JP7709726B2 - Channel chip, separation system, and separation method - Google Patents

Description

The present disclosure relates to a channel chip, a separation system, and a separation method.

Dielectrophoresis is used as a particle control technology in microspaces such as microfluidic devices. In the bio field, various research and development projects are being conducted on the characteristics analysis and separation and concentration of cells and microorganisms. There are various forms, but Patent Document 1 is an example.

The separation device disclosed in Patent Document 1 comprises a flow path through which a sample liquid (suspension) containing circulating cancer cells (a specific type of dielectric particles) flows in a predetermined direction (liquid flow direction), a replacement section, an analysis section, and a separation section. The separation section comprises a pair of electrodes, a power supply section, and a collection section. The power supply section generates an AC voltage and supplies it between the pair of electrodes. As a result, a positive dielectrophoretic force (attraction force) acts on the cancer cells, and the cancer cells are attracted to the pair of electrodes and flow through the flow path in the extension direction of the pair of electrodes, and are collected in the collection section.

JP 2017-134020 A

The present disclosure provides a flow path chip, a separation system, and a control method that can improve the accuracy of separating a specific type of dielectric particle from a suspension.

A flow channel chip according to one embodiment of the present disclosure includes a substrate having an inlet into which a suspension containing multiple types of dielectric particles including a specific type of dielectric particles is introduced and a flow channel through which the multiple types of dielectric particles of the suspension introduced from the inlet flow, a first electrode that guides the specific type of dielectric particles among the multiple types of dielectric particles to a first end side in the width direction of the flow channel, and a second electrode that is located between the inlet and the first electrode and guides the multiple types of dielectric particles to a second end side in the width direction of the flow channel.

A separation system according to one aspect of the present disclosure includes the above-mentioned flow path chip, and a voltage control device that controls the voltage of the second electrode so as to guide the multiple types of dielectric particles, including the specific type of dielectric particles contained in the suspension, to a second end side in the width direction of the flow path, and controls the voltage of the first electrode so as to guide the specific type of dielectric particles among the multiple types of dielectric particles to a first end side in the width direction of the flow path.

A separation method according to one aspect of the present disclosure is a separation method using the above-mentioned flow channel chip, in which the voltage of the second electrode is controlled so as to guide the multiple types of dielectric particles, including the specific type of dielectric particles contained in the suspension, to a second end side in the width direction of the flow channel, and the voltage of the first electrode is controlled so as to guide the specific type of dielectric particles among the multiple types of dielectric particles to a first end side in the width direction of the flow channel.

According to aspects of the present disclosure, the accuracy of separating specific types of dielectric particles from a suspension can be improved.

FIG. 1 is a block diagram of a configuration example of a separation system including a channel chip according to a first embodiment; 2 is a schematic plan view of the channel chip of FIG. FIG. 3 is an enlarged view of a portion around the second electrode of the channel chip of FIG. 4A to 4C are cross-sectional views of a channel chip showing how dielectric particles are attracted to a second electrode. FIG. 11 is a partial plan view of a channel chip showing the movement of dielectric particles when the amplitude of the voltage applied to the second electrode changes over time. Graph showing the change in separation rate over time in the separation system of FIG. FIG. 13 is an enlarged view of a portion around a second electrode in a configuration example of a channel chip according to a second embodiment;

1. Embodiment
1.1 First embodiment
1.1.1 Overview
FIG. 1 is a block diagram of a configuration example of a separation system 1 according to a first embodiment. The separation system 1 of FIG. 1 enables separation of a specific type of dielectric particles P1 from a suspension L1. The suspension L1 includes a plurality of types of dielectric particles including the specific type of dielectric particles P1. The separation system 1 of FIG. 1 separates the specific type of dielectric particles P1 from the plurality of types of dielectric particles included in the suspension L1 by utilizing the principle of dielectrophoresis. In this embodiment, the suspension L1 is blood. The plurality of types of dielectric particles are, for example, cells included in the blood. Examples of cells included in the blood include cancer cells and white blood cells. In this embodiment, for ease of explanation, it is assumed that the suspension L1 includes two types of dielectric particles P1 and P2. The specific type of dielectric particles P1 are cancer cells, particularly circulating cancer cells (CTCs). The dielectric particles P2 are white blood cells. The separation system 1 of FIG. 1 is used to separate circulating cancer cells (specific type of dielectric particles P1) from blood (suspension L1).

The separation system 1 in FIG. 1 includes a flow path chip 10 through which the suspension L1 flows. The flow path chip 10 in FIG. 1 includes a base 10a, a first electrode 50, and a second electrode 60. The base 10a has an inlet 21 into which the suspension L1 containing multiple types of dielectric particles P1 and P2 including a specific type of dielectric particle P1 is introduced, and a flow path 30 through which the multiple types of dielectric particles P1 and P2 of the suspension L1 introduced from the inlet 21 flow. The first electrode 50 guides the specific type of dielectric particles P1 of the multiple types of dielectric particles P1 and P2 to the first end 311 side of the width direction W1 of the flow path 30. The second electrode 60 is between the inlet 21 and the first electrode 50 and guides the multiple types of dielectric particles P1 and P2 to the second end 312 side of the width direction W1 of the flow path 30.

In the flow channel chip 10 of FIG. 1, the second electrode 60 is disposed between the inlet 21 and the first electrode 50. The second electrode 60 can guide the multiple types of dielectric particles P1 and P2 to the second end 312 of the width direction W1 of the flow channel 30. In other words, before the first electrode 50 guides the specific type of dielectric particles P1 among the multiple types of dielectric particles P1 and P2 to the first end 311 of the width direction W1 of the flow channel 30, the second electrode 60 can position the multiple types of dielectric particles P1 and P2 on the second end 312 of the width direction W1 of the flow channel 30. This can reduce the probability that the dielectric particles P2 other than the specific type of dielectric particles P1 among the multiple types of dielectric particles P1 and P2 are present on the first end 311 of the width direction W1 of the flow channel 30. Therefore, according to the flow channel chip 10, the accuracy of separation of the specific type of dielectric particles P1 from the suspension L1 can be improved.

[1.1.2 Details]
The following further describes the channel chip 10 and the separation system 1 of the first embodiment. As shown in FIG.

[1.1.2.1 Flow Channel Chip]
The flow channel chip 10 constitutes a micro flow channel for separating a specific type of dielectric particles P1 from the suspension liquid L1. In the separation system 1, the suspension liquid L1 is flowed through the flow channel chip 10, and the specific type of dielectric particles P1 are separated from the suspension liquid L1 in the flow channel chip 10. In the separation system 1, the flow channel chip 10 is configured to be disposable from the viewpoint of preventing contamination.

Figure 2 is a schematic plan view of the flow channel chip 10. The flow channel chip 10 in Figure 2 includes a base body 10a, a first electrode 50, a second electrode 60, first electrode pads 71 and 72, and second electrode pads 81 and 82.

The base 10a has the inlets 21 and 22, the flow channel 30, and a number of collecting parts 40-1 and 40-2 (hereinafter collectively referred to as 40). The base 10a is a part that defines the outer shape of the flow channel chip 10. In this embodiment, the base 10a is a rectangular plate. The base 10a is formed, for example, using a substrate made of glass or silicone (for example, polydimethylsiloxane (PDMS)). As an example, the base 10a may be configured by attaching a second substrate (for example, a PDMS substrate) on which spaces corresponding to the inlets 21 and 22, the flow channel 30, and the multiple collecting parts 40-1 and 40-2 are formed, to a first substrate (for example, a glass substrate) on which the first electrode 50, the second electrode 60, the first electrode pads 71 and 72, and the second electrode pads 81 and 82 are formed on the surface.

As shown in FIG. 1, the inlet 21 is a portion of the substrate 10a into which the suspension L1 is introduced. The inlet 21 is connected to a supply source of the suspension L1 by a tube, for example, and the suspension L1 is supplied through the tube. The inlet 22 is a portion of the substrate 10a into which the replacement liquid L2 is introduced, as shown in FIG. 1. The replacement liquid L2 is used, for example, to remove unnecessary components from the suspension L1 and transport multiple types of dielectric particles P1 and P2 of the suspension L1. The unnecessary components are components that are unnecessary in the separation of a specific type of dielectric particle P1 from the suspension L1. Examples of the unnecessary components include small cells P3 such as red blood cells contained in blood and a solution. The replacement liquid L2 may be selected so as to be capable of transporting multiple types of dielectric particles P1 and P2 and not to inhibit the application of the dielectrophoretic force to the multiple types of dielectric particles P1 and P2. In particular, the replacement liquid L2 is a liquid having a lower conductivity than the solution of the suspension L1 in order to facilitate the separation of the specific type of dielectric particle P1. However, this does not apply if the conductivity of the suspension L1 solution is low.

The flow path 30 is a portion of the base 10a through which multiple types of dielectric particles P1, P2 of the suspension L1 introduced from the inlet 21 flow. As shown in FIG. 2, the flow path 30 includes a main flow path 31, a connecting flow path 32, multiple (two in the illustrated example) branch flow paths 33-1, 33-2 (hereinafter collectively referred to as 33), connection paths 34, 35, and a filter 90. In this embodiment, the surface of the flow path 30 facing the first substrate of the base 10a is the bottom surface, and the surface of the flow path 30 facing the second substrate of the base 10a is the top surface.

The main flow path 31 constitutes the main part of the flow path 30. The main flow path 31 is a part for separating a specific type of dielectric particle P1 in the flow path 30. In this embodiment, the main flow path 31 is rectangular in plan view (seen from the thickness direction of the substrate 10a). The cross-sectional shape of the main flow path 31 is rectangular in a plane perpendicular to the length direction of the main flow path 31. The width direction of the main flow path 31 corresponds to the width direction W1 of the flow path 30. The first end 311 and the second end 312 of the width direction W1 of the main flow path 31 correspond to the first end and the second end of the width direction W1 of the flow path 30. As shown in FIG. 2, a first electrode 50 is arranged in the main flow path 31. This point will be explained in detail later.

The connecting flow path 32 is a portion between the main flow path 31 and the inlet 21 in the flow path 30. Therefore, the connecting flow path 32 is located upstream (left side in FIG. 2) with respect to the main flow path 31. In this embodiment, the connecting flow path 32 is rectangular in plan view (seen from the thickness direction of the base body 10a). The connecting flow path 32 has a rectangular cross-sectional shape in a plane perpendicular to the length direction of the connecting flow path 32. A first end in the length direction of the connecting flow path 32 is connected to the inlet 21, and a second end in the length direction of the connecting flow path 32 is connected to the main flow path 31. The width direction of the connecting flow path 32 corresponds to the width direction W1 of the flow path 30. The first end 321 and the second end 322 in the width direction W1 of the connecting flow path 32 correspond to the first end and the second end in the width direction W1 of the flow path 30. In this embodiment, the width of the connecting flow path 32 is narrower than the width of the main flow path. As shown in FIG. 2, a second electrode 60 is arranged in the connecting flow path 32. This point will be explained in detail later.

The branch flow paths 33-1 and 33-2 are portions of the flow path 30 that transport the dielectric particles P1 and P2 separated from each other in the main flow path 31 so that they do not mix again. The branch flow paths 33-1 and 33-2 are on the opposite side of the main flow path 31 from the connecting flow path 32. Therefore, each branch flow path 33 is located downstream (on the right side in FIG. 2) with respect to the main flow path 31. The branch flow path 33-1 is connected to the first end 311 side of the width direction W1 of the main flow path 31. As shown in FIG. 1, the branch flow path 33-1 is a portion through which the specific type of dielectric particles P1 separated in the main flow path 31 flows. The branch flow path 33-2 is connected to the second end 312 side of the width direction W1 of the main flow path 31. As shown in FIG. 2, the branch flow path 33-1 is a portion through which the remaining dielectric particles P2 flow after the specific type of dielectric particles P1 is separated from the multiple types of dielectric particles P1 and P2.

The connection path 34 is a portion of the flow path 30 that connects the inlet 21 and the connecting flow path 32. The connection path 34 is located between the first end in the longitudinal direction of the connecting flow path 32 and the inlet 21. The connection path 35 is a portion of the flow path 30 that connects the inlet 22 and the connecting flow path 32. The connection path 35 is located on the first end side in the longitudinal direction of the connecting flow path 32 between the first end 321 in the width direction W1 of the connecting flow path 32 and the inlet 22.

The filter 90 is located between the inlet 21 and the second electrode 60 in the flow path 30. The filter 90 is connected to the second end side of the width direction W1 of the flow path 30. The filter 90 removes particles smaller than the multiple types of dielectric particles P1, P2 from the suspension L1. The filter 90 separates particles by size. The particles smaller than the multiple types of dielectric particles P1, P2 are particles smaller than the smallest dielectric particle among the multiple types of dielectric particles P1, P2. In this embodiment, the particles smaller than the multiple types of dielectric particles P1, P2 are small cells P3 such as red blood cells, which are the above-mentioned unnecessary components of the suspension L1. The filter 90 in FIG. 2 separates the multiple types of dielectric particles P1, P2 from the suspension L1 by the principle of hydrodynamic filtration (HDF). Specifically, the filter 90 in FIG. 2 includes a collection section 91, multiple discharge paths 92, and a connecting path 93. The dimensions (length, width, and height) of the multiple discharge paths 92 are set to be smaller than the dimensions of the connecting flow path 32 to which the multiple discharge paths 92 are connected, but to pass particles smaller in size than the multiple types of dielectric particles P1 and P2. The first ends of the multiple discharge paths 92 in the length direction are connected to the second ends 322 in the width direction W1 of the connecting flow path 32 at the first end side in the length direction of the connecting flow path 32. The multiple discharge paths 92 are located downstream of the connecting path 35 in the flow path 30. As a result, unnecessary components of the suspension L1 that entered the connecting flow path 32 via the inlet 21 and the connecting path 34 are pushed out to the multiple discharge paths 92 by the replacement liquid L2 that entered the connecting flow path 32 via the inlet 22 and the connecting path 35. The multiple types of dielectric particles P1 and P2 flow in the connecting flow path 32 in a state biased toward the second ends 322 in the width direction W1 of the connecting flow path 32 without being pushed out to the multiple discharge paths 92. According to the filter 90, the plurality of types of dielectric particles P1, P2 can be guided to the second end side of the width direction W1 of the flow path 30. In this way, the filter 90 also realizes the orientation of the plurality of types of dielectric particles P1, P2 to the second end side of the width direction W1 of the flow path 30, but depending on the shape of the flow path 30 (particularly when the width of the flow path 30 is wide), the plurality of types of dielectric particles P1, P2 tend to disperse as they proceed through the flow path 30. Therefore, it is difficult to stably position the plurality of types of dielectric particles P1, P2 on the second end side of the width direction W1 of the flow path 30 by the filter 90 alone. The connecting path 93 connects the second ends of the plurality of discharge paths 92 in the length direction to the collecting section 91. As a result, the unnecessary components removed from the suspension L1 are transported to the collecting section 91. The collecting section 91 is provided with, for example, a discharge port, and as a result, the solution S3 containing the unnecessary components removed from the suspension L1 is discharged from the flow path chip 10 to the outside. In the filter 90, only particles of a desired size or larger can be introduced into the main flow path 31 by changing the dimensions (length, width, and height) of the discharge path 92.

The multiple collection units 40 include a first collection unit 40-1 connected to the first end side of the width direction W1 of the flow channel 30, and a second collection unit 40-2 connected to the second end side of the width direction W1 of the flow channel 30. The first collection unit 40-1 is connected to the first end 311 side of the width direction W1 of the main flow channel 31 via the branch flow channel 33-1. The first collection unit 40-1 collects a specific type of dielectric particles P1 flowing through the branch flow channel 33-1. The first collection unit 40-1 may, for example, have an outlet, which allows the solution S1 containing the specific type of dielectric particles P1 to be supplied from the flow channel chip 10 to the outside. The second collection unit 40-2 is connected to the second end 312 side of the width direction W1 of the main flow channel 31 via the branch flow channel 33-2. The second collection unit 40-2 collects the dielectric particles P2 flowing through the branch flow channel 33-2. The second collection section 40-2 may, for example, have an outlet through which the solution S2 containing the dielectric particles P2 may be supplied from the flow channel chip 10 to the outside.

The first electrode 50 is used to guide a specific type of dielectric particle P1 among the multiple types of dielectric particles P1 and P2 in the suspension L1 to the first end side in the width direction W1 of the flow path 30. In this embodiment, as shown in FIG. 2, the first electrode 50 is disposed in the main flow path 31 of the flow path 30, and guides a specific type of dielectric particle P1 among the multiple types of dielectric particles P1 and P2 in the suspension L1 to the first end 311 side in the width direction W1 of the main flow path 31. The first electrode 50 is configured to apply a dielectrophoretic force to the specific type of dielectric particle P1 in a direction toward the first end side in the width direction W1 of the flow path 30 (the first end 311 in the width direction W1 of the main flow path 31). As an example, as shown in FIG. 2, the specific type of dielectric particle P1 receives a force F11 in the direction of flow through the flow path 30 and moves within the flow path 30. The first electrode 50 applies a dielectrophoretic force F12 to the specific type of dielectric particles P1, thereby exerting a force F13 on the specific type of dielectric particles P1 in a direction toward the first end 311 of the width direction W1 of the main flow channel 31.

The first electrode 50 is disposed on one side of the flow path 30. In this embodiment, the first electrode 50 is disposed on the bottom surface of the main flow path 31. The first electrode 50 may be formed, for example, of a relatively inexpensive planar electrode. As an example, the first electrode 50 may be configured to include an electrode layer formed on the first substrate of the base body 10a and a protective layer formed on the electrode layer. The material of the electrode layer is, for example, a metal such as Al. The protective layer is, for example, silicon oxide.

The first electrode 50 is a comb-shaped electrode having a plurality of teeth 511, 521 arranged in a first predetermined direction D1. The first predetermined direction D1 is a direction from the first end (upper end in FIG. 2) to the second end (lower end in FIG. 2) of the width direction W1 of the flow channel 30 along the direction in which the suspension L1 flows in the flow channel 30 (the right direction in FIG. 2). The plurality of teeth 511, 521 includes a plurality of first teeth 511 and a plurality of second teeth 521. The first teeth 511 and the second teeth 521 are arranged alternately. The plurality of first teeth 511 extend from the first end to the second end of the width direction W1 of the flow channel 30. That is, the plurality of first teeth 511 extend from the first end 311 to the second end 312 of the width direction W1 of the main flow channel 31. The plurality of second teeth 521 extend from the second end to the first end of the width direction of the flow channel 30. In other words, the multiple second teeth 521 extend from the second end 312 to the first end 311 in the width direction W1 of the main flow path 31.

The first electrode 50 in FIG. 2 includes a pair of electrode patterns 51, 52. The electrode pattern 51 includes a plurality of first tooth portions 511 and a connecting portion 512 that is located on the first end 311 side of the width direction W1 of the main flow channel 31 and connects the base ends of the plurality of tooth portions 511. The connecting portion 512 is located outside the flow channel 30. The electrode pattern 52 includes a plurality of second tooth portions 521 and a connecting portion 522 that is located on the second end 312 side of the width direction W1 of the main flow channel 31 and connects the base ends of the plurality of second tooth portions 521. The connecting portion 522 is located outside the flow channel 30.

The second electrode 60 is between the inlet 21 and the first electrode 50. The second electrode 60 is used to guide the multiple types of dielectric particles P1 and P2 of the suspension L1 to the second end 312 of the width direction W1 of the flow channel 30. FIG. 3 is an enlarged view of the area around the second electrode 60 of the flow channel chip 10. In FIG. 3, only the second electrode 60 is illustrated in order to simplify the drawing. As shown in FIG. 3, the second electrode 60 is disposed in the connecting flow channel 32 of the flow channel 30, and guides the multiple types of dielectric particles P1 and P2 of the suspension L1 to the second end 322 of the width direction W1 of the connecting flow channel 32. The second electrode 60 is configured to apply a dielectrophoretic force to the multiple types of dielectric particles P1 and P2 in a direction toward the second end of the width direction W1 of the flow channel 30 (the second end 322 of the width direction W1 of the connecting flow channel 32). As an example, as shown in FIG. 3, the multiple types of dielectric particles P1 and P2 move in the flow channel 30 under the force F21 in the direction of flow through the flow channel 30. The second electrode 60 applies a dielectrophoretic force F22 to the multiple types of dielectric particles P1 and P2, thereby exerting a force F23 on the multiple types of dielectric particles P1 and P2 in a direction toward the second end 322 of the width direction W1 of the connecting flow path 32.

The second electrode 60 is disposed on one side of the flow path 30. In this embodiment, the second electrode 60 is disposed on the bottom surface of the connecting flow path 32. The second electrode 60 may be formed, for example, of a relatively inexpensive planar electrode. As an example, the second electrode 60 may be configured to include an electrode layer formed on the first substrate of the base body 10a and a protective layer formed on the electrode layer. The material of the electrode layer is, for example, a metal such as Al. The protective layer is, for example, silicon oxide.

2 and 3, the second electrode 60 is a comb-shaped electrode having a plurality of teeth 611, 621 arranged in a second predetermined direction D2. The second predetermined direction D2 is a direction toward the opposite side to the first predetermined direction D1 in the width direction W1 of the flow channel 30. More specifically, the second predetermined direction D2 is a direction from the second end (lower end in FIG. 2) to the first end (upper end in FIG. 2) of the width direction W1 of the flow channel 30 along the direction in which the suspension L1 flows in the flow channel 30 (rightward in FIG. 2). The plurality of teeth 611, 621 includes a plurality of first teeth 611 and a plurality of second teeth 621. The first teeth 611 and the second teeth 621 are arranged alternately. The plurality of first teeth 611 extend from the first end to the second end of the width direction W1 of the flow channel 30. That is, the first teeth 611 extend from the first end 321 to the second end 322 in the width direction W1 of the connecting flow path 32. The second teeth 621 extend from the second end to the first end in the width direction of the flow path 30. That is, the second teeth 621 extend from the second end 322 to the first end 321 in the width direction W1 of the connecting flow path 32. As shown in FIG. 3, in the second electrode 60, the tip 611a of the first teeth 611 and the tip 621a of the second teeth 621 are outside the flow path 30, that is, outside the connecting flow path 32. In the second electrode 60 in FIG. 3, it is only necessary that the tip 611a of the first teeth 611 and the tip 621a of the second teeth 621 are outside the flow path 30, so that the second electrode 60 and the flow path 30 can be easily aligned. In particular, when the base body 10a is constructed by bonding a first substrate to a second substrate as described above, the second substrate on which the recess corresponding to the flow channel 30 is formed does not need to be aligned with high precision to the first substrate on which the second electrode 60 is formed, and therefore high alignment precision is not required. This facilitates the manufacture of the flow channel chip 10.

The second electrode 60 in FIG. 2 includes a pair of electrode patterns 61, 62. The electrode pattern 61 includes a plurality of first teeth 611 and a connecting portion 612 that is located on the first end 321 side of the width direction W1 of the connecting flow channel 32 and connects the base ends of the plurality of teeth 611. The connecting portion 612 is located outside the flow channel 30. The electrode pattern 62 includes a plurality of second teeth 621 and a connecting portion 622 that is located on the second end 322 side of the width direction W1 of the connecting flow channel 32 and connects the base ends of the plurality of second teeth 621. The connecting portion 622 is located outside the flow channel 30.

4(a) to (c) are cross-sectional views of the flow channel chip 10 showing the movement of multiple types of dielectric particles P1 and P2 by the second electrode 60. FIG. 4(a) is a cross-sectional view of the flow channel chip 10 at the end of the second electrode 60 on the inlet 21 side (the left end in FIG. 2). FIG. 4(b) is a cross-sectional view of the flow channel chip 10 at the center of the second electrode 60. FIG. 4(c) is a cross-sectional view of the flow channel chip 10 at the end of the second electrode 60 on the first electrode 50 side (the right end in FIG. 2). As can be seen from FIG. 4(a) to (c), the dielectric particles P1 and P2 in the connecting flow channel 32 of the flow channel 30 are attracted to the second electrode 60. As a result, the dielectric particles P1 and P2 are attracted to the bottom surface of the flow channel 30 on which the second electrode 60 is provided. Furthermore, the dielectric particles P1 and P2 are led to the second end 322 side of the width direction W1 of the connecting flow channel 32.

In this embodiment, a filter 90 is provided between the inlet 21 and the second electrode 60 in the flow channel 30, and the filter 90 also orients the multiple types of dielectric particles P1, P2 toward the second end side of the width direction W1 of the flow channel 30. In other words, in the flow channel chip 10, after the multiple types of dielectric particles P1, P2 are oriented to a certain extent toward the second end side of the width direction W1 of the flow channel 30 by the filter 90, the multiple types of dielectric particles P1, P2 are further stably positioned toward the second end side of the width direction W1 of the flow channel 30 by the dielectrophoretic force of the second electrode 60.

The first electrode pads 71 and 72 are used to apply a first predetermined voltage to the first electrode 50. The first electrode pads 71 and 72 are connected to the pair of electrode patterns 51 and 52 of the first electrode 50, respectively, to apply a first predetermined voltage between the pair of electrode patterns 51 and 52 of the first electrode 50. The first electrode pads 71 and 72 are connected to the pair of electrode patterns 51 and 52 of the first electrode 50, respectively, by, for example, a wiring pattern or the like. The first electrode pads 71 and 72 are arranged so as to be located on the outer surface of the base 10a. By controlling the voltage between the first electrode pads 71 and 72, the voltage of the first electrode 50 can be controlled.

The second electrode pads 81 and 82 are provided separately from the first electrode pads 71 and 72. The second electrode pads 81 and 82 are used to apply a second predetermined voltage, which is different from the first predetermined voltage, to the second electrode 60. The second electrode pads 81 and 82 are connected to the pair of electrode patterns 61 and 62 of the second electrode 60, respectively, in order to apply a second predetermined voltage between the pair of electrode patterns 61 and 62 of the second electrode 60. The second electrode pads 81 and 82 are connected to the pair of electrode patterns 61 and 62 of the second electrode 60, respectively, by, for example, a wiring pattern or the like. The second electrode pads 81 and 82 are arranged so as to be located on the outer surface of the base 10a. By controlling the voltage between the second electrode pads 81 and 82, the voltage of the second electrode 60 can be controlled.

As described above, in the flow channel chip 10, the second electrode 60, which is a position control electrode specialized for position control, is arranged upstream of the first electrode 50, which is a dielectrophoretic electrode specialized for separation. In the flow channel chip 10, since the multiple types of dielectric particles P1 and P2 can be controlled to the desired positions before the specific type of dielectric particle P1 is separated by the first electrode 50, the separation accuracy can be improved. Separation is possible even if a lower voltage is applied to the first electrode 50, and the flow rate can be increased at the same voltage, and the separation speed can be improved. In addition, since the second electrode 60 for position control is installed separately from the first electrode 50 for separation, the voltages of the first electrode 50 and the second electrode 60 can be set individually. For example, it is possible to apply a voltage of a frequency and amplitude suitable for the separation of the specific type of dielectric particle P1 to the first electrode 50, while applying a voltage of a frequency and amplitude suitable for the position control of the multiple types of dielectric particles P1 and P2 to the second electrode 60. This also improves the separation accuracy and separation speed.

1.1.2.2 Voltage Control Device
1 controls a voltage applied to the flow channel chip 10 to generate a dielectrophoretic force. In this embodiment, the voltage control device 11 separates a specific type of dielectric particle P1 from multiple types of dielectric particles P1, P2 contained in the suspension L1 by controlling the voltage of the first electrode 50 and the voltage of the second electrode 60, respectively. The voltage control device 11 includes, for example, a function generator.

The voltage control device 11 in FIG. 1 is connected to the first electrode 50 via the first electrode pads 71 and 72. The voltage control device 11 in FIG. 1 is connected to the second electrode 60 via the second electrode pads 81 and 82.

The voltage control device 11 controls the voltage of the first electrode 50 so as to guide the specific type of dielectric particles P1 of the multiple types of dielectric particles P1, P2 to the first end side of the width direction W1 of the flow path 30. In this embodiment, the voltage control device 11 applies a first predetermined voltage to the first electrode 50 via the first electrode pads 71, 72. The first predetermined voltage is, for example, an AC voltage. The frequency of the first predetermined voltage is set so that a positive dielectrophoretic force acts on the specific type of dielectric particles P1 by the first electrode 50. In this case, the frequency is set so that no dielectrophoretic force acts on the dielectric particles P2 other than the specific type of dielectric particles P1 of the multiple types of dielectric particles P1, P2, or even if a positive or negative dielectrophoretic force (attractive force or repulsive force) acts on the dielectric particles P2, the dielectrophoretic force is relatively small. The frequency of the first predetermined voltage is, for example, 600 kHz.

The voltage control device 11 controls the voltage of the second electrode 60 so as to guide the multiple types of dielectric particles P1, P2, including the specific type of dielectric particle P1, contained in the suspension L1, to the second end side of the width direction W1 of the flow path 30. In this embodiment, the voltage control device 11 applies a second predetermined voltage to the second electrode 60 via the second electrode pads 81, 82. The second predetermined voltage is different from the first predetermined voltage. The second predetermined voltage is, for example, an AC voltage different from the first predetermined voltage. The frequency of the second predetermined voltage is set so that a positive dielectrophoretic force acts on the multiple types of dielectric particles P1, P2, including the specific type of dielectric particle P1, by the second electrode 60. The frequency of the second predetermined voltage is, for example, 1500 kHz.

The second predetermined voltage may be an AC voltage with a fixed amplitude and frequency. When such a second predetermined voltage is continuously applied to the second electrode 60, as shown in FIG. 3, the dielectric particles P1 and P2 are attracted to the second electrode 60 (particularly the teeth 611 and 621) and accumulate near the teeth 611 and 621 on the second end 322 side of the width direction W1 of the connecting flow path 32. When the dielectric particles P1 and P2 accumulate to a certain extent, they flow from the connecting flow path 32 into the main flow path 31 in a form pushed out by the subsequent dielectric particles P1 and P2. When an AC voltage with a fixed amplitude and frequency is continuously applied to the second electrode 60, the dielectric particles P1 and P2 accumulated on the second end 322 side of the width direction W1 of the connecting flow path 32 are pushed out by the subsequent dielectric particles P1 and P2. The dielectric particles P1, P2 pushed out by the succeeding dielectric particles P1, P2 will rise from the second electrode 60 and move through the connecting flow path 32 toward the main flow path 31. If it is desired to stably position the dielectric particles P1, P2 on the second end 322 side of the width direction W1 of the connecting flow path 32, it is better not to use such pushing. In addition, the dielectric particles P1, P2 remain in contact with the second electrode 60 until they are pushed out by the succeeding dielectric particles P1, P2, so the contact time with the second electrode 60 is relatively long. Therefore, considering the burden on the dielectric particles P1, P2, it is better for the contact time to be short.

Therefore, the second predetermined voltage may be set so that the amplitude changes with time. For example, the second predetermined voltage may be set so that a first period in which the amplitude is a first value and a second period in which the amplitude is a second value alternate. For example, the first period may be an on period in which the first value is a specified value, and the second period may be an off period in which the second value is 0. In this case, the second predetermined voltage is applied intermittently to the second electrode 60. That is, a duty ratio may be set for the second predetermined voltage. The duty ratio may be, for example, 50% or more or 90% or more, or 99% or less.

5 is a partial plan view of the flow channel chip 10 showing the movement of the dielectric particles P1 and P2 when the amplitude of the voltage (second predetermined voltage) applied to the second electrode 60 changes with time. By changing the amplitude of the second predetermined voltage with time, the dielectrophoretic force acting on the dielectric particles P1 and P2 by the second electrode 60 can be changed over time. Therefore, the dielectric particles P1 and P2 are attracted to the second electrode 60 while the dielectrophoretic force is relatively large, and the dielectric particles P1 and P2 tend to move away from the second electrode 60 while the dielectrophoretic force is relatively small. Therefore, the dielectric particles P1 and P2 tend to move away from the second electrode 60 and flow into the main flow channel 31 without being pushed by the following dielectric particles P1 and P2. This improves the accuracy of the orientation of the dielectric particles P1 and P2 by the second electrode 60 compared to the case of relying on the above-mentioned push-out. In addition, the time that the dielectric particles P1 and P2 contact the second electrode 60 can be shortened, and the burden on the dielectric particles P1 and P2 can be reduced.

The second predetermined voltage may be set so that its frequency changes over time. The dielectrophoretic force acting on the dielectric particles by the second electrode 60 is affected by the frequency of the voltage applied to the second electrode 60. Therefore, by changing the frequency of the second predetermined voltage over time, it becomes possible to change the dielectrophoretic force acting on the dielectric particles P1, P2 by the second electrode 60 over time.

In this way, at least one of the amplitude and frequency of the second predetermined voltage may be changed over time. The time change of the amplitude of the second predetermined voltage may be performed by setting a duty ratio or by amplitude modulation. The time change of the frequency of the second predetermined voltage may be performed by frequency modulation. In this way, it is possible to change the dielectrophoretic force acting on the dielectric particles P1 and P2 by the second electrode 60 over time. Therefore, while the dielectrophoretic force is relatively large, the dielectric particles P1 and P2 are attracted to the second electrode 60, and while the dielectrophoretic force is relatively small, the dielectric particles P1 and P2 are easily separated from the second electrode 60. This improves the accuracy of the orientation of the dielectric particles P1 and P2 by the second electrode 60 compared to the case where the above-mentioned pushing is relied upon. In addition, the time during which the dielectric particles P1 and P2 are in contact with the second electrode 60 can be shortened, and the burden on the dielectric particles P1 and P2 can be reduced.

The voltage control device 11 described above can perform a separation method using the flow channel chip 10. This separation method controls the voltage of the second electrode 60 so as to guide multiple types of dielectric particles P1, P2, including a specific type of dielectric particle P1 contained in the suspension L1, to the second end side of the width direction W1 of the flow channel 30, and controls the voltage of the first electrode 50 so as to guide the specific type of dielectric particle P1 among the multiple types of dielectric particles P1, P2 to the first end side of the width direction W1 of the flow channel 30. This separation method can improve the accuracy of separation of the specific type of dielectric particle P1 from the suspension L1.

[1.1.2.3 Analysis device]
The analysis device 12 in Fig. 1 performs an analysis regarding separation of a specific type of dielectric particle P1 from a plurality of types of dielectric particles P1 and P2 contained in a suspension L1. The analysis device 12 in Fig. 1 includes an imaging device 121, a processing device 122, and a display device 123.

The imaging device 121 acquires an image of a target portion in the flow channel chip 10. The target portion is, for example, the main flow channel 31. From the image of the main flow channel 31, the movement trajectories of the dielectric particles P1 and P2 passing through the main flow channel 31 are obtained. The imaging device 121 includes, for example, a camera having an imaging element such as a CCD image sensor or a CMOS image sensor, and an optical microscope module. The optical microscope module may be a phase contrast microscope or an epi-illumination microscope. The optical microscope module may be configured to be switchable between a phase contrast microscope and an epi-illumination microscope, for example, by lens replacement. When performing fluorescent observation, a fluorescent filter is used as appropriate. The operation of the imaging device 121 may be controlled by the processing device 122.

The display device 123 displays information from the processing device 122. The display device 123 is, for example, a liquid crystal display or an organic electroluminescence display.

The processing device 122 controls the operation of the analysis device 12. The processing device 122 can be realized, for example, by a computer system including one or more processors (microprocessors) and one or more memories. The one or more processors execute programs (stored in one or more memories, etc.) to realize a predetermined function. As an example, the processing device 122 performs image analysis on the image captured by the imaging device 121 and determines the movement trajectories of the dielectric particles P1 and P2 passing through the main flow path 31. The processing device 122 may display, on the display device 123, the image captured by the imaging device 121 or the movement trajectories determined by image analysis.

1.1.3 Testing
In order to confirm the effect of the separation system 1 including the above-mentioned flow channel chip 10, the separation rate of a specific type of dielectric particles P1 was measured. FIG. 6 is a graph showing the time change of the separation rate in the separation system 1 of FIG. 1. In FIG. 6, the circular dots indicate the separation rate measured at a predetermined interval (for example, 10 seconds), and the solid line indicates the average separation rate in the corresponding period. The separation rate in FIG. 6 is the ratio of the dielectric particles P1 flowing in the branch flow channel 33-1 to the total dielectric particles P1 flowing in the branch flow channel 33-1 and the branch flow channel 33-2. In FIG. 6, during the period from time t1 to t2 and the period from time t3 to t4, a voltage (second predetermined voltage) is not applied to the second electrode 60. During the period from time t2 to t3 and the period from time t4 to t5, a voltage (second predetermined voltage) is applied to the second electrode 60. As can be seen from FIG. 6, the separation rate is higher during the periods when a voltage is applied to the second electrode 60 (the periods from time t2 to t3 and the periods from time t4 to t5) than during the periods when a voltage is not applied to the second electrode 60 (the periods from time t1 to t2 and the periods from time t3 to t4).

[1.1.4 Effects, etc.]
The flow path chip 10 described above includes a base 10a having an inlet 21 into which a suspension L1 containing a plurality of types of dielectric particles P1, P2 including a specific type of dielectric particle P1 is introduced and a flow path 30 through which the plurality of types of dielectric particles P1, P2 of the suspension L1 introduced from the inlet 21 flows, a first electrode 50 that guides the specific type of dielectric particles P1 of the plurality of types of dielectric particles P1, P2 to a first end side in the width direction W1 of the flow path 30, and a second electrode 60 that is between the inlet 21 and the first electrode 50 and guides the plurality of types of dielectric particles P1, P2 to a second end side in the width direction W1 of the flow path 30. With this configuration, the accuracy of separation of the specific type of dielectric particles P1 from the suspension L1 can be improved.

In addition, in the flow channel chip 10, the first electrode 50 is a comb-shaped electrode having multiple teeth 511, 521 arranged in a first predetermined direction D1. The second electrode 60 is a comb-shaped electrode having multiple teeth 611, 621 arranged in a second predetermined direction D2. The first predetermined direction D1 and the second predetermined direction D2 are directions toward opposite sides in the width direction W1 of the flow channel 30. This configuration can improve the accuracy of separation of a specific type of dielectric particles P1 from the suspension L1.

In addition, in the flow channel chip 10, the first electrode 50 and the second electrode 60 are each located on one side of the flow channel 30. With this configuration, the first electrode 50 and the second electrode 60 can each be configured as a planar electrode, which reduces manufacturing costs.

In addition, in the flow channel chip 10, the first predetermined direction D1 is a direction from the second end to the first end of the width direction W1 of the flow channel 30 along the direction in which the suspension L1 flows in the flow channel 30. The second predetermined direction D2 is a direction from the first end to the second end of the width direction W1 of the flow channel 30 along the direction in which the suspension L1 flows in the flow channel 30. With this configuration, the accuracy of separation of a specific type of dielectric particle P1 from the suspension L1 can be improved.

In addition, in the flow channel chip 10, the multiple teeth 611, 621 of the second electrode 60 include a first tooth 611 extending from a first end to a second end in the width direction W1 of the flow channel 30, and a second tooth 621 extending from the second end to the first end in the width direction W1 of the flow channel 30. The tip 611a of the first tooth 611 and the tip 621a of the second tooth 621 are outside the flow channel 30. This configuration makes it easier to align the second electrode 60 with the flow channel 30, and facilitates the manufacture of the flow channel chip 10.

In addition, in the channel chip 10, the channel 30 includes a main channel 31 and a connecting channel 32 between the main channel 31 and the inlet 21. The first electrode 50 is in the main channel 31. The second electrode 60 is in the connecting channel 32. The width of the connecting channel 32 is narrower than the width of the main channel 31. This configuration reduces manufacturing costs.

In addition, in the flow channel chip 10, the base 10a has a first collection section 40-1 connected to the first end side of the flow channel 30 in the width direction W1, and a second collection section 40-2 connected to the second end side of the flow channel 30 in the width direction W1. This configuration can improve the accuracy of separation of a specific type of dielectric particle P1 from the suspension L1.

In addition, in the flow channel chip 10, the flow channel 30 is provided with a filter 90 that is connected to the second end side of the flow channel 30 in the width direction W1 between the inlet 21 and the second electrode 60 and removes particles P3 that are smaller in size than the multiple types of dielectric particles P1 and P2 from the suspension L1. This configuration can improve the accuracy of separating a specific type of dielectric particle P1 from the suspension L1.

The flow channel chip 10 also includes first electrode pads 71, 72 for applying a first predetermined voltage to the first electrode 50, and second electrode pads 81, 82 provided separately from the first electrode pads for applying a second predetermined voltage different from the first predetermined voltage to the second electrode 60. This configuration can improve the accuracy of separating a specific type of dielectric particle P1 from the suspension L1.

In addition, in the flow channel chip 10, the second predetermined voltage is set so that at least one of the amplitude and the frequency changes over time. This configuration improves the precision of the orientation of the dielectric particles P1, P2 by the second electrode 60. In addition, the time that the dielectric particles P1, P2 are in contact with the second electrode 60 can be shortened, reducing the burden on the dielectric particles P1, P2.

The above-described separation system 1 includes a flow path chip 10 and a voltage control device 11 that controls the voltage of the second electrode 60 so as to guide multiple types of dielectric particles P1, P2, including a specific type of dielectric particle P1 contained in the suspension L1, to the second end side of the width direction W1 of the flow path 30, and controls the voltage of the first electrode 50 so as to guide the specific type of dielectric particle P1 among the multiple types of dielectric particles P1, P2 to the first end side of the width direction W1 of the flow path 30. This configuration can improve the accuracy of separation of the specific type of dielectric particle P1 from the suspension L1.

In addition, in the separation system 1, the channel chip 10 is disposable. This configuration prevents contamination and further improves the ease of use of the separation system 1.

The above-described separation method is a separation method using a flow path chip 10, in which the voltage of the second electrode 60 is controlled so as to guide multiple types of dielectric particles P1, P2, including a specific type of dielectric particle P1 contained in the suspension L1, to the second end side of the width direction W1 of the flow path 30, and the voltage of the first electrode 50 is controlled so as to guide the specific type of dielectric particle P1 among the multiple types of dielectric particles P1, P2 to the first end side of the width direction W1 of the flow path 30. With this configuration, the accuracy of separation of the specific type of dielectric particle P1 from the suspension L1 can be improved.

[1.2 Second embodiment]
7 is an enlarged view of a portion around the second electrode 60 in a configuration example of the flow channel chip 10A of embodiment 2. The flow channel chip 10A of embodiment 2 differs from the flow channel chip 10 of embodiment 1 in the position of the second electrode 60 relative to the connecting flow channel 32.

The second electrode 60 in FIG. 7 is disposed in the connecting flow path 32 of the flow path 30, as in the first embodiment, and guides the multiple types of dielectric particles P1 and P2 of the suspension L1 to the second end 322 in the width direction W1 of the connecting flow path 32. The second electrode 60 is configured to apply a dielectrophoretic force to the multiple types of dielectric particles P1 and P2 in a direction toward the second end of the width direction W1 of the flow path 30 (the second end 322 in the width direction W1 of the connecting flow path 32). As an example, as shown in FIG. 7, the multiple types of dielectric particles P1 and P2 move in the flow path 30 under the force F21 in the flow direction through the flow path 30. The second electrode 60 applies a dielectrophoretic force F22 to the multiple types of dielectric particles P1 and P2, thereby applying a force F23 in a direction toward the second end 322 in the width direction W1 of the connecting flow path 32.

7, the second electrode 60 is a comb-shaped electrode having a plurality of teeth 611, 621 arranged in the second predetermined direction D2 on the bottom surface of the flow path 30, as in the first embodiment. The plurality of teeth 611, 621 includes a plurality of first teeth 611 and a plurality of second teeth 621. The first teeth 611 and the second teeth 621 are arranged alternately. The plurality of first teeth 611 extend from the first end to the second end in the width direction W1 of the flow path 30. That is, the plurality of first teeth 611 extend from the first end 321 to the second end 322 in the width direction W1 of the connecting flow path 32. The plurality of second teeth 621 extend from the second end to the first end in the width direction of the flow path 30. That is, the plurality of second teeth 621 extend from the second end 322 to the first end 321 in the width direction W1 of the connecting flow path 32. In the second electrode 60 of FIG. 7, the tip 611a of the first tooth portion 611 is not outside the connecting flow path 32, but is inside the connecting flow path 32 at a predetermined distance from the second end 322 of the connecting flow path 32 in the width direction W1. In other words, the tip 611a of the first tooth portion 611 is inside the flow path 30 at a predetermined distance from the second end of the flow path 30 in the width direction W1. On the other hand, the tip 621a of the second tooth portion 621 is outside the connecting flow path 32, that is, outside the flow path 30.

In the second electrode 60 in FIG. 7, the tip 611a of the first tooth portion 611 is not outside the connecting flow path 32, but is inside the connecting flow path 32 at a predetermined distance from the second end 322 in the width direction W1 of the connecting flow path 32, so that a passage for the dielectric particles P1 and P2 is easily formed between the second end 322 in the width direction W1 of the connecting flow path 32 and the tip 611a of the first tooth portion 611. In other words, as shown by arrow A in FIG. 7, the dielectric particles P1 and P2 guided by the second electrode 60 to the second end 322 side in the width direction W1 of the connecting flow path 32 tend to pass between the tip 611a of the first tooth portion 611 of the second electrode 60 and the second end 322 in the width direction W1 of the connecting flow path 32 and move from the second electrode 60 to the first electrode 50. Therefore, even if there is no pushing by the subsequent dielectric particles P1 and P2 as described in the first embodiment, they will naturally move away from the second electrode 60 and move toward the main flow path 31. This improves the precision of the orientation of the dielectric particles P1, P2 by the second electrode 60. In addition, the time that the dielectric particles P1, P2 are in contact with the second electrode 60 can be shortened, reducing the burden on the dielectric particles P1, P2. The specified distance is not particularly limited, but can be set appropriately so that the dielectric particles P1, P2 can be moved from the second electrode 60 to the first electrode 50.

As described above, in the flow channel chip 10A, the multiple teeth 611, 621 of the second electrode 60 include the first teeth 611 extending from the first end to the second end in the width direction W1 of the flow channel 30, and the second teeth 621 extending from the second end to the first end in the width direction W1 of the flow channel 30. The tip 611a of the first teeth 611 is inside the flow channel 30 at a predetermined distance from the second end in the width direction W1 of the flow channel 30. The tip 621a of the second teeth 621 is outside the flow channel 30. According to this configuration, the dielectric particles P1, P2 guided to the second end side in the width direction W1 of the flow channel 30 are easily directed from the second electrode 60 to the first electrode 50 through between the tip 611a of the first teeth 611 of the second electrode 60 and the second end in the width direction W1 of the flow channel 30, so that the accuracy of the orientation of the dielectric particles P1, P2 by the second electrode 60 is improved. In addition, the time that the dielectric particles P1 and P2 are in contact with the second electrode 60 can be shortened, reducing the burden on the dielectric particles P1 and P2.

2. Modifications
The embodiments of the present disclosure are not limited to the above-mentioned embodiments. The above-mentioned embodiments can be modified in various ways depending on the design, etc., as long as the object of the present disclosure can be achieved. Below, modified examples of the above-mentioned embodiments are listed. The modified examples described below can be applied in appropriate combination.

In one modified example, the separation system 1 does not necessarily have to include an analysis device 12. The separation system 1 only needs to include at least a flow path chip 10 and a voltage control device 11.

In one modified example, the suspension L1 is not limited to blood. The suspension L1 is not particularly limited as long as it contains dielectric particles to be separated. The dielectric particles are not limited to the above-mentioned cells. The dielectric particles may be, for example, membrane vesicles, microorganisms, fungi, spores, viruses, exosomes, or nucleic acids such as DNA and RNA.

In one modified example, the shape of the channel chip 10 can be changed. In particular, the shape of the base 10a is not limited to the above embodiment. The shape of the base 10a may be set appropriately according to the channel 30. The channel 30 may be curved, not linear as in the above embodiment. The channel 30 does not need to be clearly separated into a main channel 31, a connecting channel 32, a branch channel 33, and connecting paths 34 and 35. The widths of the main channel 31 and the connecting channel 32 may be the same, and the connecting channel 32 may be curved with respect to the main channel 31.

In one variation, the inlet 22 is not required. In other words, replacement of the components of the suspension L1 with the replacement liquid L2 is not required. Also, depending on the shape of the flow path 30, the collection section 40 is not required.

In one modified example, the number and shape of the first electrodes 50 can be changed. The first electrodes 50 only need to be able to guide a specific type of dielectric particles from multiple types of dielectric particles to the first end side of the width direction W1 of the flow path 30. Depending on the shape of the first electrodes 50, the first electrode pads 71 and 72 can be omitted.

In one modified example, the shape of the second electrode 60 can be changed. The second electrode 60 only needs to be able to guide multiple types of dielectric particles to the second end side of the width direction W1 of the flow channel 30. The flow channel chip 10 may include multiple second electrodes 60. The multiple second electrodes 60 may cooperate with each other to guide multiple types of dielectric particles to the second end side of the width direction W1 of the flow channel 30. For example, when the first to fourth dielectric particles are guided to the second end side of the width direction W1 of the flow channel 30 by the multiple second electrodes 60, the first second electrode 60 may guide the first and second dielectric particles to the second end side of the width direction W1 of the flow channel 30, and the second second electrode 60 may guide the third and fourth dielectric particles to the second end side of the width direction W1 of the flow channel 30. Depending on the shape of the second electrode 60, the second electrode pads 81 and 82 may be omitted.

In one variation, the number and shape of the filters 90 can be changed. The filters 90 are not limited to a configuration that utilizes HDF (hydrodynamic filtration). The filters 90 may be configured to utilize DLD (deterministic lateral displacement), for example. Also, the filters 90 are not required.

3. Aspects
As is apparent from the above-described embodiment and modified examples, the present disclosure includes the following aspects. In the following, reference symbols are given in parentheses only to clarify the correspondence with the embodiment.

The first aspect is a flow path chip (10; 10A) including a base (10a) having an inlet (21) into which a suspension (L1) containing a plurality of types of dielectric particles (P1, P2) including a specific type of dielectric particle (P1) is introduced and a flow path (30) through which the plurality of types of dielectric particles (P1, P2) of the suspension (L1) introduced from the inlet (21) flows, a first electrode (50) that guides the specific type of dielectric particle (P1) among the plurality of types of dielectric particles (P1, P2) to a first end side in the width direction (W1) of the flow path (30), and a second electrode (60) that is between the inlet (21) and the first electrode (50) and guides the plurality of types of dielectric particles (P1, P2) to a second end side in the width direction (W1) of the flow path (30). According to this aspect, the accuracy of separation of the specific type of dielectric particle (P1) from the suspension (L1) can be improved.

The second aspect is a flow channel chip (10; 10A) based on the first aspect. In the second aspect, the first electrode (50) and the second electrode (60) are each located on one side of the flow channel (30). According to this aspect, the first electrode (50) and the second electrode (60) can each be configured as a planar electrode, which reduces manufacturing costs.

The third aspect is a flow channel chip (10; 10A) based on the first or second aspect. In the third aspect, the first electrode (50) is a comb-shaped electrode having a plurality of teeth (511, 521) arranged in a first predetermined direction (D1) on the bottom surface of the flow channel (30). The second electrode (60) is a comb-shaped electrode having a plurality of teeth (611, 621) arranged in a second predetermined direction (D2) on the bottom surface of the flow channel (30). The first predetermined direction (D1) and the second predetermined direction (D2) are directions toward opposite sides in the width direction (W1) of the flow channel (30). According to this aspect, the accuracy of separation of a specific type of dielectric particle (P1) from the suspension (L1) can be improved.

The fourth aspect is a flow path chip (10; 10A) based on the third aspect. In the fourth aspect, the first predetermined direction (D1) is a direction from the second end to the first end of the width direction (W1) of the flow path (30) along the direction in which the suspension (L1) flows in the flow path (30). The second predetermined direction (D2) is a direction from the first end to the second end of the width direction (W1) of the flow path (30) along the direction in which the suspension (L1) flows in the flow path (30). According to this aspect, the accuracy of separation of a specific type of dielectric particle (P1) from the suspension (L1) can be improved.

The fifth aspect is a flow channel chip (10) based on any one of the second to fourth aspects. In the fifth aspect, the multiple teeth (611, 621) of the second electrode (60) include a first tooth (611) extending from a first end to a second end in the width direction (W1) of the flow channel (30), and a second tooth (621) extending from the second end to the first end in the width direction (W1) of the flow channel (30). The tip (611a) of the first tooth (611) and the tip (621a) of the second tooth (621) are outside the flow channel (30). According to this aspect, it is easy to align the second electrode (60) with the flow channel (30), and it is easy to manufacture the flow channel chip (10).

The sixth aspect is a flow channel chip (10A) based on any one of the second to fourth aspects. In the sixth aspect, the multiple tooth portions (611, 621) of the second electrode (60) include a first tooth portion (611) extending from a first end to a second end in the width direction (W1) of the flow channel (30) and a second tooth portion (621) extending from the second end to the first end in the width direction (W1) of the flow channel (30). The tip (611a) of the first tooth portion (611) is located inside the flow channel (30) at a predetermined distance from the second end in the width direction (W1) of the flow channel (30). The tip (621a) of the second tooth portion (621) is located outside the flow channel (30). According to this aspect, the dielectric particles (P1, P2) guided to the second end side of the width direction (W1) of the flow path (30) pass between the tip (611a) of the first tooth portion (611) of the second electrode (60) and the second end of the width direction (W1) of the flow path (30) and easily move from the second electrode (60) to the first electrode (50), improving the accuracy of the orientation of the dielectric particles (P1, P2) by the second electrode (60). In addition, the time that the dielectric particles (P1, P2) are in contact with the second electrode (60) can be shortened, reducing the burden on the dielectric particles (P1, P2).

The seventh aspect is a flow channel chip (10; 10A) based on any one of the first to sixth aspects. In the seventh aspect, the flow channel (30) includes a main flow channel (31) and a connecting flow channel (32) between the main flow channel (31) and the inlet (21). The width of the connecting flow channel (32) is narrower than the width of the main flow channel (31). According to this aspect, the manufacturing cost can be reduced.

The eighth aspect is a flow path chip (10; 10A) based on any one of the first to seventh aspects. In the eighth aspect, the base (10a) has a first collection section (40-1) connected to a first end side of the flow path (30) in the width direction (W1) and a second collection section (40-2) connected to a second end side of the flow path (30) in the width direction (W1). According to this aspect, it is possible to improve the accuracy of separation of a specific type of dielectric particles (P1) from a suspension (L1).

The ninth aspect is a flow path chip (10; 10A) based on any one of the first to eighth aspects. In the ninth aspect, the flow path (30) is provided with a filter (90) that is connected to the second end side in the width direction of the flow path (30) between the inlet (21) and the second electrode (60) and removes particles (P3) smaller in size than the multiple types of dielectric particles (P1, P2) from the suspension (L1). According to this aspect, the accuracy of separation of a specific type of dielectric particle (P1) from the suspension (L1) can be improved.

The tenth aspect is a flow channel chip (10; 10A) based on any one of the first to ninth aspects. In the tenth aspect, the flow channel chip includes a first electrode pad (71, 72) for applying a first predetermined voltage to the first electrode (50), and a second electrode pad (81, 82) provided separately from the first electrode pad for applying a second predetermined voltage different from the first predetermined voltage to the second electrode (60). According to this aspect, the accuracy of separation of a specific type of dielectric particle (P1) from the suspension (L1) can be improved.

The eleventh aspect is a flow path chip (10; 10A) based on the tenth aspect. In the eleventh aspect, the second predetermined voltage is set so that at least one of the amplitude and the frequency changes with time. According to this aspect, the precision of the orientation of the dielectric particles (P1, P2) by the second electrode (60) is improved. In addition, the time that the dielectric particles (P1, P2) are in contact with the second electrode (60) can be shortened, and the burden on the dielectric particles (P1, P2) can be reduced.

The twelfth aspect is a separation system (1), comprising a flow path chip (10; 10A) according to any one of the first to eleventh aspects, and a voltage control device (11) that controls the voltage of the second electrode (60) so as to guide the plurality of types of dielectric particles (P1, P2) including the specific type of dielectric particle (P1) contained in the suspension (L1) to the second end side of the width direction (W1) of the flow path (30), and controls the voltage of the first electrode (50) so as to guide the specific type of dielectric particle (P1) among the plurality of types of dielectric particles (P1, P2) to the first end side of the width direction (W1) of the flow path (30). According to this aspect, the accuracy of separation of the specific type of dielectric particle (P1) from the suspension (L1) can be improved.

The thirteenth aspect is a separation system (1) based on the twelfth aspect. In the thirteenth aspect, the channel chip (10; 10A) is disposable. According to this aspect, contamination can be prevented, and the ease of use of the separation system (1) is further improved.

The fourteenth aspect is a separation method using the flow channel chip (10; 10A) according to any one of the first to eleventh aspects, in which the voltage of the second electrode (60) is controlled so as to guide the plurality of types of dielectric particles (P1, P2) including the specific type of dielectric particle (P1) contained in the suspension (L1) to the second end side of the width direction (W1) of the flow channel (30), and the voltage of the first electrode (50) is controlled so as to guide the specific type of dielectric particle (P1) among the plurality of types of dielectric particles (P1, P2) to the first end side of the width direction (W1) of the flow channel (30). According to this aspect, the accuracy of separation of the specific type of dielectric particle (P1) from the suspension (L1) can be improved.

The present disclosure is applicable to a flow path chip, a separation system, and a separation method. Specifically, the present disclosure is applicable to a flow path chip, a separation system, and a separation method for separating a specific type of dielectric particles from multiple types of dielectric particles contained in a suspension.

REFERENCE SIGNS LIST 1 Separation system 10, 10A Channel chip 10a Substrate 11 Voltage control device 21 Inlet 30 Channel 31 Main channel 32 Connecting channel 40-1 First collection section 40-2 Second collection section 50 First electrode 511 First tooth section (tooth section)
521 Second tooth portion (tooth portion)
60 Second electrode 611 First tooth portion (teeth portion)
611a Tip 621 Second tooth portion (tooth portion)
621a Tip 71, 72 First electrode pad 81, 82 Second electrode pad 90 Filter L1 Suspension P1, P2 Dielectric particles P3 Particles W1 Width direction D1 First predetermined direction D2 Second predetermined direction

Claims (10)

A substrate having an inlet through which a suspension containing a plurality of types of dielectric particles including a specific type of dielectric particles is introduced and a flow path through which the plurality of types of dielectric particles of the suspension introduced from the inlet flows;
a first electrode that guides the specific type of dielectric particles among the plurality of types of dielectric particles to a first end side in a width direction of the flow path;
a second electrode disposed between the inlet and the first electrode and configured to guide the plurality of types of dielectric particles to a second end side in a width direction of the flow path;
Equipped with
each of the first electrode and the second electrode is on one side of the flow channel;
The plurality of teeth of the second electrode include
a first tooth portion extending from a first end to a second end in a width direction of the flow channel;
a second tooth portion extending from a second end toward a first end in a width direction of the flow channel;
Including,
a tip end of the first tooth portion is located inside the flow passage and spaced a predetermined distance from a second end of the flow passage in a width direction of the flow passage,
The tip of the second tooth portion is outside the flow path.
Flow channel chip. the first electrode is a comb-shaped electrode having a plurality of teeth arranged along a first predetermined direction,
the second electrode is a comb-shaped electrode having a plurality of teeth arranged along a second predetermined direction,
The first predetermined direction and the second predetermined direction are directions toward opposite sides to each other in a width direction of the flow path.
The channel chip according to claim 1 . the first predetermined direction is a direction from a second end toward a first end in a width direction of the flow path along a direction in which the suspension flows in the flow path,
the second predetermined direction is a direction from a first end to a second end in a width direction of the flow path along a direction in which the suspension flows in the flow path,
The channel chip according to claim 2 . The plurality of teeth of the second electrode include
a first tooth portion extending from a first end to a second end in a width direction of the flow channel;
a second tooth portion extending from a second end toward a first end in a width direction of the flow channel;
Including,
A tip of the first tooth portion and a tip of the second tooth portion are outside the flow path.
The channel chip according to claim 1 . The substrate is
A first collection section connected to a first end side in a width direction of the flow channel;
a second collection section connected to a second end side of the flow channel in a width direction;
having
The channel chip according to any one of claims 1 to 4 . a first electrode pad for applying a first predetermined voltage to the first electrode;
a second electrode pad provided separately from the first electrode pad for applying a second predetermined voltage to the second electrode, the second predetermined voltage being different from the first predetermined voltage;
Equipped with
The channel chip according to any one of claims 1 to 5 . The second predetermined voltage is set so that at least one of an amplitude and a frequency changes with time.
The channel chip according to claim 6 . A channel chip according to any one of claims 1 to 7 ,
a voltage control device that controls a voltage of the second electrode so as to guide the plurality of types of dielectric particles including the specific type of dielectric particles contained in the suspension to a second end side in a width direction of the flow channel, and controls a voltage of the first electrode so as to guide the specific type of dielectric particles among the plurality of types of dielectric particles to a first end side in the width direction of the flow channel;
Equipped with
Separation system. The channel chip is disposable.
The separation system of claim 8 . A separation method using the channel chip according to any one of claims 1 to 7 ,
controlling a voltage of the second electrode so as to guide the plurality of types of dielectric particles including the specific type of dielectric particles contained in the suspension to a second end side in a width direction of the flow channel;
a voltage applied to the first electrode is controlled so as to guide the specific type of dielectric particles among the plurality of types of dielectric particles to a first end side in a width direction of the flow channel;
Separation method.