Collection device of micro objects

Abstract

To provide a collection device of micro objects which is capable of improving collection efficiency of micro objects.SOLUTION: A collection device 1 of micro objects comprises: a collection container 11 in which the shape of an inner periphery of a housing part 11a is an approximately circular shape or approximately elliptic shape in a plan view, and which is capable of holding liquid in the housing part; a collection substrate 12 which is arranged in the housing part 11a and collects a plurality of micro objects α dispersed into liquid; a plurality of pores 12a which can hold air 16 formed on the surface of the collection substrate 12; a thin film 13 which transforms light formed on the surface of the collection substrate 12 into heat; and laser light sources 41 to 49 which irradiate the collection substrate 12 with light.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a minute object collecting device that collects a plurality of minute objects dispersed in a liquid contained in a holding container onto a collection substrate. [Background technology]

[0002] Conventionally, this type of minute object collecting device is disclosed, for example, in Patent Document 1. This minute object collecting device includes a laser device that emits laser light, and a honeycomb polymer membrane that is configured to hold a liquid in which bacteria are dispersed. When the laser light emitted by the laser device is irradiated onto a thin film formed on the honeycomb polymer membrane, convection occurs in the liquid due to a photothermal effect. When bacteria pass above the pores due to this convection, they collide with the partition walls that define the pores in the honeycomb polymer membrane, and the bacteria are captured in the pores.

[0003] Furthermore, a conventional micro-object collecting device of this type is a micro-object accumulation system disclosed in Patent Document 2. This micro-object accumulation system includes a holding device that holds a substrate provided with a photothermal conversion region in a liquid, and a light heating device that emits first and second light beams. The first and second light beams are irradiated onto the photothermal conversion region at a distance from each other, and the liquid is heated, thereby generating first and second bubbles at the irradiation positions of the first and second light beams. The generated first and second bubbles cause convection in the liquid in a specific direction, and multiple micro-objects accumulate in the region between the first and second bubbles. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2017-202446 A [Patent Document 2] International Publication No. 2020 / 218347 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in both of the conventional minute object collecting devices disclosed in Patent Document 1 and Patent Document 2, the efficiency of collecting minute objects is insufficient.

[0006] An object of the present invention is to provide a micro-object collecting device capable of improving the efficiency of collecting micro-objects. [Means for solving the problem]

[0007] For this purpose, the present invention provides A holding container having an inner periphery of a container portion that is generally circular or generally elliptical in plan view and that is capable of holding liquid in the container portion; a collection substrate disposed in the container for collecting a plurality of minute objects dispersed in the liquid; A plurality of pores capable of retaining air formed on the surface of the collection substrate; a photothermal conversion region formed on the surface of the collection substrate for converting light into heat; a light source for irradiating the collection substrate with light; A micro-object collecting device was constructed, comprising:

[0008] According to this configuration, when the light source irradiates the photothermal conversion region formed on the surface of the collection substrate, heat is generated locally in the photothermal conversion region, and microbubbles are generated. At this time, when heat is generated locally in the pores that hold air, microbubbles are generated with the air held in the pores as nuclei, and the generation of microbubbles is promoted. The locally generated heat increases the temperature of the liquid closer to the light irradiation point, so a temperature gradient is generated in the liquid. This temperature gradient causes convection in the liquid held in the storage section of the holding container, but this convection is efficiently generated because it promotes the generation of microbubbles. Micro objects dispersed in the liquid are efficiently captured by the microbubbles formed on the surface of the collection substrate and captured in the pores due to this efficiently generated convection.

[0009] In addition, according to this configuration, since the shape of the inner circumference of the container that holds the liquid in the holding container is approximately circular or approximately elliptical in plan view, the liquid held in the container generates convection without stagnating at the corners, as in the case of a container that has a rectangular shape in plan view with corners on the inner circumference of the container. Therefore, micro-objects dispersed in the liquid also move in the container of the holding container on the convection of the liquid without stagnating at the corners. As a result, due to the fact that the generation of microbubbles is promoted and convection is efficiently generated, the probability that micro-objects dispersed in the liquid move over the pores is increased, and the collection efficiency of the micro-objects being captured by the microbubbles is improved. Effect of the Invention

[0010] According to the present invention, it is possible to provide a micro-object trapping device capable of improving the efficiency of trapping micro-objects. [Brief description of the drawings]

[0011] [Figure 1] 1 is a block diagram showing a schematic configuration of a micro-object collection device according to an embodiment of the present invention; [Diagram 2] FIG. 2(a) is a side cross-sectional view showing the schematic configuration of a collection kit that constitutes the micro-object collection device shown in FIG. 1, and FIG. 2(b) is a diagram explaining how microbubbles are generated when the collection kit shown in FIG. 2(a) is irradiated with light. [Diagram 3] 3A is an oblique view of a collection substrate contained in the collection kit shown in FIG. 2, FIG. 3B is a side cross-sectional view, and FIG. 3C is a partially enlarged side cross-sectional view showing the structure of a modified pore formed in the collection substrate. [Figure 4] 4 is a graph showing the heat conversion efficiency due to the photothermal effect of the gold thin film formed on the collection substrate shown in FIG. 3. [Diagram 5] 2 is a perspective view showing a holding container positioning mechanism in the micro-object collecting device shown in FIG. 1. [Figure 6] 6 is a perspective view illustrating a modified example of the holding container positioning mechanism shown in FIG. 5. [Figure 7]FIG. 4(a) is a plan view of a collection substrate for explaining the irradiation area of ​​the laser light irradiated to the collection substrate shown in FIG. 3, and FIG. 4(b) is a plan view of the collection substrate for explaining an example in which the irradiation area of ​​the laser light is formed in one location. [Figure 8] FIG. 1 is a side cross-sectional view of a conventional collection substrate for explaining a problem associated with the conventional collection substrate. [Figure 9] 7(a) is a plan view showing a modified example of the formation region of pores formed on the surface of the collection substrate shown in FIG. 7(a), and FIG. 7(b) is a plan view showing a modified example of the formation region of pores and thin films formed on the surface of the collection substrate shown in FIG. 7(a). [Figure 10] FIG. 4(a) is a side cross-sectional view of a collection substrate showing a modification in which pores formed in the collection substrate shown in FIG. 3(b) have different opening areas, and (b) is a plan view. [Figure 11] 3(a) is a side cross-sectional view of a collection substrate showing a modified example in which pores are formed in the collection substrate shown in FIG. 3(b) having a large opening area, and FIG. [Figure 12] FIG. 1A is a partially enlarged plan view of a collection substrate constituting a collection device of one embodiment and each modified example, showing the arrangement of pores in the collection substrate; FIG. 1B is a partially enlarged plan view of a collection substrate showing a modified example of the arrangement of pores. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Next, an embodiment of the minute object collecting device of the present invention will be described.

[0013] In the present invention and its embodiments, the term "micro object" refers to an object having a size ranging from the order of nanometers to the order of micrometers. The shape of the micro object is not particularly limited, and may be, for example, a sphere, an elliptical sphere, or a rod shape. When the micro object is an elliptical sphere, at least one of the length in the major axis direction and the length in the minor axis direction of the elliptical sphere may be in the range from the order of nanometers to the order of micrometers. When the micro object is a rod shape, at least one of the width and length of the rod may be in the range from the order of nanometers to the order of micrometers.

[0014] The microscopic object may include an object of biological origin. More specifically, the microscopic object may include, for example, a cell, a microorganism (bacteria, fungi, etc.), an antigen (allergen, etc.), a virus, or a biological material. The "biological material" may include a biopolymer such as a protein, a nucleic acid, a lipid, or a polysaccharide.

[0015] Other examples of minute objects include metal nanoparticles, metal nanoparticle aggregates, metal nanoparticle assembly structures, semiconductor nanoparticles, organic nanoparticles, resin beads, and PM (Particulate Matter). A "metal nanoparticle" is a metal particle having a size on the order of nanometers. A "metal nanoparticle aggregate" is an aggregate formed by the aggregation of multiple metal nanoparticles. A "metal nanoparticle assembly structure" is a structure in which multiple metal nanoparticles are fixed to the surface of a bead via interaction sites, and are arranged with gaps between them at intervals equal to or less than the diameter of the metal nanoparticle. A "semiconductor nanoparticle" is a semiconductor particle having a size on the order of nanometers. An "organic nanoparticle" is a particle made of an organic compound having a size on the order of nanometers. A "resin bead" is a particle made of resin having a size on the order of nanometers to micrometers. A "PM" is a particulate matter having a size on the order of micrometers.

[0016] Furthermore, in the present invention and its embodiments, "nanometer order" includes a range of 1 nm to 1000 nm (= 1 μm). "Micrometer order" includes a range of 1 μm to 1000 μm (= 1 mm). Therefore, the term "range from nanometer order to micrometer order" includes a range of 1 nm to 1000 μm. The term "range from nanometer order to micrometer order" typically indicates a range of several nm to several hundreds μm, preferably a range of 100 nm to 100 μm, and more preferably a range of 1 μm to several tens of μm.

[0017] In the present invention and its embodiments, a "pore" is a hole having an opening ranging from the order of nanometers to the order of micrometers. The shape of the pore is not particularly limited, and may include any shape such as a cylinder, a prism, or a sphere other than a perfect sphere (e.g., a hemisphere or a hemi-elliptical sphere).

[0018] In the present invention and its embodiments, the term "microbubbles" refers to air bubbles on the order of micrometers.

[0019] 1 is a block diagram showing a schematic configuration of a minute object collecting device 1 according to an embodiment of the present invention. In the following drawings, the same or corresponding parts are given the same reference numerals and overlapping explanations are omitted.

[0020] The collection device 1 includes a collection kit 10, an XYZ axis stage 20, an adjustment mechanism 30, laser light sources 41-49, optical components 50, an objective lens 60, an illumination device 70, an imaging device 80, and a control device 90. Hereinafter, the x and y directions represent horizontal directions. The x and y directions are mutually perpendicular. The z direction represents the vertical direction. The direction of gravity is downward in the z direction.

[0021] The collection kit 10 holds a sample S. In this embodiment, the sample S is a liquid in which minute objects α are dispersed. A detailed configuration of the collection kit 10 will be described with reference to FIG. 2. The collection kit 10 is placed on an XYZ axis stage 20.

[0022] The adjustment mechanism 30 adjusts the x-, y-, and z-direction positions of the XYZ-axis stage 20 on which the collection kit 10 is mounted in response to a command from the control device 90. In this embodiment, the position of the objective lens 60 is fixed, so the relative positional relationship between the collection kit 10 and the objective lens 60 is adjusted by adjusting the position of the XYZ-axis stage 20. As the adjustment mechanism 30, for example, a driving mechanism such as a servo motor and a focusing handle attached to the microscope can be used, but the specific configuration of the adjustment mechanism 30 is not particularly limited. The adjustment mechanism 30 may adjust the position of the objective lens 60 relative to the fixed collection kit 10.

[0023] The nine laser light sources 41-49 each emit, for example, near-infrared (for example, 1064 nm wavelength) laser light L1-L9 in response to a command from the control device 90. However, the wavelength of the laser light L1-L9 is not limited thereto as long as it is within the light absorption band of the material of the thin film 13 (see FIG. 3) described later.

[0024] The optical system of the collection device 1 is adjusted so that the laser beams L1 to L9 from the laser light sources 41 to 49 are guided to the objective lens 60 by the optical component 50, for example.

[0025] The objective lens 60 collects the laser beams L1 to L9 from the laser light sources 41 to 49. The light collected by the objective lens 60 is irradiated onto the collection kit 10. Here, "irradiate" includes the case where the laser beams L1 to L9 pass through the collection kit 10. In other words, it is not limited to the case where the beam waist of the light collected by the objective lens 60 is located inside the collection kit 10. The optical component 50 and the objective lens 60 can be incorporated into, for example, an inverted microscope body or an upright microscope body.

[0026] The lighting device 70 emits white light WL to illuminate the sample S in the collection kit 10 in response to a command from the control device 90. As one embodiment, a halogen lamp can be used for the lighting device 70. The objective lens 60 is also used to capture the white light WL irradiated from the lighting device 70 to the collection kit 10. The white light WL captured by the objective lens 60 is guided to the photographing device 80 by the optical component 50.

[0027] In response to a command from the control device 90, the photographing device 80 photographs the sample S (see FIG. 2) in the collection kit 10 irradiated with the white light WL, and outputs the photographed image to the control device 90. The photographing device 80 is a video camera including a CCD (Charge Coupled Device) image sensor or a CMOS (Complementary Metal Oxide Semiconductor) image sensor.

[0028] The control device 90 controls the adjustment mechanism 30, the laser light sources 41-49, the lighting device 70, and the photographing equipment 80. The control device 90 also performs predetermined image processing on the image captured by the photographing equipment 80. The control device 90 is realized by a microcomputer including a CPU (Central Processing Unit), a memory, an input / output buffer, etc., all of which are not shown.

[0029] 1 and may include optical fibers or the like, as long as the optical system of collection device 1 is capable of irradiating collection kit 10 with laser light L1-L9 from laser light sources 41-49 and capturing white light WL from collection kit 10 into photographing device 80. In collection device 1, illumination device 70 and photographing device 80 are merely devices for photographing the state of sample S and are not essential components for collection of micro objects by collection device 1. In addition, it is not necessary to provide nine laser light sources 41-49, and at least one will suffice.

[0030] FIG. 2(a) is a side cross-sectional view showing a detailed configuration of the collection kit 10. The collection kit 10 includes a collection container 11 that contains a sample S in which minute objects α are dispersed, and a collection substrate 12. The collection container 11 constitutes a holding container in which the inner periphery of the storage section 11a is circular in plan view, or a shape similar to a circle, or a polygon with a number of sides close to that of a circle, or an ellipse, or a shape similar to an ellipse, and can hold liquid in the storage section 11a. The collection container 11 is formed, for example, from a transparent resin or glass. The collection substrate 12 is disposed in the storage section 11a and collects a plurality of minute objects α dispersed in the liquid of the sample S.

[0031] Fig. 3(a) is a perspective view showing a schematic configuration of the collection substrate 12, and Fig. 3(b) is a side cross-sectional view. A large number of pores 12a capable of holding air are formed on the surface of the collection substrate 12. In addition, a thin film 13 is formed on the surface of the collection substrate 12, as shown in Fig. 3(b). The thin film 13 constitutes a photothermal conversion region that converts the laser beams L1 to L9 irradiated from the laser light sources 41 to 49 into heat. The laser light sources 41 to 49 constitute light sources that irradiate the collection substrate 12 with light.

[0032] In this embodiment, the collection substrate 12 is formed by photolithography using a glass substrate 14 made of tempac glass as a base. That is, a resist film 15 is formed on the glass substrate 14, and the resist film 15 is selectively removed by exposure using a photomask, thereby selectively forming a plurality of pores 12a on the glass substrate 14 in the portions where the resist film 15 is not present. In this embodiment, SU-8 is used as the material for the resist film 15.

[0033] Thereafter, the thin film 13 is formed on the surface of the collection substrate 12 by using a method such as vapor deposition, sputtering, or electroless plating, and the thin film 13 is formed on the bottom surface of the pores 12a and the upper surface of the resist film 15. The material of the thin film 13 is preferably a material having high light absorption (for example, light-to-heat conversion efficiency) in the wavelength band of the laser beams L1 to L9 (near-infrared band in this embodiment). In this embodiment, a gold (Au) thin film having a thickness on the order of nanometers is used as the material of the thin film 13, and is formed by vapor deposition. However, it may be a metal element other than gold (for example, silver) or a metal nanoparticle assembly structure (for example, a structure using gold nanoparticles or silver nanoparticles). Alternatively, it may be a material other than a metal that has a high light absorption rate in the wavelength band of the laser beams L1 to L9. Such a material may be a material close to a black body (for example, a carbon nanotube black body).

[0034] 4 is a graph showing the heat conversion efficiency due to the photothermal effect of the thin film 13 constituting the photothermal conversion region. The horizontal axis of the graph is the film thickness [nm] of the gold thin film used as the thin film 13, and the vertical axis is the substrate temperature [°C] of the collection substrate 12.

[0035] As described below, when the laser beams L1 to L9 are irradiated onto the thin film 13, heat is generated at the light irradiated portion of the collection substrate 12, and microbubbles are generated. However, from the graph, it is considered that when the gold thin film is 4 nm or less in thickness, the laser beams L1 to L9 pass through the thin film 13, the heat conversion efficiency decreases, and microbubbles are not generated. Also, when the gold thin film is 20 nm or more in thickness, it is considered that the thermal conductivity of the thin film 13 is high, the heat conversion efficiency decreases, and microbubbles are not generated. For this reason, the thin film 13 is preferably formed from a gold thin film having a thickness of 4 nm to 20 nm.

[0036] By forming the thin film 13 from a gold thin film having a thickness of 4 [nm] or more, it is possible to prevent the laser beams L1 to L9 irradiated from the laser light sources 41 to 49 from penetrating the gold thin film, thereby reducing the thermal conversion efficiency and preventing the generation of microbubbles. Also, by forming the thin film 13 from a gold thin film having a thickness of 20 [nm] or less, it is possible to prevent the thermal conductivity of the thin film 13 from becoming too high, thereby reducing the thermal conversion efficiency and preventing the generation of microbubbles.

[0037] In this embodiment, as shown in FIG. 3(a), a resist film 15 having a thickness of 5 μm is formed on a glass substrate 14 having a thickness of 0.2 mm and a square shape with sides of 5 mm in plan view. The thin film 13 is evaporated to a thickness of 10 nm. The pores 12a are formed in a cylindrical shape with a diameter φ of 5 μm and a depth of 5 μm, and are arranged at a pitch of 10 μm in the x and y directions. Each pore 12a of this size is capable of holding air 16 in the liquid of the sample S, as shown in FIG. 2.

[0038] From the viewpoint of photolithography technology, it is desirable that the pores 12a have a cylindrical shape. However, in order to store air, it is desirable that the pores 12b have a substantially cylindrical shape with a reverse tapered side surface that makes the opening area smaller than the bottom area, as shown in the partially enlarged cross-sectional side view of Fig. 3(c). With this configuration, it is possible to make it difficult for the air stored in the pores 12b to escape.

[0039] 5 is a perspective view showing a holding container positioning mechanism of collection device 1. The holding container positioning mechanism determines the relative position of collection container 11 and XYZ axis stage 20, which is a mounting plate on which collection container 11 is placed.

[0040] In this embodiment, the collection vessel 11 has a cylindrical shape with a bottom, and a pair of protrusions 11b, 11b are formed at opposing positions on the outer periphery of the cylindrical shape, protruding from the outer periphery. Meanwhile, a circular through hole 20a is formed in the XYZ axis stage 20. A step 20b is formed around the inner periphery of the circular through hole 20a, into which the outer periphery edge of the circular bottom of the collection vessel 11 fits, and a pair of grooves 20c, 20c are formed at opposing positions on the step 20b, into which the protrusions 11b, 11b fit. The protrusions 11b, 11b form an engagement portion formed on the outer periphery of the collection vessel 11, and the grooves 20c, 20c form an engaged portion that engages with the engagement portion, and the holding vessel positioning mechanism according to this embodiment is composed of the protrusions 11b, 11b and the grooves 20c, 20c. A pair of protrusions 11b, 11b of collection vessel 11 fit into grooves 20c, 20c of XYZ axis stage 20, and collection vessel 11 is placed on XYZ axis stage 20, whereby the relative positions of collection vessel 11 and XYZ axis stage 20 are determined.

[0041] The holding container positioning mechanism is not limited to this configuration, and may be configured as shown in FIG. 6, for example. In this configuration, the inner circumference of the container portion 11a of the collection container 11' is hollowed out in a cylindrical shape, and the outer circumference 11c is rectangular. A rectangular through hole 20e is formed in the XYZ-axis stage 20'. A rectangular step 20f into which the outer periphery of the rectangular bottom of the collection container 11' fits is formed on the inner circumference of the rectangular through hole 20e. The outer circumference 11c of the collection container 11' constitutes an engagement portion, and the step 20f of the XYZ-axis stage 20' constitutes an engaged portion that engages with the engagement portion, and the holding container positioning mechanism according to this modified example is composed of the outer circumference 11c of the collection container 11' and the step 20f of the XYZ-axis stage 20'. Outer periphery 11c of collection container 11' fits into step 20f of XYZ axis stage 20', and collection container 11' is placed on XYZ axis stage 20', whereby the relative positions of collection container 11' and XYZ axis stage 20' are determined.

[0042] The holding container positioning mechanism on the XYZ-axis stage 20, 20' side may be configured as a jig, and the jig may be attached to the XYZ-axis stage 20, 20', rather than being configured on the XYZ-axis stage 20, 20' itself. Also, in the holding container positioning mechanism shown in Fig. 5, a groove may be formed as the engaged portion on the outer periphery of the collection container 11 instead of the protrusion 11b, and a protrusion shaped to fit into this groove may be formed as the engaging portion instead of the groove 20c at the location facing the step 20b.

[0043] Furthermore, the collection device 1 has a substrate positioning mechanism that determines the relative positions of the collection substrate 12 and the collection container 11. In this embodiment, this substrate positioning mechanism is composed of four sides of the collection substrate 12 having a rectangular outer shape as shown in Fig. 3(a) and a rectangular step 11d (see Fig. 2) formed on the bottom surface of the storage section 11a of the collection container 11. The four outer sides of the rectangular bottom of the collection substrate 12 are fitted into and stored in the rectangular step 11d, thereby determining the relative positions of the collection substrate 12 and the collection container 11.

[0044] Fig. 7(a) is a plan view of the collection substrate 12 of the present embodiment, showing irradiation regions (hereinafter referred to as laser spots) LS1-LS9 as black dots on which the laser beams L1-L9 are irradiated on the collection substrate 12. In the present embodiment, the laser spots LS1-LS9 are formed at nine locations on the thin film 13 on the surface of the collection substrate 12. However, the number of laser spots is not limited to nine, and they may be formed at only one location as shown in Fig. 7(b). In this case, if, for example, one laser light source 41 is provided instead of the laser light sources 41-49, the laser spot LS1 is formed at one location.

[0045] When collecting minute objects α, first, the control device 90 places the collection container 11 on the XYZ axis stage 20 so that the bottom of the collection container 11 fits into the step 20b of the XYZ axis stage 20 and the protrusions 11b, 11b of the collection container 11 engage with the grooves 20c, 20c of the XYZ axis stage 20. This process is realized, for example, by a feeding mechanism (not shown) of the collection kit 10. At this time, the four outer sides of the rectangular bottom of the collection substrate 12 fit into the rectangular step 11d on the inner bottom surface of the collection container 11, and the collection substrate 12 is accommodated therein.

[0046] Next, the control device 90 controls the lighting device 70 to emit white light WL for irradiating the sample S on the collection kit 10, and controls the photographing device 80 to start photographing the sample S.

[0047] Next, the control device 90 adjusts the position of the XYZ axis stage 20 by controlling the adjustment mechanism 30 so that the laser beams L1 to L9 from the laser light sources 41 to 49 are irradiated to appropriate positions on the collection substrate 12, for example, positions where the laser spots LS1 to LS9 in Fig. 7(a) are formed. This position adjustment can be realized by extracting the pattern of the pores 12a from the image captured by the imaging device 80, for example, by using an image processing technique for pattern recognition.

[0048] Next, the control device 90 controls the laser light sources 41-49 to emit laser beams L1-L9. The laser beams L1-L9 are focused by the objective lens 60, and the focused beams are irradiated onto the thin film 13 of the collection substrate 12. This causes convection in the liquid of the sample S, and the micro objects α dispersed in the liquid are collected near the laser spots LS1-LS9 and trapped in the pores 12a. Thereafter, the control device 90 controls the laser light sources 41-49 to stop irradiating the thin film 13 of the collection substrate 12 with the laser beams L1-L9.

[0049] The manner in which the minute particles α are captured and the mechanism thereof will be explained as follows.

[0050] FIG. 2(b) shows the state of collection of minute objects α from the sample S when a laser spot LS1 is formed at one location in the center of the collection substrate 12 as shown in FIG. 7(b).

[0051] 2(a), before the start of irradiation with the laser light L1 from the laser light source 41, the micro-objects α can freely move in the liquid of the sample S. Almost no micro-objects α are captured in the pores 12a of the collection substrate 12.

[0052] However, when irradiation of the laser beam L1 (hereinafter also referred to as "light irradiation") is started, the vicinity of the laser spot LS1 is locally heated due to the photothermal effect of the thin film 13 of the laser spot LS1. As a result, microbubbles MB are generated in the laser spot LS1.

[0053] At this time, when heat is locally generated in the pores 12a that hold the air 16, microbubbles MB are generated with the air 16 held in the pores 12a as nuclei, and the generation of microbubbles MB is promoted. The locally generated heat increases the temperature of the liquid closer to the light irradiation point, so a temperature gradient is generated in the liquid. This temperature gradient causes convection in the liquid held in the storage section 11a of the collection vessel 11, but this convection is efficiently generated because it promotes the generation of microbubbles MB. Due to this efficiently generated convection, the minute objects α dispersed in the liquid are efficiently collected by the microbubbles MB formed on the surface of the collection substrate 12 and are captured in the pores 12a.

[0054] More specifically, a stagnation region where the flow velocity of the convection current is zero occurs between the microbubbles MB and the thin film 13. The minute objects α carried by the convection current stay in this stagnation region and are captured. Here, "capture" refers to the action of the minute objects α gathering in the vicinity of the microbubbles MB. As a result, the frequency (number of times per unit time) of the minute objects α passing above the pores 12a around the microbubbles MB increases compared to the case without light irradiation. The minute objects α are captured in the pores 12a when passing above the pores 12a. Here, "capture" refers to the action of capturing the minute objects α in the space inside the pores 12a.

[0055] According to the collection device 1 of the present embodiment, the shape of the inner circumference of the storage section 11a that holds the liquid in the collection container 11 is approximately circular or approximately elliptical in plan view, so that the liquid held in the storage section 11a of the collection container 11 generates convection without stagnating at the corners, as in a holding container that has a rectangular shape in plan view with corners on the inner circumference of the storage section. Therefore, the minute objects α dispersed in the liquid also move in the storage section 11a of the collection container 11 on the convection of the liquid without stagnating at the corners. As a result, due to the fact that the generation of microbubbles MB is promoted and convection is efficiently generated, the probability that the minute objects α dispersed in the liquid move over the pores 12a increases, and the collection efficiency of the minute objects α being captured by the microbubbles MB and captured by the pores 12a is improved.

[0056] Furthermore, according to the collection device 1 of the present embodiment, the holding container positioning mechanism accurately positions the collection container 11 relative to the XYZ-axis stage 20 on which the collection container 11 is placed. That is, by engaging the convex portions 11b, 11b formed on the outer periphery of the collection container 11 with the grooves 20c, 20c formed in the XYZ-axis stage 20, the collection container 11 is accurately positioned relative to the XYZ-axis stage 20 on which the collection container 11 is placed.

[0057] Therefore, the irradiation positions of the light irradiated by the laser light sources 41-49 on the collection substrate 12 placed in the collection container 11 can be accurately determined by accurately determining the relative positions of the laser light sources 41-49 and the XYZ axis stage 20. This makes it possible to accurately irradiate the laser light L1-L9 onto the thin film 13 at the desired position, generate heat at the desired position on the collection substrate 12, and generate the desired convection in the liquid of the sample S.

[0058] Furthermore, according to the collection device 1 of the present embodiment, the collection substrate 12 is accurately positioned relative to the collection container 11 by the substrate positioning mechanism. That is, the four sides of the collection substrate 12 fit into rectangular steps 11d formed in the bottom of the collection container 11, whereby the collection substrate 12 is accurately positioned relative to the collection container 11.

[0059] This makes it possible to more accurately determine the irradiation positions of the laser beams L1 to L9 that are irradiated by the laser light sources 41 to 49 onto the collection substrate 12 disposed in the collection container 11. This makes it possible to more accurately irradiate the thin film 13 at desired positions with the laser beams L1 to L9, generate heat at desired positions on the collection substrate 12, and generate desired convection in the liquid of the sample S.

[0060] Furthermore, according to the collection device 1 of this embodiment, it is possible to simultaneously form a plurality of laser spots LS1 to LS9 at a plurality of locations on the thin film 13. Therefore, it is possible to simultaneously generate heat at a plurality of locations on the collection substrate 12, and simultaneously generate liquid convection at a plurality of locations in the sample S. This increases the amount of minute objects α that can be simultaneously collected by liquid convection, and further improves the collection efficiency at which the minute objects α are captured in the pores 12a.

[0061] In addition, in the collection device 1 of this embodiment, the collection substrate 12 is based on a glass substrate 14, and a plurality of pores 12a are formed in areas where there is no resist film 15 selectively formed on the glass substrate 14, and a thin film 13 is formed on the bottom surfaces of the pores 12a and on the upper surface of the resist film 15.

[0062] In the conventional micro object collection device disclosed in Patent Document 1, the honeycomb polymer film that forms the pores is produced by flowing an airflow containing water vapor above the honeycomb solution, causing condensation on the solution surface due to the temperature difference between the honeycomb solution and the airflow, and using multiple water droplets arranged in a honeycomb shape by self-organization as a template. However, according to the collection device 1 of the present embodiment, multiple pores 12a are formed using photolithography technology, so that the pores 12a can be formed with higher accuracy than the conventional formation of pores using self-organization.

[0063] In the collection device 1 of this embodiment, as shown in Fig. 3(b), the multiple pores 12a do not have any communicating portions between the pores 12a. On the other hand, in the collection substrate 100 of the minute object collection device disclosed in Patent Document 1, as conceptually shown in the side cross-sectional view of Fig. 8, communication portions 101 are formed between the pores 12a. In other words, adjacent pores 12a communicate with each other on the bottom surface side.

[0064] According to the collection device 1 of this embodiment, since there is no communication between the pores 12a, liquid is unlikely to enter the pores 12a and the air 16 that triggers the generation of microbubbles is unlikely to escape from the pores. When the air 16 accumulated in the pores 12a is used to generate the microbubbles MB, it is possible to generate the microbubbles MB with lower thermal energy than when the microbubbles MB are generated without the air 16 in the pores 12a.

[0065] In the above embodiment, the case where the pores 12a are provided on the entire surface of the collection substrate 12 has been described. However, as in the collection substrate 12A shown in the plan view of Fig. 9(a), the collection substrate 12A may be configured to have an area where the pores 12a are formed and an area where the pores 12a are not formed. According to this configuration, the area where the pores 12a capable of holding air are formed in the collection substrate 12A is selectively formed, and the pores 12a capable of holding air are formed only in desired areas.

[0066] Alternatively, as in the case of a collection substrate 12A shown in FIG. 9(a), laser light sources 41 to 49 may be configured to form laser spots LS1 to LS9 in regions overlapping with a region in which a plurality of pores 12a are formed.

[0067] According to this configuration, heat is generated in the region where the multiple pores 12a are formed and the laser spots LS1 to LS9 formed by the laser light sources 41 to 49 overlap, and microbubbles MB are selectively formed in the region. Therefore, the microbubbles MB become noise bubbles, and it is possible to prevent the formation of microbubbles MB in regions where the formation of microbubbles MB is not desired.

[0068] Furthermore, like collection substrate 12B shown in a plan view in Figure 9(b), collection substrate 12B may be configured to have an area where multiple pores 12a are formed and an area where multiple pores 12a are not formed, and thin film 13 may be formed in the area where multiple pores 12a are formed.

[0069] According to this configuration, the thin film 13 is formed only in the region where the plurality of pores 12a are formed, which has an area overlapping with the laser spots LS1 to LS9. Therefore, compared to the case where the thin film 13 is formed on the entire surface of the collection substrate 12, heat dissipation can be suppressed, and the light-to-heat conversion efficiency can be improved.

[0070] Furthermore, as shown in collection substrate 12C in a side cross-sectional view in Figure 10(a) and a plan view in Figure 10(b), collection substrate 12C may be configured such that in the region where multiple pores 12a are formed, pores 12a, 12c having the same depth but different opening areas are formed side by side on the surface.

[0071] According to this configuration, a large air mass is formed in the pore 12c with a large opening area, and microbubbles are generated around the pore 12c with a large opening area. Since the micro-object α is collected in the convection pool formed below the microbubble MB, when the microbubble MB moves, there is a possibility that the micro-object α already collected will be released during the movement of the microbubble MB. When the microbubble MB is formed around a large air mass as a nucleus as in this configuration, the center of the microbubble MB is unlikely to move. Therefore, it is possible to reduce the possibility that the micro-object α already collected by the microbubble MB will be released.

[0072] Furthermore, as in collection substrate 12D shown in a side cross-sectional view in Figure 11(a) and a plan view in Figure 11(b), collection substrate 12D may be configured such that, in the region where multiple pores 12a are formed, multiple pores 12a that are shallow and have a small opening area are formed within pores 12d that are deep and have a large opening area.

[0073] According to this configuration, the plurality of pores 12a, which are shallow and have a small opening area, tend to trap heat due to the small space of each pore, and the heat conversion efficiency due to the photothermal effect of the thin film 13 is improved. On the other hand, the pores 12d, which have a large opening area, tend to trap large air masses, and thus promote the generation of microbubbles MB. Therefore, by forming the plurality of pores 12a, which are shallow and have a small opening area, in the pores 12d, which have a deep depth and a large opening area, the above-mentioned improvement in heat conversion efficiency and promotion of microbubble generation are combined, and the microbubbles MB are more likely to be generated. Therefore, the collection efficiency at which the minute objects α are captured by the pores 12a and 12d is further improved.

[0074] In the above embodiment and each modified example, the multiple pores 12a are arranged in a line in the x and y directions as shown in the plan view of Fig. 12(a). However, the multiple pores 12a may be arranged in a two-dimensional hexagonal lattice (honeycomb) shape as shown in the plan view of Fig. 12(b). With this configuration, the x and y lengths of the region in which the multiple pores 12a are distributed can be reduced, so that more pores 12a can be arranged in the same area, and more air 16, which serves as a trigger for generating microbubbles, can be stored in the pores 12a.

[0075] To summarise the above, the present invention can be expressed as follows.

[0076] <1> A holding container having an inner periphery of a container portion that is circular or similar to a circle in plan view, or a polygon having a number of sides close to a circle, or an ellipse, or a shape similar to an ellipse, and that can hold liquid in the container portion; a collection substrate disposed in the container for collecting a plurality of minute objects dispersed in the liquid; A plurality of pores capable of retaining air formed on the surface of the collection substrate; a photothermal conversion region formed on the surface of the collection substrate for converting light into heat; a light source for irradiating the collection substrate with light; A micro-object collection device comprising:

[0077] <2> The holding container is characterized in that the holding container has a holding container positioning mechanism for positioning the holding container relative to a mounting plate on which the holding container is placed. <1> The minute object collecting device according to claim 1 .

[0078] <3> The holding container positioning mechanism is characterized in that it is composed of an engaging portion or an engaged portion formed on the outer periphery of the holding container, and an engaged portion or an engaging portion formed on the placement plate, which engages with the engaging portion or the engaged portion. <2> The minute object collecting device according to claim 1 .

[0079] <4> The method further comprises: providing a substrate positioning mechanism for positioning the collection substrate relative to the holding container; <1> from <3> 13. A micro-object collecting device according to any one of claims 1 to 12.

[0080] <5> The light source forms a plurality of light irradiation areas on the collection substrate. <1> from <4> 13. A micro-object collecting device according to any one of claims 1 to 12.

[0081] <6> The collection substrate has an area where the plurality of pores are formed and an area where the plurality of pores are not formed. <1> from <5> 13. A micro-object collecting device according to any one of claims 1 to 12.

[0082] <7> The light source forms a light irradiation area in an area overlapping an area in which the plurality of pores are formed. <6> The minute object collecting device according to claim 1 .

[0083] <8> The light-to-heat conversion region is formed in the region in which the plurality of pores are formed. <6> or <7> The minute object collecting device according to claim 1 .

[0084] <9> The collection substrate is characterized in that in a region where the plurality of pores are formed, the pores are formed side by side on the surface, the pores having the same depth but different opening areas. <6> from <8> 13. A micro-object collecting device according to any one of claims 1 to 12.

[0085] <10> The collection substrate is characterized in that, in a region in which the plurality of pores are formed, a plurality of pores having a shallow depth and a small opening area are formed among the pores having a deep depth and a large opening area. <6> from <8> 13. A micro-object collecting device according to any one of claims 1 to 12.

[0086] <11> The collection substrate is based on a glass substrate, the plurality of pores are formed in a portion of the glass substrate where the resist film is not formed selectively, The photothermal conversion region is formed on the bottom surface of the pore and on the upper surface of the resist film. Characterized by <1> from <10> 13. A micro-object collecting device according to any one of claims 1 to 12.

[0087] <12> The plurality of pores are characterized in that there are no interconnections between the pores. <11> The minute object collecting device according to claim 1 .

[0088] <13> The pores are characterized in that they are substantially cylindrical in shape with inversely tapered side surfaces that make the opening area smaller than the bottom area. <11> or <12> The minute object collecting device according to claim 1 .

[0089] <14> The photothermal conversion region is formed of a gold thin film having a thickness of 4 nm to 20 nm. <11> from <13> 13. A micro-object collecting device according to any one of claims 1 to 12.

[0090] <15> The plurality of pores are arranged in a hexagonal lattice pattern in two dimensions. <1> from <14> 13. A micro-object collecting device according to any one of claims 1 to 12. [Explanation of symbols]

[0091] 1...Collection device 10...Collection kit 11, 11'...Collection vessel (holding vessel) 11a… Storage section 11b...Convex portion (engagement portion) 11c...Outer periphery (engagement part) 11d…Rectangular step 12...Collection substrate 12a, 12b, 12c, 12d...pores 13...Thin film (light-to-heat conversion area) 14…Glass substrate 15...Resist film 16. Air 20,20'...XYZ axis stage (mounting plate) 20a…Circular through hole 20b...Step 20c...Groove (engaged part) 20e…Rectangular through hole 20f…Step (engaged part) 30…Adjustment mechanism 41~49…Laser light source 50...Optical components 60…Objective lens 70…Lighting equipment 80...Filming equipment 90...Control device S…Sample α…Minute object MB: Microbubbles LS1~LS9…Laser spot (light irradiation area)

Claims

1. A holding container having an inner periphery of a container portion that is circular or similar to a circle in plan view, or a polygon having a number of sides close to a circle, or an ellipse, or a shape similar to an ellipse, and that can hold liquid in the container portion; a collection substrate disposed in the container for collecting a plurality of minute objects dispersed in the liquid; A plurality of pores capable of retaining air formed on the surface of the collection substrate; a photothermal conversion region formed on the surface of the collection substrate for converting light into heat; a light source that irradiates the collection substrate with light; A micro-object collection device comprising:

2. 2. The minute object collecting device according to claim 1, further comprising a holding container positioning mechanism for positioning the holding container relative to a mounting plate on which the holding container is placed.

3. The micro-object collection device described in claim 2, characterized in that the holding container positioning mechanism is composed of an engaging portion or an engaged portion formed on the outer periphery of the holding container, and an engaged portion or an engaging portion formed on the placement plate, which engages with the engaging portion or engaged portion.

4. 4. The minute object collecting device according to claim 1, further comprising a substrate positioning mechanism for positioning the collecting substrate and the holding container relative to each other.

5. 4. The minute object collection device according to claim 1, wherein the light source forms a plurality of light irradiation areas on the collection substrate.

6. 6. The apparatus for collecting minute objects according to claim 5, wherein the collection substrate has an area where the plurality of pores are formed and an area where the plurality of pores are not formed.

7. 7. The minute object collecting device according to claim 6, wherein the light source forms a light irradiation area in an area overlapping an area in which the plurality of pores are formed.

8. 8. The apparatus for collecting minute objects according to claim 7, wherein the light-to-heat conversion region is formed in a region in which the plurality of pores are formed.

9. 8. The micro-object collection device according to claim 7, wherein the collection substrate has pores of the same depth but different opening areas formed side by side on the surface in the region where the plurality of pores are formed.

10. The collection substrate is characterized in that, in the region in which the plurality of pores are formed, a plurality of pores having a shallow depth and a small opening area are formed among the pores having a deep depth and a large opening area.

11. The collection substrate is based on a glass substrate, the plurality of pores are formed in a portion of the glass substrate where the resist film is not formed selectively, The photothermal conversion region is formed on the bottom surface of the pore and on the upper surface of the resist film.

8. The apparatus for collecting minute objects according to claim 7.

12. 12. The minute object collecting device according to claim 11, wherein the plurality of pores have no communicating portions between the pores.

13. 12. The minute object collecting device according to claim 11, wherein the fine hole has a substantially cylindrical shape with a reverse tapered side surface such that the opening area is smaller than the bottom area.

14. 12. The minute object collection device according to claim 11, wherein the photothermal conversion region is formed from a gold thin film having a thickness of 4 nm to 20 nm.

15. 12. The minute object collecting device according to claim 11, wherein the plurality of pores are arranged in a hexagonal lattice pattern in two dimensions.

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