Sperm sorting device and sorting method

Abstract

[Problem] To improve a sperm yield. [Solution] A sperm sorting device 1 comprises: a bottom wall 11; a side wall 12; and an internal space 13 defined by the bottom wall 11 and the side wall 12. The internal space 13 has: an input part 31; a collection part 32; and a communication part 33 for connecting the input part 31 and the recovery part 32. The communication part 33 includes: a bottom surface 43; and an inner wall 44 extending upward from the bottom surface 43 and across the input part 31 and the recovery part 32. Motile sperm 200 introduced into the input part 31 move to the collection part 32 along the bottom surface 43 of the communication part 33 and a surface of the inner wall 44. Even motile sperm 200 with a low acceleration against gravity can move from the input part 31 to the collection part 32 through the communication part 33.

Description

Sperm sorting device and method

[0001] The present invention relates to a sperm sorting device and a sperm sorting method for sorting sperm with high motility.

[0002] Patent Document 1 proposes a device comprising a tubular container, a tubular sampling section with one open end and the other closed, and an annular bottom wall connecting the outer periphery of the sampling section to the inner periphery of the tubular container. In a vertically standing tubular container, semen is poured into an area defined by the annular bottom wall, the outer periphery of the sampling section, and the inner periphery of the tubular container. Sperm with high motility (hereinafter also referred to as "motile sperm") move through the culture medium poured into the tubular container together with the semen, moving inward from the sampling section. Sperm with low motility (hereinafter also referred to as "immotile sperm") remain at the annular bottom wall. This allows the device to separate motile and immotile sperm.

[0003] French Patent Publication No. 2539628

[0004] When motile sperm move upward along the outer circumferential surface of the sampling section, they may change direction or become stuck and not be able to move all the way up the outer circumferential surface. For example, moving upward against gravity requires more energy than moving horizontally or downward, and without such energy, even motile sperm cannot move to the inside of the sampling section. As a result, motile sperm may remain outside the sampling section.

[0005] The present invention has been made in consideration of the above problems, and aims to provide a sperm sorting device and a sorting method that can improve the yield of highly motile sperm.

[0006] (1) The sperm sorting device has a bottom wall, a side wall, and an internal space partitioned by the bottom wall and the side wall, and the internal space has an input section, a recovery section, and a connecting section connecting the input section and the recovery section, and the connecting section has a bottom surface and an inner wall extending upward from the bottom surface and across the input section and the recovery section.

[0007] Sperm injected into the input section move along the bottom surface and inner wall surface of the connecting section to the collection section. Even sperm with a small acceleration against gravity can move from the input section to the collection section through the connecting section.

[0008] (2) The bottom surface may be inclined obliquely upward from the input section toward the recovery section.

[0009] Sperm with low motility do not climb the bottom and remain in the injection section, while sperm with high motility move to the recovery section.

[0010] (3) The collection section may be recessed downward from the bottom surface, and the acute angle formed by the surface that defines the collection section and is continuous with the bottom surface with respect to the vertical direction may be smaller than the acute angle formed by the bottom surface with respect to the vertical direction.

[0011] Since the sperm have difficulty moving upward along the surface of the collection section, it is difficult for the sperm to return from the collection section to the communication section.

[0012] (4) The bottom of the recovery section may be lower than the bottom of the input section.

[0013] The sperm are less likely to return from the recovery section to the connecting section. Also, when heating from below, the temperature of the recovery section can be made higher than the temperature of the input section.

[0014] (5) The inner wall may be plural, and the distance between adjacent inner walls may decrease from the input section toward the recovery section.

[0015] Sperm moving along the surface of the inner wall are more likely to head towards the collection area.

[0016] (6) The bottom wall may have a circular outer shape in a plan view, and the input portion may be located on the outer periphery of the recovery portion in a plan view.

[0017] (7) The input section, the communication section, and the recovery section may be aligned in a first direction, and the inner wall may be aligned in a second direction intersecting the first direction and the vertical direction.

[0018] (8) The present invention is a method for sorting sperm using a sperm sorting device having an input section and a recovery section in an internal space, comprising the steps of: inputting sperm into the input section and a liquid in which the input section and the recovery section are immersed; raising the temperature of the liquid in the recovery section to be higher than the temperature of the liquid in the input section; and recovering the sperm located in the recovery section.

[0019] Sperm introduced into the input section move towards the collection section where the liquid temperature is high, and sperm with high motility are collected in the collection section.

[0020] (9) The present invention relates to a system including a sperm sorting device and a heat conductor. The sperm sorting device includes a bottom wall, a side wall, and an internal space defined by the bottom wall and the side wall. The internal space has an input section and a recovery section. The heat conductor can be attached to the periphery of the recovery section.

[0021] By attaching the heat conductor to the periphery of the recovery section, the liquid filling the recovery section is heated more efficiently than the liquid filling the input section.

[0022] (10) The internal space of the sperm sorting device may further have a connecting section connecting the input section and the recovery section, and the connecting section may have a bottom surface and an inner wall extending upward from the bottom surface and across the input section and the recovery section.

[0023] (11) The sperm sorting device may have a partition wall separating the input section and the recovery section.

[0024] (12) The present invention may be a thermal conductor used in a sperm sorting device having an input section and a recovery section in an internal space, the thermal conductor being mountable around the recovery section.

[0025] (13) The present invention provides a method for sorting sperm using a system including a sperm sorting device having an input section and a recovery section in its internal space, and a thermal conductor, the system comprising the steps of attaching the thermal conductor to the periphery of the recovery section, inputting sperm into the input section and a liquid for immersing the input section and the recovery section, heating the sperm sorting device, and recovering the sperm located in the recovery section.

[0026] According to the present invention, sperm with high motility are collected.

[0027] FIG. 1 is a plan view showing a sperm sorting device 1 according to the first embodiment. FIG. 2 is a perspective view showing the sperm sorting device 1 according to the first embodiment. FIG. 3 is a cross-sectional view taken along line III-III in FIG. 1, showing the sperm sorting device 1 into which a sperm sample 220 and a liquid 103 have been introduced. FIG. 4 is a flowchart showing the flow of a sorting method for sorting introduced sperm 210. FIG. 5 is a cross-sectional view showing a state in which a sperm sample 220 has been introduced into the sperm sorting device 1 according to the first embodiment. FIG. 6 is a cross-sectional view showing a state in which a liquid 103 has been introduced into the sperm sorting device 1 according to the first embodiment. FIG. 7 is a cross-sectional view showing a state in which the sperm sorting device 1 according to the first embodiment is being heated. FIG. 8 is a cross-sectional view showing a state in which sperm are being collected from the sperm sorting device 1 according to the first embodiment. FIG. 9 is a plan view showing a sperm sorting device 110 according to the second embodiment. FIG. 10 is a perspective view showing the sperm sorting device 110 according to the second embodiment. FIG. 11 is a cross-sectional view taken along line XI-XI in FIG. 9, showing the sperm sorting device 110 into which a sperm sample 220 and a liquid 103 have been introduced. FIG. 12 is a cross-sectional view showing a sperm sorting device 1 and a thermal conductor 101 according to a modified example, showing the sperm sorting device 1 and the thermal conductor 101 into which a sperm sample 220 and a liquid 103 have been introduced. FIG. 13 is a cross-sectional view showing a sperm sorting device 410 and a thermal conductor 501 according to another modified example, showing the sperm sorting device 410 and the thermal conductor 501 into which a sperm sample 220 and a liquid 103 have been introduced. FIG. 14 is a flowchart showing the flow of a sorting method for sorting introduced sperm 210 in the sperm sorting device 1, 410 according to the modified example and another modified example. FIG. 15 is a plan view showing a sperm sorting device 301 according to yet another modified example. FIG. 16 is a perspective view showing a sperm sorting device 301 according to yet another modified example.

[0028] Hereinafter, first and second embodiments of the present invention will be described with reference to the accompanying drawings as appropriate. Note that the embodiments described below are merely examples of how the present invention is realized, and it goes without saying that the embodiments can be modified as appropriate without departing from the spirit and scope of the present invention.

[0029] Hereinafter, the directions relating to the sperm selection device 1 according to the first embodiment are indicated as a vertical direction 7 and a radial direction 8. The radial direction 8 is a direction perpendicular to the vertical direction 7. The vertical direction 7 is the thickness direction of the bottom wall 11, and is the direction in which both main surfaces of the bottom wall 11 face. The vertical direction 7 is also the vertical direction when the sperm selection device 1 is placed on a horizontal surface. The radial direction 8 is the direction in which the diameter of the bottom wall 11 faces.

[0030] [Regarding characteristics related to sperm motility] Prior to describing the sperm sorting devices 1, 110 according to the first and second embodiments, characteristics related to the motility of sperm to be sorted will be described. Sperm are present in a sperm sample 220 (see FIG. 5 ) collected, for example, from a human male, to which a buffer solution such as Hank's solution or a culture solution has been added to remove foreign matter. The multiple sperm present in the sperm sample 220 have different motility. In this embodiment, sperm with high motility that move through the buffer solution or culture solution to the collection section 32 in the sperm sorting device 1 are referred to as motile sperm 200 (see FIG. 3 ), and sperm with low motility that cannot move to the collection section 32 are referred to as non-motile sperm 201. In this embodiment, the sperm to be collected are motile sperm 200.

[0031] The movement of motile sperm 200 has the following three known characteristics. Motile sperm 200 move in the direction of higher temperatures in a liquid (hereinafter referred to as the first characteristic). The shape of the head of the motile sperm 200 has a characteristic suitable for stable movement when moving parallel to a wall (hereinafter referred to as the second characteristic). The motile sperm 200 move most stably in a liquid when moving parallel to a wall, for example, at a position 10 μm from the wall. Motile sperm 200 move toward the region where the gap narrows (hereinafter referred to as the third characteristic). The motile sperm 200 move, for example, toward a tapered region. The sperm sorting device 1, 110 according to each embodiment utilizes at least some of the above-mentioned characteristics to guide the motile sperm 200 to the collection position.

[0032] 1 and 2, the sperm sorting device 1 has a circular outer shape in a plan view. The sperm sorting device 1 is a molded product made of a synthetic resin such as polystyrene, polypropylene, polyethylene, or polyamide. The sperm sorting device 1 includes a bottom wall 11, a side wall 12, and an internal space 13.

[0033] The bottom wall 11 has a circular disk shape in plan view. The radial direction 8 is a direction along the radius of the center of the outline of the bottom wall 11. Both main surfaces of the bottom wall 11 face in the up-down direction 7.

[0034] The side wall 12 has an annular outer shape in a plan view. The side wall 12 extends in the up-down direction 7 from the outer edge of the bottom wall 11. The upper end of the side wall 12 is located higher than the upper end of the bottom wall 11. The lower end of the side wall 12 is located lower than the lower end of the bottom wall 11. The sperm sorting device 1 is placed on a desk or the like at the lower end of the side wall 12. A flange 14 that protrudes outward in the radial direction 8 is located on the outer peripheral surface of the side wall 12. The flange 14 has an annular outer shape in a plan view, and protrudes from the outer peripheral surface of the side wall 12 over the entire circumferential direction. Note that the flange 14 is omitted from Figure 3.

[0035] An internal space 13 is defined by the bottom wall 11 and the side wall 12. The internal space 13 is open upward and has an input section 31, a recovery section 32, and a communication section 33. The opening of the internal space 13 is closed by, for example, a lid (not shown) supported on the upper end of the flange 14.

[0036] As shown in Figures 1 to 3, the insertion part 31 is located along the inner peripheral surface of the side wall 12. The insertion part 31 is located on the outermost side in the internal space 13. The length of the insertion part 31 in the radial direction 8 is set to a length that allows the tip of a micropipette 300 (see Figures 5 and 6), for example, to enter. The bottom surface 41 of the insertion part 31 is continuous with the inner peripheral surface of the side wall 12. When the sperm selection device 1 is placed on a horizontal surface, the bottom surface 41 of the insertion part 31 extends horizontally.

[0037] The recovery unit 32 is located at the center of the bottom wall 11. The recovery unit 32 has a circular outer shape in a plan view. The recovery unit 32 is a hole recessed downward from the bottom surface 43 of the communication unit 33. The recovery unit 32 has a tapered shape with an inner diameter that narrows as it extends downward. The diameter of the upper end of the recovery unit 32 is set to a size that allows the tip of, for example, a micropipette 300 (see FIG. 8 ) to enter. In the up-down direction 7, the position of the bottom surface 42 of the recovery unit 32 is lower than the positions of the bottom surface 41 of the input unit 31 and the bottom surface 43 of the communication unit 33. The lower end of the recovery unit 32 is lower than the lower end of the input unit 31 and the lower end of the communication unit 33.

[0038] A surface 45 extends upward from the outer edge of the bottom surface 42 of the collection section 32. The surface 45 is continuous with the bottom surface 43 of the communication section 33. The collection section 32 is defined by the bottom surface 42 and the surface 45. As shown in FIG. 3 , the acute angle A1 formed by the surface 45 defining the collection section 32 with respect to the vertical direction is smaller than the acute angle A2 formed by the bottom surface 43 with respect to the vertical direction (A1<A2). The angle A1 is preferably, for example, in the range of 0 to 15 degrees, more preferably in the range of 3 to 11 degrees, and most preferably in the range of 6 to 7 degrees. The angle A2 is, for example, preferably in the range of 10 to 70 degrees, more preferably in the range of 20 to 60 degrees, and most preferably in the range of 30 to 45 degrees. In this embodiment, the angle A1 is 7 degrees, and the angle A2 is 45 degrees.

[0039] The communication section 33 is located between the input section 31 and the recovery section 32. The communication section 33 connects the input section 31 and the recovery section 32. The recovery section 32, the communication section 33, and the input section 31 are arranged in this order from the center of the bottom wall 11 toward the outside in the radial direction. The communication section 33 has a bottom surface 43 and an inner wall 44.

[0040] The bottom surface 43 connects the inner peripheral edge of the bottom surface 41 of the input section 31 and the outer peripheral edge of the surface 45 of the recovery section 32. When the sperm selection device 1 is placed on a horizontal surface, the bottom surface 43 is an inclined surface that slopes obliquely upward from the input section 31 toward the recovery section 32. The position of the bottom surface 43 in the vertical direction 7 becomes higher from the outer peripheral side to the inner peripheral side.

[0041] The inner wall 44 has a plate-like outer shape in a plan view. The inner wall 44 extends upward from the bottom surface 43. The inner wall 44 extends across the input section 31 and the recovery section 32. Note that extending across the input section 31 and the recovery section 32 does not necessarily mean that the inner wall 44 is connected to the inner end of the input section 31 and the outer end of the recovery section 32. As long as the inner wall 44 has the function of partitioning a passage for the motile sperm 200 in the connecting section 33, the inner wall 44 may be slightly spaced from the inner end of the input section 31 or slightly spaced from the outer end of the recovery section 32.

[0042] As shown in FIGS. 1 and 2 , multiple inner walls 44 are positioned radially along the radial direction 8 on the upper surface of the bottom wall 11, spaced apart from one another in the circumferential direction. In this embodiment, six inner walls 44 are positioned, but the number of inner walls 44 may be changed as appropriate. The inner ends of the inner walls 44 in the radial direction 8 are flush with the surface 45 of the collection section 32 or slightly protrude inward in the radial direction 8 from the surface 45 of the collection section 32. The outer ends of the inner walls 44 in the radial direction 8 are substantially flush with the inner circumferential end of the bottom surface 41 of the input section 31 or slightly protrude outward in the radial direction 8 from the bottom surface 41 of the input section 31. The circumferential thickness of the inner walls 44 gradually decreases toward the outer and inner ends in the radial direction 8. The upper ends of the inner walls 44 are positioned below the upper ends of the side walls 12.

[0043] The circumferential distance between adjacent inner walls 44 is narrower on the collection section 32 side (inner side in the radial direction 8) than on the input section 31 side (outer side in the radial direction 8). In addition, the circumferential distance between adjacent inner walls 44 generally gradually narrows from the input section 31 toward the collection section 32.

[0044] (Method of using the sperm sorting device 1) The following describes how to use the sperm sorting device 1. Hank's Balanced Salt Solution (HBSS) or phosphate buffered saline (PBS) is added to semen collected from a human male in advance to loosen mucin clumps, and then foreign matter is removed using a filter to prepare a sperm sample 220. The sperm sample 220 may also be concentrated sperm that has been further centrifuged using a density gradient solution.

[0045] 4 and 5, a sperm sample 220 is introduced into the input section 31 of the sperm sorting device 1 using a micropipette 300 or the like (step S1). The liquid volume of the sperm sample 220 is an amount that does not exceed the uppermost position of the bottom surface 43 of the connecting section 33. Therefore, the sperm sample 220 introduced into the input section 31 remains in the input section 31 and the connecting section 33, and does not enter the recovery section 32. The temperature of the sperm sample 220 is, for example, within the range of 20°C to 37°C.

[0046] Next, as shown in Figures 4 and 6, a liquid 103 is poured into the internal space 13 of the sperm selection device 1 (step S2). The liquid 103 is, for example, Hank's Balanced Salt Solution (HBSS) or phosphate buffer solution (PBS). The liquid 103 is poured into the input section 31 using, for example, a micropipette 300. The amount of the poured liquid 103 is such that it exceeds the uppermost position of the bottom surface 43 of the connecting section 33 but does not exceed the upper end of the inner wall 44. This causes the input section 31, the connecting section 33, and the recovery section 32 to be immersed in the liquid 103. The temperature of the liquid 103 is, for example, within the range of 20°C to 37°C.

[0047] 4 and 7, the liquid 103 is heated (step S3). The sperm selection device 1 is placed on a hot plate 100 set to a desired temperature, for example, between 25°C and 37°C, whereby the sperm selection device 1 is heated from below, and the liquid 103 filled in the internal space 13 is heated. The temperature of the hot plate 100 is selected from, for example, 25°C, 30°C, or 37°C. The selected temperature of the hot plate 100 is preferably higher than or the same as the temperature of the liquid 103.

[0048] As shown in FIG. 7 , the bottom 62 of the recovery section 32 is lower than the bottom 63 of the communication section 33 and the bottom 61 of the input section 31 and is closer to the top surface 102 of the hot plate 100. This makes the liquid 103 filling the recovery section 32 more easily heated than the liquid 103 filling the communication section 33 and the input section 31. As a result, the temperature of the liquid 103 filling the recovery section 32 becomes higher than the temperature of the liquid 103 filling the communication section 33 and the input section 31. When the temperature of the hot plate 100 is the same as the temperature of the liquid 103 filling the internal space 13 before heating, the recovery section 32 is more likely to be kept warm. As a result, the temperature of the liquid 103 filling the recovery section 32 becomes higher than the temperature of the liquid 103 filling the communication section 33 and the input section 31.

[0049] 4, the sperm sorting device 1 is left for a predetermined time (step S4). The predetermined time is, for example, preferably within a range of 5 to 120 minutes, more preferably within a range of 15 to 90 minutes, even more preferably within a range of 30 to 75 minutes, and most preferably within a range of 45 to 60 minutes. During this time, the motile sperm 200 contained in the sperm sample 220 introduced into the introduction section 31 move toward the collection section 32, which has a higher temperature, from the introduction section 31 and the communication section 33, which have a lower temperature, due to the first feature described above.

[0050] Furthermore, due to the second feature described above, the motile sperm 200 move in the liquid 103 against gravity along the bottom surface 43 of the input section 31. Furthermore, due to the third feature described above, the motile sperm 200 move from the input section 31 toward the connecting section 33 surrounded by the inner wall 44 and the bottom surface 43. The motile sperm 200 that have moved to the connecting section 33 move toward the recovery section 32, where the passage gradually narrows. As a result, the motile sperm 200 move from the input section 31 toward the recovery section 32 while climbing up the bottom surface 43 located between the two inner walls 44.

[0051] The motile sperm 200 that have moved to the collection section 32 move toward the bottom surface 42 of the collection section 32 due to the second and third features. The motile sperm 200 that have moved toward the bottom surface 42 remain near the bottom surface 42 of the collection section 32 due to the second and third features. Furthermore, the position of the bottom surface 42 of the collection section 32 is lower than the positions of the bottom surface 41 of the input section 31 and the bottom surface 43 of the connection section 33. Furthermore, the angle A1 of the surface 45 of the collection section 32 is smaller than the angle A2 of the bottom surface 43. As a result, for the motile sperm 200 near the bottom surface 43 in the collection section 32 to return to the connection section 33, a greater movement (acceleration and distance) is required than for the motile sperm 200 to move from the connection section 33 to the collection section 32. Therefore, the motile sperm 200 that have moved to the collection section 32 are less likely to return to the connection section 33.

[0052] On the other hand, the immotile sperm 201 cannot move up the bottom surface 43 located in the connecting section 33 against gravity. Therefore, the immotile sperm 201 remain in the input section 31 and the connecting section 33 and do not move to the recovery section 32.

[0053] After a predetermined time has elapsed (step S4_YES), as shown in Fig. 8, the motile sperm 200 located in the collection section 32 are collected together with the liquid 103 by the micropipette 300 or the like (step S5). This completes the selection of sperm.

[0054] (Action and effect of the sperm sorting device 1 according to the first embodiment) Motile sperm 200 introduced into the introduction section 31 of the sperm sorting device 1 move to the collection section 32 along the bottom surface 43 and the inner wall 44 of the connecting section 33, so that the motile sperm 200 can easily move from the introduction section 31 to the collection section 32 through the connecting section 33.

[0055] In addition, the bottom surface 43 of the connecting section 33 is inclined obliquely upward from the input section 31 to the recovery section 32, so that the immotile sperm 201 do not climb the bottom surface 43 but remain in the input section 31. As a result, only the motile sperm 200 move to the recovery section 32.

[0056] In addition, since the angle A1 of the surface 45 of the collection section 32 is smaller than the angle A2 of the bottom surface 43, the motile sperm 200 are less likely to move upward along the surface 45 of the collection section 32. As a result, the motile sperm 200 are less likely to return from the collection section 32 to the communication section 33.

[0057] Furthermore, since the bottom surface 42 of the recovery section 32 is lower than the bottom surface 41 of the input section 31 and the bottom surface 43 of the connection section 33 , it is difficult for the motile sperm 200 to return from the recovery section 32 to the connection section 33 .

[0058] In addition, the circumferential distance between adjacent inner walls 44 becomes smaller as one moves from the input section 31 toward the collection section 32, so that motile sperm 200 moving along the surface of the inner wall 44 are likely to move toward the collection section 32.

[0059] [Second embodiment] Next, a sperm sorting device 110 according to a second embodiment will be described. In the second embodiment, the method of using the sperm sorting device 110 and the movement of the motile sperm 200 are the same as those of the sperm sorting device 1 in the first embodiment, and therefore, the description of the second embodiment will be omitted.

[0060] The directions relating to the sperm selection device 110 according to the second embodiment are indicated as an up-down direction 7, a front-back direction 5, and a left-right direction 6. The front-back direction 5 and the left-right direction 6 are directions perpendicular to the up-down direction 7. The front-back direction 5 is a direction connecting the input section 131, the connection section 133, and the recovery section 132 in the sperm selection device 110. The left-right direction 6 is a direction perpendicular to the up-down direction 7 and the front-back direction 5, and is a direction crossing the connection section 133.

[0061] As shown in Figures 9 to 11, the sperm selection device 110 has a gourd-shaped outer shape in a plan view, with the width at the center in the front-rear direction 5 being narrower than the width at both ends. The sperm selection device 110 has a shape in which, for example, the center in the front-rear direction 5 (an example of a first direction) is concave in the left-right direction 6 (an example of a second direction). The outer shape of the bottom wall 211 is oval in a plan view. The side wall 212 extends from the outer edge of the bottom wall 211 in the up-down direction 7. The lower end of the side wall 212 is placed on a desk or the like. The sperm selection device 110 is a molded product made of a synthetic resin such as polystyrene, polypropylene, polyethylene, or polyamide.

[0062] The internal space 113 of the sperm selection device 110 is partitioned by a bottom wall 211 and a side wall 212. The internal space 113 is long in the front-rear direction 5 and short in the left-right direction 6. The internal space 113 has a collection section 132, a communication section 133, and an input section 131. The input section 131 is located at one end side in the front-rear direction 5 (the front side in Figure 9) in the internal space 113. The dimensions of the input section 131 in the front-rear direction 5 and the left-right direction 6 are set so that the tip of a micropipette or the like can enter it. When the sperm selection device 110 is placed on a horizontal surface, the bottom surface 141 of the input section 131 extends horizontally.

[0063] The recovery unit 132 is located at the other end side in the front-rear direction 5 (rear side in FIG. 9 ) of the internal space 113. The dimensions of the recovery unit 132 in the front-rear direction 5 and the left-right direction 6 are smaller than the dimensions of the input unit 131. The dimensions of the recovery unit 132 in the front-rear direction 5 and the left-right direction 6 are set so that the tip of a micropipette or the like can enter. In the up-down direction 7, the bottom 162 of the bottom wall 211 of the recovery unit 132 is located higher than the lower end of the side wall 212.

[0064] The connecting section 133 is located between the input section 131 and the collection section 132 in the front-rear direction 5. The connecting section 133 connects the input section 131 and the collection section 132. The external shape of the connecting section 133 narrows in the left-right direction 6 from the input section 131 toward the collection section 132 in a plan view. The connecting section 133 has a bottom surface 143 and an inner wall 144.

[0065] The bottom surface 143 is the upper surface of the bottom wall 211. The bottom surface 143 connects the bottom surface 141 of the input section 131 and the surface 145 of the collection section 132. The bottom surface 143 is an inclined surface that slopes obliquely upward from the input section 131 toward the collection section 132 when the sperm selection device 110 is placed on a horizontal surface.

[0066] The inner wall 144 has a plate-like outer shape in a plan view. The inner wall 144 extends upward from the bottom surface 143. The inner wall 144 extends between the input section 131 and the recovery section 132. As shown in Figures 9 and 10 , a plurality of inner walls 144 are arranged at intervals in the left-right direction 6. The intervals between adjacent inner walls 144 in the left-right direction 6 gradually narrow from the front end to the rear end. The area defined by adjacent inner walls 144 and the bottom surface 143 serves as a passage for motile sperm 200 in the communication section 133.

[0067] The bottom surface 142 of the recovery section 132 is lower in the up-down direction 7 than the bottom surface 141 of the input section 131 and the bottom surface 143 of the communication section 133. The bottom 161 of the recovery section 132 is lower than the bottom 161 of the input section 131. The lower end of the recovery section 132 is lower than the lower end of the input section 131 and the lower end of the communication section 133.

[0068] A surface 145 extends upward from the outer edge of the bottom surface 142 of the collection section 132. The surface 145 is continuous with the bottom surface 143 of the communication section 133. As shown in FIG. 11 , the acute angle A3 formed by the surface 145 defining the collection section 132 with respect to the vertical direction is smaller than the acute angle A4 formed by the bottom surface 143 with respect to the vertical direction (A3<A4). The angle A3 is preferably, for example, in the range of 0 to 15 degrees, more preferably in the range of 3 to 11 degrees, and most preferably in the range of 6 to 7 degrees. The angle A4 is, for example, preferably in the range of 10 to 70 degrees, more preferably in the range of 20 to 60 degrees, and most preferably in the range of 30 to 45 degrees. In this embodiment, the angle A3 is 7 degrees, and the angle A4 is 45 degrees.

[0069] Since the angle A3 of the surface 145 of the collection section 132 is smaller than the angle A4 of the bottom surface 143, the motile sperm 200 are less likely to move upward along the surface 145 of the collection section 132. This makes it less likely that the motile sperm 200 will return from the collection section 132 to the connection section 133.

[0070] The sperm selection device 110 according to the second embodiment described above also achieves the same effects as the sperm selection device 1 according to the first embodiment.

[0071] (Modification) In the above embodiment, an example in which the hot plate 100 is used as a heating method for the sperm selection device 1 has been described, but this is not limiting. Also, as shown in Fig. 12, in addition to the hot plate 100, the periphery of the recovery section 32 may be covered with a thermal conductor 101 such as aluminum that has a higher thermal conductivity than air, thereby making the recovery section 32 easier to heat than the input section 31 and the communication section 33. Also, the lower end of the recovery section 32 may be located at the same position as the lower end of the side wall 12.

[0072] The thermal conductor 101 is, for example, an aluminum block, and its outer shape in a plan view may be a rectangular parallelepiped or cylindrical. The sperm selection device 1 and the thermal conductor 101 constitute a sperm selection system 120 (an example of a system). A hole 111 that opens upward and is recessed downward is located on the upper surface of the thermal conductor 101. The length from the bottom surface 112 of the hole 111 to the bottom surface 115 of the thermal conductor 101 is approximately the same as the distance from the bottom 62 of the collection section 32 to the upper surface 102 of the hot plate 100. In other words, the length from the bottom surface 112 of the hole 111 to the bottom surface 115 of the thermal conductor 101 is approximately the same as the distance from the bottom 62 of the collection section 32 to the lower end of the side wall 12. The angle A5 formed between the vertical direction 7 and the inner surface 114 of the hole 111 is approximately the same as the angle formed between the vertical direction 7 and the wall that constitutes the surface 45 of the collection section 32. As a result, the outer surface of the recovery section 32 comes into close contact with the inner surface of the hole 111 .

[0073] The thermal conductor 101 may be integrated with the sperm selection device 1 in advance, or may be attached at the time of use. If it is attached at the time of use, it is preferable to attach it before introducing the liquid 103 or the sperm sample 220 into the sperm selection device 1.

[0074] 13, a sperm sorting device 410 and a thermal conductor 501 may be used, with an input section 431 and a recovery section 432 as the internal space 413. The bottom surface 441 of the input section 431 extends horizontally when the sperm sorting device 410 is placed on a horizontal surface. The recovery section 432, which has a circular outer shape in plan view, is located at the center of the input section 431, which has a circular outer shape in plan view. A partition wall 444, which rises upward from the bottom surface 441, is located at the inner edge of the input section 431 in the radial direction 8. The partition wall 444 is located around the entire circumferential circumference of the recovery section 432. The partition wall 444 has a circular outer shape in plan view. The partition wall 444 separates the input section 431 and the recovery section 432. The inner peripheral surface of the partition wall 444 extends in the vertical direction 7 and is flush with the surface 445 of the recovery unit 432. The surface 445 of the recovery unit 432 extends in the vertical direction 7 and is connected to the bottom surface 442. The bottom surface 442 tapers downward. The bottom 462 of the recovery unit 432 is located lower in the vertical direction 7 than the bottom 461 of the input unit 431.

[0075] The thermal conductor 501, like the thermal conductor 101, may be, for example, an aluminum block, and may have a rectangular or cylindrical outer shape in a plan view. The sperm selection device 410 and the thermal conductor 501 constitute a sperm selection system 520 (an example of a system). A hole 511 is located on the upper surface of the thermal conductor 501, recessed downward to match the shape of the periphery of the collection section 432. The outer shape of the hole 511 is circular in a plan view. The outer surface of the collection section 432 is in close contact with the inner surface of the hole 511. The length from the bottom surface 512 of the hole 511 to the bottom surface 515 of the thermal conductor 501 is approximately the same as the distance from the bottom 462 of the collection section 432 to the upper surface 102 of the hot plate 100. In other words, the length from the bottom surface 512 of the hole 511 to the bottom surface 515 of the thermal conductor 501 is approximately the same as the distance from the bottom 462 of the recovery section 432 to the lower end of the side wall 412. The thermal conductor 501 may be integrated with the sperm sorting device 410 in advance, or may be attached at the time of use. If it is attached at the time of use, it is preferable to attach it before introducing the liquid 103 or sperm sample 220 into the sperm sorting device 410.

[0076] Next, a sperm sorting method using the sperm sorting system 120, 520 will be described with reference to Fig. 14. Fig. 14 illustrates a sorting method in the sperm sorting system 120, 520, to which the thermal conductor 101, 501 can be attached when using the sperm sorting device 1, 410. As shown in Figs. 12 to 14, the thermal conductor 101, 501 is attached to the outer surface of the recovery section 32, 432 of the sperm sorting device 1, 410 using the thermal conductor 101, 501 (step S11). The sperm sorting device 1 with the thermal conductor 101, 501 attached is placed on the upper surface 102 of the hot plate 100, for example.

[0077] Next, the liquid 103 is poured into the internal space 13, 413 of the sperm sorting device 1, 410 (step S12). The pouring of the liquid 103 is similar to the pouring of the liquid 103 in Fig. 4. Note that in the sperm sorting device 410, the amount of the liquid 103 poured is such that it exceeds the uppermost position of the partition wall 444 but does not exceed the upper end of the side wall 12.

[0078] Next, the sperm sample 220 is input into the input section 31, 431 of the sperm sorting device 1, 410 (step S13). The input of the sperm sample 220 is similar to the sperm input in FIG.

[0079] Next, the liquid 103 is heated (step S14). The heat provided from the hot plate 100 is transmitted through the thermal conductor 101, 501 to heat the liquid 103 located in the recovery section 32, 432. Because the thermal conductivity of the thermal conductor 101, 501 is higher than the thermal conductivity of the air layer located below the input section 31, 431 (and the connecting section 33), the amount of heat transmitted to the recovery section 32, 432 is greater than the amount of heat transmitted to the input section 31, 431 (and the connecting section 33). As a result, the temperature of the liquid 103 located in the recovery section 32, 432 becomes higher than the temperature of the liquid 103 located in the input section 31, 431 (and the connecting section 33).

[0080] Next, as in Fig. 4, the sperm sorting device 1, 410 is left for a predetermined time (step S15). After the predetermined time has elapsed (step S15_YES), as shown in Fig. 8, the motile sperm 200 located in the collection section 32, 432 are collected together with the liquid 103 by the micropipette 300 or the like (step S16). This completes the sperm sorting.

[0081] Furthermore, in the above embodiment, the bottom surface 41 of the input section 31 is horizontal, but this is not limiting. By tapering the bottom surface 43 of the input section 31 without lowering the position of the bottom of the input section 31, the volume of the input section 31 can be reduced. Since the number of motile sperm 200 remaining in the input section 31 is reduced, the number of motile sperm 200 guided to the collection section 32 can be increased. Furthermore, even if the amount of sperm sample 220 is small, the number of motile sperm 200 remaining in the input section 31 can be reduced, and the number of motile sperm 200 moving to the collection section 32 can be increased.

[0082] In the above embodiment, the collecting portion 32 is tapered, but the present invention is not limited to this. The surface 45 of the collecting portion 32 may extend along the vertical direction 7.

[0083] In the above embodiment, the sperm sample 220 is introduced into the sperm selection device 1, and then the liquid 103 is introduced, but the order is not limited to this. The sperm sample 220 may be introduced into the sperm selection device 1 after the liquid 103 is introduced.

[0084] In the above embodiment, the connecting portion 33, 133 is inclined in the radial direction 8 or the front-rear direction 5, but this is not limiting. The connecting portion 33, 133 may extend horizontally in the same manner as the input portion 31, 131 when placed on a horizontal surface. The connecting portion 33, 133 may also be flush with the input portion 31, 131.

[0085] In addition, in the sperm selection device 410, the partition 444 is positioned around the entire circumferential direction of the outer periphery of the collection section 432, and the outer shape of the partition 444 in a plan view is annular, but this is not limited to this. The partition 444 may be positioned outside the outer periphery of the collection section 432 in the radial direction 8. The outer shape of the partition 444 in a plan view may be an ellipse, a polygon, a part of a ring, or a shape with multiple parts spreading radially.

[0086] 15 and 16, the sperm selection device 301 may have more inner walls 344 than the sperm selection device 1 according to the first embodiment. In this modification, the number of inner walls 344 may be, for example, 12.

[0087] The bottom surface 343 on the bottom wall 311 of the sperm sorting device 301 may be shorter in the radial direction 8 than the bottom surface 43 on the bottom wall 11 of the sperm sorting device 1. The width of the input section 331 on the bottom wall 311 of the sperm sorting device 301 along the radial direction 8 may be greater than the corresponding width of the input section 31 on the bottom wall 11 of the sperm sorting device 1. Furthermore, the inner end of the bottom surface 343 on the bottom wall 311 of the sperm sorting device 301 in the radial direction 8 may be lower in the vertical direction 7 than the inner end of the bottom surface 43 on the bottom wall 11 of the sperm sorting device 1 in the radial direction 8. This may make it easier for motile sperm 200 to move from the input section 331 to the collection section 332.

[0088] In addition, in the second embodiment, a heat conductor (not shown) that can be attached to the periphery of the recovery section 132 of the sperm selection device 110 may be used. The sperm selection device 110 may be integrated with the heat conductor in advance.

[0089] The sperm sorting device 1, 110, 301, 410 is discarded after sperm sorting, while the attachable heat conductor 101, 501 may be removed from the discarded sperm sorting device 1, 110, 301, 410 and reused for sperm sorting using a new sperm sorting device 1, 110, 301, 410.

[0090] 1,110,301,410...Sperm sorting device 5...Front-back direction (first direction) 6...Left-right direction (second direction) 7...Up-down direction 11,211,311,411...Bottom wall 12,212,312,412...Side wall 13,113,313,413...Internal space 31,131,331,431...Input section 32,132,332,432...Recovery section 33,133,333,433...Communication section 43,143,343...Bottom surface 44,144,344...Inner wall 61,62,461,462...Bottom 101,501...Heat conductor 120,520...Sperm sorting system (system) 103...Liquid 200...Motile sperm (sperm) 444... Bulkhead

Claims

1. A sperm sorting device comprising: a bottom wall; a side wall; and an internal space partitioned by the bottom wall and the side wall, wherein the internal space has an input section, a recovery section, and a connecting section connecting the input section and the recovery section, and wherein the connecting section comprises: a bottom surface; and an inner wall extending upward from the bottom surface and across the input section and the recovery section.

2. A sperm sorting device as set forth in claim 1, wherein the bottom surface is inclined obliquely upward from the input section toward the recovery section.

3. A sperm sorting device as described in claim 1, wherein the collection section is recessed downward from the bottom surface, and the acute angle formed by the surface that defines the collection section and is continuous with the bottom surface with respect to the vertical direction is smaller than the acute angle formed by the bottom surface with respect to the vertical direction.

4. A sperm sorting device according to claim 2, wherein the bottom of the collection section is lower than the bottom of the input section.

5. A sperm sorting device according to claim 1, wherein the inner walls are plural, and the distance between adjacent inner walls decreases from the input section toward the recovery section.

6. A sperm sorting device as described in claim 1, wherein the bottom wall has a circular outer shape in a plan view, and the input section is located on the outer periphery of the recovery section in a plan view.

7. A sperm sorting device as described in claim 1, wherein the input section, the communication section, and the recovery section are aligned in a first direction, and the inner walls are aligned in a second direction that intersects the first direction and the vertical direction.

8. A method for sorting sperm using a sperm sorting device having an input section and a recovery section within its internal space, comprising the steps of: inputting sperm into the input section and introducing a liquid in which the input section and the recovery section are immersed; raising the temperature of the liquid in the recovery section to be higher than the temperature of the liquid in the input section; and recovering the sperm located in the recovery section.

9. A system comprising a sperm sorting device and a thermal conductor, wherein the sperm sorting device comprises a bottom wall, a side wall, and an internal space defined by the bottom wall and the side wall, the internal space having an input section and a recovery section, and the thermal conductor is attachable to the periphery of the recovery section.

10. The system described in claim 9, wherein the internal space of the sperm sorting device further has a connecting portion connecting the input portion and the recovery portion, the connecting portion comprising: a bottom surface; and an inner wall extending upward from the bottom surface and across the input portion and the recovery portion.

11. The system according to claim 9, wherein the sperm sorting device has a partition separating the input section from the recovery section.

12. A thermal conductor used in a sperm sorting device having an input section and a recovery section in its internal space, the thermal conductor being mountable around the recovery section.

13. A method for sorting sperm using a system comprising a sperm sorting device having an input section and a recovery section in its internal space, and a thermal conductor, the method comprising the steps of: attaching the thermal conductor to the periphery of the recovery section; introducing sperm into the input section and a liquid for immersing the input section and the recovery section; heating the sperm sorting device; and recovering the sperm located in the recovery section.

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