Filtration device and filtration method

Abstract

To provide a filtration device and a filtration method that can easily retain cells captured on a filter.SOLUTION: A filtration device 1 for filtering a liquid containing cells, includes: a filter 10 having a first main surface 10a, a second main surface 10b opposite to the first main surface 10a, a membrane portion 11 having a filter base portion 13 defining a plurality of through-holes 12 extending from the first main surface 10a to the second main surface 10b, and a plurality of protrusions 14 provided on at least the filter base portion 13 on the first main surface 10a; a holder 20 for holding the filter 10; and a heating portion 30 for heating the filter 10. The first main surface 10a is located upstream of the second main surface 10b. The plurality of protrusions 14 expand when the filter 10 is heated by the heating portion 30.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a filtration device and a filtration method. [Background technology]

[0002] Filtration devices for separating filtration targets, such as cells, from a liquid containing the filtration targets are known. For example, Patent Document 1 discloses a suspended solid separation device using a membrane module including a porous membrane with a shape memory function. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-189759 Summary of the Invention [Problem to be solved by the invention]

[0004] The suspended solid separation device described in Patent Document 1 has a problem in that it is difficult to retain the filtration target captured in the porous membrane, and the filtration target is likely to fall off.

[0005] Therefore, the present disclosure provides a filtration device and a filtration method that can easily retain cells captured on a filter. [Means for solving the problem]

[0006] A filtration device according to one embodiment of the present disclosure includes: A filtration device for filtering a liquid containing cells, comprising: a filter having a first main surface, a second main surface opposite to the first main surface, a membrane portion having a filter base portion defining a plurality of through holes penetrating from the first main surface toward the second main surface, and a plurality of protrusions provided on the filter base portion at least on the first main surface; a holder for holding the filter; a heating unit that heats the filter; Equipped with the first main surface is located upstream of the second main surface, The plurality of protrusions expand when the filter is heated by the heating unit.

[0007] A filtration method according to one embodiment of the present disclosure includes: A method for filtering a liquid containing cells using the above-mentioned filtration device, comprising: heating the filter by the heating unit of the filtering device; providing a liquid containing the cells to the filter; capturing the cells with the filter and retaining the cells on the plurality of protrusions; Includes: [Effects of the Invention]

[0008] According to the present disclosure, it is possible to provide a filtering device and a filtering method that can easily retain cells that have fallen off and been captured by a filter. [Brief explanation of the drawings]

[0009] [Figure 1] Schematic diagram showing a filtering device according to a first embodiment of the present disclosure. [Figure 2] FIG. 2 is a schematic plan view showing a filter of the filtration device of FIG. [Figure 3] FIG. 3 is a schematic plan view showing a part of the membrane part of the filter of FIG. 2. [Figure 4A] Cross section AA of Figure 3 [Figure 4B] Cross section B-B of Figure 3 [Figure 5] Enlarged view of area R1 in Figure 3 [Figure 6A] Enlarged view of region R3 in Figure 4A. [Figure 6B] A diagram showing the region R3 when the filter 10 is heated. [Figure 7] FIG. 1 is a diagram showing an example of a system for filtering a liquid containing a filtering target using a filtering device according to a first embodiment. [Figure 8]1 is a flowchart illustrating a filtration method using the filtration device according to the first embodiment. [Figure 9] FIG. 10 is a partial cross-sectional view showing a part of a filter according to a first modification of the first embodiment. [Figure 10] Enlarged view of region R4 in Figure 9 [Figure 11] Schematic diagram showing a filtration device according to a second embodiment. [Figure 12] FIG. 10 is a diagram showing an example of a system for filtering a liquid containing a filtering target using a filtering device according to a second embodiment. [Figure 13] 10 is a flowchart illustrating a filtration method using the filtration device according to the second embodiment. [Figure 14A] Table showing the number of cells when a liquid containing a filtration target is filtered using the filtration device of Example 1. [Figure 14B] Table showing the number of cells when a liquid containing a filtration target is filtered using the filtration device of Comparative Example 1 [Figure 15A] Table showing the number of cells when a liquid containing a filtration target is filtered using the filtration device of Example 1. [Figure 15B] Table showing the number of cells when a liquid containing a filtration target is filtered using the filtration device of Comparative Example 2 DETAILED DESCRIPTION OF THE INVENTION

[0010] (Background to this disclosure) Filtration devices that use a filter to filter a liquid containing a substance to be filtered are known. For example, Patent Document 1 discloses a filtration separation device that uses a membrane module including a porous membrane with a shape memory function.

[0011] After filtering a liquid containing a substance to be filtered, the substance captured by the filter may fall off from the filter base, accumulating in the through holes and causing clogging, resulting in reduced filtration efficiency.

[0012] The inventors have investigated the possibility of providing protrusions on the surface of a filter to increase the surface area of ​​the filter and make it easier to hold the objects to be filtered captured by the filter. They have also investigated the possibility of forming the filter from a heat-expandable material and heating the filter to further increase the surface area of ​​the filter, making it easier to hold the objects to be filtered and preventing them from falling off the base, and have arrived at the following invention.

[0013] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In each drawing, elements are shown exaggerated for ease of explanation.

[0014] (Embodiment 1) [Overall configuration] Fig. 1 is a schematic diagram illustrating a filtration device 1 according to a first embodiment of the present disclosure. Fig. 2 is a schematic plan view illustrating a filter 10 of the filtration device 1 of Fig. 1. Fig. 3 is a schematic plan view illustrating a portion of a membrane portion 11 of the filter 10 of Fig. 2.

[0015] Filtration device 1 is a device that filters a liquid containing cells. For example, as shown in Figure 1, when liquid is supplied to filtration device 1 along arrow F1, the filter 10 captures the filtration target contained in the liquid, and the liquid that has passed through filter 10 is discharged along arrow F2. After the liquid has passed through, the filtration target is held by filter 10 and can be observed.

[0016] The filtration device 1 includes a filter 10, a holding unit 20 that holds the filter 10, and a heating unit 30 that heats the filter 10.

[0017] <filter> The filter 10 separates the material to be filtered from the liquid by passing the liquid containing the material to be filtered through the filter 10.

[0018] The filter 10 is made of a thermally expandable material. The thermally expandable material is, for example, a material that expands with an increase in temperature. In the first embodiment, the filter 10 is made of a material having a thermal expansion coefficient of, for example, 1×10 -5It is made of resins such as acrylic, polycarbonate, polyvinyl chloride, polyethylene, polypropylene, polystyrene, polyacetal (POM) resin, or PET, with a hardness of 1 / K or higher.

[0019] As shown in FIG. 1, filter 10 is formed in the shape of a film having a first main surface 10a and a second main surface 10b opposite to first main surface 10a. As shown in FIGS. 2 and 3, filter 10 has a film portion 11 that captures a filtering target contained in a liquid. Film portion 11 is formed to a thickness of, for example, 10 μm or more and 50 μm or less. As shown in FIGS. 4A and 4B described below, in film portion 11, first main surface 10a and second main surface 10b are formed flat. In the first embodiment, filter 10 has an annular frame portion 16 arranged to surround the outer periphery of film portion 11. Note that, in the example of FIG. 2, filter 10 has a circular shape in a plan view, but filter 10 may have a shape other than a circle, such as a rectangle or other polygon.

[0020] In this specification, the term "filtering target" refers to a target to be filtered by the filter 10. In the first embodiment, a biological substance is used as the filtering target.

[0021] Furthermore, as used herein, "biologically derived materials" refers to materials derived from living organisms, such as cells (eukaryotes), bacteria (true bacteria), and viruses. Examples of cells (eukaryotes) include eggs, sperm, induced pluripotent stem cells (iPS cells), ES cells, stem cells, mesenchymal stem cells, mononuclear cells, single cells, cell clumps, floating cells, adherent cells, neurons, leukocytes, lymphocytes, cells for regenerative medicine, autologous cells, cancer cells, circulating cancer cells (CTCs), HL-60, HELA, and fungi. Examples of bacteria (true bacteria) include gram-positive bacteria, gram-negative bacteria, Escherichia coli, and Mycobacterium tuberculosis. Examples of viruses include DNA viruses, RNA viruses, rotaviruses, (avian) influenza viruses, yellow fever viruses, dengue fever viruses, encephalitis viruses, hemorrhagic fever viruses, and immunodeficiency viruses. In the first embodiment, the filter 10 is particularly effective in separating induced pluripotent stem cells (iPS cells), ES cells, stem cells, and circulating cancer cells (CTCs) from a liquid.

[0022] The membrane portion 11 is provided with a plurality of through holes 12 that penetrate from the first main surface 10a to the second main surface 10b. The plurality of through holes 12 are defined by the filter base portion 13. In the first embodiment, the filter base portion 13 includes a first filter base portion 13a extending in a first direction (X direction) and a second filter base portion 13b extending in a second direction (Y direction). The first filter base portion 13a and the second filter base portion 13b are arranged perpendicular to each other, and therefore, square through holes 12 are defined in the membrane portion 11. Furthermore, in the first embodiment, the plurality of through holes 12 are arranged in a square lattice array. By forming the through holes 12 to be smaller than the objects to be filtered, the objects to be filtered can be captured by the filter 10.

[0023] 3, the through-holes 12 are designed such that the length L1 of one side is, for example, 0.1 μm or more and 500 μm or less. The through-holes 12 are formed to be smaller than the object to be filtered. Furthermore, the distance L2 between adjacent through-holes 12 is designed to be, for example, 0.75 μm or more and 350 μm or less.

[0024] Fig. 4A is a cross-sectional view taken along line AA in Fig. 3. Fig. 4B is a cross-sectional view taken along line BB in Fig. 3. The plurality of protrusions 14 will be described with reference to Figs. 3, 4A and 4B.

[0025] As shown in FIG. 3, a plurality of protrusions 14 are provided on at least the first main surface 10a of the filter 10.

[0026] Heating the filter 10 causes the filter 10 to expand. As the filter 10 expands due to heating, the plurality of protrusions 14 also expand. Therefore, by heating the filter 10, the surface area of ​​the first main surface 10a of the filter 10 can be increased, making it possible to hold the captured filtration target and reducing the detachment of the filtration target from the filter 10.

[0027] In Fig. 3, the plurality of protrusions 14 are provided on the filter base portion 13 between one through-hole 12 and an adjacent through-hole 12. As shown in Figs. 4A and 4B, the plurality of protrusions 14 are provided to protrude from the first main surface 10a. Furthermore, the first main surface 10a is formed flat in a portion where the plurality of protrusions 14 are not arranged. In other words, a flat portion is provided between two adjacent protrusions 14.

[0028] Returning to FIG. 1 , in the first embodiment, the first main surface 10a of the filter 10 is located upstream of the second main surface 10b. The upstream side is the side closer to the inlet through which the liquid flows into the holding portion 20. The downstream side is the side closer to the outlet through which the liquid is discharged from the holding portion 20. When the first main surface 10a is located upstream, the material to be filtered is more likely to come into contact with the plurality of protrusions 14. As a result, more material to be filtered can be captured on the first main surface 10a of the filter 10.

[0029] Fig. 5 is an enlarged view of region R1 in Fig. 3. Fig. 5 shows a unit lattice, which is the smallest unit for forming an array of through holes 12 arranged in a square lattice arrangement. That is, in a square lattice arrangement, four through holes 12 is the smallest unit for forming the array. In embodiment 1, filter base 13 forming the unit lattice includes at least one protrusion 14. Filter base 13 forming the unit lattice is region R2 surrounded by a dashed line.

[0030] As shown in FIG. 5, adjacent through holes 12 are spaced apart by a distance L2. In other words, the filter base 13 has a width L2. The width L2 is the distance from a first end E1 of the plurality of through holes, located on the side of a first through hole 12a, to a second end E2 of the plurality of through holes, located on the side of a second through hole 12b adjacent to the first through hole 12a. In the first embodiment, the plurality of through holes 12 are disposed between the first end E1 and the second end E2. Furthermore, in the first embodiment, the plurality of protrusions 14 are disposed at a position spaced a first distance L1 from the first end E1 and a second distance L4 from the second end E2. That is, in the filter base 13, the plurality of protrusions 14 are not disposed within a range of distance L3 from the first end and a range of distance L4 from the second end. In this case, the first distance L3 and the second distance L4 are equal to or greater than 1 / 5 of the distance from the first end E1 to the second end E2, i.e., the width L2 of the filter base 13. In other words, the plurality of protrusions 14 are provided on the filter base 13 at positions spaced apart from the first end E1 and the second end E3 by a distance equal to or greater than 1 / 5 of the width L2 of the filter base 13.

[0031] By arranging the plurality of protrusions 14 between the first end E1 and the second end E2, it becomes easier to capture the material to be filtered near the center in the width direction of the filter base portion 13 than near the through-holes 12. This makes it possible to prevent the through-holes 12 from being blocked by the material to be filtered, thereby improving filtration efficiency.

[0032] Furthermore, since the first distance L3 and the second distance L4 are 1 / 5 or more of the width L2 of the filter base portion 13, the material to be filtered is more likely to be captured near the center of the filter base portion 13 rather than at the ends E1, E2.

[0033] Furthermore, in the first embodiment, the plurality of protrusions 14 have a substantially circular shape in a plan view. Furthermore, in the first embodiment, the plurality of protrusions 14 are randomly arranged on the first main surface 10a, and are spaced apart so as not to contact each other.

[0034] Fig. 6A is an enlarged view of region R3 in Fig. 4A. Fig. 6B is a view showing region R3 when filter 10 is heated. For the sake of explanation, Fig. 6A and Fig. 6B show cells C1 as the object to be filtered.

[0035] In the first embodiment, the plurality of protrusions 14 are formed so that their height is smaller than the thickness of the membrane portion 11. Therefore, as shown in FIG. 6A, the height H1 of the plurality of protrusions 14 is formed so that it is smaller than the thickness H2 of the membrane portion 11. More specifically, the plurality of protrusions 14 may be formed so that their height H1 is 0.1 μm or more and 2.0 μm or less. Note that, as shown in FIG. 6A, the height H1 of the plurality of protrusions 14 refers to the distance from the surface of the filter base portion 13, i.e., the first main surface 10a of the filter 10, to the top of the protrusions 14. Furthermore, the statement that the height H1 of the plurality of protrusions 14 is smaller than the thickness H2 of the membrane portion 11 means that the height of each of the plurality of protrusions 14 is formed so that it is smaller than the thickness H2 of the membrane portion 11.

[0036] When the height H1 of the multiple protrusions 14 is smaller than the thickness H2 of the membrane portion 11, the resistance when passing a liquid through the filter 10 is reduced, thereby improving filtration efficiency. Furthermore, when the height H1 of the multiple protrusions 14 is smaller than the thickness H2 of the membrane portion 11, damage to the filter 10 due to stress concentration can be suppressed, thereby improving the mechanical strength of the filter 10. Furthermore, when the height H1 of the multiple protrusions 14 is 0.1 μm or more and 2.0 μm or less, the distance between the captured filtering target and the first main surface 10a is shortened, thereby suppressing movement of the filtering target due to the flow of the liquid. Therefore, the filtering target can be more easily observed.

[0037] 6A and 6B, the fact that the plurality of protrusions 14 provided on the filter 10 facilitates the capture of the filtration target substance will be described. As shown in FIG. 6A, when the protrusions 14 are provided on the first main surface 10a of the filter 10, the surface area is increased, making it easier for the cells C1 trapped in the filter base portion 13 to be retained in the filter 10. When the filter 10 is heated, the filter 10 expands, as shown in FIG. 6B, and the plurality of protrusions 14 also expand. The expansion of the plurality of protrusions 14 increases the contact area between the cells C1 and the first main surface 10a of the filter 10 or the plurality of protrusions 14, thereby preventing the cells C1 trapped in the filter 10 from falling off the filter 10. Furthermore, the expansion of the plurality of protrusions 14 facilitates the accumulation of liquid in the filter base portion 13, thereby preventing the captured filtration target substance from drying out and maintaining the activity of the filtration target substance, such as cells.

[0038] Furthermore, by forming the portions of first main surface 10a where protrusions 14 are not provided flat, it is possible to reduce distance D1 between first main surface 10a and the contact points between cell C1 and protrusions 14 shown in Fig. 6A. Reducing distance D1 makes cell C1 less susceptible to the influence of liquid flow, making it easier for cell C1 to be held on first main surface 10a, and preventing cell C1 from falling off filter 10.

[0039] <Holding part> Returning to FIG. 1, filter 10 is held by holding portion 20. Holding portion 20 is formed in a cylindrical shape, and its inner surface holds frame portion 16 of filter 10. Holding portion 20 functions as a flow path for liquid when liquid is passed through filter 10. As shown in FIG. 2, in the first embodiment, filter 10 is formed in a circular shape, so holding portion 20 is preferably cylindrical. Depending on the shape of filter 10, holding portion 20 may be formed in a cylindrical shape having a cross-sectional shape other than circular.

[0040] The holding portion 20 may have a groove (not shown) formed on the inner surface thereof, for example, and may hold the filter 10 by sandwiching the frame portion 16 in the groove. The holding portion 20 may be made of, for example, a synthetic resin or a metal material.

[0041] <Heating part> The heating unit 30 heats the filter 10. Examples of the heating unit 30 include a heater or an oven. When an oven is used as the heating unit 30, the filter 10 is heated by placing it in the oven while it is fixed to the holding unit 20. The heating unit 30 heats the filter 10 to a temperature in the range of, for example, 30°C or higher and 40°C or lower. By heating the filter 10 with the heating unit 30, the multiple protrusions 14 provided on the filter 10 expand.

[0042] [Filtration method] A filtration method using the filtration device 1 will be described with reference to Fig. 7 and Fig. 8. Fig. 7 is a diagram showing an example of a system for filtering a liquid containing a filtration target using the filtration device 1. Fig. 8 is a flowchart for explaining the filtration method using the filtration device 1.

[0043] When filtering a liquid containing a substance to be filtered using the filtration device 1, as shown in FIG. 8 , a supply container 41 containing the liquid containing the substance to be filtered is connected to the upstream side of the filtration device 1. A pump 42 for pumping the liquid inside the supply container 41 is connected between the filtration device 1 and the supply container 41. A waste liquid collection container 43 for collecting the liquid that has passed through the filtration device 1 is connected to the downstream side of the filtration device 1. When filtering a liquid, the pump 42 pumps the liquid inside the supply container 41 and passes it through the filtration device 1, and the liquid that has passed through the filtration device 1 is collected in the waste liquid collection container 43. At least a portion of the substance to be filtered is captured by the filter 10 of the filtration device 1. After observation is completed, the substance to be filtered captured by the filter 10 is collected in a cell collection container 44 connected downstream of the filtration device 1. A valve 45 is provided between the filtration device 1 and the waste liquid collection container 43 and the cell collection container 44, so that the liquid discharged from the filtration device 1 is collected in either the waste liquid collection container 43 or the cell collection container 44.

[0044] As shown in Fig. 8, in a filtration method using filtration device 1, first, in step S1, filter 10 is heated by heating unit 30. In the example of Fig. 7, filtration device 1 is placed in heating unit 30 while connected to supply container 41 and waste liquid collection container 43, and heating unit 30 is controlled as needed to heat filter 10. In step S1, heating unit 30 is controlled so that the temperature of filter 10 becomes approximately 37°C, for example. Heating filter 10 causes multiple protrusions 14 to expand, as shown in Fig. 6B.

[0045] Next, in step S2, the liquid containing the material to be filtered is supplied to the filter 10 of the filtration device 1. The liquid can be supplied to the filtration device 1 by pumping up the liquid from the supply container 41 with the pump 42. Alternatively, the liquid may be supplied to the filtration device 1 by gravity without using a pump. The liquid that has passed through the filter 10 is discharged from the filtration device 1 into the waste liquid collection container 43. At this time, the valve 45 is controlled so that the flow path from the filtration device 1 to the waste liquid collection container 43 is open.

[0046] Next, in step S3, the object to be filtered is captured and held. The object to be filtered in the liquid supplied to the filter 10 is captured by the filter 10 and held by the plurality of projections 14 that have expanded.

[0047] After capturing the object to be filtered on the filter 10 and observing the object to be filtered, the valve 45 is controlled to open the flow path from the filtration device 1 to the cell collection container 44, and the cells captured on the filter 10 are allowed to fall through the through-holes 12 and discharged into the cell collection container 44.

[0048] [effect] According to the above-described embodiment, the following effects can be achieved.

[0049] The filtration device 1 is a device for filtering a liquid containing cells, and includes a filter 10, a holding unit 20 that holds the filter 10, and a heating unit 30 that heats the filter 10. The filter 10 has a first main surface 10a, a second main surface 10b opposite the first main surface 10a, a membrane unit 11 having a filter base 13 that defines a plurality of through-holes 12 that penetrate from the first main surface 10a to the second main surface 10b, and a plurality of protrusions 14 provided on at least the first main surface 10a. The plurality of protrusions 14 expand when the filter 10 is heated by the heating unit 30.

[0050] With this configuration, it is possible to provide a filtering device that can easily retain cells captured on the filter.

[0051] The filter 10 is made of a thermally expandable resin.

[0052] With this configuration, the plurality of protrusions 14 can be easily expanded by heating the filter 10 .

[0053] The first main surface 10a is located upstream of the second main surface 10b, and the plurality of protrusions 14 are provided on the first main surface 10a.

[0054] With this configuration, when a liquid is passed through the filtration device 1, the cells collide with the filter 10 at the first main surface 10a, and the provision of multiple protrusions 14 on the first main surface 10a makes it easier for the cells to collide with the filter 10. When the cells collide with the filter 10 more easily, the cells are more easily captured by the filter 10, and the number of captured cells can be increased.

[0055] When viewed from a direction perpendicular to the first main surface 10a, the plurality of through holes 12 are arranged in a lattice pattern, such as an orthorhombic lattice, a hexagonal lattice, a triangular lattice, a square lattice, a rectangular lattice, or a parallelepiped lattice. The plurality of protrusions 14 includes at least one protrusion provided on the filter base 13 that constitutes a unit lattice, which is the smallest unit for forming the array.

[0056] This configuration increases the surface area of ​​the filter 10, making it easier to capture cells. Furthermore, if the filter base 13 constituting the unit lattice is provided with multiple protrusions 14, the protrusions 14 are arranged more densely, allowing cells to be held in close proximity on the filter 10. This allows for observation of interactions between cells.

[0057] The height H1 of the protrusions 14 is smaller than the thickness H2 of the membrane portion 11 of the filter 10. The height H1 of the protrusions 14 is the distance from the surface of the filter base portion 13 to the top of the protrusions 14.

[0058] This configuration can reduce resistance when liquid passes through filter 10, thereby improving filtration efficiency. It can also reduce stress concentration on protrusions 14, improving the mechanical strength of filter 10.

[0059] The height H1 of the protrusion 14 is not less than 0.1 μm and not more than 2.0 μm.

[0060] With this configuration, the distance between the contact point of the cell with the protrusion 14 and the first main surface 10a is reduced, which makes it possible to prevent the cell from moving due to the flow of the liquid, thereby making it easy to observe the cell.

[0061] The plurality of protrusions 14 are provided on the first main surface 10a, and flat portions are provided between the plurality of protrusions 14 on the first main surface 10a of the filter base portion 13.

[0062] With this configuration, the distance between the contact points of the cells with the protrusions 14 and the first main surface 10a is reduced, so that the cells can be held by the flow of liquid and are prevented from falling off the filter 10.

[0063] The filter base 13 has a first end E1 on the side of the first through hole 12a among the plurality of through holes 12 and a second end E2 on the side of the second through hole 12b adjacent to the first through hole 12a. The plurality of protrusions 14 are provided between the first end E1 and the second end E2.

[0064] With this configuration, cells can be captured near the center of the filter base 13 rather than near the through-holes 12. This prevents the through-holes 12 from becoming clogged with cells, improving filtration efficiency. Furthermore, by forming multiple protrusions 14 near the center of the filter base 13, liquid can be held between the multiple protrusions 14, making it difficult for the captured cells to dry out, allowing the cells to be observed while maintaining their activity.

[0065] The multiple protrusions 14 are positioned at a first distance L3 from the first end E1 and a second distance L4 from the second end E2, and the first distance L3 and the second distance L4 are greater than or equal to 1 / 5 of the distance from the first end E1 to the second end E2.

[0066] This configuration makes it easier to capture cells closer to the inside of the filter base portion 13. In addition, the cells are less susceptible to the influence of the flow of liquid, making it easier to observe the cells.

[0067] A method for filtering a liquid containing cells using the filtration device 1 includes the steps of heating the filter 10 using the heating section 30 of the filtration device 1, and supplying the liquid containing cells to the filter 10, capturing the cells with the filter 10, and retaining the cells on the multiple protrusions 14.

[0068] With this configuration, it is possible to provide a filtration method that can easily retain cells on the filter.

[0069] In the above-described embodiment, the example in which the plurality of protrusions 14 are provided on the first main surface 10a has been described, but the present invention is not limited to this. The plurality of protrusions 14 may also be provided on the second main surface 10b.

[0070] In the above-described embodiment, the protrusions 14 are arranged randomly on the first main surface 10a, but the present invention is not limited to this. The protrusions 14 may be arranged regularly.

[0071] In the above-described embodiment, the plurality of protrusions 14 are formed in a circular shape in a plan view, but the present invention is not limited to this. The plurality of protrusions 14 may be formed in any shape.

[0072] In the above-described embodiment, the filter 10 is made of resin, but the present invention is not limited to this. -5 The filter 10 may be formed from a metal such as palladium, nickel, gold, aluminum, or an alloy thereof, having a thermal expansion coefficient of 1 / K or more. Because metals have high thermal conductivity, forming the filter 10 from a metal can shorten the heating time and reduce the time required for the temperature of the filter 10 to change, thereby reducing the load on the cells.

[0073] Furthermore, in the above-described embodiment, an example in which an oven is used as the heating unit 30 has been described, but this is not limiting. For example, the heating unit 30 may be configured to include a tubular pipe arranged to surround the holding unit 20. In this case, the filter 10 together with the holding unit 20 can be heated by continuously passing a liquid heated to a temperature in the range of 30°C to 40°C using an external heat source such as a heater through the pipe. In this case, the filter 10 can be heated in a shorter time. Alternatively, the heating unit 30 may be a device that heats the filter 10 by continuously passing a liquid heated to a temperature in the range of 30°C to 40°C through the filter 10. In this case, the filter 10 can be heated in an even shorter time, thereby reducing the time required for the temperature of the filter 10 to change and reducing the stress on the cells.

[0074] [Variations] FIG. 9 is a partial cross-sectional view showing a portion of filter 10 according to Variation 1 of Embodiment 1. FIG. 10 is an enlarged view of region R4 in FIG. 9. As shown in FIGS. 9 and 10, recesses 115 may be provided between multiple protrusions 114 on first main surface 110a of filter base 113. For example, when multiple protrusions 114 are provided on first main surface 110a that is not flat but has projections and recesses, recesses 115 may exist between the multiple protrusions 114. Note that, when recesses 115 are provided between multiple protrusions 114 as shown in FIG. 10, height H4 of protrusion 114 is the height from the bottom of recess 115 to the top of protrusion 114.

[0075] By providing recesses 115 between the plurality of protrusions 114, the surface area of ​​the first main surface 110a can be increased. This makes it easier to capture cells. Furthermore, since liquid can be stored in the recesses 115, the captured cells can maintain their activity without drying out. Furthermore, since the plurality of protrusions 114 has a higher expansion coefficient than the recesses 115, when the filter 10 is heated, the difference in height between the top of the protrusions 114 and the bottom of the recesses 115 increases, allowing more liquid to be stored in the recesses 115.

[0076] (Embodiment 2) A filtration device according to a second embodiment of the present invention will be described. In the second embodiment, differences from the first embodiment will be mainly described. In the second embodiment, the same or equivalent configurations as those in the first embodiment will be denoted by the same reference numerals. In the second embodiment, descriptions that overlap with those in the first embodiment will be omitted.

[0077] Fig. 11 is a schematic diagram showing a filtration device 1A according to embodiment 2. As shown in Fig. 11, embodiment 2 differs from embodiment 1 in that the filtration device 1A further includes a cooling unit 31. Other configurations of the filtration device 1A are the same as those of embodiment 1, and therefore description thereof will be omitted.

[0078] The cooling unit 31 is, for example, a cooling device that circulates cooling water inside a pipe to cool an object. As described in the first embodiment, the heating unit 30 heats the filter 10, causing the multiple protrusions 14 provided on the filter 10 to expand. The expansion of the multiple protrusions 14 makes it easier to capture and hold the object to be filtered. When the cooling unit 31 then cools the filter 10, the multiple protrusions 14 on the filter 10 contract. The contraction of the multiple protrusions 14 causes the captured object to fall off the filter 10, allowing the object to be collected. The cooling unit 31 cools the filter 10, for example, to a temperature in the range of 2°C to 20°C.

[0079] By cooling the filter 10 with the cooling section 31, the filtering target matter captured on the filter 10 can be efficiently discharged from the filtering device 1A.

[0080] Fig. 12 is a diagram showing an example of a system for filtering a liquid containing a filtering target using the filtering device 1A according to embodiment 2. Fig. 13 is a flowchart for explaining a filtering method using the filtering device 1A according to embodiment 2. The filtering method using the filtering device 1A will be explained with reference to Figs. 12 and 13.

[0081] As shown in FIG. 12, the device for filtering a liquid containing a material to be filtered in the second embodiment is the same as the device described in the first embodiment with reference to FIG. 7, except that a filtering device 1A is provided.

[0082] As described in the first embodiment, first, in step S11 of FIG. 13, the filter 10 is heated by the heating unit 30. Next, in step S12 of FIG. 13, a liquid containing the filtration target is supplied to the filter 10, and in step S13, the filtration target is captured and held in the filter 10. Steps S11 to S13 are similar to steps S1 to S3 of FIG. 8 described in the first embodiment, and therefore detailed description will be omitted. Once the filtration target is captured and held in step S13, the filtration target captured on the filter 10 can be observed. The filtration target is observed, for example, by capturing an image of the surface of the filter 10 with an imaging unit (not shown).

[0083] After the observation of the cells is completed, in step S14, the filter 10 is cooled by the cooling unit 31. In step S14, the cooling unit 31 is controlled so that the temperature of the filter 10 drops to about 4°C, for example. When the temperature of the filter 10 is lowered, the protrusions 14 of the filter 10 contract, and the captured filtration target material falls off the filter 10 and can be discharged from the filtration device 1A. At this time, the valve 45 is controlled so that the flow path from the filtration device 1A to the cell collection container 44 is open.

[0084] In the above-described embodiment, an example has been described in which cells are captured by filter 10 and observed, and then the cells are dropped through through-holes 12 and discharged into cell collection container 44, but this is not limiting. For example, after cells are captured by filter 10 and observed, filter 10 may be cooled in a state in which holding portion 20 is filled with a collection liquid contained in a container separate from supply container 41 provided upstream of filtration device 1, and the cells may be discharged together with the collection liquid.

[0085] In the above-described embodiment, the cooling unit 31 is a cooling device that circulates cooling water inside a pipe, but the cooling unit 31 is not limited to this. The cooling unit 31 may be a device that can continuously pass cooling water through the filter 10.

[0086] (Example) The filtration device of Example 1 and the filtration device of Comparative Example 1 were compared in terms of the number of cells trapped on the filter 10 and the number of cells recovered after being trapped on the filter 10.

[0087] As Example 1, the filtration device 1A described in Embodiment 2 was used. After the filter 10 was heated to 37°C by the heating unit 30 to filter the cell-containing liquid, the number of cells captured by the filter 10 was counted. Furthermore, after counting the number of filtration targets captured by the filter 10, the filter 10 was cooled to 4°C by the cooling unit 31 to discharge the filtration targets from the filtration device 1A, and the number of filtration targets collected in the cell collection container 44 was counted. The filtration targets were HL-60 cells having a diameter of 12 μm.

[0088] The details of the filtration device 1A of Example 1 will be described. The filter 10 used was circular in plan view, with the membrane portion 11 having a diameter of 25 mm. The thickness H2 (see FIG. 6A) of the membrane portion 11 was 10 μm. The through-holes 12 provided in the membrane portion 11 were formed as squares with a side length L1 (see FIG. 3) of 10 μm. The width L2 (see FIG. 3) of the filter base portion 13 was 8 μm. The multiple protrusions 14 had a height H1 (see FIG. 6A) of 1 μm. The holding portion 20 was formed in a cylindrical shape with an inner diameter of 25 mm, a height H5 (see FIG. 11) of the holding portion 20 of 70 mm, and a height H6 (see FIG. 11) from the upstream end of the holding portion 20 to the filter 10 of 5 mm.

[0089] The filtration device of Comparative Example 1 has the same configurations as the filter 10 and the holding unit 20 of the filtration device 1A of Example 1, but does not have the heating unit 30 and the cooling unit 31.

[0090] 14A is a table showing the number of cells obtained when a liquid containing a filtration target is filtered using the filtration device 1A of Example 1. The number of cells was calculated by counting the number of cells contained in the supply container 41, the number of cells captured by the filter 10 after the liquid was passed through the filtration device 1A, and the number of cells collected in the cell collection container 44 after the captured cells were discharged from the filtration device 1A. In the table of FIG. 14A, "Supply Container" indicates the number of cells counted in the supply container 41, "Filter" indicates the number of cells counted in the filter 10, and "Cell Collection Container" indicates the number of cells counted in the cell collection container 44.

[0091] FIG. 14B is a table showing the number of cells when a liquid containing a filtration target is filtered using the filtration device of Comparative Example 1, and shows the same items as in the table of FIG. 14A.

[0092] The number of cells contained in the liquid in the supply container 41 and the cell collection container 44 was counted using a Thermo Fisher Scientific automated cell counter, Countess. Furthermore, the number of cells in the filter 10 was counted by image processing of an image of the filter 10. The cell counting by image processing was performed as follows. First, an image of the first main surface 10a of the filter 10 was taken using an optical microscope. The optical microscope was adjusted so that the focus was on the cells trapped on the first main surface 10a of the filter 10 from the first main surface 10a side of the holder 20. The captured image was imported into ImageJ image processing software, and the brightness of the captured image was adjusted and a threshold value was set so that the number of cells could be counted. The measurement function of ImageJ was used to count the number of cells trapped on the first main surface 10a of the filter 10 in the image. The number of cells trapped on the first main surface 10a of the filter 10 was calculated based on the ratio between the number of unit cells in the image and the design value of the number of unit cells for the filter 10. The number of cells in filter 10 was counted while filter 10 was heated by heating unit 30. On the other hand, the number of cells in cell collection container 44 was counted after filter 10 was cooled by cooling unit 31. Therefore, when cell counting is performed using filtration device 1 of embodiment 1 as an example, it is considered that the number of cells in filter 10 will be similar to that in the case of filtration device 1A of example 1. In comparative example 1, the number of cells in filter 10 and cell collection container 44 was counted without heating or cooling filter 10.

[0093] As shown in Figures 14A and 14B, filter 10 in Example 1 is able to capture approximately 2.9 times more cells than Comparative Example 1. By heating filter 10, the multiple protrusions 14 expand and the surface area increases, which shows that filter 10 is able to capture more cells. Furthermore, in cell collection container 44, Example 1 is able to collect approximately 4.6 times more cells than Comparative Example 1. By cooling filter 10 after cells are captured in filter 10, the multiple protrusions 14 contract and the surface area decreases, making it easier for the captured cells to drop out, and it shows that more cells can be collected.

[0094] Next, the number of cells trapped by the filter 10 and the number of cells recovered after being trapped by the filter 10 were similarly compared for the filtration device of Example 1 and the filtration device of Comparative Example 2.

[0095] The filtration device of Comparative Example 2 has a filter different from that of filtration device 1A of Example 1. Specifically, the filter of the filtration device of Comparative Example 2 does not have protrusions. The other configurations of the filtration device of Comparative Example 2 are the same as those of filtration device 1A of Example 1. The method of counting the number of cells is the same as in the comparison between Example 1 and Comparative Example 1.

[0096] Fig. 15A is a table showing the number of cells when a liquid containing a filtration target is filtered using the filtration device 1A of Example 1. Fig. 15B is a table showing the number of cells when a liquid containing a filtration target is filtered using the filtration device of Comparative Example 2, and shows the same items as in the table of Fig. 15A.

[0097] As shown in Figures 15A and 15B, filter 10 in Example 1 was able to capture approximately 2.9 times more cells than in Comparative Example 2. It can be seen that the provision of protrusions 14 on filter 10 increases the surface area of ​​filter 10, making it easier to capture cells. Furthermore, in cell collection container 44, Example 1 was able to collect approximately 4.2 times more cells than Comparative Example 2. It is believed that the number of collected cells was also greater in Example 1 because more cells were captured by filter 10 in Example 1 than in Comparative Example 2.

[0098] (Outline of the embodiment) (1) The filtration device of the present disclosure is a filtration device for filtering a liquid containing cells, and includes a filter having a first main surface, a second main surface opposite the first main surface, a membrane portion having a filter base portion defining a plurality of through holes penetrating from the first main surface toward the second main surface, and a plurality of protrusions provided on the filter base portion of at least the first main surface, a holding portion for holding the filter, and a heating portion for heating the filter, wherein the first main surface is located upstream of the second main surface, and the plurality of protrusions expand when the filter is heated by the heating portion.

[0099] (2) In the filtering device of (1), the filter may be made of a thermally expandable resin.

[0100] (3) In the filtration device of (1) or (2), the plurality of protrusions may be provided on the first main surface of the filter base.

[0101] (4) In the filtration device of any one of (1) to (3), when viewed from a direction perpendicular to the first main surface, the plurality of through holes may be arranged in a lattice pattern including an orthorhombic lattice, a hexagonal lattice, a triangular lattice, a square lattice, a rectangular lattice, or a parallelepiped lattice, and the plurality of protrusions may include at least one protrusion provided on the filter base portion that constitutes a unit lattice, which is the smallest unit for forming the arrangement.

[0102] (5) In any one of the filtration devices (1) to (4), the height of the protrusions may be smaller than the thickness of the membrane portion of the filter, and the height of the protrusions may be the distance from the surface of the filter base portion to the top of the protrusions.

[0103] (6) In the filtration device of any one of (1) to (5), the height of the protrusions may be 0.1 μm or more and 2 μm or less, and the height of the protrusions may be the distance from the surface of the filter base to the top of the protrusions.

[0104] (7) In any one of the filtration devices (1) to (6), the plurality of protrusions may be provided on a first main surface of the filter base portion, and recesses may be provided between the plurality of protrusions on the first main surface of the filter base portion.

[0105] (8) In any one of the filtration devices (1) to (6), the plurality of protrusions may be provided on a first main surface of the filter base portion, and flat portions may be provided between the plurality of protrusions on the first main surface of the filter base portion.

[0106] (9) In any one of the filtration devices (1) to (8), the filter base portion has a first end portion on the side of a first through hole among the plurality of through holes and a second end portion on the side of a second through hole adjacent to the first through hole, and the plurality of protrusions may be provided between the first end portion and the second end portion.

[0107] (10) In the filtration device of (9), the plurality of protrusions may be positioned at a first distance from the first end and a second distance from the second end, and the first distance and the second distance may be 1 / 5 or more of the distance from the first end to the second end.

[0108] (11) The filtering device of any one of (1) to (10) may further include a cooling unit that cools the filter.

[0109] (12) The filtration method of the present disclosure is a method for filtering a liquid containing cells using any one of the filtration devices (1) to (11), and includes the steps of heating the filter using a heating unit of the filtration device, supplying the liquid containing cells to the filter, and capturing the cells with the filter and retaining the cells on multiple protrusions.

[0110] (13) The filtration method of (12), further comprising the step of cooling the filter. [Industrial Applicability]

[0111] The filtration filter of the present invention is useful for filtering a liquid containing cells, such as a cell suspension. [Explanation of symbols]

[0112] 1, 1A filtration device 10 Filters 10a, 110a First principal surface 10b Second principal surface 11 Membrane part 12 Through holes 12a 1st through hole 12b 2nd through hole 13, 113 Filter base 14, 114 protrusion 16 Frame 20 Holding part 30 Heating section 31 Cooling section 115 recess

Claims

1. A filtration device for filtering a liquid containing cells, comprising: a filter including a first main surface, a second main surface opposite to the first main surface, a membrane portion having a filter base portion defining a plurality of through holes penetrating from the first main surface toward the second main surface, and a plurality of protrusions provided on the filter base portion at least on the first main surface; a holder for holding the filter; a heating unit that heats the filter; Equipped with the first main surface is located upstream of the second main surface, the plurality of protrusions expand when the filter is heated by the heating unit; Filtration device.

2. The filter is formed of a thermally expandable resin. The filtration device of claim 1 .

3. the plurality of protrusions are provided on the first main surface of the filter base; The filtration device of claim 1 .

4. When viewed from a direction perpendicular to the first main surface, the plurality of through holes are arranged in a lattice pattern including an orthorhombic lattice, a hexagonal lattice, a triangular lattice, a square lattice, a rectangular lattice, or a parallelepiped lattice; the plurality of protrusions include at least one protrusion provided on the filter base portion that constitutes a unit lattice, which is the smallest unit for constituting an array; The filtration device of claim 1 .

5. The height of the protrusion is smaller than the thickness of the membrane portion of the filter, The height of the protrusion is the distance from the surface of the filter base to the top of the protrusion. The filtration device of claim 1 .

6. The height of the protrusions is 0.1 μm or more and 2 μm or less, The height of the protrusion is the distance from the surface of the filter base to the top of the protrusion. The filtration device of claim 1 .

7. the plurality of protrusions are provided on a first main surface of the filter base, a recessed portion is provided between the plurality of protrusions on the first main surface of the filter base; The filtration device of claim 1 .

8. the plurality of protrusions are provided on a first main surface of the filter base, a flat portion is provided between the plurality of protrusions on the first main surface of the filter base; The filtration device of claim 1 .

9. the filter base portion has a first end portion on a side of a first through hole among the plurality of through holes and a second end portion on a side of a second through hole adjacent to the first through hole, The plurality of protrusions are provided between the first end and the second end. The filtration device of claim 1 .

10. the plurality of protrusions are positioned a first distance from the first end and a second distance from the second end; the first distance and the second distance are equal to or greater than 1 / 5 of the distance from the first end to the second end; 10. The filtration device of claim 9.

11. moreover, a cooling unit that cools the filter; Equipped with The filtration device of claim 1 .

12. A method for filtering a liquid containing cells using the filtering device according to any one of claims 1 to 11, comprising: heating the filter by the heating unit of the filtering device; providing a liquid containing the cells to the filter; capturing the cells with the filter and retaining the cells on the plurality of protrusions; Including, Filtration method.

13. Further comprising the step of cooling the filter. The filtration method according to claim 12.

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