Fine particle separation apparatus and fine particle separation method

Abstract

To provide a fine particle separation technique for separating fine particles highly efficiently and highly precisely.SOLUTION: A fine particle separation apparatus includes: a first channel for introducing a first fluid including a first particle and a second particle; a second channel for introducing a second fluid not including particles; a third channel for introducing the first fluid and the second fluid as a laminar flow by merging the first channel with the second channel; a laser light source for irradiating the third channel with laser light; a first output port provided on the downstream side of an irradiation position of the laser light to take out a third fluid including the first particle; and a second output port provided on the downstream side of the irradiation position to take out a fourth fluid including the second particle having a scattering cross-section area larger than the first particle.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a particle separation device and a particle separation method, and more particularly to a particle separation technique that utilizes the spatial distribution of fluid velocity formed in a microchannel. [Background technology]

[0002] Recent advances in nanotechnology have led to the development of nanoparticles of various materials. Micrometer- to nanometer-scale particles are used in a variety of fields, from electronics and optics to medicine and bioengineering, and are extremely important. Separation of particles has typically been achieved using centrifugation or membrane filtration. These particle separation methods essentially distinguish between particles based solely on differences in their specific gravity or size. However, nanoscale particles such as quantum dots, metal nanoparticles, and nanocarbon materials exhibit various electrical and optical properties, even when the same material has no significant differences in specific gravity or size. Optical radiation pressure (also known as "light pressure") is expected to be used as a method for separating and extracting such nanoparticles.

[0003] Proposed methods include introducing a liquid in which microparticles are dispersed into a microchannel and irradiating it with laser light from the outside to apply optical pressure to the microparticles moving in the liquid (see, for example, Non-Patent Document 1), and separating microparticles by passing a liquid containing the microparticles through an optical lattice formed by laser light (see, for example, Non-Patent Document 2).By appropriately selecting the wavelength and light intensity distribution of the laser light, it is possible to separate particles based on differences in their electrical and optical properties, even for microparticles with no significant differences in specific gravity or size. [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] H. Kotari, and M. Motosuke, "Simple applications of microparticle transportation by tender optical scattering force", Microfluid nanofluid, 18:549-558 (2015) [Non-patent document 2] MP MacDonald, GC Spalding, K. Dholakia, "Microfluidic sorting in an optical lattice," Nature, 426, 421-424 (2003) Summary of the Invention [Problem to be solved by the invention]

[0005] Light pressure is extremely weak, ranging from piconewtons to femtonewtons. As the size of the particles decreases, the light pressure drops dramatically. To accurately and effectively separate and extract particles on the micrometer to nanometer scale, the laser light irradiation time must be extended, but the balance between the irradiation time and the flow rate of the liquid in the channel must be considered. If the flow rate of the particles in the microchannel is increased, the particles will diffuse within the channel and instantly pass through the laser light irradiation area. If the flow rate of the particles is slowed, the time they are exposed to the laser light will be longer, but separation will take longer. There is a trade-off between the laser light irradiation time and the particle speed, and thus highly efficient and accurate light pressure separation has not been achieved until now.

[0006] An object of the present invention is to provide a particle separation technique that separates particles with high efficiency and precision. [Means for solving the problem]

[0007] The particle separator is a first channel for introducing a first fluid containing first particles and second particles; a second channel for introducing a particle-free second fluid; a third channel that merges the first channel and the second channel and introduces the first fluid and the second fluid as a laminar flow; a laser light source that irradiates the third channel with laser light; a first output port provided downstream of the irradiation position of the laser light and configured to extract a third fluid containing the first particles; a second output port provided downstream of the irradiation position and configured to extract a fourth fluid containing the second particles having a scattering cross section larger than that of the first particles; It has. [Effects of the Invention]

[0008] A particle separation technology that separates particles with high efficiency and precision is realized. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic diagram of a particle separator according to an embodiment. [Figure 2] FIG. 2 is a top view illustrating the principle of particle separation according to the embodiment. [Figure 3] 1 is a microscope image showing particle separation due to light scattering forces. [Figure 4] FIG. 1 shows the flow velocity distribution in a microchannel. [Figure 5] This is a two-dimensional model diagram of particle separation using a microchannel. [Figure 6] FIG. 6 is a schematic diagram showing the particle distribution and flow velocity gradient at the cross section BB′ of FIG. 5. [Figure 7] FIG. 6 is a schematic diagram showing particle distribution in the CC′ cross section of FIG. 5. [Figure 8] FIG. 10 is a diagram showing the simulation results of a two-dimensional model at the entrance of the third channel. [Figure 9] FIG. 10 is a diagram showing the relationship between the irradiation time of the laser light and the moving distance of the particle. DETAILED DESCRIPTION OF THE INVENTION

[0010] In an embodiment, microparticles are efficiently separated by utilizing the velocity gradient of the laminar flow in a microchannel and the light scattering force (i.e., light pressure) caused by laser light irradiation. The spatial distribution of fluid velocity in a microchannel is parabolic or quadratic. While the flow velocity is highest at the center of the flow path, the flow velocity along the microchannel wall is extremely low, and ideally, the flow velocity is 0 m / s at the wall boundary. Therefore, the microparticles to be separated are entrained in the laminar flow along the microchannel wall and remain near the wall. Light pressure is applied to the microparticles by laser light irradiation, causing particles with large scattering cross sections to entrain in the fast flow in the center of the channel. The irradiation time and power of the laser light can be appropriately set according to the optical properties of the microparticles to be separated, without considering the dominant flow velocity in the microchannel.

[0011] When laser light is irradiated, particles with a large scattering cross section are subjected to high optical pressure, causing them to move from near the wall of the microchannel to the center of the flow path. Particles with a small scattering cross section are subjected to low optical pressure, causing them to stagnate near the wall of the microchannel. Particles pushed to the center of the flow path are carried by the fast-moving fluid toward the output port for particles with a large scattering cross section. Particles with a small scattering cross section are carried toward the output port where the laminar flow near the wall of the channel is discharged. The difference in optical pressure experienced by the particles results in a difference in flow velocity, which is then guided to the corresponding output port, allowing particles to be separated with high resolution even with a slight difference in optical pressure.

[0012] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The following description is intended to embody the technical ideas of the present disclosure, and unless otherwise specified, the present disclosure is not limited to the following description. In the drawings, components having the same function are given the same reference numerals, and duplicate descriptions may be omitted. The size, positional relationship, etc. of each component shown in each drawing may be exaggerated to facilitate understanding of the invention.

[0013] <Configuration of particle separator> FIG. 1 is a schematic diagram of a particle separator 10 according to an embodiment. The particle separator 10 includes a first channel 111 for introducing a first fluid FL1, a second channel 112 for introducing a second fluid FL2, and a third channel 113 where the first and second channels 111 and 112 merge. In the coordinate system shown in FIG. 1, the flow direction of the third channel 113 is designated the X direction, the height direction of the channel cross section perpendicular to the flow direction is designated the Y direction, and the width direction is designated the Z direction. The first fluid FL1 introduced through the first channel 111 contains first and second particles with different scattering cross sections, as described below. The second fluid FL2 introduced through the second channel 112 does not contain particles to be separated. The third channel 113 introduces the first and second fluids FL1 and FL2 as laminar flows.

[0014] The particle separator 10 also includes a laser light source 12 that irradiates the third channel 113 with laser light, and a first output port P that is provided downstream of the laser light irradiation position and that extracts a third fluid containing the first particles. out 1, and a second output port P that is provided downstream of the irradiation position and that extracts a fourth fluid containing second particles having a scattering cross section larger than that of the first particles. out 2 and a first output port P out The second output port P1 extracts the laminar flow that flows near the inner wall of the third channel 113. out 2 extracts the fluid flowing through the center of the channel.

[0015] A condensing lens 13 may be disposed between the laser light source 12 and the third channel 113. The condensing lens condenses the laser light emitted from the laser light source 12 onto the side surface of the third channel 113 as a sheet of light. The condensing lens 13 is, for example, a cylindrical lens. By irradiating the side surface of the third channel 113 with the sheet-like laser light, the fluid flowing in the third channel 113 can be irradiated with sufficient power over a certain length in the X direction. The laser light applies optical pressure to particles contained in the first fluid FL1 introduced as a laminar flow according to their scattering cross-section.

[0016] Inlet P of the first channel 111 in1, the first fluid FL1 is introduced through the inlet P in The second fluid FL2 is introduced from the second channel 112. The flow rate of the second fluid FL2 introduced from the second channel 112 is greater than the flow rate of the first fluid FL1 introduced from the first channel 111. For example, the cross-sectional area A2 of the flow path of the second channel 112 is set to be greater than the cross-sectional area A1 of the flow path of the first channel 111. At the confluence of the first channel 111 and the second channel 112, the first fluid FL1 is pushed by the second fluid FL2 to the vicinity of the wall surface of the third channel 113, forming a laminar flow along the wall surface. The second fluid FL2 becomes the dominant flow flowing through the center of the third channel 113.

[0017] At the laser light irradiation position of the third channel 113, the first fluid FL1 moves slowly along the wall surface of the third channel 113, while the second fluid FL2 flows at a relatively fast speed through the center of the third channel 113. Even in the laser light irradiation area, the first fluid FL1 passes slowly through the laser light while remaining a laminar flow. This allows the time for the particles contained in the first fluid FL1 to be effectively exposed to light to be increased. Of the particles contained in the first fluid FL1, the second particles with a large scattering cross section are subjected to a large light pressure and move from near the wall surface of the third channel 113 to the center of the channel. In the center of the channel, the second fluid FL2, which has a flow velocity faster than that of the first fluid FL1, is dominant. The second particles pushed out to the center of the third channel 113 ride the fast flow in the center and are discharged to the second output port P out 2. On the other hand, the first particle with a small scattering cross section moves slowly in the X direction near the wall of the third channel 113 and is guided to the first output port P out 1. By increasing the effective irradiation time of the particles contained in the first fluid FL1 and accelerating the second particles pushed to the center of the channel by the light pressure, the particle separation time can be shortened while increasing the light irradiation time. This configuration of the embodiment can more effectively solve the trade-off between irradiation time and separation time, which has been a conventional technical issue.

[0018] The conditions of the laser light, such as wavelength, power, and irradiation time, are set so that different light scattering forces are generated in the first and second particles to be separated, and it is not necessary to consider the dominant flow velocity in the third channel 113. Among the particles moving along the inner wall of the third channel 113, the second particles with a large scattering cross section are carried by the fast flow in the center of the channel and are quickly transported to the second output port P out This allows for highly accurate and efficient separation of fine particles.

[0019] <Principle of particle separation> FIG. 2 is a top view illustrating the principle of particle separation in this embodiment, showing the fluid flow in the XY plane. Inside the third channel 113, the first fluid FL1 (see FIG. 1) containing the first particles NP-1 and the second particles NP-2 forms a laminar flow and flows slowly along the inner wall of the channel to the laser beam irradiation position. In this example, the first particles NP-1 are metal nanoparticles with a diameter of 50 nm, and the second particles NP-2 are metal nanoparticles with a diameter of 110 nm. The scattering cross-section of the second particles NP-2 is larger than that of the first particles NP-1.

[0020] When a metal nanoparticle is irradiated with laser light, an electric dipole is generated inside the metal nanoparticle. If the particle is small enough that the interference of the electromagnetic field created by this dipole moment can be ignored, the scattered light from the metal nanoparticle is emitted in all directions with the same intensity. In this process, the momentum of the light changes, and a momentum corresponding to the change is applied to the metal nanoparticle as light pressure. The light pressure is expressed as an energy density, εσ|E0| 2 / 2, where ε is the dielectric constant, σ is the scattering cross section, and |E0| 2 is the intensity of the incident laser light. The magnitude of the optical pressure acting on the particle is proportional to the scattering cross section σ.

[0021] When laser light is incident in the Z direction from the side of the third channel 113 and irradiates the fluid inside, the first particle NP-1 and the second particle NP-2 moving along the wall of the third channel 113 are subjected to a light scattering force, i.e., optical pressure. The second particle NP-2, which has a larger scattering cross-section, experiences a larger optical pressure than the first particle NP-1. Therefore, the second particle NP-2, irradiated with the laser light, moves faster and larger in the Z direction (width direction) than the first particle NP-1, and rides the fast flow in the center of the channel. On the other hand, the first particle NP-1, which has a smaller optical scattering force, moves slowly along the wall of the third channel 113 without moving away from it. The difference in optical pressure experienced by the particles manifests as a difference in flow speed and direction, allowing for high-resolution particle separation using even slight differences in optical pressure.

[0022] Figure 3 shows a microscope image demonstrating particle separation by light scattering. Silver nanoparticles with a diameter of 50 nm (NP-1) and 110 nm (NP-2) were dispersed in water and introduced into a microchannel. A 532 nm laser beam was irradiated from the side of the microchannel. A YAG laser with an output power of 2.5 W was used as the laser source 12. To increase the power density of the laser beam entering the microchannel, a cylindrical lens with a focal length of 150 mm was used as the focusing lens 13. The cylindrical lens focused the laser beam emitted from the laser source 12 into a sheet-like beam with a cross-section of approximately 1.5 mm x 20 μm, which then irradiated the microchannel. While the first particle NP-1 did not move much from the vicinity of the microchannel wall, the second particle NP-2 was observed to be subjected to greater light pressure and move away from the microchannel wall.

[0023] By utilizing this phenomenon, the first particle NP-1 and the second particle NP-2 branch off into separate routes as they move through the microchannel in the X direction. However, considering the speed of the fluid flowing uniformly through the microchannel, the time that the first particle NP-1 and the second particle NP-2 are irradiated with the laser light is insufficient. Therefore, in this embodiment, a laminar flow is introduced into the third channel 113 to limit the speed of the first particle NP-1 and the second particle NP-2 at the laser light irradiation position, thereby ensuring sufficient irradiation time with the laser light.

[0024] <Flow velocity distribution in microchannels> FIG. 4 shows the flow velocity distribution in the microchannel 110. The flow direction is the X direction, the height direction of the microchannel 110 is the Y direction, and the width direction is the Z direction. The flow velocity distribution in a 100 μm × 300 μm cross section of the channel (in the YZ plane) is calculated. The simulation is performed using the Navier-Stokes equations, which correspond to the equations of motion of an incompressible fluid:

[0025]

number

[0026]

number

[0027] The fluid used is water. The flow rate of water introduced into the microchannel 110 is 10.1 nl / s. Viscous forces, including surface forces, dominate the water flow in the microchannel 110, rather than inertial forces (volume forces). Therefore, in the above Stokes equation, the inertial term is treated as negligible. Due to the viscous forces of the liquid, the flow in the microchannel 110 becomes a stable laminar flow, as shown in Figure 4. The flow velocity near the walls of the microchannel 110 is low and increases toward the center, resulting in a stratified flow velocity distribution across the channel cross section. The flow velocity at the center of the channel is 667 μm / s, the flow velocity near the walls is nearly 0 μm / s, and the average flow velocity is 336.7 μm / s.

[0028] Based on the flow velocity distribution in Figure 4, the first fluid FL1 containing the first particles NP-1 and the second particles NP-2 can be made to pass slowly through the laser light by entraining it in a slow flow along the wall of the microchannel due to surface forces, i.e., viscous forces.

[0029] 5 is a two-dimensional model diagram of particle separation using a microchannel 110. As described above, a first fluid FL1 containing first particles NP-1 and second particles NP-2 is introduced into a first channel 111. A second fluid FL2 containing no particles is introduced into a second channel 112. The first fluid FL1 and the second fluid FL2 are, for example, water. In FIG. 5, the second channel 112 converges with the first channel 111 at an angle of approximately 90°, but the two fluids may converge at any angle, such as in a Y-shape.

[0030] The flow path cross section of the second channel 112 is larger than the flow path cross section of the first channel 111, and the flow rate of the second channel 112 is larger than the flow rate of the first channel 111. The width w of the third channel 113 after the merging is equal to or larger than the width of the second channel 112, and the first fluid FL1 and the second fluid FL2 are introduced into the third channel 113 as laminar flows. In the third channel 113 immediately after the merging, the first fluid FL1 containing the first particles NP-1 and the second particles NP-2 moves slowly along the sidewall on the laser irradiation side of the third channel 113. The second fluid FL2 flows, occupying most of the space of the third channel 113, including the central portion.

[0031] At the position of irradiation of the laser light in the third channel 113, the first particle NP-1 and the second particle NP-2 are subjected to optical pressure according to their respective scattering cross-sections. The second particle NP-2, which has a larger scattering cross-section, is subjected to greater optical pressure and moves toward the center of the third channel 113. As the first particle NP-1 and the second particle NP-2 progress in the X direction through the third channel 113, the time that they are irradiated with the sheet-like laser light becomes longer, and the branching of the second particle NP-2 in the Z direction becomes greater.

[0032] The second particles NP-2 are pushed away from the wall surface of the third channel 113 to the center of the flow path, and then flow in the X direction with the fast flow in the center of the channel, and are output from the second output port P out On the other hand, the first particle NP-1, which is subjected to weak optical pressure, does not move far from the vicinity of the wall surface of the third channel 113, but moves slowly in the X direction along the slow flow, and is guided to the first output port P out It leads to 1.

[0033] FIG. 6 is a schematic diagram showing the particle distribution and flow velocity gradient at the B-B' cross section of FIG. 5, and FIG. 7 is a schematic diagram showing the particle distribution at the C-C' cross section of FIG. 5. The B-B' cross section in FIG. 6 is a YZ cross section at the point where the first channel 111 and the second channel 112 converge. The second fluid FL2 flowing in from the second channel 112 has a fast flow velocity in the center of the channel and a slow flow velocity near the channel wall, resulting in a parabolic or quadratic fluid velocity distribution. The first particles NP-1 and second particles NP-2 contained in the first fluid FL1 are pushed by the large amount of second fluid FL2, forming a slow flow near the wall and being introduced into the third channel 113.

[0034] The cross section CC' in Figure 7 is a cross section downstream of the laser beam irradiation position, and the first particle NP-1 and the second particle NP-2 are subjected to optical pressure according to their respective scattering cross sections. The second particle NP-2 is subjected to stronger optical pressure than the first particle NP-1, and is carried by the fast flow in the center of the channel and is transported to the second output port P outOn the other hand, the first particles NP-1, even after being irradiated with the laser light, are distributed not far from the wall surface of the channel due to their small light scattering power, and are guided to the first output port P out It leads to 1.

[0035] By utilizing the flow velocity distribution inside the channel and the difference in light pressure caused by laser light irradiation, particles with different scattering cross sections can be separated with high efficiency and precision.

[0036] <Flow rate ratio and particle distribution range> 8 is a diagram showing the results of a simulation of a two-dimensional model at the inlet of the third channel 113. in The flow rate Q1 of the first fluid FL1 introduced from the inlet P of the second channel 112 in The ratio of the flow rate Q2 of the second fluid FL2 introduced from 2 is changed to measure the distribution range of all the particles at the inlet of the third channel 113. The height h×width w of the cross section of the third channel 113 is 100 μm×300 μm.

[0037] In the simulation, the flow rate Q2 of the second fluid FL2 was kept constant at 10 nl / s, and the flow rate Q1 of the first fluid FL1 was varied to change the flow rate ratio of the first fluid FL1 to the second fluid: 1:100, 3:100, 5:100, and 10:100. The larger the flow rate ratio of the second fluid to the first fluid FL1, the smaller the distribution range (μm) of the particles from the channel wall, and the more pronounced laminar flow became. When the flow rate ratio of the first fluid FL1 to the second fluid FL2 was 1:10, the particles were distributed over a range of more than 50 μm from the wall of the 100 μm × 300 μm channel, making it difficult for laminar flow to form.

[0038] When the flow rate ratio of the first fluid FL1 to the second fluid FL2 is 1:20, the particles are distributed within a range of less than 40 μm from the wall of the 100 μm × 300 μm channel, forming a laminar flow. As the flow rate ratio of the second fluid FL2 to the first fluid FL1 increases to 100 / 3 or 100 / 1, the distribution range of the particles from the wall becomes narrower, and the laminar flow becomes more pronounced. From these simulation results, the flow rate of the second fluid FL2 is at least 20 times, preferably at least 30 times, and more preferably at least 100 times, the flow rate of the first fluid FL1. For example, by making the cross-sectional area of the second channel 112 at least 20 times, preferably at least 30 times, and more preferably at least 100 times that of the first channel, a laminar flow can be effectively formed and introduced into the third channel 113.

[0039] By making the cross-sectional area of the third channel 113 larger than that of the second channel 112, the laminar flow of the liquid near the wall after joining becomes even slower.

[0040] <Laser irradiation time and travel distance> Figure 9 is a diagram showing the relationship between the laser light irradiation time (seconds) and the particle movement distance (µm). The first particles NP-1 are silver nanoparticles with a diameter of 50 nm, and the second particles NP-2 are silver nanoparticles with a diameter of 110 nm. The laser light is a YAG laser beam with a wavelength of 532 nm and an output of 2.5 W. As shown in Figure 1, the beam is focused into a sheet-like light by a cylindrical lens and irradiated from the side of the third channel 113 in the Z direction (channel width direction).

[0041] The second particles NP-2 move significantly in the Z direction in proportion to the irradiation time. In contrast, the first particles NP-1, which have a small scattering cross section, move very little even if the irradiation time is long. The longer the irradiation time, the greater the difference in distance in the Z direction between the first particles NP-1 and the second particles NP-2. In this example, by irradiating the side of the third channel 113 with laser light for 2 or 3 seconds, the second particles NP-2 can be separated from the laminar flow in which the first particles NP-1 exist and can be carried into the fast flow in the center of the channel.

[0042] Although the present invention has been described above based on specific embodiments, the present invention is not limited to the above-mentioned configuration examples. The cross-sectional shape of the flow path of each channel is not limited to a rectangle, but may be a circle, an oval (racetrack type), an ellipse, or the like. In either case, the cross-sectional areas of the first channel 111 and the second channel 112 are set so that the flow rate of the second fluid introduced into the second channel 112 is greater than the flow rate of the first fluid introduced into the first channel 111. The inlet P of the first channel 111 in 1 and the inlet P of the second channel 112 in The ratio of the cross-sectional areas of the first fluid FL1 and the second fluid FL2, or the flow rate ratio of the first fluid FL1 and the second fluid FL2, is appropriately designed so that the first fluid FL1 and the second fluid FL2 are introduced into the third channel 113 as laminar flows. The cross-sectional area of the flow path of the third channel 113 is set larger than the cross-sectional area of the flow path of the second channel 112 so that the velocity of the laminar flow formed by the joining of the first fluid FL1 and the second fluid FL2 is reduced. By irradiating the third channel 113 with laser light, the second particles are separated with high efficiency and high precision from the laminar flow flowing near the wall surface of the third channel 113.

[0043] The above disclosure includes the following features. (Section 1) a first channel for introducing a first fluid containing first particles and second particles; a second channel for introducing a particle-free second fluid; a third channel that merges the first channel and the second channel and introduces the first fluid and the second fluid as a laminar flow; a laser light source that irradiates the third channel with laser light; a first output port provided downstream of the irradiation position of the laser light and configured to extract a third fluid containing the first particles; a second output port provided downstream of the irradiation position and configured to extract a fourth fluid containing the second particles having a scattering cross section larger than that of the first particles; A particle separation device comprising: (Section 2) The cross-sectional area of the second channel is larger than the cross-sectional area of the first channel. Item 1. The particle separator according to item 1. (Section 3) At the irradiation position, the first fluid containing the first particles and the second particles flows along a wall surface of the third channel, and the second fluid flows through a center portion of the third channel. Item 1 or 2. The particle separator according to item 1 or 2. (Section 4) the second particles move from the vicinity of the wall surface of the third channel to the central portion by the irradiation of the laser light. Item 3. The particle separator according to item 3. (Section 5) At the irradiation position, the flow velocity of the second fluid is greater than the flow velocity of the first fluid; the second particles that have moved to the central portion of the third channel are transported to the second output port faster than the first particles. Item 5. The particle separator according to item 4. (Section 6) a focusing lens disposed between the laser light source and the third channel; and the condensing lens converts the laser light into a sheet-like light and condenses the light onto a side surface of the third channel; Item 6. The particle separator according to any one of items 1 to 5. (Section 7) The condenser lens is a cylindrical lens. Item 7. The particle separator according to item 6. (Section 8) introducing a first fluid containing first particles and second particles into a first channel; introducing a particle-free second fluid through a second channel; introducing the first fluid and the second fluid as laminar flows into a third channel formed by joining the first channel and the second channel; irradiating the third channel with laser light; a third fluid containing the first particles is extracted from a first output port downstream of the irradiation position of the laser light; and extracting a fourth fluid including the second particles having a larger scattering cross section than the first particles at a second output port downstream of the irradiation location. Particulate separation method. (Section 9) introducing the second fluid into the second channel at a flow rate greater than that of the first fluid; Item 9. The method for separating fine particles according to item 8. (Section 10) At the irradiation position, the first fluid containing the first particles and the second particles flows along a wall surface of the third channel, and the second fluid flows through a center portion of the third channel. Item 10. The method for separating fine particles according to Item 8 or 9. [Explanation of symbols]

[0044] 10 Particulate separation device 12 Laser light source 13 Condenser lens 110 Microchannel 111 Channel 1 112 Second Channel 113 Third Channel FL1 1st fluid FL2 2nd fluid NP-1 1st particle NP-2 2nd particle P in 1. P in 1 Inlet P out 1 First output port P out 2 Second output port

Claims

1. a first channel for introducing a first fluid containing first particles and second particles; a second channel for introducing a particle-free second fluid; a third channel that merges the first channel and the second channel and introduces the first fluid and the second fluid as a laminar flow; a laser light source that irradiates the third channel with laser light; a first output port provided downstream of the irradiation position of the laser light and configured to extract a third fluid containing the first particles; a second output port provided downstream of the irradiation position and configured to extract a fourth fluid containing the second particles having a scattering cross section larger than that of the first particles; A particle separation device comprising:

2. a cross-sectional area of the second channel is larger than a cross-sectional area of the first channel; The particle separator according to claim 1 .

3. At the irradiation position, the first fluid containing the first particles and the second particles flows along a wall surface of the third channel, and the second fluid flows through a center portion of the third channel. The particle separator according to claim 1 .

4. the second particles move from the vicinity of the wall surface of the third channel to the central portion by the irradiation of the laser light; The particle separator according to claim 3 .

5. At the irradiation position, the flow velocity of the second fluid is greater than the flow velocity of the first fluid; the second particles that have moved to the central portion of the third channel are transported to the second output port faster than the first particles. The particle separator according to claim 4 .

6. a focusing lens disposed between the laser light source and the third channel; and the condensing lens converts the laser light into a sheet-like light and condenses the light onto a side surface of the third channel; The particle separator according to claim 1 .

7. The condenser lens is a cylindrical lens. The particle separator according to claim 6 .

8. introducing a first fluid containing first particles and second particles through a first channel; introducing a particle-free second fluid through a second channel; introducing the first fluid and the second fluid as laminar flows into a third channel formed by joining the first channel and the second channel; irradiating the third channel with laser light; a third fluid containing the first particles is extracted from a first output port downstream of the irradiation position of the laser light; and extracting a fourth fluid containing the second particles having a scattering cross section greater than that of the first particles at a second output port downstream of the irradiation location. Particulate separation method.

9. introducing the second fluid into the second channel at a flow rate greater than that of the first fluid; The method for separating fine particles according to claim 8.

10. At the irradiation position, the first fluid containing the first particles and the second particles flows along a wall surface of the third channel, and the second fluid flows through a center portion of the third channel. The method for separating fine particles according to claim 8.

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