阅读说明：本技术 微小物体的集聚系统以及微小物体的集聚方法 (System and method for collecting fine objects ) 是由 饭田琢也 床波志保 石川弘树 山崎力 于 2020-04-22 设计创作，主要内容包括：样本台(1)构成为对设置了薄膜(12)的基板(11)进行保持。激光模块(4)包含多个发光区域(421),从多个发光区域(421)分别发出多个激光光线(L)。光波导(44)以及透镜(45)将多个激光光线(L)聚光到同一聚光点(F)。调整机构(6)构成为对样本台(1)与聚光透镜(光波导(44)以及透镜(45))之间的相对位置关系进行调整。控制装置(50)构成为能够进行单一照射模式和多点照射模式的切换。单一照射模式是对调整机构(6)进行控制使得多个激光光线(L)的聚光点(F)与薄膜(12)一致的模式。多点照射模式是对调整机构(6)进行控制使得聚光点(F)偏离薄膜(12)的模式。(The sample stage (1) is configured to hold a substrate (11) on which a thin film (12) is provided. The laser module (4) includes a plurality of light emitting regions (421), and a plurality of laser beams (L) are emitted from the plurality of light emitting regions (421), respectively. The optical waveguide (44) and the lens (45) condense the plurality of laser beams (L) to the same condensing point (F). The adjustment mechanism (6) is configured to adjust the relative positional relationship between the sample stage (1) and the condenser lenses (the optical waveguide (44) and the lens (45)). The control device (50) is configured to be capable of switching between a single irradiation mode and a multi-point irradiation mode. The single irradiation mode is a mode in which the adjustment mechanism (6) is controlled so that the focal point (F) of the plurality of laser beams (L) coincides with the film (12). The multi-spot irradiation mode is a mode in which the adjustment mechanism (6) is controlled so that the focal point (F) is deviated from the film (12).)

1. A system for collecting fine objects, which collects a plurality of fine objects dispersed in a liquid, the system comprising:

a holding device configured to hold the substrate on which the photothermal conversion region is provided;

a laser light source including a plurality of light emitting regions from which a plurality of laser beams are emitted, respectively;

the condensing lens condenses the laser rays to the same condensing point;

an adjustment mechanism configured to adjust a relative positional relationship between the holding device and the condenser lens; and

a control device for controlling the adjusting mechanism,

the control device is configured to be capable of switching between a single irradiation mode and a multipoint irradiation mode, wherein the single irradiation mode and the multipoint irradiation mode are modes in which at least a part of the plurality of laser beams is irradiated to the photothermal conversion region,

the single irradiation mode is a mode in which the adjustment mechanism is controlled so that the focal point of the plurality of laser beams coincides with the photothermal conversion region,

the multi-spot irradiation mode is a mode in which the adjustment mechanism is controlled such that at least a part of the plurality of laser light rays passes through the photothermal conversion region while the light-condensing point is shifted from the photothermal conversion region.

2. The system for condensing tiny objects according to claim 1, wherein,

in the multi-spot irradiation mode, the control device controls the adjustment mechanism to adjust the distance between the condensing lens and the photothermal conversion region, thereby setting the interval between the plurality of laser beams irradiated to the photothermal conversion region.

3. The system for condensing small objects according to claim 1 or 2, wherein,

the laser light source is a vertical resonance surface light emitting laser.

4. The system for collecting micro objects as claimed in any one of claims 1 to 3, wherein,

the condensing lens includes a graded index type optical fiber and a plano-convex lens,

the optical fiber has one end covering the plurality of light emitting regions and the other end joined to the planar side of the plano-convex lens.

5. The system for collecting micro objects as claimed in any one of claims 1 to 4, wherein,

the control device controls the adjustment mechanism such that a plurality of bubbles and convection toward gaps of the plurality of bubbles are generated in the photothermal conversion region by irradiation of the plurality of laser beams, and the plurality of fine objects are thereby collected in the gaps, when the multi-point irradiation mode is selected under the condition that the liquid is prepared in the photothermal conversion region.

6. A method for aggregating a plurality of fine objects dispersed in a liquid, the method comprising:

preparing the liquid on a photothermal conversion region provided on a substrate; and

a step of adjusting a relative positional relationship between a condensing lens for condensing a plurality of laser beams to the same condensing point and the photothermal conversion region,

the step of adjusting comprises the step of selectively setting a 1 st state and a 2 nd state,

the 1 st state is a state in which the relative positional relationship is adjusted so that the focal point of the plurality of laser beams coincides with the photothermal conversion region,

the 2 nd state is a state in which the relative positional relationship is adjusted such that at least a part of the plurality of laser light rays passes through the photothermal conversion region and the focal point is deviated from the photothermal conversion region,

the method for collecting fine objects further includes:

generating a plurality of bubbles and convection to gaps of the plurality of bubbles in the photothermal conversion region by irradiation of the plurality of laser beams when the 2 nd state is selected; and

and a step of collecting the plurality of fine objects in the gap.

7. The method for collecting minute objects according to claim 6, wherein,

a plurality of pores for capturing the plurality of fine objects and a plurality of partition walls for partitioning adjacent pores among the plurality of pores from each other are formed on the substrate,

the photothermal conversion region is provided so as to cover at least a part of the plurality of pores and the plurality of partition walls.

Technical Field

The present disclosure relates to a system and a method for collecting fine objects, and more particularly, to a technique for collecting a plurality of fine objects dispersed in a liquid.

Background

A technique for aggregating a plurality of fine objects (fine particles, cells, microorganisms, or the like) dispersed in a liquid has been proposed. For example, japanese patent laid-open publication No. 2017-202446 (patent document 1) and international publication No. 2018/159706 (patent document 2) disclose techniques for aggregating a plurality of fine objects dispersed in a liquid by light irradiation. When light is irradiated to the photothermal conversion region that converts light into heat, the liquid near the light irradiation position is locally heated. Thereby, microbubbles are generated and convection is generated in the liquid. In this way, a plurality of fine objects are convected and transported toward the microbubbles, and are collected near the light irradiation position.

Prior art documents

Patent document

Patent document 1: japanese patent laid-open publication No. 2017-202446

Patent document 2: international publication No. 2018/159706

Disclosure of Invention

Problems to be solved by the invention

In an aggregation system for aggregating a plurality of fine objects dispersed in a liquid by light irradiation, it is required to aggregate more fine objects in a shorter time, in other words, to aggregate the fine objects more efficiently.

In order to efficiently collect fine objects, it is also conceivable to increase the output of light irradiated to the photothermal conversion region. However, the amount of temperature increase near the light irradiation position increases with an increase in light output. Among the minute objects, there are minute objects whose thermal damage should be suppressed. For example, since microorganisms are generally not heat-resistant, they may die if an excessive temperature rise is caused by light irradiation. Therefore, depending on the fine objects, it may be desirable to suppress thermal damage to the fine objects. On the other hand, there may be a minute object that can simply increase the light output without particularly considering the above-described case. Therefore, it is desirable that a user of the aggregation system can select how to aggregate the fine objects according to the kind or characteristics of the fine objects.

The present disclosure has been made to solve the above problems, and an object of the present disclosure is to enable a user to select a collection method of a plurality of fine objects dispersed in a liquid.

Means for solving the problems

(1) A micro object aggregation system according to an aspect of the present disclosure aggregates a plurality of micro objects dispersed in a liquid. The system for collecting fine objects comprises: a holding device configured to hold the substrate on which the photothermal conversion region is provided; a laser light source including a plurality of light emitting regions from which a plurality of laser beams are emitted, respectively; the condensing lens condenses a plurality of laser rays to the same condensing point; an adjustment mechanism configured to adjust a relative positional relationship between the holding device and the condenser lens; and a control device for controlling the adjusting mechanism. The control device is configured to be capable of switching between a single irradiation mode and a multipoint irradiation mode, wherein the single irradiation mode and the multipoint irradiation mode are respectively modes in which at least a part of the plurality of laser beams is irradiated to the photothermal conversion region. The single irradiation mode is a mode in which the adjustment mechanism is controlled so that the focal point of the plurality of laser beams coincides with the photothermal conversion region. The multi-spot irradiation mode is a mode in which the adjustment mechanism is controlled so that at least a part of the plurality of laser beams passes through the photothermal conversion region and the focal point is deviated from the photothermal conversion region.

(2) In the multi-spot irradiation mode, the control device controls the adjustment mechanism to adjust the distance between the condensing lens and the photothermal conversion region, thereby setting the interval between the plurality of laser beams irradiated to the photothermal conversion region.

(3) The laser light source is a vertical resonance surface light emitting laser.

(4) The condenser lens includes a graded-index type optical fiber and a plano-convex lens. The optical fiber has one end covering the plurality of light emitting regions and the other end joined to the flat side of the plano-convex lens.

(5) When the multipoint irradiation mode is selected under the condition that the liquid is prepared in the photothermal conversion region, the control device controls the adjusting mechanism so that the plurality of bubbles and convection toward the gaps of the plurality of bubbles are generated in the photothermal conversion region by irradiation of the plurality of laser beams, thereby collecting the plurality of fine objects in the gaps.

(6) The method for aggregating fine objects according to another aspect of the present disclosure aggregates a plurality of fine objects dispersed in a liquid. The method for collecting fine objects includes steps 1 to 4. The 1 st step is a step of preparing a liquid on a photothermal conversion region provided on a substrate. The 2 nd step is a step of adjusting a relative positional relationship between a condensing lens that condenses a plurality of laser beams to the same condensing point and the photothermal conversion region. The adjusting step (step 2) includes a step of selectively setting the 1 st state and the 2 nd state. The 1 st state is a state in which the relative positional relationship is adjusted so that the focal point of the plurality of laser beams coincides with the photothermal conversion region. The 2 nd state is a state in which the relative positional relationship is adjusted so that at least a part of the plurality of laser beams passes through the photothermal conversion region and the focal point is deviated from the photothermal conversion region. The 3 rd step is a step of generating a plurality of bubbles and convection to gaps of the plurality of bubbles in the photothermal conversion region by irradiation of the plurality of laser beams when the 2 nd state is selected. The 4 th step is a step of collecting a plurality of fine objects in the gap.

(7) The substrate is formed with a plurality of pores for capturing a plurality of fine objects and a plurality of partition walls for partitioning adjacent pores among the plurality of pores. The photothermal conversion region is provided so as to cover at least a part of the plurality of pores and the plurality of partition walls.

Effects of the invention

According to the present disclosure, a user can select a collection method of a plurality of fine objects dispersed in a liquid.

Drawings

Fig. 1 is a view schematically showing the overall configuration of a system for collecting fine objects according to the present embodiment.

Fig. 2 is a diagram showing a stereoscopic image of a laser module.

Fig. 3 is a view schematically showing the structure of the laser module.

Fig. 4 is a cross-sectional view of the laser module along line IV-IV of fig. 3.

Fig. 5 is a cross-sectional view of the laser module along the V-V line of fig. 3.

Fig. 6 is a perspective view schematically showing the structure of the flat plate nesting set.

Fig. 7 is a cross-sectional view of the plate nesting set taken along line VII-VII of fig. 6.

Fig. 8 is a perspective view schematically showing the structure of the honeycomb concentration kit.

Fig. 9 is a cross-sectional view of the honeycomb nesting set along line IX-IX of fig. 8.

Fig. 10 is a diagram for explaining a method of switching between the single irradiation mode and the multi-spot irradiation mode.

Fig. 11 is a flowchart illustrating a method of collecting fine objects according to the present embodiment.

Fig. 12 is a diagram for explaining a mechanism of collecting fine objects in a single irradiation mode.

Fig. 13 is a diagram for explaining a mechanism of collecting fine objects in the multi-spot irradiation mode.

Fig. 14 is a graph showing the optical simulation results and the actual measurement results in the vicinity of the laser spot at the intervals between the plurality of laser beams corresponding to the case where the irradiation distance D is 0.2 mm.

Fig. 15 is a graph showing the optical simulation results and the actual measurement results in the vicinity of the laser spot at the intervals between the plurality of laser beams corresponding to the case where the irradiation distance D is 0.3 mm.

Fig. 16 is a graph showing the optical simulation results and the actual measurement results in the vicinity of the laser spot at the intervals between the plurality of laser beams corresponding to the case where the irradiation distance D is 0.4 mm.

Fig. 17 is a graph showing the optical simulation results and the actual measurement results in the vicinity of the laser spot at the intervals between the plurality of laser beams corresponding to the case where the irradiation distance D is 0.5 mm.

Fig. 18 is a graph showing the optical simulation results and the actual measurement results in the vicinity of the laser spot at the intervals between the plurality of laser beams corresponding to the case where the irradiation distance D is 0.6 mm.

Fig. 19 is a graph showing the optical simulation results and the actual measurement results in the vicinity of the laser spot at the intervals between the plurality of laser beams corresponding to the case where the irradiation distance D is 0.7 mm.

Fig. 20 is a graph showing the optical simulation results and the actual measurement results in the vicinity of the laser spot at the intervals between the plurality of laser beams corresponding to the case where the irradiation distance D is 0.8 mm.

Fig. 21 is a graph showing the optical simulation results and the actual measurement results in the vicinity of the laser spot at the intervals between the plurality of laser beams corresponding to the case where the irradiation distance D is 0.9 mm.

Fig. 22 is a graph showing the optical simulation results and the actual measurement results in the vicinity of the laser spot at the intervals between the plurality of laser beams corresponding to the case where the irradiation distance D is 1.0 mm.

Fig. 23 is a graph showing the optical simulation result and the actual measurement result in the vicinity of the laser spot at the intervals between the plurality of laser beams corresponding to the case where the irradiation distance D is 1.1 mm.

Fig. 24 is a graph showing the optical simulation results and the actual measurement results in the vicinity of the laser spot at the intervals between the plurality of laser beams corresponding to the case where the irradiation distance D is 1.2 mm.

Fig. 25 is a graph showing the observation result of the vicinity of the laser spot.

Fig. 26 is a graph showing the observation results of microbubbles generated when light is irradiated to the honeycomb concentration set.

Fig. 27 is a graph showing the observation results of the honeycomb concentration set after a single irradiation.

Fig. 28 is a view showing the observation result of the honeycomb concentration kit after the multi-spot irradiation.

Fig. 29 is a graph showing the measurement results of the temperature increase amount caused by light irradiation to the flat plate stacking kit.

Fig. 30 is a graph showing the measurement results of the temperature increase amount caused by light irradiation to the honeycomb collection set.

Detailed Description

In the present disclosure, "nanoscale" encompasses the range from 1nm to 1000nm (═ 1 μm). "micron-sized" encompasses the range from 1 μm to 1000 μm (═ 1 mm). Thus, "a range from nano-scale to micro-scale" encompasses a range from 1nm to 1000 μm. The "range from the nano-scale to the micro-scale" typically shows a range of several nm to several hundreds of μm, preferably shows a range of 100nm to 100 μm, and more preferably may show a range of 1 μm to several tens of μm.

In the present disclosure, the term "minute object" means an object having a size ranging from a nanometer to a micrometer. The shape of the fine objects is not particularly limited, and examples thereof include a spherical shape, an oval sphere, and a rod shape (rod shape). When the fine objects are in the shape of an elliptical sphere, at least one of the length of the elliptical sphere in the major axis direction and the length of the elliptical sphere in the minor axis direction may be in a range from the nanometer level to the micrometer level. When the fine objects are rod-shaped, at least one of the width and the length of the rod may be in a range from the nanometer level to the micrometer level.

Examples of the fine objects include metal nanoparticles, metal nanoparticle aggregates, metal nanoparticle aggregate structures, semiconductor nanoparticles, organic nanoparticles, resin beads, and PM (Particulate Matter). The "metal nanoparticles" are metal particles having a size of the order of nanometers. The "metal nanoparticle aggregate" is an aggregate formed by aggregating a plurality of metal nanoparticles. The "metal nanoparticle aggregated structure" is, for example, a structure in which a plurality of metal nanoparticles are fixed to the surface of a base material (resin beads or the like) via interaction sites, and are arranged at intervals of not more than the diameter of the metal nanoparticles with a gap therebetween. The "semiconductor nanoparticles" are semiconductor particles having a size of the order of nanometers. The "organic nanoparticles" are particles made of an organic compound having a size of the order of nanometers. The "resin beads" are particles made of a resin having a size ranging from a nanometer level to a micrometer level. The "PM" is a particulate substance having a size of the order of micrometers. Examples of the PM include PM2.5, SPM (Suspended Particulate Matter), and the like.

The minute objects may be substances derived from living organisms (biological substances). More specifically, the minute objects may include cells, microorganisms (bacteria, fungi, etc.), biopolymers (proteins, nucleic acids, lipids, polysaccharides, etc.), antigens (allergens, etc.), and viruses.

In the present disclosure, the term "honeycomb shape" means a shape in which a plurality of regular hexagons are arrayed in a hexagonal lattice shape (honeycomb shape) in a two-dimensional direction. Pores are formed in each of the plurality of regular hexagons. Each fine pore is a pore having an opening ranging from a nanometer level to a micrometer level. The pores may be through-holes or non-through-holes. The shape of the pores is not particularly limited, and may include any shape such as a cylindrical shape, a prismatic shape, a spherical shape (for example, a hemispherical shape or a semi-ellipsoidal spherical shape) other than a regular spherical shape, and the like. A structure having a structure in which a plurality of fine pores are arranged in a honeycomb shape is referred to as a "honeycomb structure".

In the present disclosure, the term "microbubble" means a micro-scale bubble.

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In addition, the same or corresponding parts in the drawings are denoted by the same reference numerals, and description thereof will not be repeated.

[ embodiment ]

In the present embodiment, resin beads or bacteria are used as an example of the fine objects. The material of the resin beads is polystyrene. However, the material of the resin beads is not limited thereto, and may be propylene, polyolefin, polyethylene, polypropylene, or the like. Furthermore, pseudomonas aeruginosa was used as the bacterium. Pseudomonas aeruginosa is a bacillus. The length of the major axis of a typical pseudomonas aeruginosa is about 2 μm and the length of the minor axis is about 0.5 μm. Pseudomonas aeruginosa is a gram-negative bacterium.

Hereinafter, the x direction and the y direction denote horizontal directions. The x-direction and the y-direction are orthogonal to each other. The z direction represents a vertical direction. The direction of gravity is downward in the z direction. The upward direction in the z direction may be simply referred to as "upward" and the downward direction in the z direction may be simply referred to as "downward".

In the present embodiment, two types of aggregation kits for aggregating fine objects are prepared. The detailed structure of these stacking kits will be described with reference to fig. 6 to9, and one will be referred to as "flat stacking kit 10" and the other as "honeycomb stacking kit 20".

< Structure of Collection System >

Fig. 1 is a diagram schematically showing the overall configuration of a fine object aggregation system 100 according to the present embodiment. Referring to fig. 1, the collecting system 100 includes a specimen stage 1, a specimen supply device 2, a light source stage 3, a laser module 4, a cooling device 5, an adjustment mechanism 6, a power supply 7, an imaging device 8, an illumination device 9, and a control device 50. While the flat stacking kit 10 is used in the following description, the honeycomb stacking kit 20 may be used instead of the flat stacking kit 10.

The sample stage 1 is an XYZ-axis stage, and is configured to be movable in the x direction, the y direction, and the z direction. The sample stage 1 holds the flat gathering kit 10. The sample S is dropped onto the flat collection kit 10. The sample stage 1 corresponds to a "holding device" according to the present disclosure.

The sample supply device 2 supplies the liquid sample S to the flat collection kit 10 in response to a command from the control device 50. As the sample supply device 2, for example, a dispenser can be used.

The light source stage 3 is an XYZ-axis stage, and is configured to be movable in the x direction, the y direction, and the z direction. The light source table 3 holds the laser module 4 and the cooling device 5.

The laser module 4 is a semiconductor laser module (laser light source) and emits a large number of laser beams L in response to a command from the control device 50. The wavelength of the laser light L is in this example in the near infrared region, for example 850 nm. The structure of the laser module 4 will be described in detail with reference to fig. 2 to 5.

The cooling device 5 cools the laser module 4. By using a peltier element (not shown) as the cooling device 5, the cooling device 5 can be downsized.

The adjustment mechanism 6 is configured to be able to adjust the x-direction, y-direction, and z-direction positions of the sample stage 1 and the x-direction, y-direction, and z-direction positions of the light source stage 3 in accordance with a command from the control device 50. In the example described below, when determining the light irradiation position, the horizontal position (the x-direction and y-direction positions) of the sample stage 1 can be adjusted, and the height (the z-direction position) of the light source stage 3 can be adjusted. Thus, the relative positional relationship between the flat collection kit 10 mounted on the sample stage 1 and the laser module 4 provided on the light source stage 3 can be adjusted.

However, the structure of the adjustment mechanism 6 is not particularly limited as long as the relative positional relationship between the flat focusing kit 10 and the laser module 4 can be adjusted. The adjustment mechanism 6 may adjust the position of the flat focusing kit 10 with respect to the fixed laser module 4, or may adjust the position of the laser module 4 with respect to the fixed flat focusing kit 10, for example.

The power supply 7 supplies current for driving the laser module 4. Further, the power supply 7 supplies electric power for driving the cooling device 5.

The photographing apparatus 8 photographs the specimen S on the flat condensing kit 10 according to an instruction from the control device 50, and outputs the photographed image to the control device 50. For the photographing Device 8, a camera including a CCD (Charge Coupled Device) image sensor or a CMOS (Complementary Metal Oxide Semiconductor) image sensor may be used.

The illumination device 9 emits white light WL for illuminating the sample S on the flat collection kit 10 in accordance with an instruction from the control device 50. As an example, a halogen lamp can be used as the lighting device 9. The white light WL emitted from the illumination device 9 is guided to the imaging device 8 by an optical fiber, for example, and is irradiated from the imaging device 8 toward an imaging region. The imaging device 8 and the illumination device 9 are merely devices for imaging the sample S, and are not essential components of the aggregation system 100 for aggregating fine objects.

The control device 50 controls the respective devices (the specimen supplying apparatus 2, the adjusting mechanism 6, the power supply 7, the imaging device 8, and the illumination device 9) constituting the collecting system 100. The control device 50 may be implemented by a microcomputer including a processor such as a CPU (Central Processing Unit), a Memory such as a ROM (Read Only Memory) and a RAM (Random Access Memory), an input/output port (none of which is shown), and the like.

Fig. 2 is a diagram showing a stereoscopic image of the laser module 4. Fig. 3 is a diagram schematically showing the structure of the laser module 4. Referring to fig. 2 and 3, the laser module 4 is provided on the light source stage 3 and disposed below the sample stage 1. A flat gathering kit 10 is provided on the sample stage 1. A plurality of laser light L (a plurality of laser light L) emitted upward from the laser module 4 are irradiated to the flat condensing kit 10 on the specimen stage 1. In fig. 3 and fig. 10 described later, the cooling device 5 is not shown.

Fig. 4 is a cross-sectional view of the laser module 4 along the line IV-IV of fig. 3. Fig. 5 is a cross-sectional view of the laser module 4 along the V-V line of fig. 3. Referring to fig. 4, the laser module 4 includes a substrate 41, a surface light emitting element 42, a joining member 43, an optical waveguide 44, and a lens 45.

The substrate 41 is a flat plate made of an insulating material, and is, for example, a printed wiring board or a ceramic substrate. A surface light emitting element 42 is mounted on the surface of the substrate 41. A part of the electrode 411 is formed on the back surface of the substrate 41. The electrode 411 is electrically connected to the surface light-emitting element 42 by wire bonding, for example. The surface light emitting element 42 is supplied with a drive current from the power supply 7 (see fig. 1) via the electrode 411.

Referring to fig. 5, the Surface light Emitting element 42 is an array type Vertical resonator Surface Emitting LASER (VCSEL). The surface light-emitting element 42 has a plurality of (30 in this example) light-emitting regions 421 and electrode pads 422. The plurality of light emitting regions 421 are arranged in an array. All the light emitting regions 421 emit light simultaneously and emit laser beams L, respectively. The plurality of emitted laser beams L are emitted in a direction perpendicular to the surface of the surface light emitting element 42 (upward in the z direction). In addition, the numerical values in FIG. 5 indicate the sizes (unit: μm) of the respective constituent elements.

Referring back to fig. 4, the bonding member 43 is, for example, an adhesive, and bonds the optical waveguide 44 to the surface light emitting element 42. The bonding member 43 is made of a material transparent to light (in this example, near-infrared light) emitted from the surface light emitting element 42.

The optical waveguide 44 condenses the plurality of laser beams L emitted from the surface light emitting element 42. The material of the optical waveguide 44 is transparent to the light emitted from the surface light-emitting element 42, and is, for example, resin or glass. The optical waveguide 44 includes a core 441 and a cladding (clad) 442.

The core 441 has a cylindrical shape. An incident end (corresponding to "one end" according to the present disclosure) of the core 441 is formed to cover all the light-emitting regions 421 so that all the laser light L emitted from the surface light-emitting element 42 is incident. The cladding 442 has a cylindrical shape. The cladding 442 is formed to cover the side of the core 441.

The lens 45 is a plano-convex lens having a flat surface and a convex surface. The plane of the lens 45 is joined to an ejection end (corresponding to "the other end" referred to in the present disclosure) of the optical waveguide 44. The convex surface of the lens 45 protrudes in the emission direction of light emitted from the laser light emission portion of the laser module 4.

The propagation path of the laser beam L in the laser module 4 configured as described above will be described. The optical waveguide 44 is a Graded Index (GI) type optical fiber. Therefore, the refractive index of the core 441 of the optical waveguide 44 is highest at the radial center of the core 441, and becomes smoothly lower toward the radial outside. The laser light L propagating inside the core 441 has a plurality of modes having propagation distances different from each other. Light of the lower order mode proceeds at the core center, and light of the higher order mode proceeds off the core center. Although the propagation distance of light of the low order mode is short, the propagation speed of light of the low order mode is relatively slow due to the high refractive index at the center of the core. In contrast, for light of a high-order mode, the propagation distance is long, and on the other hand, the propagation speed is relatively fast. The refractive index profile of the core 441 is designed so that the difference in propagation time between modes is sufficiently short.

The plurality of laser light beams L propagating inside the core 441 having such a refractive index distribution form nodes P and antinodes Q. The positions of the node P and the antinode Q can be changed according to the wavelength of the laser beam L. The length of the optical waveguide 44 is determined so that the emission end of the optical waveguide 44 is not located halfway from the node P to the antinode Q with respect to the traveling direction of the laser beam L. In other words, the length of the optical waveguide 44 is determined so that the emission end of the optical waveguide 44 is located halfway from the antinode Q to the node P as shown in fig. 4, or so that the emission end of the optical waveguide 44 coincides with the antinode Q. As a result, the plurality of laser beams L propagating through the optical waveguide 44 are emitted from the emission end of the optical waveguide 44 with a converging tendency. The plurality of emitted laser beams L are further condensed by the lens 45 to form the same condensed point F.

< Structure of Collection kit >

Fig. 6 is a perspective view schematically showing the structure of the flat nesting set 10. Fig. 7 is a cross-sectional view of the flat nesting set 10 taken along line VII-VII of fig. 6.

Referring to fig. 6 and 7, the flat aggregation kit 10 has a flat plate shape. The sample S is dropped onto the upper surface US of the flat plate shape.

In the example shown in fig. 7, the sample S is a liquid in which the resin beads R are dispersed. The type of the liquid (dispersion medium) is not particularly limited, but in this example, water is used. A nonionic surfactant for promoting aggregation of the resin beads R may be added to the sample S (see patent document 2 for details of the function of the surfactant).

The flat gathering kit 10 includes a substrate 11 and a film 12. The substrate 11 is made of a material that is transparent to the white light WL without affecting photothermal conversion (described later) of the laser beam L by the thin film 12. Examples of such a material include quartz and silicon. In the present embodiment, a glass substrate (cover glass) is used as the substrate 11.

The film 12 absorbs the laser light L from the laser module 4 and converts the light energy into thermal energy. The material of the thin film 12 is preferably a material having high photothermal conversion efficiency in the wavelength region (in the present embodiment, the near infrared region) of the laser beam L. In the present embodiment, a gold thin film having a thickness of the order of nanometers (specifically, 10nm, for example) is formed as the thin film 12. The gold thin film can be formed by a known method such as sputtering or electroless plating. The thin film 12 may not be formed on the entire surface of the substrate 11, and may be formed on at least a part of the substrate 11.

When the thin film 12 is a gold thin film, free electrons on the surface of the gold thin film form surface plasmons (plasmons) and vibrate with the laser beam L. Thereby causing polarization. The energy of this polarization is transformed into the energy of lattice vibration by coulomb interaction between the free electrons and the nuclei. As a result, the gold thin film generates heat. Hereinafter, this effect is also referred to as "photothermal effect".

However, the material of the thin film 12 is not limited to gold, and may be a metal element other than gold (for example, silver) or a metal nanoparticle aggregate structure (for example, a structure using gold nanoparticles or silver nanoparticles) that can generate a photothermal effect. Alternatively, the material of the thin film 12 may be a material other than a metal having high light absorptivity in the wavelength region of the laser beam L. As such a material, a material close to a black body (for example, a carbon nanotube black body) can be cited. The thickness of the thin film 12 may be determined in design or experimentally in consideration of laser output and the absorption wavelength region and the photothermal conversion efficiency of the material of the thin film 12. The region where the thin film 12 is formed corresponds to the "photothermal conversion region" referred to in the present disclosure.

Fig. 8 is a perspective view schematically showing the structure of the honeycomb concentration kit 20. Fig. 9 is a cross-sectional view of the honeycomb nesting set 20 taken along line IX-IX of fig. 8. However, in fig. 9, the sample S is not illustrated. Referring to fig. 8 and 9, the honeycomb collection kit 20 includes a substrate 21, a honeycomb polymer film 22, and a film 23.

For the substrate 21, for example, a cover glass is used. The honeycomb polymer film 22 is a polymer film in which a honeycomb structure is formed on the substrate 21. As the material of the honeycomb polymer film 22, resin is used. A thin film 23 is further formed on the honeycomb polymer film 22.

The film 23 is made of a material that absorbs the laser beam L and converts light energy into heat energy, similarly to the film 12 (see fig. 6 and 7) formed on the flat condensing kit 10. In the present embodiment, the thin film 23 is a gold thin film having a thickness of the order of nanometers (specifically, 40nm to 50nm, for example). The film 23 has a honeycomb structure reflecting the structure of the honeycomb polymer film 22. Therefore, the thin film 23 is formed with a plurality of fine pores 24 for trapping a plurality of fine objects, and a plurality of partition walls 25 for partitioning adjacent ones of the plurality of fine pores 24 from each other (see patent document 2 for a detailed structure of the honeycomb assembly 20). The film 23 is provided to cover at least a part of the upper portions of the plurality of pores 24 and the plurality of partition walls 25.

The shapes of the flat stacking kit 10 and the honeycomb stacking kit 20 are not limited to the flat plate shape. The flat nesting set 10 and the honeycomb nesting set 20 may also be containers that form an interior space for holding the sample S. Specifically, a glass base plate having a cylindrical shape (see patent document 2) can be used as the flat stacking kit 10 or the honeycomb stacking kit 20. In this case, the bottom surface of the glass bottom plate corresponds to the "substrate" referred to in the present disclosure. The gold film can be formed on the bottom surface of the glass bottom plate.

< Single irradiation mode and multipoint irradiation mode >

Referring again to fig. 3, the distance from the tip of the laser module 4 (the convex surface of the lens 45) to the upper surface US (the thin film 12) of the flat condensing kit 10 along the emission direction (z direction) of the laser beam L is hereinafter referred to as "irradiation distance D". As described with reference to fig. 1, the adjustment mechanism 6 is configured to be able to adjust the z-direction position of the light source stage 3 in response to a command from the control device 50. Therefore, the control device 50 can set the irradiation distance D to an arbitrary value by controlling the adjustment mechanism 6.

The condensing system 100 according to the present embodiment is configured to be capable of switching between the "single irradiation mode" and the "multi-spot irradiation mode" by setting the irradiation distance D. The single irradiation mode is a mode in which a single laser beam L is irradiated to the sample S. The multi-spot irradiation mode is a mode in which a large amount of laser light L is irradiated to the sample S. Further, "multi-point irradiation" means irradiation of 2 or more points.

Fig. 10 is a diagram for explaining a method of switching between the single irradiation mode and the multi-spot irradiation mode. Referring to fig. 3 and 10, the plurality of laser beams L emitted upward from the front end of the laser module 4 are separated near the lens 45, but intersect each other above the lens to form a focal point F. Then, the plurality of laser light beams L are divided again further upward than the focal point F.

When the control device 50 sets the irradiation distance D so that the position of the focal point F coincides with the upper surface US of the flat condensing kit 10, the single laser beam L is irradiated to the flat condensing kit 10. That is, a single irradiation (single irradiation mode, state 1) to the flat condensing kit 10 can be realized.

In contrast, when the control device 50 sets the irradiation distance D such that the position of the focal point F is lower than the upper surface US of the flat condensing kit 10, the flat condensing kit 10 is irradiated with the plurality of laser beams L. That is, multi-spot irradiation to the flat condensing kit 10 (multi-spot irradiation mode, state 2) can be realized. Although not shown in this example, the controller 50 may set the irradiation distance D such that the position of the focal point F is located above the upper surface US of the flat condensing kit 10, thereby realizing multi-spot irradiation.

In the multi-spot irradiation mode, the interval between the plurality of laser beams L at the position of the upper surface US of the flat condensing kit 10 is referred to as a "spot interval". The spot interval becomes wider as the upper surface US of the flat condensing kit 10 is positioned further upward than the condensing point F. Therefore, the control device 50 can also set the spot interval to a desired value by controlling the adjustment mechanism 6 to adjust the irradiation distance D.

< Collection flow >

Fig. 11 is a flowchart showing a method of collecting fine objects (resin beads R or bacteria B) in the present embodiment. In the flowchart, steps after step S3 are basically realized by software processing performed by the control device 50, but a part or all of them may be realized by hardware (circuit) provided in the control device 50.

Referring to fig. 11, in step S1, a sample S in which fine objects are dispersed is prepared. The prepared sample S is stored in the sample supply device 2.

In step S2, the control device 50 sets the flat gathering kit 10 on the specimen stage 1. This process can be realized by, for example, a substrate feeding mechanism (not shown) provided in the stacking system 100.

In step S3, the controller 50 controls the sample supply device 2 so that an appropriate amount of the sample S is dropped onto the flat collection kit 10. The amount of the sample S dropped may be a very small amount, for example, from several μ L to several hundred μ L, or may be a larger amount.

In step S4, the control device 50 controls the illumination device 9 so as to emit white light WL for irradiating the sample S. Further, the control device 50 controls the photographing apparatus 8 so that photographing of the sample S is started. The process of step S4 is a process for observing the specimen S, and is not necessarily required for the aggregation of the resin beads R.

In step S5, the control device 50 controls the adjustment mechanism 6 to adjust the horizontal position of the sample stage 1 so that the laser beam L is irradiated to the target position in the sample S. Specifically, the control device 50 extracts the outline pattern of the sample S from the image captured by the capturing apparatus 8 by using the image processing technique of pattern recognition, thereby being able to acquire the position of the sample S in the horizontal direction. Then, the control device 50 can align the irradiation position of the laser beam L in the horizontal direction with the target position in the sample S by appropriately adjusting the position of the light source stage 3 in the horizontal direction from the initial position.

In step S6, the control device 50 controls the adjustment mechanism 6 to adjust the height of the light source stage 3 so that the irradiation distance D becomes a desired value. Thus, switching between the single irradiation mode and the multi-spot irradiation mode can be realized. The position in the vertical direction of the condensing point F at which all the laser beams L are condensed is known from the specification of the laser module 4 (the wavelength of the laser beam L, the shape of the optical waveguide 44 and the lens 45, and the like). Therefore, the control device 50 can set the irradiation distance D to a desired value by appropriately adjusting the height of the light source stage 3 from the initial height.

In step S7, the control device 50 controls the power supply 7 so that the irradiation of the laser beam L is started.

In step S8, the control device 50 continues to irradiate the laser beam L to the flat condensing kit 10 for a predetermined time. The predetermined time is, for example, several tens of seconds to several minutes, and is predetermined by the user. The fine objects are condensed by the light irradiation.

In step S9, the control device 50 controls the power supply 7 so that the irradiation of the laser beam L to the flat condensing bundle 10 is stopped. Further, the control device 50 controls the illumination device 9 so as to stop the irradiation of the white light WL to the flat condensing kit 10. Thereby, the series of processes ends.

Fig. 12 is a diagram for explaining a mechanism of collecting fine objects in a single irradiation mode. Fig. 12 and fig. 13 described later are used to describe the processing in step S8 in more detail.

Referring to fig. 12, when the irradiation of the laser beam L is started, the vicinity of the laser spot is locally heated by the photothermal effect of the thin film 12 at the laser spot. As a result, the dispersion medium of the sample S in the vicinity of the laser spot boils, and microbubbles MB are generated at the laser spot. The microbubble MB grows with the passage of time.

The closer to the laser spot, the higher the temperature of the dispersion medium. That is, a temperature gradient is generated in the dispersion medium due to the light irradiation. Due to this temperature gradient, regular thermal convection (buoyancy convection) is stably generated in the dispersion medium. As indicated by reference character HC, the direction of the thermal convection generated at the time of the single irradiation is a direction once toward the microbubbles MB and then away from the microbubbles MB.

The reason why the thermal convection is generated in this manner can be explained as follows. The dispersion medium existing above the region where the microbubbles MB are generated becomes relatively thin due to heating and rises due to buoyancy. Accordingly, the relatively low-temperature dispersion medium existing in the horizontal direction of the microbubbles MB flows into the microbubbles MB.

The minute objects are carried by thermal convection toward the microbubbles MB and are collected near the laser spot. In more detail, a region where the flow velocity of convection is almost zero (stagnation region) is generated between the microbubbles MB and the film 12. The fine objects carried by the thermal convection stay in the stagnation region and are collected. When the irradiation of the laser beam L is stopped, the thermal convection becomes weak, and the laser beam is stopped quickly.

Fig. 13 is a diagram for explaining a mechanism of collecting fine objects in the multi-spot irradiation mode. However, in fig. 13, only 2 laser beams L are shown in order to avoid complication of the paper surface.

Referring to fig. 13, in the multi-spot irradiation mode, microbubbles MB are generated in the vicinity of each of the plurality of laser spots. However, depending on the spot interval, there is also a case where the adjacent microbubbles MB are fused with each other in the course of growth. Therefore, in the multi-spot irradiation mode, the number of microbubbles MB that is the same as the number of laser spots remains at maximum. In the multi-spot irradiation mode, as in the single irradiation mode, the fine objects are transported by thermal convection, and accumulated in the stagnation region of each microbubble MB.

According to the findings obtained by the inventors of the present invention, in the multi-spot irradiation mode, a fast convection is generated toward the gap between the adjacent microbubbles MB. Due to the influence of the convection, many fine objects are gathered in the stagnation region generated between the adjacent microbubbles MB. As a result, when the light irradiation conditions such as laser output are matched between the single irradiation mode and the multi-spot irradiation mode, the amount of accumulation of the fine objects in the multi-spot irradiation mode may be increased.

< results of optical simulation and actual measurement >

In order to confirm that the single irradiation and the multi-spot irradiation are switched in the condensing system 100 as described with reference to fig. 10, various numerical values are assigned to the irradiation distance D without providing the flat condensing kit 10, and optical simulation of the illuminance distribution is performed. Further, the actual appearance of the laser spot at each irradiation distance D is photographed by the photographing device 8. In the following examples, the irradiation distance D was varied in the range of 0.2 to 1.2mm with 0.1mm as a scale.

Fig. 14 to 24 are graphs showing optical simulation results and actual measurement results in the vicinity of the laser spot in the case where the irradiation distance D is 0.2mm to 1.2mm, respectively. In each figure, the optical simulation result of the illuminance distribution is shown in the upper part, and the actual measurement result of the illuminance distribution is shown in the lower part.

When the optical simulation result and the actual measurement result are compared in each of fig. 14 to 24, it is found that both are well matched. From fig. 14, it was confirmed that the single irradiation was achieved in the case where the irradiation distance D was 0.2 mm. Further, from fig. 15 to 24, it was confirmed that the multi-spot irradiation was realized when the irradiation distance D was 0.3mm to 1.2 mm. Further, it was also confirmed that the spot interval became wider as the irradiation distance D became longer.

Fig. 25 is a graph showing the observation result of the vicinity of the laser spot. As shown in the lowermost image, the spot diameter in a state where the irradiation distance D is short and the plurality of laser beams L are completely condensed (single irradiation mode) is about 140 μm. This is a result of agreement with a theoretical value calculated from the specification of the laser module 4.

< production of microbubbles >

Next, the generation methods of the microbubbles MB in the single irradiation mode and the multi-spot irradiation mode with respect to the cell cluster 20 were confirmed.

Fig. 26 is a view showing the observation result of the microbubbles MB generated when the light is irradiated to the cell aggregation set 20. In the example shown in fig. 26, the microbubbles MB are not generated when the irradiation distance D is long. However, when the irradiation distance D is gradually shortened and the plurality of laser beams L are condensed to some extent, a plurality of small microbubbles MB are generated (multi-spot irradiation mode). When the irradiation distance D is shorter and the plurality of laser beams L are completely condensed, a single large microbubble MB is generated (single irradiation mode).

< results of bacterial aggregation >

Next, the results of the accumulation of bacteria B in each of the single irradiation mode and the multi-spot irradiation mode will be described. The output of the laser light transmitted through the honeycomb concentration kit 20 in the single illumination mode was 180 mW. The total output of the laser beams L transmitted through the honeycomb collection kit 20 in the multi-spot irradiation mode was 180 mW. The light irradiation time was set to 20 seconds. That is, the light irradiation conditions are unified between the single irradiation mode and the multi-spot irradiation mode.

In the examples shown below, the death and viability of the bacteria B accumulated by light irradiation was determined by fluorescent staining of the bacteria B. In the present embodiment, SYTO9 (registered trademark) and PI (Propidium Iodide) are used as the fluorescent dye. SYTO9 is a DNA staining reagent having membrane permeability, and stains DNA regardless of whether damage is generated in the cell membrane of bacteria (outer membrane in the case of pseudomonas aeruginosa, a gram-negative bacterium). That is, SYTO9 stains both live bacteria (live bacteria) and dead bacteria (dead bacteria). When a bacterium containing SYTO9 was irradiated with light having an excitation wavelength of SYTO9, green fluorescence was emitted. On the other hand, PI has no membrane permeability. Therefore, only bacteria (dead bacteria) having a damage on the cell membrane are stained with PI. When PI is excited from the outside, red fluorescence is emitted. Hereinafter, the fluorescence observation image based on the excitation wavelength of SYTO9 is also referred to as a "SYTO 9 image", and the fluorescence observation image based on the excitation wavelength of PI is also referred to as a "PI image".

Fig. 27 is a diagram showing the observation result of the honeycomb concentration kit 20 in the single irradiation mode. Fig. 28 is a diagram showing the observation result of the honeycomb concentration kit 20 in the multi-spot irradiation mode. Fig. 27 and 28 show a transmission image, a SYTO9 image, and a PI image in this order from above.

First, referring to fig. 27 showing the light irradiation result in the single irradiation mode, under the above-described light irradiation conditions, scorching of the honeycomb concentration set 20 was observed in the transmission image. This means that the plurality of laser light L is condensed at 1 point and thus the temperature rise of the honeycomb concentration set 20 is large. In the SYTO9 image, strong fluorescence was observed at the position of the laser spot. This revealed that many bacteria B were collected around the laser spot and trapped in the fine hole 24. However, the fluorescence in the PI image was also as strong as the fluorescence in the SYTO9 image. This indicates that many of the bacteria trapped in the pores 24 have died.

Next, referring to fig. 28 showing the light irradiation results in the multi-spot irradiation mode, no scorching of the honeycomb concentration set 20 was observed in the transmission image under the multi-spot irradiation. In the SYTO9 image, strong fluorescence was observed at the positions of the plurality of laser spots in the same manner as in the case of the single irradiation mode.

On the other hand, the fluorescence in the PI image is weaker than that in the single irradiation mode. This revealed that the bacteria trapped in the pores 24 had a high survival rate. This is for the following reason. The energy input is equal for both single and multi-spot irradiation modes. However, in the multi-spot irradiation mode, the laser output density (unit: W/m) at each laser spot is higher than that in the single irradiation mode²) Becomes low. Further, the distance between the laser spots is increased, so that heat conduction into the pores 24 can be suppressed. Therefore, the amount of temperature increase in the fine pores 24 in the honeycomb concentration set 20 at each laser spot becomes small. As a result, thermal damage to the bacteria B can be reduced in the multi-spot irradiation mode.

< temperature distribution in Collection kit >

Finally, the results of measuring the surface temperatures of the flat collection kit 10 and the honeycomb collection kit 20 by a surface temperature distribution measuring apparatus (thermography) will be described.

Fig. 29 is a graph showing the measurement results of the temperature increase amount due to light irradiation to the flat condensing kit 10. Fig. 30 is a graph showing the measurement results of the temperature increase amount caused by light irradiation to the honeycomb concentration set 20. Fig. 29 and 30 show, as a comparative example, the upper part of the measurement result in the case of irradiating a single laser beam having a wavelength of 975nm emitted from a general laser device (not shown). In the lower part, the measurement results in the case where the irradiation distance D of the laser module 4 is set so that a single irradiation occurs in the present embodiment are shown. The laser outputs were set to the same values (180mW) in both the comparative example and the present embodiment.

Referring to fig. 29, the maximum temperature of the flat collection kit 10 in both the comparative example and the present embodiment is about 70 ℃. However, in the present embodiment, the area of the region where the temperature rise occurs is narrower than in the comparative example.

Referring to fig. 30, the light irradiation to the honeycomb collection member 20 is performed at a maximum temperature of about 120 ℃ in both the comparative example and the present embodiment, and a large difference is not generated between the comparative example and the present embodiment, as in the case of the light irradiation to the flat collection member 10. In the present embodiment, the laser output is the same as that of the comparative example, while the spot diameter is large. Therefore, the laser output density at the laser spot is lower in the present embodiment than in the comparative example. Even in this case, in the honeycomb collection kit 20, it was observed that the area of the region where the temperature increase occurred in the present embodiment and the area of the region where the temperature increase occurred in the comparative example were about the same.

As described above, in the present embodiment, the laser module 4 including the surface emitting element 42 as the VCSEL element, the optical waveguide 44 as the GI type optical fiber, and the lens 45 as the plano-convex lens is used. According to the above structure, the laser module 4 is designed to condense a plurality of laser light L to the same condensing point F. Therefore, the single irradiation is realized by adjusting the irradiation distance D so that the upper surface US (film 12) of the flat condensing kit 10 is located at the same place as the condensing point F. Further, multi-spot irradiation is realized by adjusting the irradiation distance D so that the upper surface US of the flat condensing kit 10 is located away from the condensing point F.

The modes of generation of the microbubbles MB and the thermal convection are different between the single irradiation mode and the multi-spot irradiation mode (see fig. 12 and 13), and the laser output density is also different. Therefore, when trying to collect a large number of fine objects around one microbubble, the user can select a single irradiation mode. Alternatively, the user can select the multi-spot irradiation mode when trying to collect the fine objects in a large area around a large number of microbubbles and/or when trying to reduce thermal damage to the fine objects. Therefore, according to the present embodiment, the user can select the aggregation mode of the plurality of fine objects dispersed in the liquid.

Further, in the laser module 4, the surface emitting element 42, the optical waveguide 44, and the lens 45 are integrally formed. By packaging (modularizing) the laser module 4 in this manner, the cluster system 100 can be miniaturized. Further, by effectively utilizing the feature that the size can be reduced, the plurality of laser modules 4 can be arranged in an array. By providing a microarray having a plurality of flat aggregation kits 10 or a plurality of honeycomb aggregation kits 20 arranged in an array above the flat aggregation kits, it is possible to simultaneously advance aggregation of the fine objects in each aggregation kit. As a result, the fine objects can be collected in a shorter time.

The embodiments disclosed herein are to be considered in all respects as illustrative and not restrictive. The scope of the present disclosure is defined by the claims rather than the description of the above embodiments, and is intended to include meanings equivalent to the claims and all modifications within the scope.

Description of the symbols

1 sample stage, 2 sample supply device, 3 light source stage, 4 laser module, 41 substrate, 411 electrode, 42 surface light emitting element, 421 light source, 43 bonding member, 44 optical waveguide, 441 core, 442 cladding, 45 lens, 5 cooling device, 6 adjusting mechanism, 7 power supply, 8 shooting equipment, 9 lighting device, 50 control device, 10 flat plate gathering kit, 20 honeycomb gathering kit, 11, 21 substrate, 12, 23 film, 22 honeycomb polymer film, 24 pore, 25 partition wall, 100 gathering system.