Microfluidic devices

Abstract

To provide a microfluidic device that can uniformly culture hepatocytes at high density and efficiently collect excreted bile.SOLUTION: A microfluidic device 1 comprises: a device body 2 having an upper surface 2a and a lower surface 2b; a first recess 3 for culturing cells and a second recess 4 for supplying or discharging a fluid, which open on the upper surface 2a of the device body 2 at positions spaced apart in a first horizontal direction D1 parallel to the upper surface 2a of the device body 2; and a microchannel 5 connecting the bottom surface 3a of the first recess 3 with the bottom surface 4a of the second recess 4. The microchannel 5 comprises a plurality of first grooves 51 formed at least on the bottom surface 3a of the first recess 3 and aligned in a second horizontal direction D2 perpendicular to the first horizontal direction D1.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to microfluidic devices. [Background technology]

[0002] It has been proposed to use a microfluidic device with a microchannel for culturing hepatocytes and collecting and analyzing bile excreted from the hepatocytes. For example, Patent Documents 1 and 2 listed below disclose a bile collection chip in which a tubular microchannel has a bottom surface on which a region for culturing hepatocytes has comb-like irregularities, and a well through which a culture medium can be introduced or discharged is connected to the microchannel, and the irregularities extend to a collection port for collecting bile. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2023-20221 [Patent Document 2] International Publication No. 2022 / 118885 Summary of the Invention [Problem to be solved by the invention]

[0004] However, it has been difficult to culture hepatocytes uniformly at high density on the uneven surface of a tubular microchannel. This is because the amount of culture medium required for microchannels is limited, necessitating the use of a culture medium with a high cell density. However, attempting to introduce a cell-dense liquid into the microchannel results in high fluid resistance, making injection difficult. Furthermore, the cells tend to disperse unevenly during the injection process, resulting in inconsistent cell distribution after seeding. Furthermore, while it is desirable to limit cell culture to the uneven surface, cells are seeded throughout the microchannel, necessitating the removal of cells from areas other than the uneven surface. Furthermore, the removed cells must be discarded, which increases costs when culturing expensive cells.

[0005] In view of the above problems, an object of the present invention is to provide a microfluidic device that can culture hepatocytes uniformly and at high density and efficiently collect excreted bile. [Means for solving the problem]

[0006] The microfluidic device of the present invention comprises: a device body having an upper surface and a lower surface; a first recess for culturing cells and a second recess for supplying or discharging a fluid, the first recess and the second recess opening on the upper surface of the device body at positions spaced apart in a first lateral direction parallel to the upper surface of the device body; a microchannel communicating a bottom surface of the first recess and a bottom surface of the second recess, The microchannel includes a plurality of first grooves formed at least on the bottom surface of the first recess and aligned in a second horizontal direction perpendicular to the first horizontal direction.

[0007] According to this configuration, the first groove, which is a part of the microchannel, is formed on the bottom surface of the first recess for culturing cells, so that hepatocytes can be reliably seeded on the microchannel and cultured uniformly and at high density on the microchannel. Furthermore, bile excreted from hepatocytes flows into the first groove, so that the excreted bile can be discharged from the second recess via the microchannel and efficiently collected.

[0008] In addition, in the microfluidic device according to the present invention, the microchannel may be configured to include a plurality of holes formed between the first recess and the second recess, aligned in a second horizontal direction, and connected to the first horizontal ends of the plurality of first grooves, respectively.

[0009] With this configuration, bile that has flowed into the first groove can be appropriately guided to the second recess through the hole.

[0010] In the microfluidic device according to the present invention, the microchannel includes a plurality of second grooves formed in a bottom surface of the second recess and aligned in a second lateral direction, The second grooves may be connected to the first lateral ends of the holes, respectively.

[0011] According to this configuration, bile that has flowed into the first groove can be appropriately guided to the second recess via the hole and the second groove.

[0012] In addition, in the microfluidic device of the present invention, the first recess may be configured to include a lower space extending upward from the bottom surface, a step portion at the upper end of the lower space that has a larger cross-sectional area than the lower space, and an upper space adjacent to the upper side of the lower space and whose cross-sectional area is expanded by the step portion.

[0013] With this configuration, the lower space is recessed, making it easy to seed hepatocytes in the lower space and allowing for high-density hepatocyte culture. In addition, the upper space is larger than the lower space, making it possible to culture hepatocytes in the lower space while perfusing a medium in the upper space.

[0014] In the microfluidic device according to the present invention, a plurality of the first recesses and a plurality of the second recesses are provided along a second lateral direction, The lower spaces adjacent to each other may be independent from each other, and the upper spaces adjacent to each other may be connected to each other.

[0015] According to this configuration, the culture medium can be perfused through one upper space to the plurality of first wells, and therefore cells can be cultured efficiently.

[0016] Furthermore, in the microfluidic device according to the present invention, a plurality of the first recesses may be provided independently of each other along the first lateral direction.

[0017] According to this configuration, cells can be cultured in a plurality of first wells at the same time, and therefore cells can be cultured efficiently.

[0018] In the microfluidic device according to the present invention, a plurality of the second recesses may be provided so as to sandwich the first recess in the first lateral direction.

[0019] According to this configuration, for example, a liquid can be supplied to one second recess, and the liquid can be discharged while excretory substances such as bile are collected from another second recess.

[0020] In the microfluidic device according to the present invention, the plurality of first grooves may be formed over the entire bottom surface of the first recess.

[0021] According to this configuration, the areas where cells are cultured can be limited to above the plurality of first grooves, so that hepatocytes can be cultured at high density. [Brief explanation of the drawings]

[0022] [Figure 1] 1 is a perspective view of a microfluidic device according to an embodiment of the present invention; [Figure 2] 1 is a plan view of a microfluidic device according to an embodiment of the present invention; [Figure 3] Cross-sectional view of the microfluidic device shown in Figure 2, taken along line III-III [Figure 4] Cross-sectional view of the microfluidic device shown in Figure 2, taken along line IV-IV. [Figure 5] 3 is a cross-sectional view of the microfluidic device 1 taken along line VV in FIG. [Figure 6] 6 is a cross-sectional view of the microfluidic device 1 taken along line VI-VI in FIG. [Figure 7] Perspective view of the first substrate [Figure 8] Perspective view of the second substrate [Figure 9] A perspective view showing an example of how to use a microfluidic device. [Figure 10] 1 is a plan view of a microfluidic device according to another embodiment; [Figure 11] 1 is a plan view of a microfluidic device according to another embodiment; [Figure 12]1 is a plan view of a microfluidic device according to another embodiment; [Figure 13] 1 is a plan view of a microfluidic device according to another embodiment; [Figure 14] 1 is a plan view of a microfluidic device according to another embodiment; [Figure 15] 1 is a plan view of a microfluidic device according to another embodiment; [Figure 16] 1 is a plan view of a microfluidic device according to another embodiment; [Figure 17] 1 is a plan view of a microfluidic device according to another embodiment; DETAILED DESCRIPTION OF THE INVENTION

[0023] The microfluidic device according to the present invention will be described with reference to the drawings. Note that the drawings disclosed in this specification are merely schematic illustrations. That is, the dimensional ratios in the drawings do not necessarily match the actual dimensional ratios, and the dimensional ratios between the drawings do not necessarily match.

[0024] Fig. 1 is a perspective view of a microfluidic device 1 according to this embodiment, and Fig. 2 is a plan view of the microfluidic device 1 according to this embodiment. Fig. 3 is a cross-sectional view of the microfluidic device 1 shown in Fig. 2 taken along line III-III, Fig. 4 is a cross-sectional view of the microfluidic device 1 shown in Fig. 2 taken along line IV-IV, Fig. 5 is a cross-sectional view of the microfluidic device 1 shown in Fig. 2 taken along line VV, and Fig. 6 is a cross-sectional view of the microfluidic device 1 shown in Fig. 2 taken along line VI-VI.

[0025] The microfluidic device 1 includes a device body 2 having a substantially rectangular parallelepiped shape. The device body 2 has an upper surface 2a and a lower surface 2b that face each other in a vertical direction D3. In this embodiment, the upper surface 2a and the lower surface 2b are rectangular. In the following description, a horizontal direction parallel to the upper surface 2a and along one side of the upper surface 2a is referred to as a first horizontal direction D1, and a horizontal direction parallel to the upper surface 2a and perpendicular to the first horizontal direction D1 is referred to as a second horizontal direction D2.

[0026] The microfluidic device 1 has a first recess 3 and a second recess 4 that open on the upper surface 2a of the device body 2. The first recess 3 and the second recess 4 have bottom surfaces 3a and 4a, respectively, that are located midway in the up-down direction D3 of the device body 2. The first recess 3 and the second recess 4 also have openings 3b and 4b, respectively, that are located on the upper surface 2a of the device body 2.

[0027] The first recess 3 and the second recess 4 are arranged side by side in the first horizontal direction D1. The first recess 3 and the second recess 4 are also arranged spaced apart from each other. In other words, it can be said that the opening 3b of the first recess 3 and the opening 4b of the second recess 4 are arranged spaced apart from each other.

[0028] The first well 3 is used for seeding and culturing cells. The second well 4 is used for supplying or discharging liquid to or from the microfluidic device 1. In this embodiment, two second wells 4 are provided on either side of the first well 3 in the first lateral direction D1, and, for example, liquid is supplied to one of the second wells 4 and discharged from the other second well 4.

[0029] 3, the first recess 3 includes a lower space 31 extending upward from the bottom surface 3a, and an upper space 32 adjacent to the upper side of the lower space 31 and having a larger cross-sectional area than the lower space 31. The first recess 3 includes a step portion 33 at the upper end of the lower space 31 that has a larger cross-sectional area than the lower space 31, and the cross-sectional area of ​​the upper space 32 is enlarged by this step portion 33.

[0030] The bottom surface 3a is, but is not limited to, square-shaped as shown in FIG. 2. The lower space 31 extends upward from the bottom surface 3a with a constant cross-sectional area. The opening 3b is wider than the bottom surface 3a and is located further outward than the bottom surface 3a in a plan view. The opening 3b is, but is not limited to, approximately elliptical-shaped as shown in FIG. 2. The upper space 32 extends downward from the opening 3b with a constant cross-sectional area. The opening 3b is formed so that its width in the second horizontal direction D2 is greater than its width in the first horizontal direction D1. As a result, the distance from the lower space 31 to the second horizontal direction D2 of the step portion 33 is longer than its distance in the first horizontal direction D1.

[0031] The lower space 31 has a width of 4 mm in the first horizontal direction D1, a width of 4 mm in the second horizontal direction D2, and a height of 3 mm in the vertical direction D3. The upper space 32 has a width of 6 mm in the first horizontal direction D1, a width of 12 mm in the second horizontal direction D2, and a height of 5 mm in the vertical direction D3. The width of the upper space 32 in the second horizontal direction D2 is set to the maximum width at which the curve in the second horizontal direction D2 widens to its widest.

[0032] The bottom surface 4a of the second recess 4 is, although not limited to, a generally elliptical shape as shown in FIG. 2. The second recess 4 extends upward from the bottom surface 4a with a constant cross-sectional area. As a result, the opening 4b overlaps the bottom surface 4a in a plan view. The second recess 4 has, for example, a width of 2 mm in the first horizontal direction D1, a width of 6 mm in the second horizontal direction D2, and a height of 8 mm in the up-down direction D3. The width of the second recess 4 in the second horizontal direction D2 is set to the maximum width at which the curve in the second horizontal direction D2 widens to its widest.

[0033] 2 and 6, the microfluidic device 1 includes a microchannel 5 that communicates between the bottom surface 3a of the first recess 3 and the bottom surface 4a of the second recess 4. The microchannel 5 extends in a first lateral direction D1.

[0034] The microchannel 5 includes a plurality of first grooves 51 formed on the bottom surface 3a of the first recess 3. The plurality of first grooves 51 are aligned in the second lateral direction D2. The plurality of first grooves 51 are preferably formed over the entire bottom surface 3a of the first recess 3. In this embodiment, as shown in FIG. 2, the plurality of first grooves 51 are formed over the entire bottom surface 3a in the first lateral direction D1 and over substantially the entire bottom surface 3a in the second lateral direction D2.

[0035] The cross section of the first groove 51 in this embodiment is rectangular. However, the cross section of the first groove 51 is not limited to a rectangular shape, and may be a trapezoid or semi-ellipse whose width narrows toward the groove bottom.

[0036] The width of the first grooves 51 (width in the second horizontal direction D2) is, for example, 3 to 100 μm, and is 5 μm in this embodiment. The depth of the first grooves 51 (height in the vertical direction D3) is, for example, 5 to 150 μm, and is 10 μm in this embodiment. The spacing between the first grooves 51 is 1 to 2 times the width, and is 20 μm in this embodiment. There may be, for example, 20 to 1000 first grooves 51, but for ease of explanation, only 13 are shown in this embodiment.

[0037] The microchannel 5 also has a plurality of second grooves 52 formed on the bottom surface 4a of the second recess 4. The plurality of second grooves 52 are aligned in the second horizontal direction D2. The width of the second grooves 52 (width in the second horizontal direction D2) is, for example, 3 to 100 μm, and in this embodiment, 5 μm. The depth of the second grooves 52 (height in the vertical direction D3) is, for example, 5 to 150 μm, and in this embodiment, 10 μm. The interval between the second grooves 52 is 1 to 50 times the width, and in this embodiment, 20 μm. The width of this interval is selected depending on the adhesiveness of the cells to be used.

[0038] The microchannel 5 also has a plurality of holes 53 formed between the first recess 3 and the second recess 4. The plurality of holes 53 are aligned in the second horizontal direction D2. The plurality of holes 53 are connected to the ends of the plurality of first grooves 51 in the first horizontal direction D1, respectively. The plurality of second grooves 52 are also connected to the ends of the plurality of holes 53 in the first horizontal direction D1, respectively.

[0039] It is preferable that the first groove 51, the second groove 52, and the holes 53 all have the same cross-sectional shape and are connected to each other. As a result, the bottom and side surfaces of the first groove 51, the second groove 52, and the holes 53 are continuous without any steps, so the flow of liquid is not obstructed. The length of the holes 53 is, for example, 2 mm. The holes 53 may also be connected to adjacent holes. This reduces the fluid resistance within the holes, improving the flow of liquid.

[0040] The device body 2 of this embodiment may include a first substrate 21 shown in Fig. 7 and a second substrate 22 shown in Fig. 8 that is arranged in partial contact with the upper surface of the first substrate 21. That is, the microfluidic device 1 may be formed by stacking and bonding the second substrate 22 so that the lower surface of the second substrate 22 is in partial contact with the upper surface of the first substrate 21. An example of a method for manufacturing such a microfluidic device 1 will be described below.

[0041] (Substrate preparation process) First, a first substrate 21 and a second substrate 22 are prepared, which constitute the microfluidic device 1. At this stage, the first substrate 21 and the second substrate 22 are, for example, rectangular plate-shaped members.

[0042] The first substrate 21 and the second substrate 22 are preferably made of a substantially non-porous material. Here, "substantially non-porous" refers to a state in which the apparent surface area of ​​the substrate is close to its actual surface area. Examples of materials that form such non-porous bodies include inorganic materials such as glass and silicon, and resin materials such as polymethyl methacrylate (PMMA), polycarbonate (PC), cycloolefin copolymer (COC), cycloolefin polymer (COP), polystyrene (PS), and silicone. Two or more of these resin materials may be combined. The materials used for the first substrate 21 and the second substrate 22 may also be different.

[0043] (Shape processing of first substrate 21) Lithography is used to etch the first substrate 21 to a fine depth in the regions where the first groove 51, the second groove 52, and the holes 53 are to be formed. This etching depth is set according to the depths of the first groove 51 and the second groove 52 and the height corresponding to the diameter of the holes 53, as described above. If the cross-sectional shapes of the first groove 51, the second groove 52, and the holes 53 are the same, this processing will form the uneven groove 21a over the entire region where the microchannel 5 is to be formed. Thereafter, the second substrate 22 is bonded to the upper surface of the first substrate 21, and as a result, the uneven groove 21a is partially covered with the second substrate 22, and multiple holes 53 are formed.

[0044] (Shape processing of second substrate 22) The through holes 22a and 22b are formed in the second substrate 22 in the areas where the first recess 3 and the second recess 4 are to be formed by injection molding, cutting or the like.

[0045] (Joining process) The first substrate 21 and second substrate 22 thus shaped are bonded together to obtain the microfluidic device 1 shown in Fig. 1. Bonding methods that can be used include bonding using surface modification using light or plasma, thermal bonding, adhesion using an adhesive, and bonding using a solvent. An example of a bonding method is as follows.

[0046] First, a surface activation process is performed on the bonding surfaces of the first substrate 21 and the second substrate 22. As a method of surface activation process, a method of irradiating ultraviolet light can be used. Specifically, this is performed by irradiating vacuum ultraviolet light (VUV) with a wavelength of 200 nm or less from an ultraviolet light source. As the ultraviolet light source, a Xe excimer lamp with a peak wavelength of around 172 nm, a low-pressure mercury lamp with an emission line at 185 nm, a deuterium lamp with an emission line in the wavelength range of 120 to 200 nm, or the like can be suitably used. The illuminance of the vacuum ultraviolet light is, for example, 10 to 500 mW / cm. 2 The irradiation time is set appropriately depending on the materials from which the first substrate 21 and the second substrate 22 are made, but is, for example, 0.1 to 60 seconds.

[0047] Next, the bonding surfaces of the first substrate 21 and the second substrate 22 that have been subjected to the surface activation treatment are brought into contact with each other and pressed together using a press or the like. This step is carried out in a heated environment as necessary to strengthen the bond. In the bonding step, bonding conditions such as the heating temperature and pressing force are set depending on the constituent materials of the first substrate 21 and the second substrate 22. Specific conditions include a temperature during pressing of, for example, 40 to 150°C, and a pressing force for bonding of, for example, 0.1 to 10 MPa. This bonding step is preferably carried out in a state where the surface activation state of the bonding surfaces of the first substrate 21 and the second substrate 22 is maintained. From this perspective, it is advisable to carry out the bonding step within, for example, 10 minutes after completion of the ultraviolet irradiation.

[0048] After pressurizing the first substrate 21 and the second substrate 22, they may be further heated for a predetermined time, if necessary. As a detailed example, after maintaining the pressurized state of the first substrate 21 and the second substrate 22 for a predetermined time, the pressurized state may be released and the temperature may be raised to a predetermined temperature, which may be maintained until the desired bonding state is achieved. Here, the predetermined temperature is a temperature at which the first substrate 21 and the second substrate 22 will not be deformed by heating.

[0049] After that, a cooling step is performed, and the microfluidic device 1 in which the second substrate 22 is in partial contact with the upper surface of the first substrate 21 is obtained.

[0050] The second substrate 22 may be composed of two plate-like members divided at the position of the step portion 33 of the first recess 3. In this case, a through hole may be formed in one of the plate-like members in an area where the lower space 31 is to be formed, and a through hole may be formed in the other plate-like member in an area where the upper space 32 is to be formed.

[0051] Next, a description will be given of an example of a method of using the microfluidic device 1. Here, an example will be shown in which the microfluidic device 1 is used for collecting bile secreted from hepatocytes.

[0052] i) First, as shown by the solid arrow in FIG. 9, hepatocytes are seeded in the lower space 31 of the first well 3. At this time, since the lower space 31 is recessed, it is easy to seed the hepatocytes in the lower space 31. The hepatocytes are preferably introduced as dispersed cells. Alternatively, they may be introduced as cell clusters. The size of the cell clusters at this time is, for example, about 30 to 100 μm.

[0053] The hepatocytes placed in the first well 3 adhere to the bottom surface 3a. The hepatocytes adhere to the bottom surface 3a so as to cover the upper part of the first groove 51.

[0054] ii) Next, a culture medium (medium) is supplied to the first recess 3, and hepatocytes are cultured. As shown by the dashed-dotted arrows in FIG. 9 , the culture medium is supplied from one side of the upper space 32 in the second horizontal direction D2 and discharged from the other side of the second horizontal direction D2 to the upper space 32, thereby perfusing the culture medium in the upper space 32. The first recess 3 has an upper space 32 that is larger than the lower space 31, so that hepatocytes can be cultured in the lower space 31 while the culture medium is perfusing in the upper space 32. Because the lower space 31 is recessed, the influence of the perfusion of the culture medium on the hepatocytes in the lower space 31 can be reduced. The hepatocytes grow until they cover most or all of the bottom surface 3a of the first recess 3. As the hepatocytes grow, bile canaliculi (microbile ducts) are formed within the hepatocytes. Bile excreted from the bile canaliculi flows into the first groove 51.

[0055] 9, liquid is supplied from one of the second recesses 4, and the liquid is discharged from the other second recess 4 while bile is collected from the microchannel 5. At this time, most or all of the bottom surface 3a of the first recess 3 is covered with hepatocytes, so that the culture medium in the first recess 3 can be largely or completely prevented from flowing into the first groove 51. This makes it possible to collect bile excreted from the hepatocytes at a high concentration.

[0056] Although the embodiments of the present invention have been described above with reference to the drawings, the specific configurations should not be considered to be limited to these embodiments. The scope of the present invention is defined not only by the description of the above embodiments but also by the claims, and further includes all modifications within the meaning and scope of the claims.

[0057] The structures employed in the above-described embodiments can be employed in any other embodiment. The specific configurations of the components are not limited to the above-described embodiments, and various modifications are possible within the scope of the present invention.

[0058] (1) In the above embodiment, the microchannel 5 is provided with a plurality of holes 53 that are arranged in the second horizontal direction D2 between the first recess 3 and the second recess 4 and are connected to the ends of the plurality of first grooves 51 in the first horizontal direction D1, but is not limited to this. For example, the microchannel 5 may be provided with one hole between the first recess 3 and the second recess 4 that is connected to all of the ends of the plurality of first grooves 51 in the first horizontal direction D1.

[0059] (2) The microchannel 5 may also have a plurality of third grooves formed between the first recess 3 and the second recess 4, aligned in the second horizontal direction D2, and connected to the ends of the plurality of first grooves 51 in the first horizontal direction D1.

[0060] (3) In the above embodiment, the microchannel 5 includes a plurality of second grooves 52 formed in the bottom surface 4a of the second recess 4 and aligned in the second horizontal direction D2, and the plurality of second grooves 52 are connected to the ends of the plurality of holes 53 in the first horizontal direction D1, respectively. However, this is not limiting. For example, the microchannel 5 may include one groove formed in the bottom surface 4a of the second recess 4, and the one groove may be connected to all of the ends of the plurality of holes 53 in the first horizontal direction D1.

[0061] (4) In the above embodiment, the first recess 3 includes the lower space 31 extending upward from the bottom surface 3a, the step portion 33 at the upper end of the lower space 31 that has a larger cross-sectional area than the lower space 31, and the upper space 32 adjacent to the upper side of the lower space 31 and whose cross-sectional area is enlarged by the step portion 33. However, the first recess 3 may be a cylindrical depression that does not include the step portion 33.

[0062] (5) In the above embodiment, the second groove 52 is formed across the entire bottom surface 4a of the second recess 4 in the first horizontal direction D1, but this is not limiting. For example, as shown in Fig. 10, the second groove 52 may be formed up to the center of the bottom surface 4a of the second recess 4 in the first horizontal direction D1.

[0063] (6) In the above embodiment, the bottom surface 3a of the first recess 3 has a square shape, but this is not limited thereto. For example, the bottom surface 3a of the first recess 3 may have a circular shape as shown in Fig. 11. In this case, the lower space 31 has a cylindrical shape.

[0064] (7) In the above embodiment, two second recesses 4 are provided on either side of the first recess 3 in the first horizontal direction D1, but this is not limiting. For example, only one second recess 4 may be provided for each first recess 3, as shown in Fig. 12. Note that, for ease of explanation, Fig. 12 omits the device body 2 and illustrates the microchannel 5 (first groove 51, second groove 52, hole 53) in a simplified manner (the same applies to Figs. 13 to 17).

[0065] (8) In the above embodiment, only one first recess 3 is provided, but this is not limited to this. For example, a plurality of first recesses 3 may be provided independently of each other along the first horizontal direction D1, as shown in Fig. 13. In the example shown in Fig. 13, two first recesses 3 are provided independently of each other along the first horizontal direction D1, but three or more first recesses 3 may be provided.

[0066] (9) The first recess 3 and the second recess 4 may also be arranged as shown in FIG.

[0067] (10) The first recess 3 and the second recess 4 may also be arranged as shown in Fig. 15. In the example shown in Fig. 15, the second recess 4 is sandwiched between the first recess 3 in the first horizontal direction D1.

[0068] (11) Furthermore, as shown in Fig. 16, a configuration may be adopted in which a plurality of first recesses 3 and a plurality of second recesses 4 are provided along the second horizontal direction D2. In the example shown in Fig. 16, two first recesses 3 and two second recesses 4 are provided along the second horizontal direction D2, but three or more first recesses 3 and two second recesses 4 may be provided. In this case, as shown in Fig. 16, the first recesses 3 may be configured such that adjacent lower spaces 31 are independent from each other and adjacent upper spaces 32 are connected to each other.

[0069] (12) The first recess 3 and the second recess 4 may also be arranged as shown in Fig. 17. The embodiment shown in Fig. 17 is a combination of the embodiment shown in Fig. 14 and the embodiment shown in Fig. 16. [Explanation of symbols]

[0070] 1: Microfluidic device 2: Device itself 2a:Top surface 2b: Bottom surface 3: First recess 3a: Bottom 3b:Aperture 4: Second recess 4a: Bottom 4b:Aperture 5: Microchannel 21: First board 21a: Uneven groove 22: Second board 22a: Through hole 22b: Through hole 31: Lower space 32: Upper space 33: Step 51: 1st groove 52: 2nd groove 53 :hole D1: 1st horizontal direction D2: 2nd horizontal direction D3: Up and down direction

Claims

1. a device body having an upper surface and a lower surface; a first recess for culturing cells and a second recess for supplying or discharging a fluid, the first recess and the second recess opening on the upper surface of the device body at positions spaced apart in a first lateral direction parallel to the upper surface of the device body; a microchannel communicating a bottom surface of the first recess and a bottom surface of the second recess, A microfluidic device, wherein the microchannel comprises a plurality of first grooves formed at least on the bottom surface of the first recess and aligned in a second horizontal direction perpendicular to the first horizontal direction.

2. 2. The microfluidic device according to claim 1, wherein the microchannel comprises a plurality of holes formed between the first recess and the second recess in a second horizontal direction and connected to respective ends of the first grooves in the first horizontal direction.

3. the microchannel includes a plurality of second grooves formed on a bottom surface of the second recess and aligned in a second horizontal direction; The microfluidic device according to claim 2 , wherein the second grooves are connected to first lateral ends of the holes, respectively.

4. 3. The microfluidic device according to claim 1, wherein the first recess comprises a lower space extending upward from a bottom surface, a step portion at an upper end of the lower space that has a larger cross-sectional area than the lower space, and an upper space adjacent to the upper side of the lower space and whose cross-sectional area is enlarged by the step portion.

5. a plurality of the first recesses and a plurality of the second recesses are provided along a second lateral direction; The microfluidic device according to claim 4 , wherein the adjacent lower spaces are independent of each other and the adjacent upper spaces are in communication with each other.

6. The microfluidic device according to claim 1 , wherein a plurality of the first recesses are provided independently of each other along the first lateral direction.

7. The microfluidic device according to claim 1 , wherein a plurality of the second recesses are provided so as to sandwich the first recess in the first horizontal direction.

8. The microfluidic device according to claim 1 , wherein the plurality of first grooves are formed over the entire bottom surface of the first recess.

Images