled from the pipette using the magnet.

3. The biological sample processing device according to claim 2, characterized in that, The aforementioned biological sample processing device also includes a computing unit for detecting the contact between the tip of the pipette and the magnetic microbeads. When the tip of the pipette comes into contact with the magnetic microbeads, the pipette stops its aspiration action based on the first aspiration speed and stops descending.

4. The biological sample processing device according to claim 3, characterized in that, The suction force of the magnetic microspheres at the second suction speed is less than the attraction force of the magnet attracting the magnetic microspheres.

5. The biological sample processing device according to claim 1, characterized in that, The suction force of the aforementioned pipette for drawing the aforementioned magnetic microspheres is less than the attraction force of the aforementioned magnet for drawing the aforementioned magnetic microspheres.

6. The biological sample processing device according to claim 3, characterized in that, The aforementioned biological sample processing device also includes a pressure sensor for measuring the pressure inside the aforementioned pipette. The aforementioned processing unit compares the pressure measured by the aforementioned pressure sensor with a threshold to detect contact between the tip of the aforementioned pipette and the aforementioned magnetic microbeads.

7. The biological sample processing device according to claim 2, characterized in that, The pipette descends to a first predetermined position, which is below the liquid surface of the biological sample and above the upper surface of the magnetic microspheres, while performing a suction action at the first suction speed. After the pipette descends to the first set position, it repeatedly performs a predetermined descent, aspiration based on the second aspiration speed, and a standby time for a predetermined period of time until it reaches the second set position below the upper surface of the magnetic microbeads.

8. The biological sample processing device according to claim 7, characterized in that, After the pipette descends to the second set position, it performs a standby operation for a period of time sufficient to allow the magnetic beads inside the pipette to be expelled from the pipette using the magnet.

9. The biological sample processing device according to claim 3, characterized in that, The aforementioned biological sample processing device also includes a camera for photographing the side of the aforementioned container. Based on the image captured by the camera, the aforementioned processing unit determines the respective positions of the tip of the pipette and the magnetic microbeads, thereby detecting contact between the tip of the pipette and the magnetic microbeads.

10. The biological sample processing device according to claim 3, characterized in that, The aforementioned biological sample processing device also includes a camera for photographing the side of the aforementioned container. Based on the images captured by the camera, the aforementioned processor determines the liquid level height of the biological sample. After the pipette descends to the liquid level of the biological sample, it begins to perform aspiration at the first aspiration rate.

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