Observation apparatus and observation method

Abstract

This invention provides a technique for performing appropriate alignment when observing particles trapped near electrodes on substrates such as microfluidic chips. [Solution] This observation device is for observing particles captured by a plurality of electrodes extending in a direction intersecting a channel formed on a transparent substrate, and comprises an imaging unit 31, a camera movement mechanism 32 that moves the imaging area of ​​the imaging unit 31, and a control unit 10. The control unit 10 comprises an end electrode detection unit 511 that detects end electrodes arranged at the ends of the channel, an adjacent electrode detection unit 512 that detects adjacent electrodes adjacent to the end electrodes, a channel wall detection unit 513 that detects the side walls of the channel, and an observation position adjustment unit 514 that adjusts the observation position for observing particles based on the positions of the end electrodes, adjacent electrodes, and side walls.

Description

Technical Field

[0001] The present invention relates to an observation apparatus and an observation method for efficiently adjusting an observation position in the observation of minute dielectric particles using a microchannel chip.

Background Art

[0002] Conventionally, an apparatus having a microchannel and electrodes, called a microchannel chip, has been used for observing and separating particulate biological samples such as bacteria and cells. For example, the separation chip described in Patent Document 1 is a separation chip that uses hydrodynamic filtration (HDF) and dielectrophoresis (DEP) as a method for separating and concentrating rare cells such as circulating tumor cells (CTC) in blood without labels and without damage. In the DEP section of this separation chip, particles having specific electrical properties are induced by dielectrophoresis to separate and recover desired types of particles.

[0003] In addition to those that induce specific particles by such dielectrophoresis, microchannel chips of the particle capture type that can separate and observe particles by capturing specific particles on electrodes exposed in the channel also exist. Such particle capture type microchannel chips may be used for applications such as confirming the presence or absence of bacteria and microorganisms.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Some observation devices for observing minute particles, such as microfluidic chips, have an auto-alignment function that automatically adjusts the observation position (field of view and focus). Generally, the auto-alignment function adjusts the observation position based on markers placed on the container or chip containing the object to be observed, or on the characteristic structure of the container or chip. The correctness of the auto-alignment can then be determined by whether or not the object to be observed is clearly visible.

[0006] When observing microfluidic chips, which have minute channel structures, even a slight misalignment in the chip's mounting position can cause a significant shift in the field of view. Therefore, an auto-alignment function can greatly reduce observation time and improve efficiency.

[0007] However, in particle-capturing microfluidic chips, when used to check for the presence of bacteria or microorganisms, there may be very few or no particles captured near the electrodes. Therefore, even with the auto-alignment function, it may not be possible to determine whether proper alignment has been achieved.

[0008] This invention has been made in view of these circumstances, and aims to provide a technique for performing appropriate alignment when observing particles trapped near an electrode. [Means for solving the problem]

[0009] To solve the above problems, the first invention of the present application is an observation device for observing particles captured by a plurality of electrodes extending in a direction intersecting a channel formed on a transparent substrate, comprising: a camera capable of photographing a region of the substrate including the electrodes; a camera movement mechanism for moving the camera's shooting region; and a control unit for controlling the camera and the camera movement mechanism, wherein the control unit includes: an end electrode detection unit that moves the camera using the camera movement mechanism based on the image captured by the camera to detect an end electrode which is an electrode positioned at the upstream or downstream end of the channel; an adjacent electrode detection unit that moves the camera using the camera movement mechanism based on the image captured by the camera to detect an adjacent electrode adjacent to the end electrode detected by the end electrode detection unit; a channel wall detection unit that moves the camera using the camera movement mechanism based on the positions of the end electrode and the adjacent electrode to detect a side wall of the channel; and an observation position adjustment unit that moves the camera using the camera movement mechanism based on the positions of the end electrode, the adjacent electrode and the side wall to adjust the observation position for observing the particles.

[0010] The second invention of this application is an observation apparatus of the first invention, wherein the width of the end electrode among the plurality of electrodes of the substrate is different from the width of the other electrodes.

[0011] The third invention of this application is an observation apparatus of the first invention, wherein the control unit further includes a focus position adjustment unit that adjusts the focus of the camera with respect to the surface of the electrode after the camera has been aligned to the observation position by the observation position adjustment unit.

[0012] The fourth invention of this application is an observation method for observing particles captured by a plurality of electrodes extending in a direction intersecting a channel formed on a transparent substrate, comprising: a) an end electrode detection step of moving the camera based on an image captured by a camera capable of photographing a region of the substrate including the electrodes, to detect end electrodes which are electrodes arranged at the upstream or downstream end of the channel; b) an adjacent electrode detection step of moving the camera to detect adjacent electrodes adjacent to the end electrodes detected by the end electrode detection unit; c) a channel wall detection step of moving the camera based on the positions of the end electrodes and the adjacent electrodes to detect the side walls of the channel; and d) an observation position adjustment step of moving the camera based on the positions of the end electrodes, the adjacent electrodes and the side walls to adjust the observation position for observing the particles. [Effects of the Invention]

[0013] According to the first to fourth inventions of this application, appropriate alignment can be performed when observing particles trapped near the electrodes. [Brief explanation of the drawing]

[0014] [Figure 1] This is a schematic diagram of the observation device. [Figure 2] This is a control block diagram of the control unit. [Figure 3] This is a top view of a microfluidic chip. [Figure 4] This is a top view of each layer of the microfluidic chip. [Figure 5] This is a partial top view of the electrode layer of a microfluidic chip. [Figure 6] This is a partial cross-sectional view of a microfluidic chip when dielectric particles are trapped. [Figure 7] This is a flowchart showing the process of observing the particles to be inspected. [Figure 8] This is a flowchart showing the flow of the imaging area adjustment process. [Figure 9] This is a flowchart showing the flow of the end electrode detection process. [Figure 10] It is a diagram showing an example of the position in the x-direction of the imaging area. [Figure 11] It is a flowchart showing the flow of the adjacent electrode detection process. [Figure 12] It is a flowchart showing the flow of the flow path wall detection process. [Figure 13] It is a diagram schematically showing how the electrodes and the flow path wall appear in the captured image of the imaging unit. [Figure 14] It is a diagram showing an example of the position in the y-direction of the imaging area.

Embodiments for Carrying Out the Invention

[0015] Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In the following, based on the state where the microchannel chip 9 is placed horizontally, the longitudinal direction of the microchannel chip 9 is defined as the x-direction, the short side direction is defined as the y-direction, and the vertical direction is defined as the z-direction for explanation.

[0016] <1. Observation Device> FIG. 1 is a schematic diagram of an observation device 1 according to an embodiment. This observation device 1 is a device for observing target particles in a sample liquid flowing in the flow path 80 in the microchannel chip 9. The target particles are, for example, microorganisms, cells, proteins, or nucleic acids. Also, the microorganisms are, for example, bacteria, fungi, or viruses.

[0017] As shown in FIG. 1, the observation device 1 includes a dielectrophoresis device 2, an imaging device 3, and a control unit 10.

[0018] The dielectrophoresis device 2 includes a chip mounting table 21, a sample liquid supply unit 22, a power supply unit 23, and a sample liquid recovery unit 24.

[0019] The chip mounting table 21 is a table for horizontally holding the microchannel chip 9. The chip mounting table 21 has an observation window 210 that penetrates vertically at a position that overlaps vertically with the vicinity of the second comb-tooth electrode portion 72, which becomes the observation region when the microchannel chip 9 is placed.

[0020] The sample liquid supply unit 22 is a mechanism for supplying sample liquid into the microfluidic chip 9 placed on the chip mounting stage 21. In this embodiment, the sample liquid supply unit 22 includes a syringe pump 221, a supply pipe 222, and a pump drive unit 223. The syringe pump 221 contains the sample liquid. One end of the supply pipe 222 is connected to the discharge port 221a of the syringe pump 221, and the other end of the supply pipe 222 is connected to the sample liquid supply port 81 of the microfluidic chip 9. The pump drive unit 223 can drive the plunger 224 of the syringe pump 221 up and down according to a command from the control unit 10. When the pump drive unit 223 drives the plunger 224 toward the discharge port 221a, the sample liquid in the syringe pump 221 is supplied to the microfluidic chip 9 via the discharge port 221a and the supply pipe 222.

[0021] The power supply unit 23 is a power supply device for supplying power to the first comb-tooth electrode section 71 and the second comb-tooth electrode section 72 of the microfluidic chip 9, which will be described later. Specifically, the power supply unit 23 is connected to the electrode pads 731-734 and 741-744, which will be described later, and applies an AC voltage between electrode pads 731-741, 732-742, 733-743, and 734-744.

[0022] The sample liquid recovery unit 24 includes a recovery pipe 241 and a waste liquid chamber 242. One end of the recovery pipe 241 is connected to the sample liquid outlet 82 of the microfluidic chip 9, and the other end of the recovery pipe 241 is connected to the waste liquid chamber 242. As a result, the sample liquid that flows into the microfluidic chip 9 from the sample liquid supply port 81 passes through the channel 80, is discharged from the sample liquid outlet 82, and is then recovered into the waste liquid chamber 242 via the recovery pipe 241.

[0023] The imaging device 3 is a device for observing particles in the channel 80 of a microfluidic chip 9 placed on a chip mounting stage 21. The imaging device 3 has an imaging unit 31 and a camera movement mechanism 32.

[0024] The imaging unit 31 includes an imaging unit 311 and an imaging optical system 312. The imaging unit 311 is a so-called camera. The imaging unit 311 is an image sensor such as a CCD (Charge Coupled Device) or CMOS (Complementary Metal-Oxide-Semiconductor). The imaging optical system 312 is an optical microscope module including an objective lens. The optical microscope module is, for example, a phase-contrast microscope or an epi-optical microscope.

[0025] The camera movement mechanism 32 adjusts the imaging area and focal position of the imaging unit 31 by moving the imaging unit 31 in the horizontal and vertical directions. By taking images at the position adjusted by the camera movement mechanism 32, the imaging unit 311 can capture the area including the second comb-tooth electrode portion 72 of the microfluidic chip 9.

[0026] The control unit 10 is a control means for controlling the operation of each part of the observation device 1. As conceptually shown in Figure 1, the control unit 10 of this embodiment is composed of a computer having an arithmetic processing unit 101 such as a CPU, a memory 102 such as RAM, and a storage unit 103 such as a hard disk drive.

[0027] The control unit 10 of this embodiment is configured by installing the operation control program Pi for the observation device 1 on a computer. The storage unit 103 of the control unit 10 stores a computer program P, which includes the operation control program Pi, and data D.

[0028] The control unit 10 temporarily reads the computer program P and data D stored in the storage unit 103 into the memory 102, and the arithmetic processing unit 101 performs calculations based on the computer program P and data D, thereby controlling the operation of each part in the observation device 1. As a result, the particle capture process in the dielectrophoresis apparatus 2 and the preparation process for imaging and the imaging process of particles in the imaging device 3 proceed.

[0029] Figure 2 is a control block diagram of the control unit 10. As shown in Figure 2, the control unit 10 has a dielectrophoresis control unit 40 and an imaging control unit 50 as processing units implemented in software.

[0030] The dielectrophoresis control unit 40 controls the operation of each part of the dielectrophoresis apparatus 2. The dielectrophoresis control unit 40 controls the inflow of the sample solution into the microfluidic chip 9 by controlling the operation of the pump drive unit 223 of the sample solution supply unit 22. In addition, the dielectrophoresis control unit 40 controls the operation of the power supply unit 23 so that particles to be examined in the sample solution can be captured or released in the channel 80 within the microfluidic chip 9 by the first comb electrode unit 71 and the second comb electrode unit 72.

[0031] The shooting control unit 50 includes a shooting area control unit 51 and a focus position control unit 52. The shooting area control unit 51 adjusts the shooting area of ​​the imaging unit 311 in the horizontal direction by operating the camera movement mechanism 32 to move the horizontal position of the imaging unit 31.

[0032] More specifically, the imaging area control unit 51 includes an end electrode detection unit 511, an adjacent electrode detection unit 512, a flow path wall detection unit 513, and an observation position adjustment unit 514. A detailed explanation of the end electrode detection unit 511, the adjacent electrode detection unit 512, the flow path wall detection unit 513, and the observation position adjustment unit 514 will be given later.

[0033] The focus position control unit 52 adjusts the focal position of the imaging unit 311 by operating the camera movement mechanism 32 to move the vertical position of the imaging unit 31.

[0034] Next, the structure of the microfluidic chip 9 will be explained with reference to Figures 1, 3, and 4. Figure 3 is a top view of the microfluidic chip 9. Figure 4 is a top view of each layer 91, 92, and 93 of the microfluidic chip 9. Specifically, the top row of Figure 4 is a top view of the upper layer 91, the middle row is a top view of the intermediate layer 92, and the bottom row is a top view of the lower layer 93.

[0035] As conceptually shown in Figure 1, the microfluidic chip 9 consists of three layers in order from top to bottom: an upper layer 91, an intermediate layer 92, and a lower layer 93. The upper layer 91 is made of a transparent material such as acrylic resin. The intermediate layer 92 is made of a transparent material such as adhesive tape. The lower layer 93 is made of a transparent material such as glass.

[0036] As shown in Figure 3, the microfluidic chip 9 is a plate-shaped member that is rectangular when viewed from above. The microfluidic chip 9 has a channel 80 extending in the longitudinal direction inside it. The microfluidic chip 9 also has a cylindrical sample liquid supply port 81 and a sample liquid outlet 82 that are connected to the channel 80. The upper end of the sample liquid supply port 81 protrudes above the upper surface of the microfluidic chip 9, and the lower end of the sample liquid supply port 81 is connected to the vicinity of one end of the channel 80 in the longitudinal direction. The upper end of the sample liquid outlet 82 protrudes above the upper surface of the microfluidic chip 9, and the lower end of the sample liquid outlet 82 is connected to the vicinity of the other end of the channel 80 in the longitudinal direction. When sample liquid flows into the channel 80 from the sample liquid supply port 81, the sample liquid flows through the channel 80 from one end to the other in the longitudinal direction and flows out from the sample liquid outlet 82.

[0037] As shown in Figure 4, the upper layer 91 has a rectangular plate-shaped upper plate portion 911 and cylindrical sample liquid supply port 81 and sample liquid discharge port 82 extending upward from the edge of a circular through hole provided in the upper plate portion 911. The upper plate portion 911 also has a first notch 912 and a second notch 913 that are recessed inward from the rectangular outer shape. The first notch 912 is recessed from the long side on one side in the y direction of the upper plate portion 911 toward the other side in the y direction. The first notch 912 is positioned to overlap vertically with the first electrode pad group 73, which will be described later. The second notch 913 is recessed from the long side on the other side in the y direction of the upper plate portion 911 toward the one side in the y direction. The second notch 913 is positioned to overlap vertically with the second electrode pad group 74, which will be described later.

[0038] The intermediate layer 92 has a rectangular plate-shaped middle plate portion 921. The middle plate portion 921 also has a flow path through hole 922, a third notch 923, and a fourth notch 924. The flow path through hole 922 penetrates the middle plate portion 921 vertically and extends in the longitudinal direction. The internal space of the flow path through hole 922, sandwiched vertically between the upper plate portion 911 and the lower plate portion 931 (described later), forms the flow path 80. The third notch 923 is recessed from the long side on one side in the y-direction toward the other side in the y-direction of the intermediate layer 92. The third notch 923 is positioned to overlap vertically with the first electrode pad group 73. The fourth notch 924 is recessed from the long side on the other side in the y-direction toward the one side in the y-direction. The fourth notch 924 is positioned to overlap vertically with the second electrode pad group 74.

[0039] As shown in Figures 3 and 4, the flow path 80 has a constant width in the y-direction for most of its length, but near the center in the x-direction, it has a narrow flow path 800 where the width in the y-direction is reduced. The portion of the flow path 80 upstream of the narrow flow path 800 is referred to as the first flow path 801, and the portion downstream of the narrow flow path 800 is referred to as the second flow path 802.

[0040] The lower layer 93 consists of a lower plate portion 931 and an electrode layer 932. The lower plate portion 931 is a rectangular, plate-shaped glass substrate. The electrode layer 932 is a metal layer provided along the upper surface of the lower plate portion 931.

[0041] The electrode layer 932 has a first comb-tooth electrode portion 71, a second comb-tooth electrode portion 72, a first electrode pad group 73, a second electrode pad group 74, and a plurality of wirings 751 to 758.

[0042] Figure 5 is a partial top view of the electrode layer 932 near the first comb-tooth electrode section 71 and the second comb-tooth electrode section 72. As shown in Figure 5, the first comb-tooth electrode section 71 is a comb-tooth electrode formed by alternatingly combining a plurality of elongated electrodes 711, each electrically connected at one end in the y-direction, and a plurality of elongated electrodes 712, each electrically connected at the other end in the y-direction. Each electrode 711, 712 of the first comb-tooth electrode section 71 extends in a direction intersecting the flow path 80 and is arranged with spacing in the direction in which the flow path 80 extends. The y-direction central portion of each electrode 711, 712 of the first comb-tooth electrode section 71 overlaps vertically with the first flow path 801 of the flow path 80. That is, the y-direction central portion of each electrode 711, 712 of the first comb-tooth electrode section 71 is exposed within the first flow path 801.

[0043] The second comb-tooth electrode section 72 is a comb-tooth electrode formed by alternatingly combining multiple elongated electrodes 721, each electrically connected at one end in the y-direction, and multiple elongated electrodes 722, each electrically connected at the other end in the y-direction. Each electrode 721, 722 of the second comb-tooth electrode section 72 extends in a direction intersecting the flow path 80 and is arranged with spacing in the direction in which the flow path 80 extends. The central part of each electrode 721, 722 of the second comb-tooth electrode section 72 in the y-direction overlaps the narrow flow path 800 of the flow path 80 in the vertical direction. That is, the central part of each electrode 721, 722 of the second comb-tooth electrode section 72 in the y-direction is exposed within the narrow flow path 800. Also, as shown in Figure 5, the inner surface of the flow path through-hole 922 of the middle plate section 921 forms the flow path wall 800w of the narrow flow path 800.

[0044] The width in the x-direction of each electrode 711, 712 of the first comb-tooth electrode section 71 and each electrode 721, 722 of the second comb-tooth electrode section 72 is, for example, 95 μm. The thickness in the z-direction of each electrode 711, 712 of the first comb-tooth electrode section 71 and each electrode 721, 722 of the second comb-tooth electrode section 72 is, for example, 0.5 μm. The x-direction spacing between adjacent electrodes 711-712 of the first comb-tooth electrode section 71 and between adjacent electrodes 721-722 of the second comb-tooth electrode section 72 is, for example, 15 μm. The number of electrodes 721, 722 of the second comb-tooth electrode section 72 is less than the number of electrodes 711, 712 of the first comb-tooth electrode section 71.

[0045] The first electrode pad group 73 has four electrode pads 731, 732, 733, and 734. The first electrode pad group 73 overlaps the first notch 912 and the third notch 923 in the vertical direction. That is, the first electrode pad group 73 is not covered by the upper layer 91 and the intermediate layer 92, and is exposed. Each electrode pad 731, 732, 733, and 734 of the first electrode pad group 73 is connected to the power supply unit 23.

[0046] The second electrode pad group 74 has four electrode pads 741, 742, 743, and 744. The second electrode pad group 74 overlaps the second notch 913 and the fourth notch 924 in the vertical direction. That is, the second electrode pad group 74 is exposed and not covered by the upper layer 91 and the intermediate layer 92. Each of the electrode pads 741, 742, 743, and 744 of the second electrode pad group 74 is connected to the power supply unit 23.

[0047] One of the electrodes 711 of the first comb-tooth electrode section 71 has one end in the y-direction connected to the electrode pad 731 via wiring 751, and the other end in the y-direction connected to the electrode pad 741 via wiring 755. One of the electrodes 712 of the first comb-tooth electrode section 71 has one end in the y-direction connected to the electrode pad 732 via wiring 752, and the other end in the y-direction connected to the electrode pad 742 via wiring 756.

[0048] One of the electrodes 721 of the second comb-tooth electrode section 72 has one end in the y-direction connected to the electrode pad 733 via wiring 753, and the other end in the y-direction connected to the electrode pad 743 via wiring 757. One of the electrodes 722 of the second comb-tooth electrode section 72 has one end in the y-direction connected to the electrode pad 734 via wiring 754, and the other end in the y-direction connected to the electrode pad 744 via wiring 758.

[0049] When capturing particles to be inspected contained in the sample solution at the first comb-tooth electrode section 71, the control unit 10 applies AC power corresponding to the type of particle to be inspected from the power supply unit 23 between electrode pads 731-741 and electrode pads 732-742. The AC power corresponding to the type of particle to be inspected is, for example, a frequency that generates an electric field that specifically exerts dielectrophoretic force (attraction) on the dielectric particles to be inspected, and a voltage that is not large enough to destroy the dielectric particles.

[0050] Specifically, the frequency of the AC voltage is set so that a positive dielectrophoretic force (attraction) acts on the dielectric particles to be inspected due to the electric field generated between electrodes 711 and 712. Therefore, the dielectric particles to be inspected are trapped between electrodes 711 and 712 by the positive dielectrophoretic force acting on them. On the other hand, the frequency of the AC voltage is set so that no dielectrophoretic force acts on particles not to be inspected that are contained in the sample solution, or hardly at all.

[0051] When capturing particles to be inspected contained in the sample solution at the second comb-tooth electrode section 72, the control unit 10 applies AC power corresponding to the type of particle to be inspected from the power supply unit 23 between electrode pads 733-743 and electrode pads 734-744. The AC power corresponding to the type of particle to be inspected is, for example, a frequency that generates an electric field that specifically exerts dielectrophoretic force (attraction) on the dielectric particles to be inspected, and a voltage that is not large enough to destroy the dielectric particles.

[0052] Specifically, the frequency of the AC voltage is set so that a positive dielectrophoretic force (attraction) acts on the dielectric particles to be inspected due to the electric field generated between electrodes 721 and 722. Therefore, the dielectric particles to be inspected are trapped between electrodes 721 and 722 by the positive dielectrophoretic force acting on them. On the other hand, the frequency of the AC voltage is set so that no dielectrophoretic force acts on particles not to be inspected in the sample solution, or hardly at all.

[0053] Here, Figure 6 is a partial cross-sectional view of the microfluidic chip 9 when dielectric particles are captured in the second comb-tooth electrode section. When an electric field is generated between electrodes 721 and 722 so that a positive dielectrophoretic force acts on the dielectric particles to be inspected, the dielectric particles Pa to be inspected adhere to the edges of electrodes 721 and 722, as shown in Figure 6.

[0054] <2. Observation Procedure> Next, we will explain the procedure for observing the particles to be tested in the sample solution using observation device 1. Figure 7 is a flowchart showing the flow of the observation process for the particles to be tested.

[0055] As shown in Figure 7, first, the user sets the microfluidic chip 9 on the chip mounting stage 21 (step S1).

[0056] Next, the imaging area control unit 51 moves the horizontal position of the imaging unit 31 using the camera movement mechanism 32 to adjust the imaging area of ​​the imaging unit 311 to a predetermined position (step S2: imaging area adjustment step). Details of the imaging area adjustment step S2 will be described later.

[0057] Next, the focus position control unit 52 moves the vertical position of the imaging unit 31 using the camera movement mechanism 32 to adjust the focal position of the imaging unit 311 to a predetermined position (Step S3: Focus position adjustment step). Specifically, the focus position control unit 52 aligns the focal position of the imaging unit 311 with the surface of the electrodes 721 and 722, and then moves the focal position to a position shifted upward in the z direction by a predetermined distance Dz. As shown in Figure 6, the predetermined distance Dz is determined considering the attachment position of the dielectric particles Pa to be inspected.

[0058] Subsequently, the dielectrophoresis control unit 40 controls the operation of the pump drive unit 223 of the sample liquid supply unit 22 to start supplying the sample liquid into the microfluidic chip 9 (Step S4: Sample liquid supply step).

[0059] Simultaneously with the start of sample liquid supply, or around the same time, the dielectrophoresis control unit 40 supplies power from the power supply unit 23 between electrode pads 731-741 and electrode pads 732-742, generating an electric field between electrodes 711-712 of the first comb-tooth electrode unit 71. As a result, particles to be inspected contained in the sample liquid flowing through the first channel 801 are captured between electrodes 711-712 of the first comb-tooth electrode unit 71 (Step S5: First particle capture step).

[0060] Next, the dielectrophoresis control unit 40 supplies power from the power supply unit 23 between electrode pads 733-744 and between electrode pads 734-744 to generate an electric field between electrodes 721-722 of the second comb electrode unit 72. This allows the particles to be inspected contained in the sample liquid flowing through the narrow channel 800 to be captured between electrodes 721-722 of the second comb electrode unit 72. After generating an electric field in the second comb electrode unit 72, the dielectrophoresis control unit 40 stops supplying power from the power supply unit 23 between electrode pads 731-741 and between electrode pads 732-742. This releases the capture of the particles to be inspected by the first comb electrode unit 71. The particles to be inspected released from the first comb electrode unit 71 flow through the channel 80 and are captured between electrodes 721-722 of the second comb electrode unit 72 (Step S6: Second particle capture step).

[0061] Here, the number and area of ​​electrodes 711 and 712 exposed in the first channel 801 at the first comb-tooth electrode section 71 are greater than the number and area of ​​electrodes 721 and 722 exposed in the narrow channel 800 at the second comb-tooth electrode section 72. Therefore, in step S5, the first comb-tooth electrode section 71 can efficiently capture the particles to be inspected in the sample liquid flowing in the first channel 801. The particles to be inspected captured by the first comb-tooth electrode section 71 are then gathered towards the center in the y-direction as they move from the first channel 801 to the narrow channel 800. As a result, when they are captured by the second comb-tooth electrode section 72 in step S6, they are captured at a higher density than when they were captured by the first comb-tooth electrode section 71. This allows for more reliable observation of the particles to be inspected when they are captured by the imaging unit 31.

[0062] The imaging unit 31 then captures images of the particles captured by the second comb-tooth electrode unit 72 within a predetermined imaging area. The user can then perform an inspection using the obtained images (Step S7: Imaging and Inspection Process).

[0063] <3. Image shooting area adjustment process> Next, with reference to Figure 8, we will explain the specific flow of the imaging area adjustment process in step S2. Figure 8 is a flowchart showing the flow of the imaging area adjustment process.

[0064] As shown in Figure 8, in the imaging area adjustment step, first, the end electrode detection unit 511 moves the imaging unit 31 using the camera movement mechanism 32 based on the image captured by the imaging unit 31 to detect the end electrode 720a, which is an electrode positioned at the upstream end of the flow path 80 (step S21: end electrode detection step). That is, the end electrode detection unit 511 moves the imaging unit 31 using the camera movement mechanism 32 so that the end electrode 720a is included within the imaging area A of the imaging unit 31.

[0065] The end electrode detection process in step S21 will be explained with reference to Figure 9. Figure 9 is a flowchart showing the flow of the end electrode detection process. In this embodiment, as shown in Figure 5, the end electrode 720a has a larger width in the x-direction than the other electrodes 721 and 722. This configuration is used to detect the end electrode 720a based on how many electrodes 721 and 722 are included in the imaging area A.

[0066] As shown in Figure 9, in the end electrode detection step, the end electrode detection unit 511 first moves the imaging unit 31 by the camera movement mechanism 32 so that the focal position is aligned with the surface of electrodes 721 and 722 at the initial position of the imaging unit 31 (step S211). The initial position of the imaging unit 31 is set to be near the upstream end in the x-direction of the second comb-tooth electrode unit 72, but this end electrode detection step is necessary because a shift occurs when setting the microfluidic chip 9.

[0067] Next, the end electrode detection unit 511 causes the imaging unit 31 to acquire the captured image and detects electrodes 721 and 722 in the captured image (step S212). Specifically, the end electrode detection unit 511 detects as electrodes 721 and 722 regions in the captured image where regions with a brightness value lower than a predetermined threshold continue in the x direction.

[0068] Then, the end electrode detection unit 511 determines the number of electrodes 721 and 722 detected in step S212 (step S213).

[0069] Here, Figure 10 shows an example of the x-direction position of imaging region A. Figure 10 shows the x-direction positional relationship between imaging region A and the electrodes 721 and 722 of the second comb electrode section 72 when imaging region A moves downstream sequentially from region example Ax1, which is the upstream position including the second comb electrode section 72 in imaging region A, to region examples Ax2, Ax3, Ax4, and so on. Note that although region examples Ax1 to Ax8 and Ax0 shown in Figure 10 are rectangles with the x-direction as the longer side, the actual shape of imaging region A may be a square or a rectangle with the y-direction as the longer side.

[0070] In the region examples Ax1, Ax2, and Ax3 of Figure 10, the electrodes 721 and 722 included in imaging region A are only one end electrode 720a. Region example Ax1 includes the upstream end of end electrode 720a, region example Ax2 overlaps the entire imaging region A with end electrode 720a, and region example A3 includes the downstream end of end electrode 720a but does not include the adjacent electrode 720b adjacent to end electrode 720a.

[0071] In the example in Figure 10, as imaging region A moves downstream from region example Ax3, imaging region Ax4 and Ax5 include two electrodes: the end electrode 720a and the adjacent electrode 720b. Further downstream, imaging region A6 includes three electrodes, including the electrode next to the adjacent electrode 720b. Subsequently, downstream from region example Ax4, the number of electrodes 721 and 722 included in imaging region A is two or three, as shown in region example Ax6 and region example A7. In the end electrode detection step of this embodiment shown in Figure 9, this relationship is used to detect the end electrode 720a.

[0072] In step S213, if it is determined that the number of detected electrodes 721 and 722 is zero, the end electrode detection unit 511 moves the imaging unit 31 downstream in the x-direction by a distance of 2Dx using the camera movement mechanism 32 (step S214). That is, the imaging area A is moved downstream in the x-direction by a distance of 2Dx. Then, the process returns to step S212.

[0073] In step S213, if the end electrode detection unit 511 determines that there are two or more detected electrodes 721 and 722, the camera movement mechanism 32 moves the imaging unit 31 upstream in the x-direction by a distance Dx (step S215). That is, the imaging area A is moved upstream in the x-direction by a distance Dx. Then, the process returns to step S212.

[0074] In step S213, if it is determined that there is one electrode 721,722 detected, the end electrode detection unit 511 identifies the electrode 721,722 included in the current imaging area A as the end electrode 720a (step S216).

[0075] The length of distance Dx is set based on the x-direction width of electrodes 721 and 722 other than the end electrode 720a and the x-direction spacing between adjacent electrodes 721 and 722. In this embodiment, the x-direction width of electrodes 721 and 722 other than the end electrode 720a is 95 μm, and the x-direction spacing between adjacent electrodes 721 and 722 is 15 μm, so Dx is the sum of these, which is 110 μm. The method for setting distance Dx is not limited to this, and it may also be set based on the x-direction length of the imaging area A.

[0076] Returning to Figure 8, in the end electrode detection step of step S21, the end electrode detection unit 511 detects the end electrode 720a, and then the adjacent electrode detection unit 512 detects the adjacent electrode 720b adjacent to the end electrode 720a detected in the end electrode detection step, based on the image captured by the imaging unit 31 (step S22).

[0077] The adjacent electrode detection step in step S22 will be explained with reference to Figure 11. Figure 11 is a flowchart showing the flow of the adjacent electrode detection step. As shown in Figure 11, in the adjacent electrode detection step, first, the adjacent electrode detection unit 512 moves the imaging unit 31 downstream in the x direction by a distance Dx from the end of the end electrode detection step using the camera movement mechanism 32 (step S221). As a result, the imaging area A includes at least a part of the end electrode 720a and at least a part of the adjacent electrode 720b.

[0078] Then, the adjacent electrode detection unit 512 causes the imaging unit 31 to acquire an image and detects electrodes 721 and 722 in the image (step S222). Then, the adjacent electrode detection unit 512 determines the number of electrodes 721 and 722 detected in step S222 (step S223).

[0079] In step S223, if it is determined that only one electrode 721,722 has been detected, that is, if only the end electrode 720a has been detected in imaging area A, the adjacent electrode detection unit 512 returns to step S221.

[0080] On the other hand, in step S223, if it is determined that there are two electrodes 721 and 722 detected, that is, if an end electrode 720a and an adjacent electrode 720b are detected in imaging area A, the adjacent electrode detection unit 512 moves the imaging unit 31 in the x-direction using the camera movement mechanism 32 so that the center of imaging area A in the x-direction coincides with the center of the adjacent electrode 720b in the x-direction, based on the positions of the detected end electrode 720a and adjacent electrode 720b (step S223). At this time, the position of imaging area A in the x-direction becomes the position of area example Ax0 shown in Figure 10. As a result, imaging area A includes the inter-electrode regions adjacent to the adjacent electrode 720b on both sides in the x-direction. This position becomes the observation reference position in the x-direction.

[0081] In addition, depending on the x-direction length of imaging area A, the x-direction width of electrodes 721 and 722 other than the end electrode 720a, and the x-direction spacing between adjacent electrodes 721 and 722, there may be imaging positions in which four or more electrodes 721 and 722 are included in imaging area A. In such cases, in step S223, the adjacent electrode detection unit 512 should set the x-direction observation reference position based on the detected positions of the end electrode 720a and adjacent electrode 720b so that imaging area A includes a number of inter-electrode regions suitable for observation.

[0082] Return to Figure 8. After the observation reference position in the x-direction is determined in the adjacent electrode detection step of step S22, the flow channel wall detection unit 513 then moves the imaging unit 31 by the camera movement mechanism 32, using the x-direction positions of the end electrode 720a and the adjacent electrode 720b as a reference, to detect the side wall 800w of the flow channel 800 (step S23: flow channel wall detection step).

[0083] The channel wall detection process in step S23 will be explained with reference to Figures 12 to 14. Figure 12 is a flowchart showing the flow of the channel wall detection process. Figure 13 is a schematic diagram showing how electrodes 721, 722 and the channel wall 800w appear in the image captured by the imaging unit 31. Figure 14 is a diagram showing an example of the position in the y-direction of the imaging area A.

[0084] As shown in Figure 12, in the flow path wall detection process, first the flow path wall detection unit 513 sets the count n to n=1 (step S231).

[0085] Next, the imaging unit 31 is instructed to acquire an image at its current position, and the flow path wall 800w in the image is detected (step S232). If the flow path wall 800w is detected in step S232, the flow path wall detection unit 513 determines the position of the flow path wall 800w. As shown in Figure 13, the flow path wall 800w, which is the end face of the transparent intermediate plate portion 921, appears as a dark, blurred image in the captured image.

[0086] Next, the channel wall detection unit 513 determines whether or not it has detected two channel walls 800w (step S233). If it determines in step S233 that it has not detected two channel walls 800w, the channel wall detection unit 513 determines whether the current count n is odd or even (step S234).

[0087] In step S234, if the count n is determined to be odd, the flow path wall detection unit 513 moves the imaging unit 31 in the y direction using the camera movement mechanism 32, moving the imaging area A to one side in the y direction by a distance of n*Dy (step S235). Note that the distance Dy is equal to or less than the length of the imaging area A in the y direction. In Figure 14, the distance Dy is equal to the length of the imaging area A in the y direction.

[0088] On the other hand, in step S234, if it is determined that the count n is an even number, the flow path wall detection unit 513 moves the imaging unit 31 in the y direction using the camera movement mechanism 32 to move the imaging area A to the other side in the y direction by a distance of n*Dy (step S236).

[0089] After moving the imaging unit 31 in step S235 or step S236, the flow path wall detection unit 513 increments the count n (step S237) and returns to step S232.

[0090] If the loop from steps S232 to S237 is repeated without detecting two flow path walls of 800w, as shown in Figure 14, if the imaging area A was in area example Ay1 at the beginning of step S23, in the first loop (count n=1), imaging area A moves to area example Ay2, which is located at a distance Dy to one side in the y-direction from area example Ay1, as shown by the arrow in Figure 14(1). In other words, imaging area A moves to a position adjacent to area example Ay1 on one side in the y-direction.

[0091] Then, in the second loop (count n=2), as shown by the arrow in (2) in Figure 14, imaging region A moves to region example Ay3, which is located at a distance of 2*Dy to the other side in the y-direction from region example Ay2. That is, imaging region A moves to a position that is at a distance Dy to the other side in the y-direction from region example Ay1, and is adjacent to region example Ay1 on the other side in the y-direction.

[0092] Next, in the third loop (count n=3), as shown by the arrow in (3) in Figure 14, imaging region A moves to region example Ay4, which is located 3*Dy away from region example Ay3 in one direction in the y-direction. That is, imaging region A moves 2*Dy away from region example Ay1 in one direction in the y-direction.

[0093] Furthermore, in the fourth loop (count n=4), as shown by the arrow in (4) in Figure 14, imaging region A moves to region example Ay5, which is located 4*Dy away from region example Ay4 in the other direction in the y-direction. That is, imaging region A moves 2*Dy away from region example Ay1 in the other direction in the y-direction.

[0094] In this way, by repeating the loop from step S232 to step S237, the imaging area A moves from area example Ay1 to a position shifted by a distance Dy to one side, then to a position shifted by a distance Dy to the other side, then to a position shifted by a distance of 2*Dy to one side, then to a position shifted by a distance of 2*Dy to the other side, then to a position shifted by a distance of 3*Dy to one side, then to a position shifted by a distance of 3*Dy to the other side, and so on. In other words, starting from area example Ay1, the search range of the flow channel wall 800w expands sequentially in both directions of the y.

[0095] Then, in one of the loops, if the system determines in step S233 that it has detected two channel walls 800w, the channel wall detection unit 513 moves the imaging unit 31 in the y-direction using the camera movement mechanism 32 so that the center of the y-direction of the imaging area A coincides with the center of the y-direction of the narrow channel 800, based on the positions of the two identified channel walls 800w (step S238).

[0096] With the above steps completed, the imaging area adjustment process (step S2) shown in Figure 8 is completed. In this way, in steps S21 to S23, the imaging unit 31 is moved by the camera movement mechanism 32 based on the x-direction positions of the detected end electrode 720a and adjacent electrode 720b, and the y-direction positions of the flow path walls 800w on both sides of the flow path 80, thereby adjusting the observation area A for observing the particles Pa to be inspected.

[0097] By adjusting the position of imaging area A using this procedure, proper alignment can be achieved when observing particles captured near the electrodes.

[0098] <4. Variation> Although one embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment.

[0099] In the figures of the above embodiments, the shapes of the flow channels and electrode sections are examples only and can be modified as appropriate, as long as their function remains unchanged.

[0100] Furthermore, in the above embodiment, the electrodes 711, 712, 721, and 722 of the two comb-shaped electrode sections 71 and 72 were perpendicular to the direction in which the flow path 80 extends, but the present invention is not limited to this. The electrodes 711, 712, 721, and 722 of the two comb-shaped electrode sections 71 and 72 only need to intersect with the direction in which the flow path 80 extends, and may be arranged diagonally with respect to the direction in which the flow path 80 extends.

[0101] Furthermore, in the above embodiment, in the imaging area adjustment step S2, the electrode located at the upstream end of the second comb-tooth electrode section 72 had a different width in the x-direction from the other electrodes 721 and 722. Therefore, the electrode located at the upstream end was detected as the end electrode 720a. However, the present invention is not limited to this. The electrode located at the downstream end in the x-direction may have a different width from the other electrodes 721 and 722, and this downstream end may be detected as the end electrode and used as the reference in the x-direction.

[0102] Furthermore, the elements that appear in the above embodiments and modifications may be combined as appropriate, to the extent that no contradictions arise. [Explanation of Symbols]

[0103] 1: Observation device 2: Dielectrophoresis apparatus 3: Imaging device 9: Microfluidic chip 10: Control Unit 31: Imaging Unit 32: Camera movement mechanism 40: Dielectrophoresis Control Unit 50: Image capture control unit 51: Image capture area control unit 52: Focus position control unit 71: 1st comb tooth electrode part 72:Second comb tooth electrode part 80: Flow channel 511: End electrode detection unit 512: Adjacent electrode detection unit 513: Flow channel wall detection unit 514: Observation position adjustment unit 711,712,721,722: Electrode 720a: End electrode 720b: Adjacent electrodes 800: Narrow channel 801: First channel 802: Second channel A: Shooting area Pa: Particle

Claims

1. An observation device for observing particles captured by multiple electrodes extending in a direction intersecting a channel formed in a transparent substrate, A camera capable of photographing the region of the substrate including the electrodes, A camera movement mechanism that moves the shooting area of ​​the aforementioned camera, A control unit that controls the camera and the camera movement mechanism, It has, The control unit, An end electrode detection unit moves the camera using the camera movement mechanism based on the image captured by the camera to detect the end electrode, which is the electrode positioned at the upstream or downstream end of the flow path. An adjacent electrode detection unit, which moves the camera using the camera movement mechanism based on the image captured by the camera, and detects an adjacent electrode adjacent to the end electrode detected by the end electrode detection unit, A channel wall detection unit detects the side wall of the channel by moving the camera using the camera movement mechanism with reference to the positions of the end electrode and the adjacent electrode, An observation position adjustment unit adjusts the observation position for observing the particles by moving the camera using the camera movement mechanism based on the positions of the end electrode, the adjacent electrode, and the side wall. An observation device having the following features.

2. An observation device according to claim 1, An observation device wherein, among the plurality of electrodes on the substrate, the width of the end electrode is different from the width of the other electrodes.

3. An observation device according to claim 1, The control unit, After the camera is aligned to the observation position by the observation position adjustment unit, the focus position adjustment unit adjusts the camera's focus with respect to the surface of the electrode. An observation device further possessing the following.

4. An observation method for observing particles captured by multiple electrodes extending in a direction intersecting a channel formed in a transparent substrate, a) An end electrode detection step in which, based on an image captured by a camera capable of capturing the region of the substrate including the electrodes, the camera is moved to detect the end electrodes, which are the electrodes positioned at the upstream or downstream end of the flow path, b) An adjacent electrode detection step in which the camera is moved to detect an adjacent electrode adjacent to the end electrode detected by the end electrode detection unit, c) A channel wall detection step in which the camera is moved with reference to the positions of the end electrode and the adjacent electrode to detect the side wall of the channel, d) An observation position adjustment step in which the camera is moved based on the positions of the end electrode, the adjacent electrode and the side wall to adjust the observation position for observing the particles, An observation method having the following characteristics.

Images