Separation chip

Abstract

To provide a separation chip capable of preventing the order of particles moving along an electrode from being changed.SOLUTION: A separation chip 100 is used to capture specific dielectric particles P1 contained in a liquid. The separation chip 100 includes a substrate 101 and a plurality of electrode portions 12. The plurality of electrode portions 12 are disposed on one surface 1011 of the substrate 101, have at least tooth portions 1201, and extend in a first direction X. The plurality of electrode portions 12 are disposed adjacent to each other in a second direction Y intersecting the first direction X. A flow path 110 through which a liquid flows in a flow direction D intersecting the second direction Y is provided on one side of the plurality of electrode portions 12. A distance L12 between the electrodes 12 adjacent to each other in the second direction Y is less than twice a particle size R of a specific dielectric particle P1.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a separation chip.

Background Art

[0002] Conventionally, a separation chip for separating specific cells from blood has been known (see, for example, Patent Document 1). Patent Document 1 describes a chip provided with a DEP (dielectrophoresis) unit that realizes separation and recovery of cells and the like by dielectrophoresis. The DEP unit includes a pair of comb-shaped electrodes provided facing each other on a flow path. By applying an alternating voltage between the pair of electrodes, dielectrophoresis is generated. By appropriately adjusting the applied alternating voltage and frequency, desired cells such as CTCs (circulating tumor cells in blood) are induced and separated.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the separation chip as in Patent Document 1 above, particles are attracted to one of the pair of electrodes and move along the electrode. At this time, the particles are attracted to the end portion of the upper surface of the electrode and move along the end portion of the upper surface of the electrode. Then, the particles move away from the electrode and move downstream in the flow path.

[0005] Specifically, when the particles move along the end portion of the upper surface of the electrode, the particles move in two rows between the pair of electrodes. At this time, between the pair of electrodes, subsequent particles may overtake the preceding particles and the order of the particles may be reversed.

[0006] The present invention has been made in view of the above problems, and an object thereof is to provide a separation chip capable of suppressing the order of particles moving along an electrode from being reversed.

Means for Solving the Problems

[0007] The separation chip according to the first aspect of the present invention is used for capturing specific dielectric particles contained in a liquid. The separation chip includes a substrate and a plurality of electrode portions. The plurality of electrode portions are arranged on one surface of the substrate, have at least electrodes, and extend in a first direction. The plurality of electrode portions are arranged adjacent to each other in a second direction intersecting the first direction. A flow path is provided on one side of the plurality of electrode portions through which the liquid flows in a flow direction intersecting the second direction. The distance between the electrode portions adjacent to each other in the second direction is less than twice the particle diameter of the specific dielectric particles.

[0008] In one aspect of the present invention, the electrode portion may have an insulating layer covering the electrode. The distance between the insulating layers adjacent to each other in the second direction may also be less than twice the particle diameter of the specific dielectric particles.

[0009] In one aspect of the present invention, the distance between the electrodes adjacent to each other in the second direction may be less than twice the particle diameter of the specific dielectric particles.

[0010] In one aspect of the present invention, the distance between the electrode portions adjacent to each other in the second direction may be 1.5 times or less the particle diameter of the specific dielectric particles.

[0011] In one aspect of the present invention, the distance between the electrode portions adjacent to each other in the second direction may be equal to or less than the particle diameter of the specific dielectric particles.

[0012] In one aspect of the present invention, in a plan view, when a first particle, which is one of the specific dielectric particles, contacts one of the electrode portions adjacent in the second direction, and a second particle, which is another one of the specific dielectric particles, contacts the other of the electrode portions adjacent in the second direction and the first particle, an angle formed between a straight line connecting the center of the first particle and the center of the second particle and the first direction is defined as φ. An angle formed between the first direction and the flow direction is defined as θ. The separation chip may satisfy 0° ≤ φ + θ ≤ 60° or 120° ≤ φ + θ ≤ 180°.

[0013] The separation chip according to the second aspect of the present invention is used for capturing specific dielectric particles contained in a liquid. The separation chip includes a substrate and a plurality of electrode portions. The plurality of electrode portions are arranged on one surface of the substrate and extend in a first direction. The plurality of electrode portions are arranged adjacent to each other in a second direction intersecting the first direction. A flow path is provided on one side of the plurality of electrode portions for the liquid to flow in a flow direction intersecting the second direction. The electrode portion has an electrode arranged on one surface of the substrate and an insulating layer covering the electrode. One surface of the electrode has a first region and a second region different from the first region. The thickness of the insulating layer on the first region is smaller than the thickness of the insulating layer on the second region. The length of the first region in the second direction is less than twice the particle size of the specific dielectric particle.

[0014] In one aspect of the present invention, the length of the first region in the second direction may be 1.5 times or less the particle size of the specific dielectric particle.

[0015] In one aspect of the present invention, the length of the first region in the second direction may be equal to or less than the particle size of the specific dielectric particle.

[0016] In one aspect of the present invention, in a plan view, when a first particle, which is one of the specific dielectric particles, contacts one of the second regions adjacent in the second direction, and a second particle, which is another one of the specific dielectric particles, contacts the other of the second regions adjacent in the second direction and the first particle, an angle formed by a straight line connecting the center of the first particle and the center of the second particle and the first direction is defined as φ. An angle formed by the first direction and the flow direction is defined as θ. The separation chip may satisfy 0° ≦ φ + θ ≦ 60° or 120° ≦ φ + θ ≦ 180°.

[0017] In one aspect of the present invention, the insulating layer may have an opening connecting the first region and the flow path. The first region may be connected to the flow path through the opening. The first region may be located closer to the substrate side than the second region.

Advantages of the Invention

[0018] According to the present invention, it is possible to provide a separation chip capable of suppressing the switching of the order of particles moving along the electrode.

Brief Description of the Drawings

[0019]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Embodiments for Carrying Out the Invention

[0020] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and the description will not be repeated.

[0021] With reference to FIGS. 1 to 5, a dielectrophoresis device 1 provided with a separation chip 100 according to an embodiment of the present invention will be described. FIG. 1 is a plan view schematically showing the structure of the dielectrophoresis device 1 provided with the separation chip 100 according to an embodiment of the present invention.

[0022] As shown in FIG. 1, the dielectrophoresis device 1 according to an embodiment of the present invention includes a separation chip 100 and a voltage control device 500. The dielectrophoresis device 1 separates dielectric particles P1 from other particles P2 by applying a dielectrophoretic force to the dielectric particles P1 contained in a sample liquid (sample solution), and collects the dielectric particles P1. The sample liquid is not particularly limited, and is, for example, blood. The dielectric particles P1 are not particularly limited, and are, for example, cells, proteins, nucleic acids, or microorganisms. The cells are, for example, cancer cells. Also, the sample liquid may be seawater, physiological saline, pure water, or a chemical. The other particles P2 are, for example, dielectric particles of a type different from the dielectric particles P1, or non-dielectric particles. As an example, the sample liquid is blood, the dielectric particles P1 are cancer cells, and the other particles P2 are white blood cells. Note that the sample liquid is an example of the "liquid" of the present invention.

[0023] The separation chip 100 is used to capture specific dielectric particles P1 contained in a liquid. Specifically, the separation chip 100 separates dielectric particles P1 from other particles P2 by applying a dielectrophoretic force to the dielectric particles P1 contained in the sample liquid, and collects the dielectric particles P1. The diameter of the dielectric particles P1 (hereinafter sometimes referred to as the particle size) is, for example, several μm or more and 20 μm or less. That is, in the present embodiment, the minimum particle size of the dielectric particles P1 is several μm, and the maximum particle size is 20 μm. Also, in the present embodiment, the average particle size of the dielectric particles P1 is about 10 μm.

[0024] The separation chip 100 includes a substrate 101, a flow path 110, and a separation electrode 120. The flow path 110 has a supply section 111, a separation flow path 112, and a collection section 113. In this embodiment, the supply section 111 has a first supply section 1111 and a second supply section 1112. A sample solution is introduced into the first supply section 1111. A transport solution is introduced into the second supply section 1112. The transport solution is, for example, a liquid that does not contain particles. The transport solution is not particularly limited, but is, for example, a liquid medium. Each of the first supply section 1111 and the second supply section 1112 has, for example, an opening. The first supply section 1111 is connected, for example, by a tube to a supply source of the sample solution. The second supply section 1112 is connected, for example, by a tube to a supply source of the transport solution.

[0025] The separation flow path 112 extends linearly, for example, in a predetermined direction. The sample solution flows through the separation flow path 112. In this embodiment, the sample solution and the transport solution flow through the separation flow path 112. Specifically, the separation flow path 112 connects the first supply section 1111 and the second supply section 1112 to the collection section 113. The sample solution introduced into the first supply section 1111 and the transport solution introduced into the second supply section 1112 flow through the separation flow path 112 toward the collection section 113.

[0026] In this embodiment, the collection section 113 has a first collection section 1131 and a second collection section 1132. Each of the first collection section 1131 and the second collection section 1132 is connected to the downstream end of the separation flow path 112. The first collection section 1131 collects particles P2 other than the dielectric particles P1. The second collection section 1132 collects the dielectric particles P1 that have passed through the separation flow path 112. Each of the first collection section 1131 and the second collection section 1132 may have, for example, an opening. The first collection section 1131 may supply, for example, the sample solution containing the particles P2 to the outside. The second collection section 1132 may supply, for example, the transport solution containing the dielectric particles P1 to the outside.

[0027] The separation chip 100 includes a flow path cover 105. The flow path cover 105 is disposed on the substrate 101. The flow path cover 105 has an area smaller than that of the substrate 101. That is, the flow path cover 105 is disposed on a part of the substrate 101. The flow path cover 105 has a recess that constitutes the flow path 110. The flow path 110 is constituted by the substrate 101 and the flow path cover 105.

[0028] The separation electrode 120 is formed of a conductive metal. In this embodiment, the metal is a concept including an alloy. The separation electrode 120 is disposed at least in the separation flow path 112. In other words, the separation electrode 120 overlaps at least the separation flow path 112. The separation electrode 120 includes a first electrode 121 and a second electrode 122. The first electrode 121 and the second electrode 122 have, for example, a comb tooth shape facing each other. Note that the first electrode 121 and the second electrode 122 do not necessarily have a comb tooth shape.

[0029] The first electrode 121 has a plurality of tooth portions 1211, a first connection portion 1212, a second connection portion 1213, and a pad portion 1214. Note that the tooth portion 1211 is an example of the "electrode" of the present invention.

[0030] Each of the plurality of tooth portions 1211 has a substantially rectangular cross-sectional shape. Further, each of the tooth portions 1211 extends in a substantially straight line. The plurality of tooth portions 1211 are arranged substantially parallel to each other. Further, the plurality of tooth portions 1211 extend in the first direction X. Further, the plurality of tooth portions 1211 are arranged at a predetermined interval in the second direction Y intersecting the first direction X. In this embodiment, the second direction Y is orthogonal to the first direction X. Hereinafter, the second direction Y may be referred to as the width direction. Further, the flow path 110 extends along the flow direction D in which the liquid flows. The flow direction D intersects the second direction Y. In this embodiment, the flow direction D is inclined with respect to the second direction Y.

[0031] The first connecting part 1212 connects a plurality of tooth parts 1211 to each other. A comb tooth shape is formed by the plurality of tooth parts 1211 and the first connecting part 1212. The plurality of tooth parts 1211 are arranged across the separation flow path 112 in a plan view, for example. The first connecting part 1212 is arranged outside the separation flow path 112 in a plan view. The plurality of tooth parts 1211 and the first connecting part 1212 are covered by the flow path cover 105.

[0032] The second connecting part 1213 connects the first connecting part 1212 and the pad part 1214. At least a part of the second connecting part 1213 is covered by the flow path cover 105. At least a part of the pad part 1214 is arranged outside the flow path cover 105 in a plan view. In the present embodiment, the second connecting part 1213 is covered by the flow path cover 105. A part of the pad part 1214 is arranged outside the flow path cover 105 in a plan view. Thus, since at least a part of the pad part 1214 is not covered by the flow path cover 105, the pad part 1214 can be easily electrically connected to the voltage control device 500.

[0033] The second electrode 122 has a plurality of tooth parts 1221, a first connecting part 1222, a second connecting part 1223, and a pad part 1224. Note that the tooth part 1221 is an example of the "electrode" of the present invention.

[0034] Each of the plurality of tooth parts 1221 has a substantially rectangular cross-sectional shape. Also, each of the tooth parts 1221 extends in a substantially straight line. The plurality of tooth parts 1221 are arranged substantially parallel to each other. Also, the plurality of tooth parts 1221 are arranged substantially parallel to the plurality of tooth parts 1211. The first connecting part 1222 connects the plurality of tooth parts 1221 to each other. A comb tooth shape is formed by the plurality of tooth parts 1221 and the first connecting part 1222. The plurality of tooth parts 1221 are arranged across the separation flow path 112 in a plan view, for example. The first connecting part 1222 is arranged outside the separation flow path 112 in a plan view. The plurality of tooth parts 1221 and the first connecting part 1222 are covered by the flow path cover 105.

[0035] The second connection part 1223 connects the first connection part 1222 and the pad part 1224. At least a part of the second connection part 1223 is covered by the flow path cover 105. At least a part of the pad part 1224 is arranged outside the flow path cover 105 in a plan view. In the present embodiment, the second connection part 1223 is covered by the flow path cover 105. A part of the pad part 1224 is arranged outside the flow path cover 105 in a plan view. Thus, since at least a part of the pad part 1224 is not covered by the flow path cover 105, the pad part 1224 can be easily electrically connected to the voltage control device 500.

[0036] The voltage control device 500 is electrically connected to the pad part 1214 and the pad part 1224. The voltage control device 500 applies an alternating voltage corresponding to the type of the dielectric particles P1 to the first electrode 121 and the second electrode 122 via the pad part 1214 and the pad part 1224. The alternating voltage corresponding to the type of the dielectric particles P1 is, for example, a frequency that generates an electric field that specifically applies a dielectrophoretic force (attractive force) to the dielectric particles P1, and is a voltage of a magnitude that does not destroy the dielectric particles P1.

[0037] Specifically, the frequency of the alternating voltage is set so that a positive dielectrophoretic force (attractive force) acts on the dielectric particles P1 by the electric field between the first electrode 121 and the second electrode 122. Therefore, the positive dielectrophoretic force acts on the dielectric particles P1, and the dielectric particles P1 are attracted to the tooth parts 1211 and 1221. Hereinafter, the tooth parts 1211 and 1221 may be referred to as the tooth part 1201. Note that the tooth part 1201 is an example of the "electrode" of the present invention.

[0038] Then, the dielectric particles P1 flow downstream (toward the collection unit 113) along the tooth portion 1201. Specifically, the dielectric particles P1 flow along the tooth portion 1201 toward one side in the first direction X (the first connection portion 1212 side). Then, the dielectric particles P1 leave the tooth portion 1201 and flow downstream in the flow direction D along the side wall 1051 (to be described later) on the side of the second supply unit 1112 and the second collection unit 1132 (the upper side in FIG. 1) of the flow path cover 105. Thereafter, the dielectric particles P1 are collected in the second collection unit 1132.

[0039] On the other hand, the frequency of the alternating voltage is set so that the dielectrophoretic force does not act, or hardly acts, on the other particles P2. Accordingly, the other particles P2 pass through the separation channel 112 and are collected in the collection unit 113.

[0040] Continuing to refer to FIG. 1, the voltage control device 500 will be described. The voltage control device 500 includes a power supply unit 510 and a control unit 520.

[0041] The control unit 520 controls the power supply unit 510. The control unit 520 includes, for example, a processor and a storage device. The processor is, for example, a CPU (Central Processing Unit) or an MPU (Micro Processing Unit). The storage device stores data and computer programs. The storage device includes a main storage device such as a semiconductor memory and an auxiliary storage device such as a semiconductor memory, a solid state drive, and / or a hard disk drive. The storage device may include a removable medium. The storage device corresponds to an example of a non-transitory computer-readable storage medium.

[0042] The power supply unit 510 generates an alternating voltage corresponding to the dielectric particles P1 to be separated. Then, the power supply unit 510 applies the alternating voltage to the first electrode 121 and the second electrode 122 via the pad portion 1214 and the pad portion 1224. The power supply unit 510 is, for example, a signal generator such as a function generator.

[0043] By applying an alternating voltage corresponding to the dielectric particles P1 to the first electrode 121 and the second electrode 122 by the power supply unit 510, a dielectrophoretic force (attractive force) acts on the dielectric particles P1. As a result, the dielectric particles P1 are attracted to the tooth portions 1201 (tooth portions 1211 and 1221) and move along the tooth portions 1201, and the dielectric particles P1 are separated from the other particles P2. In the present embodiment, the dielectric particles P1 are collected in the second collection unit 1132, and the other particles P2 pass through the separation channel 112 and are collected in the first collection unit 1131.

[0044] Note that the voltage control device 500 may have a function of measuring the electrical characteristics (such as impedance) between the first electrode 121 and the second electrode 122. Further, the voltage control device 500 may be constituted by, for example, a source measure unit.

[0045] Next, with reference to FIG. 2, the structure of the separation chip 100 will be further described. FIG. 2 is an enlarged cross-sectional view schematically showing the structure around the tooth portion 1201 of the separation chip 100 of the present embodiment.

[0046] As shown in FIG. 2, the separation chip 100 includes an insulating film 103 in addition to the substrate 101, the separation electrode 120, and the flow path cover 105. The substrate 101 is, for example, a glass substrate. The material of the substrate 101 is, for example, quartz glass. However, the material of the substrate 101 is not limited to quartz glass. The substrate 101 has, for example, a substantially rectangular flat plate shape. However, the shape of the substrate 101 is not limited to the flat plate shape.

[0047] The separation electrode 120 is disposed on one surface 1011 of the substrate 101. The material of the separation electrode 120 is, for example, a metal such as aluminum, copper, and / or titanium. However, the material of the separation electrode 120 may be a metal other than aluminum, copper, and / or titanium. For example, the material of the separation electrode 120 may be a metal such as indium, tin, molybdenum, silver, chromium, tantalum, and / or silicon. Further, the material of the separation electrode 120 may be other than a metal, and may include, for example, an oxide such as a metal oxide, or a semiconductor. Further, the surface of the separation electrode 120 may be oxidized. Further, the separation electrode 120 may be formed of, for example, ITO (Indium Tin Oxide). Note that the material of the separation electrode 120 is not particularly limited as long as the separation electrode 120 has conductivity.

[0048] The separation electrode 120 has a substantially rectangular cross-sectional shape. The separation electrode 120 has one surface 1205 and a pair of side surfaces 1206. One surface 1205 is a surface on one side of the separation electrode 120 (the side opposite to the substrate 101). In the present embodiment, one surface 1205 of the separation electrode 120 is a surface that can be seen when the separation electrode 120 is viewed from the flow path 110 side. Further, in the present embodiment, one surface 1205 of the separation electrode 120 is a surface substantially parallel to one surface 1011 of the substrate 101.

[0049] The pair of side surfaces 1206 are connected to one surface 1205. The pair of side surfaces 1206 extend from the end of one surface 1205 in the second direction Y toward the substrate 101.

[0050] The insulating film 103 covers at least a part of one surface 1205 of the separation electrode 120. In the present embodiment, the insulating film 103 covers one surface 1205 and the pair of side surfaces 1206 of the tooth portion 1201. Further, the insulating film 103 covers a portion of one surface 1011 of the substrate 101 where the separation electrode 120 is not disposed and the separation electrode 120. Note that the insulating film 103 does not cover at least a portion of the pad portions 1214 and 1224 that is connected to the voltage control device 500.

[0051] The insulating film 103 has insulation properties. The material of the insulating film 103 is, for example, an oxide film such as a silicon oxide film, a nitride film such as a silicon nitride film, or a resin. In this embodiment, the insulating film 103 is a silicon oxide film. Also, the thickness and material of the insulating film 103 affect the electric field formed by the separation electrode 120. That is, it is also possible to control the electric field formed by the tooth portion 1201 of the separation electrode 120 according to the thickness and material of the insulating film 103. Note that the insulating film 103 also functions as a protective film that suppresses an electrochemical reaction from occurring between the tooth portion 1201 of the separation electrode 120 and the sample solution.

[0052] In this embodiment, the insulating film 103 has a plurality of cover portions 1031 and a connection portion 1035. The cover portion 1031 is a portion of the insulating film 103 that covers the tooth portion 1201. Specifically, the cover portion 1031 is a portion of the insulating film 103 that is disposed on one surface 1205 and the side surface 1206 of the tooth portion 1201. The connection portion 1035 is a portion of the insulating film 103 that connects adjacent cover portions 1031 to each other. Note that the cover portion 1031 is an example of the "insulating layer" of the present invention.

[0053] In this embodiment, the electrode portion 12 is constituted by the tooth portion 1201 and the cover portion 1031. In other words, the separation chip 100 includes a plurality of electrode portions 12, and each electrode portion 12 has a tooth portion 1201 and a cover portion 1031. Therefore, the electrode portion 12 extends along the first direction X. The plurality of electrode portions 12 are disposed adjacent to each other in the second direction Y. And a flow path 110 is provided on one side of the plurality of electrode portions 12.

[0054] The thickness of the tooth portion 1201 of the electrode portion 12 is not particularly limited. The tooth portion 1201 has a thickness of, for example, not less than several nm and not more than several μm. The width of the tooth portion 1201 is not particularly limited. The tooth portion 1201 has a width of, for example, not less than several tens of μm and not more than several hundreds of μm. Also, the thickness of the cover portion 1031 of the electrode portion 12 is not particularly limited. The cover portion 1031 has a thickness of, for example, not less than several hundreds of nm and not more than several μm.

[0055] On the other hand, the distance between adjacent electrode portions 12 and the distance between adjacent tooth portions 1201 have a predetermined size, as will be described later. The detailed structure of the electrode portion 12 will be described later.

[0056] The flow path cover 105 is disposed, for example, on one surface 1033 of the insulating film 103. A part of the flow path cover 105 may be disposed on one surface 1011 of the substrate 101. And the flow path cover 105 covers one side (the side opposite to the substrate 101) of the separation electrode 120 and the insulating film 103. Further, the flow path cover 105 constitutes the flow path 110. Specifically, the flow path cover 105 includes side walls 1051 (see FIG. 1) and a ceiling 1052. The side walls 1051 and the ceiling 1052 constitute a flow path 110 through which the sample liquid and the transport liquid flow. The side wall 1051 surrounds at least a part of the separation electrode 120 in plan view.

[0057] The material of the flow path cover 105 is not particularly limited, but is, for example, a silicone-based resin. In the present embodiment, the material of the flow path cover 105 is PDMS (polydimethylsiloxane). When the flow path cover 105 is formed of PDMS, by performing plasma treatment on the surfaces of the flow path cover 105, the insulating film 103, and the substrate 101, the flow path cover 105 is firmly adhered to the surfaces of the insulating film 103 and the substrate 101.

[0058] Next, the detailed structure of the electrode portion 12 will be described. As shown in FIG. 2, the distance L12 between adjacent electrode portions 12 in the second direction Y is less than twice the particle diameter of the dielectric particles P1. In the present embodiment, the distance L12 between adjacent electrode portions 12 in the second direction Y is the same as the distance L1031 between adjacent cover portions 1031 in the second direction Y. In the present embodiment, the distance L12 is less than twice the maximum particle diameter of the dielectric particles P1. In this case, the distance L12 is less than 40 μm. Further, the distance L12 may be less than twice the average particle diameter of the dielectric particles P1. In this case, the distance L12 is less than 20 μm.

[0059] The distance L12 is preferably 1.5 times or less the particle size of the dielectric particle P1. In the present embodiment, the distance L12 may be 1.5 times or less the maximum particle size of the dielectric particle P1. In this case, the distance L12 is 30 μm or less. Also, the distance L12 may be 1.5 times or less the average particle size of the dielectric particle P1. In this case, the distance L12 is 15 μm or less.

[0060] Also, the distance L12 is preferably equal to or less than the particle size of the dielectric particle P1. In the present embodiment, the distance L12 may be equal to or less than the maximum particle size of the dielectric particle P1. In this case, the distance L12 is 20 μm or less. Also, the distance L12 may be equal to or less than the average particle size of the dielectric particle P1. In this case, the distance L12 is 10 μm or less.

[0061] Note that the distance L12 is greater than 0 μm. In the present embodiment, the distance L12 is, for example, 2 μm or more.

[0062] The distance L1201 between the tooth portions 1201 adjacent to each other in the second direction Y may be less than 2 times the particle size of the dielectric particle P1. In the present embodiment, the distance L1201 may be less than 2 times the maximum particle size of the dielectric particle P1. In this case, the distance L1201 is less than 40 μm. Also, the distance L1201 may be less than 1.5 times the average particle size of the dielectric particle P1. In this case, the distance L1201 is less than 20 μm.

[0063] Also, the distance L1201 may be 1.5 times or less the particle size of the dielectric particle P1. In the present embodiment, the distance L1201 may be 1.5 times or less the maximum particle size of the dielectric particle P1. In this case, the distance L1201 is 30 μm or less. Also, the distance L1201 may be 1.5 times or less the average particle size of the dielectric particle P1. In this case, the distance L1201 is 15 μm or less.

[0064] Also, the distance L1201 may be equal to or less than the particle size of the dielectric particles P1. In the present embodiment, the distance L1201 may be equal to or less than the maximum particle size of the dielectric particles P1. In this case, the distance L1201 is 20 μm or less. Also, the distance L1201 may be equal to or less than the average particle size of the dielectric particles P1. In this case, the distance L1201 is 10 μm or less.

[0065] Note that the distance L1201 is greater than 0 μm. In the present embodiment, the distance L1201 is, for example, 2 μm or more.

[0066] Next, the dielectrophoretic force (attractive force) acting on the dielectric particles P1 due to the electric field between the first electrode 121 and the second electrode 122 will be described. Note that at the corner of the electrode, the electric field is strong and the gradient of the electric field strength is large. For this reason, in FIG. 2, in order to facilitate understanding of the invention, the image of the region where the force (attractive force) for attracting the dielectric particles is strong is indicated by a broken line.

[0067] ∇E between the two tooth portions 1201 2 (where ∇E represents the gradient of the electric field strength) is estimated to be the largest around the adjacent corners 127 of the two tooth portions 1201. 2 For this reason, the dielectric particles P1 are attracted to the corners 127. Therefore, the dielectric particles P1 are attracted to the widthwise end portions of the electrode portion 12. At this time, in the present embodiment, since the distance L12 between the adjacent electrode portions 12 is small, the dielectric particles P1 are attracted to both of the adjacent tooth portions 1201. Thus, the dielectrophoretic force acting on the dielectric particles P1 can be increased. Note that even if the frequency and voltage are changed, the position where the dielectric particles P1 are attracted does not change.

[0068] More specifically, the dielectrophoretic force is represented by the following general formula (1).

[0069] [Equation 1] F = 2πr 3 ε m Re[K(ω)]∇E 2 ···(1)

[0070] Here, F represents the dielectrophoretic force. r represents the radius of the dielectric particle. ε m represents the real part of the permittivity of the surrounding medium. ω represents the angular frequency. K(ω) represents the Clausius-Mossotti function.

[0071] As can also be seen from the fact that the term of ∇E 2 is included in the above formula (1), the dielectrophoretic force occurs in a non-uniform region of the alternating current electric field (hereinafter sometimes referred to as a non-uniform electric field generation region). The non-uniform region of the alternating current electric field indicates a region where the interval between the electric force lines changes. In the present embodiment, a non-uniform electric field occurs around the corner 127 located at the widthwise end of the tooth portion 1201. For this reason, the dielectric particle P1 is attracted to the corner 127.

[0072] Next, with reference to FIGS. 1 and 3, the flow (movement) of the dielectric particle P1 by the separation chip 100 of the present embodiment will be described. FIG. 3 is a plan view schematically showing the structure around the electrode portion 12 of the separation chip 100 and the dielectric particle P1. In FIG. 3, for ease of understanding, the electrode portion 12 is hatched and the flow path cover 105 and the like are omitted.

[0073] As shown in FIG. 1, when a sample liquid containing the dielectric particle P1 and the particle P2 is introduced into the first supply unit 1111 and a transport liquid is introduced into the second supply unit 1112, the dielectric particle P1 and the particle P2 flow downstream along the side wall 1051 of the flow path cover 105 on the side of the first supply unit 1111 and the first collection unit 1131 (the lower side in FIG. 1).

[0074] Since no dielectrophoretic force acts on the particle P2, or hardly acts, the particle P2 passes through the electrode portion 12. Then, the particle P2 flows downstream along the side wall 1051 of the flow path cover 105 on the side of the first supply unit 1111 and the first collection unit 1131 (the lower side in FIG. 1) and is collected in the first collection unit 1131.

[0075] On the other hand, a dielectrophoretic force acts on the dielectric particles P1. For this reason, the dielectric particles P1 are attracted to the tooth portion 1201 and move along the tooth portion 1201 toward the side wall 1051 on the side of the second supply portion 1112 and the second collection portion 1132 (the upper side in FIG. 1).

[0076] At this time, as shown in FIG. 3, in the present embodiment, the plurality of dielectric particles P1 move in a substantially straight line between adjacent electrode portions 12.

[0077] Then, the plurality of dielectric particles P1 are sequentially released from the electrode portion 12 starting from the particles that have reached the side wall 1051 on the side of the second supply portion 1112 and the second collection portion 1132 (the upper side in FIG. 3). Thereafter, as shown in FIG. 1, the dielectric particles P1 flow downstream along the side wall 1051 on the side of the second supply portion 1112 and the second collection portion 1132 (the upper side in FIG. 1) of the flow path cover 105 and are collected by the second collection portion 1132.

[0078] In the present embodiment, as described above, the distance L12 between adjacent electrode portions 12 in the second direction Y is less than twice the particle diameter of the dielectric particles P1. Therefore, when the dielectric particles P1 move along the electrode portion 12 between adjacent electrode portions 12, it is possible to suppress the subsequent dielectric particles P1 from overtaking the preceding dielectric particles P1. Thus, it is possible to suppress the order of the dielectric particles P1 moving along the electrode portion 12 from being reversed.

[0079] Further, by making the distance L12 less than twice the particle diameter of the dielectric particles P1, the dielectric particles P1 are attracted to both of the adjacent electrode portions 12. Therefore, the dielectrophoretic force acting on the dielectric particles P1 can be increased.

[0080] Note that by using the separation chip 100 of the present embodiment, for example, when analyzing cells (dielectric particles P1) moving in a line by irradiating them with laser light (also referred to as flow cytometry), it is possible to suppress the order of the cells from being reversed, so that the analysis accuracy can be improved.

[0081] Furthermore, for example, if a mechanism for hydrodynamically or electromagnetically changing the flowing direction of cells (dielectric particles P1) is provided on the downstream side of the electrode portion 12 of the separation chip 100 of the present embodiment, the accuracy in sorting cells can be improved. As a result, the loss of cells (dielectric particles P1) can be reduced, and the amount of the sample liquid used can be reduced. Therefore, it also contributes to reducing the environmental load.

[0082] Also, as described above, the electrode portion 12 has the cover portion 1031, and the distance L1031 between the cover portions 1031 adjacent to each other in the second direction Y is less than twice the particle diameter of the dielectric particle P1. Therefore, even when the electrode portion 12 has the cover portion 1031, the distance L12 between the adjacent electrode portions 12 can be easily made less than twice the particle diameter of the dielectric particle P1.

[0083] Also, as described above, the distance L1201 between the tooth portions 1201 adjacent to each other in the second direction Y may be less than twice the particle diameter of the dielectric particle P1. With such a configuration, for example, even when there is variation in the thickness of the cover portion 1031, the distance L12 between the adjacent electrode portions 12 can be surely made less than twice the particle diameter of the dielectric particle P1.

[0084] Also, as described above, the distance L12 between the electrode portions 12 adjacent to each other in the second direction Y may be 1.5 times or less the particle diameter of the dielectric particle P1. With such a configuration, it is possible to effectively suppress the order of the dielectric particles P1 moving along the electrode portion 12 from being interchanged. The effect of making the distance L12 1.5 times or less the particle diameter of the dielectric particle P1 will be described later.

[0085] Also, as described above, the distance L12 between the electrode portions 12 adjacent to each other in the second direction Y may be equal to or less than the particle diameter of the dielectric particle P1. With such a configuration, it is possible to further suppress the order of the dielectric particles P1 moving along the electrode portion 12 from being interchanged.

[0086] Next, with reference to FIG. 4, the effect of setting the distance L12 between the electrode portions 12 adjacent in the second direction Y to 1.5 times or less the particle diameter of the dielectric particles P1 will be described. FIG. 4 is a diagram for explaining the effect of setting the distance L12 between the electrode portions 12 adjacent in the second direction Y to 1.5 times or less the particle diameter of the dielectric particles P1.

[0087] As shown in FIG. 4, in a plan view, a first particle (hereinafter sometimes referred to as dielectric particle P11), which is one of the dielectric particles P1, contacts one of the electrode portions 12 adjacent in the second direction Y (the upstream electrode portion 12), and another particle (hereinafter sometimes referred to as dielectric particle P12), which is one of the dielectric particles P1, contacts the other of the electrode portions 12 adjacent in the second direction Y (the downstream electrode portion 12) and the dielectric particle P11. Also, let a straight line connecting the center P111 of the dielectric particle P11 and the center P121 of the dielectric particle P12 be L1. Also, let the angle formed by the straight line L1 and the first direction X be φ (where 0° ≤ φ ≤ 180°), the particle diameter of the dielectric particle P1 be R, and the distance between the adjacent electrode portions 12 be d. In this case, the distance d (= distance L12) satisfies the following formula (2).

[0088] [Equation 2] d = R(1 + sin φ) ··· (2)

[0089] Here, when the overlap width W1 between the dielectric particle P11 and the dielectric particle P12 is R / 2 or more when viewed from the first direction X, when the dielectric particle P11 and the dielectric particle P12 move along the electrode portion 12, the subsequent dielectric particle P12 hardly overtakes the preceding dielectric particle P11. That is, the order of the dielectric particle P11 and the dielectric particle P12 hardly changes.

[0090] When the overlap width W1 is R / 2 or more, Rsin φ becomes R / 2 or less. That is, Rsin φ ≤ R / 2 is satisfied. At this time, the angle φ is 0° ≤ φ ≤ 30°, and from the above formula (2), the distance d is d ≤ 1.5R.

[0091] Therefore, by making the distance L12 (= distance d) between the electrode portions 12 adjacent to each other in the second direction Y equal to 1.5 times or less the particle diameter R of the dielectric particles P1, when the dielectric particles P11 and the dielectric particles P12 move along the electrode portion 12, it is possible to effectively suppress the order of the dielectric particles P11 and the dielectric particles P12 from being reversed.

[0092] Next, with reference to FIG. 5, the effect of suppressing the timing at which a plurality of dielectric particles P1 move away from (are released from) the electrode portion 12 will be described. FIG. 5 is a diagram for explaining the effect of suppressing the timing at which a plurality of dielectric particles P1 move away from (are released from) the electrode portion 12. Note that the positional relationship between the dielectric particles P11 and the dielectric particles P12 is the same as that in FIG. 4.

[0093] As shown in FIG. 5, let the angle formed by the first direction X and the flow direction D be θ (where 0° ≤ θ < 90°). Also, let the distance in the flow direction D between the preceding dielectric particle P11 and the subsequent dielectric particle P12 be x. In this case, the distance x satisfies the following formula (3).

[0094] [Equation 3] x = R|cos(φ + θ)| ··· (3)

[0095] Note that |cos(φ + θ)| represents the absolute value of cos(φ + θ).

[0096] Here, if the distance x is R / 2 or more, a sufficient time difference can be ensured between the timing at which the dielectric particle P11 moves away from the electrode portion 12 and the timing at which the dielectric particle P12 moves away from the electrode portion 12. For this reason, the order of the dielectric particles P11 and the dielectric particles P12 is hardly reversed.

[0097] When the distance x is R / 2 or more, from the above formula (3), 0° ≤ φ + θ ≤ 60°, or 120° ≤ φ + θ ≤ 180°.

[0098] Therefore, by configuring the separation chip 100 so that 0° ≤ φ + θ ≤ 60° or 120° ≤ φ + θ ≤ 180°, when the dielectric particles P11 and P12 move away from the electrode portion 12, the order of the dielectric particles P11 and P12 can be effectively prevented from being reversed.

[0099] (First Modification Example) Next, with reference to FIG. 6, the separation chip 100 according to the first modification example of the present invention will be described. FIG. 6 is a plan view schematically showing the structure around the electrode portion 12 of the separation chip 100 according to the first modification example of the present invention. In FIG. 6, for easy understanding, the electrode portion 12 is hatched, and the flow path cover 105 and the like are omitted. In the first modification example, different from the above-described embodiment, an example in which only two electrode portions 12 are provided will be described.

[0100] As shown in FIG. 6, in the separation chip 100 of the first modification example, different from the above-described embodiment, the first electrode 121 has one tooth portion 1211. The second electrode 122 has one tooth portion 1221. That is, the separation chip 100 of the first modification example has only two electrode portions 12. Therefore, different from the case where there are three or more electrode portions 12, the path along which the dielectric particles P1 move along the electrode portion 12 is only one. Thus, it is possible to easily make the order of the dielectric particles P1 moving in a substantially straight line between the electrode portions 12 the same as the order of the dielectric particles P1 moving along the side wall 1051 away from the electrode portion 12.

[0101] Other structures and effects of the first modification example are the same as those of the above-described embodiment.

[0102] (Second Modification Example) Next, with reference to FIGS. 7 to 9, the separation chip 100 according to the second modification example of the present invention will be described. FIG. 7 is an enlarged cross-sectional view schematically showing the structure around the tooth portion 1201 of the separation chip 100 according to the second modification example of the present invention. In the second modification example, different from the above-described embodiment and the first modification example, an example in which an opening 1032 is formed in the cover portion 1031 of the insulating film 103 will be described.

[0103] As shown in FIG. 7, in the second modification, one surface 1205 of the tooth portion 1201 has a first region 12051 and a second region 12052 different from the first region 12051. Specifically, one surface 1205 has a first region 12051 located at the center in the width direction and a pair of second regions 12052 arranged outside the first region 12051 in the width direction.

[0104] Note that, in the second modification, unlike the above-described embodiment and the first example, the distance L12 between adjacent electrode portions 12 is not less than twice the maximum particle diameter of the dielectric particles P1.

[0105] The insulating film 103 covers at least a part of one surface 1205 of the tooth portion 1201. In the second modification, the thickness of the insulating film 103 on the first region 12051 of the tooth portion 1201 is smaller than the thickness of the insulating film 103 on the second region 12052 of the tooth portion 1201. In the second modification, the thickness of the insulating film 103 on the first region 12051 of the tooth portion 1201 is zero. Note that the thickness of the insulating film 103 on the first region 12051 may not be zero.

[0106] Specifically, the insulating film 103 has an opening 1032 that connects the first region 12051 of the tooth portion 1201 and the flow path 110. That is, in the second modification, the insulating film 103 is not formed on the first region 12051. The opening 1032 is located on the first region 12051 and penetrates the insulating film 103.

[0107] Here, in the second modification, the width W121 of the first region 12051 in the second direction Y is less than twice the particle diameter of the dielectric particles P1. Note that the width W121 of the first region 12051 in the second direction Y is the same as the width of the opening 1032 in the second direction Y. In the present embodiment, the width W121 is less than twice the maximum particle diameter of the dielectric particles P1. In this case, the width W121 is less than 40 μm. Also, the width W121 may be less than twice the average particle diameter of the dielectric particles P1. In this case, the width W121 is less than 20 μm. The width W121 of the first region 12051 is an example of the "length of the first region in the second direction" of the present invention.

[0108] Further, the width W121 of the first region 12051 is preferably 1.5 times or less the particle size of the dielectric particles P1. In the present embodiment, the width W121 may be 1.5 or less the maximum particle size of the dielectric particles P1. In this case, the width W121 is 30 μm or less. Further, the width W121 may be 1.5 times or less the average particle size of the dielectric particles P1. In this case, the width W121 is 15 μm or less.

[0109] Further, the width W121 is preferably equal to or less than the particle size of the dielectric particles P1. In the present embodiment, the width W121 may be equal to or less than the maximum particle size of the dielectric particles P1. In this case, the width W121 is 20 μm or less. Further, the width W121 may be equal to or less than the average particle size of the dielectric particles P1. In this case, the width W121 is 10 μm or less.

[0110] Note that the width W121 is greater than 0 μm. In the second modification, the width W121 is, for example, 2 μm or more.

[0111] Other configurations of the second modification are the same as those of the above-described embodiment and the first modification.

[0112] Next, with reference to FIG. 8, the dielectrophoretic force (attractive force) acting on the dielectric particles P1 by the electric field between the first electrode 121 and the second electrode 122 will be described. FIG. 8 is an enlarged cross-sectional view schematically showing the structure around the tooth portion 1201 of the separation chip 100 according to the second modification of the present invention. Note that in FIG. 8, for easy understanding of the invention, an image of a region where the force (attractive force) attracting the dielectric particles is strong is indicated by a broken line.

[0113] As shown in FIG. 8, in the separation chip 100 of the second modification, the thickness of the insulating film 103 on the first region 12051 of the tooth portion 1201 is smaller than the thickness of the insulating film 103 on the second region 12052 of the tooth portion 1201. Therefore, by adjusting the voltage value and frequency applied between the tooth portions 1201, ∇E around the adjacent first region 12051 2can be maximized. Therefore, the dielectric particles P1 are attracted to the first region 12051 of the tooth portion 1201. Here, the dielectric particles P1 are attracted to the center in the width direction of the tooth portion 1201.

[0114] At this time, in the second modification, since the width W121 (see FIG. 7) of the first region 12051 is small, the dielectric particles P1 are attracted by both the dielectrophoretic force generated at the upstream end of the first region 12051 and the dielectrophoretic force generated at the downstream end of the first region 12051.

[0115] Next, with reference to FIG. 9, the flow (movement) of the dielectric particles P1 by the separation chip 100 of the second modification will be described. FIG. 9 is a plan view schematically showing the structure around the electrode portion 12 of the separation chip 100 and the dielectric particles P1. In FIG. 9, for easy understanding, the insulating film 103 on the electrode portion 12 is hatched, and the flow path cover 105 and the like are omitted.

[0116] As shown in FIG. 9, similar to the above embodiment, a dielectrophoretic force acts on the dielectric particles P1. For this reason, the dielectric particles P1 are attracted to the electrode portion 12 and move along the electrode portion 12 toward the side wall 1051 on the side of the second supply portion 1112 and the second collection portion 1132 (upper side in FIG. 1).

[0117] At this time, in the second modification, the plurality of dielectric particles P1 move in a substantially single row on the first region 12051 of the tooth portion 1201. That is, in the second modification, the plurality of dielectric particles P1 can be moved along the center in the width direction of the tooth portion 1201.

[0118] The flow (movement) of the other dielectric particles P1 in the second modification is the same as that in the above embodiment.

[0119] Next, the effect of setting the width W121 of the first region 12051 to 1.5 times or less the particle size of the dielectric particles P1 will be briefly described. The effect of setting the width W121 of the first region 12051 to 1.5 times or less the particle size of the dielectric particles P1 is the same as the effect of setting the distance L12 between the electrode portions 12 described with reference to FIG. 4 to 1.5 times or less the particle size of the dielectric particles P1.

[0120] Specifically, the two electrode portions 12 shown in FIG. 4 are replaced with two second regions 12052, and the region between the two electrode portions 12 is replaced with the first region 12051. That is, in plan view, one of the dielectric particles P1, the first particle (dielectric particle P11), contacts one of the second regions 12052 adjacent in the second direction Y (the upstream second region 12052), and the other of the dielectric particles P1, the second particle (dielectric particle P12), contacts the other of the second regions 12052 adjacent in the second direction Y (the downstream second region 12052) and the dielectric particle P11. In this case, similar to the above embodiment, by setting the width W121 of the first region 12051 to 1.5 times or less the particle size of the dielectric particles P1, it can be seen that when the dielectric particles P11 and the dielectric particles P12 move along the first region 12051, the order of the dielectric particles P11 and the dielectric particles P12 can be effectively suppressed from being reversed. Therefore, detailed description will be omitted.

[0121] Also, similar to the effect of the above embodiment described with reference to FIG. 5, in the second modification, the separation chip 100 is configured to satisfy 0° ≤ φ + θ ≤ 60° or 120° ≤ φ + θ ≤ 180°. Therefore, when the dielectric particles P11 and the dielectric particles P12 leave the first region 12051, the order of the dielectric particles P11 and the dielectric particles P12 can be effectively suppressed from being reversed.

[0122] Other effects of the second modification are the same as those of the above embodiment.

[0123] (Third Modification) Next, with reference to FIGS. 10 and 11, the separation chip 100 according to the third modification of the present invention will be described. FIG. 10 is an enlarged cross-sectional view schematically showing the structure around the tooth portion 1201 of the separation chip 100 according to the third modification of the present invention. In the third modification, different from the above-described embodiment, the first embodiment, and the second modification, an example in which the tooth portion 1201 has a substantially concave shape in a cross-sectional view will be described.

[0124] As shown in FIG. 10, in the third modification, similar to the second modification, one surface 1205 of the tooth portion 1201 has a first region 12051 and a second region 12052 different from the first region 12051.

[0125] Here, in the third modification, a step 12053 is formed on one surface 1205 of the tooth portion 1201. Also, in the third modification, the electrode portion 12 and the tooth portion 1201 have a concave shape in a cross-sectional view. Specifically, the pair of second regions 12052 each extend inward in the width direction from the pair of side surfaces 1206. The first region 12051 is disposed substantially parallel to the second regions 12052 between the pair of second regions 12052. The first region 12051 is disposed closer to the substrate 101 than the pair of second regions 12052. The tooth portion 1201 has a pair of connection surfaces 1251, and the pair of connection surfaces 1251 connect the pair of second regions 12052 and the first region 12051. And a recess 1260 is formed in the tooth portion 1201 by the first region 12051 and the pair of connection surfaces 1251.

[0126] The insulating film 103 covers at least a part of one surface 1205 of the tooth portion 1201, similar to the second modification. Also, the thickness of the insulating film 103 on the first region 12051 of the tooth portion 1201 is smaller than the thickness of the insulating film 103 on the second region 12052 of the tooth portion 1201. In the third modification, the thickness of the insulating film 103 on the first region 12051 of the tooth portion 1201 is zero.

[0127] Specifically, the insulating film 103 has an opening 1032 that connects the first region 12051 of the tooth portion 1201 and the flow path 110, similar to the second modification. The opening 1032 is located on the first region 12051 and penetrates the insulating film 103.

[0128] Further, the insulating film 103 is not formed on at least a part of the connection surface 1251. That is, at least a part of the connection surface 1251 is connected to the flow path 110 without passing through the insulating film 103. In the present embodiment, the insulating film 103 is not formed on the connection surface 1251.

[0129] Other configurations of the third modification are the same as those of the second modification.

[0130] Next, with reference to FIG. 11, the effects of making the electrode portion 12 and the tooth portion 1201 of the separation chip 100 of the third modification concave will be described. FIG. 11 is an enlarged cross-sectional view schematically showing the structure around the tooth portion 1201 of the separation chip 100 of the third modification. In FIG. 11, for easy understanding of the invention, an image of a region where the force (attractive force) for attracting dielectric particles is strong is shown by a broken line.

[0131] As shown in FIG. 11, in the separation chip 100 of the third modification, by forming a step 12053 and / or a recess 1260 on one surface 1205 of the tooth portion 1201, compared with the separation chip 100 of the second modification shown in FIGS. 7 and 8, an AC electric field can be made more non-uniform around a predetermined position on one surface 1205 of the tooth portion 1201. That is, the change rate (gradient of the electric field strength) of the electric field strength around a predetermined position on one surface 1205 of the tooth portion 1201 can be made larger. For this reason, the dielectrophoretic force can be made stronger.

[0132] Other effects of the third modification are the same as those of the second modification.

[0133] (Fourth Modification) Next, with reference to FIG. 12, the separation chip 100 according to the fourth modification of the present invention will be described. FIG. 12 is a plan view schematically showing the structure around the electrode portion 12 of the separation chip 100 according to the fourth modification of the present invention and the dielectric particles P1. In FIG. 12, for ease of understanding, the insulating film 103 on the electrode portion 12 is hatched, and the flow path cover 105 and the like are omitted. In the fourth modification, different from the second and third modifications, an example in which only three electrode portions 12 are provided will be described.

[0134] As shown in FIG. 12, in the separation chip 100 of the fourth modification, different from the second and third modifications, for example, the first electrode 121 has one tooth portion 1211. Also, for example, the second electrode 122 has two tooth portions 1221. That is, the separation chip 100 of the fourth modification has only three electrode portions 12. Therefore, different from the case where four or more electrode portions 12 are provided, the path along which the dielectric particles P1 move along the electrode portion 12 is only one. Thus, it is possible to easily make the order of the dielectric particles P1 moving in a substantially straight line on the central electrode portion 12 the same as the order of the dielectric particles P1 moving along the side wall 1051 away from the electrode portion 12.

[0135] Note that the ∇E generated in the electrode portions 12 arranged on both sides in the width direction 2 is smaller than the ∇E generated in the central electrode portion 12 2 so that the dielectric particles P1 are not captured by the electrode portions 12 arranged on both sides in the width direction.

[0136] Other structures and effects of the fourth modification are the same as those of the second and third modifications.

[0137] (Fifth Modification) Next, with reference to FIG. 13, the separation chip 100 according to the fifth modification of the present invention will be described. FIG. 13 is a plan view schematically showing the structure of the separation chip 100 according to the fifth modification of the present invention. In the fifth modification, different from the above-described embodiment, an example in which the separation chip 100 includes, for example, HDF (Hydrodynamic filtration) 200 will be described.

[0138] As shown in FIG. 13, in the fifth modification, the separation chip 100 further includes HDF 200. HDF 200 is disposed upstream of the separation electrode 120. HDF 200 has a function as a hydrodynamic filter. For example, HDF 200 is a microchannel for the purpose of separating and / or concentrating fine particles. HDF 200 has a plurality of branch channels 201 branching from the separation channel 112. The HDF 200 is constituted by the plurality of branch channels 201 and a part of the separation channel 112. The plurality of branch channels 201 are arranged, for example, so as to extend perpendicular to the separation channel 112. Also, the plurality of branch channels 201 are arranged, for example, at substantially equal pitches along the extending direction of the separation channel 112.

[0139] The liquid flowing through the separation channel 112 flows into the plurality of branch channels 201. Also, a part of the particles contained in the liquid flowing through the separation channel 112 flows into the plurality of branch channels 201. Particles with a smaller particle size are more likely to flow into the branch channel 201, and particles with a larger particle size are less likely to flow into the branch channel 201. That is, HDF 200 separates relatively small particles from the liquid flowing through the separation channel 112. In the fifth modification, the dielectric particles P1 do not flow into the branch channel 201 of HDF 200 and substantially straight advance through the separation channel 112.

[0140] In the fifth modification, as described above, the separation chip 100 further includes HDF 200. Therefore, particles having a size less than a predetermined size can be separated from the particles contained in the sample liquid by HDF 200, and then the dielectric particles P1 can be separated from the particles having a size of a predetermined size or more by the separation electrode 120.

[0141] The other structures and effects of the fifth modification example are the same as those of the above-described embodiment and the first to fourth modification examples.

[0142] As described above, the embodiments of the present invention have been described with reference to the drawings. However, the present invention is not limited to the above-described embodiments, and can be implemented in various forms without departing from the gist thereof. Further, by appropriately combining a plurality of components disclosed in the above-described embodiments, various inventions can be formed. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, components across different embodiments and modification examples may be appropriately combined. The drawings schematically show each component mainly for easy understanding, and the thickness, length, number, interval, etc. of each illustrated component may be different from the actual ones for convenience in drawing preparation. Also, the materials, shapes, dimensions, etc. of each component shown in the above-described embodiment are examples and are not particularly limited, and various changes can be made without substantially departing from the effects of the present invention.

[0143] For example, in the above-described embodiment, the example in which the electrode portion 12 has the tooth portion 1201 and the cover portion 1031 has been described, but the present invention is not limited thereto. For example, the electrode portion 12 may not have the cover portion 1031. That is, the insulating film 103 may not be provided on the separation chip 100.

[0144] Also, for example, in the above-described embodiment, the example in which the first direction X is inclined with respect to the flow direction D has been described, but the present invention is not limited thereto. For example, the first direction X may be parallel to the flow direction D.

Industrial Applicability

[0145] The present invention can be used in the field of separation chips.

Explanation of Reference Numerals

[0146] 12: Electrode portion 100: Separation chip 101: Substrate 110: Flow path 1011: On the one hand 1031: Cover part (insulating layer) 1201, 1211, 1221: Tooth part (electrode) 1205: On the one hand 12051: First region 12052: Second region D: Flow direction L1: Straight line L12, L1031: Distance P1: Dielectric particle (specific dielectric particle) P11: Dielectric particle (specific dielectric particle, first particle) P111, P121: Center P12: Dielectric particle (specific dielectric particle, second particle) R: Particle size W121: Width (length) X: First direction Y: Second direction θ: Angle φ: Angle

Claims

1. A separation chip used for capturing specific dielectric particles contained in a liquid, comprising a substrate, a plurality of electrode portions disposed on one surface of the substrate, having at least electrodes and extending in a first direction, and, the plurality of electrode portions are disposed adjacent to each other in a second direction intersecting the first direction, on one side of the plurality of electrode portions, a flow path is provided through which the liquid flows in a flow direction intersecting the second direction, a separation chip, wherein a distance between the electrode portions adjacent to each other in the second direction is less than twice the particle size of the specific dielectric particles.

2. The electrode portion has an insulating layer covering the electrode, the separation chip according to claim 1, wherein a distance between the insulating layers adjacent to each other in the second direction is less than twice the particle size of the specific dielectric particles.

3. The separation chip according to claim 2, wherein a distance between the electrodes adjacent to each other in the second direction is less than twice the particle size of the specific dielectric particles.

4. The separation chip according to claim 1, wherein a distance between the electrode portions adjacent to each other in the second direction is 1.5 times or less the particle size of the specific dielectric particles.

5. The separation chip according to claim 4, wherein a distance between the electrode portions adjacent to each other in the second direction is less than or equal to the particle size of the specific dielectric particles.

6. In a plan view, when a first particle, which is one of the specific dielectric particles, contacts one of the electrode portions adjacent to each other in the second direction, and a second particle, which is another one of the specific dielectric particles, contacts the other of the electrode portions adjacent to each other in the second direction and the first particle, an angle formed by a straight line connecting the center of the first particle and the center of the second particle and the first direction is φ, assuming an angle formed by the first direction and the flow direction is θ, 0° ≤ φ + θ ≤ 60°, or 120° ≤ φ + θ ≤ 180° is satisfied, and the separation chip according to any one of claims 1 to 5.

7. A separation chip used for capturing specific dielectric particles contained in a liquid, comprising a substrate, a plurality of electrode portions disposed on one surface of the substrate and extending in a first direction, and, the plurality of electrode portions are disposed adjacent to each other in a second direction intersecting the first direction, on one side of the plurality of electrode portions, a flow path is provided through which the liquid flows in a flow direction intersecting the second direction, the electrode portion has an electrode disposed on one surface of the substrate and an insulating layer covering the electrode. One surface of the electrode has a first region and a second region different from the first region. The thickness of the insulating layer on the first region is smaller than the thickness of the insulating layer on the second region. The separation chip, wherein the length of the first region in the second direction is less than twice the particle size of the specific dielectric particles.

8. The separation chip according to claim 7, wherein the length of the first region in the second direction is 1.5 times or less the particle size of the specific dielectric particles.

9. The separation chip according to claim 8, wherein the length of the first region in the second direction is equal to or less than the particle size of the specific dielectric particles.

10. In a plan view, when a first particle, which is one of the specific dielectric particles, contacts one side of the second region adjacent in the second direction, and a second particle, which is another one of the specific dielectric particles, contacts the other side of the second region adjacent in the second direction and the first particle, the angle formed between the straight line connecting the centers of the first particle and the second particle and the first direction is φ, assuming the angle formed between the first direction and the flow direction is θ, 0° ≤ φ + θ ≤ 60°, or 120° ≤ φ + θ ≤ 180° The separation chip according to any one of claims 7 to 9, which satisfies the above conditions.

11. The insulating layer has an opening connecting the first region and the flow path. The first region is connected to the flow path through the opening. The separation chip according to any one of claims 7 to 9, wherein the first region is located closer to the substrate side than the second region.

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