Extracellular potential measurement plate

Abstract

To provide a technique capable of effectively measuring extracellular potential even when the number of cells in a cell suspension is small.SOLUTION: An extracellular potential measurement plate 1 includes: a working electrode 20 for measuring an extracellular potential; reference electrodes 31, 32; and dielectrophoretic electrodes 41, 42. The dielectrophoretic electrode 41 is located closer to the working electrode 20 than the reference electrode 31. The dielectrophoretic electrode 42 is located closer to the working electrode 20 than the reference electrode 32. The working electrode 20 is located between dielectrophoretic electrodes 41, 42.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to an extracellular potential measurement plate.

Background Art

[0002] Conventionally, a system for measuring an extracellular potential generated by cell activity using a cell measurement container equipped with an electrode array (Micro-Electrode Array) composed of a plurality of electrodes is known. In this system, for example, the extracellular potential of nerve cells can be measured. The structure of a conventional cell measurement container is described in Patent Document 1 and the like.

[0003] The electrode array of the cell measurement container includes a working electrode and a reference electrode. When measuring the extracellular potential, first, a culture solution (cell suspension) containing cells is dropped onto the working electrode. That is, the cell suspension is dropped so as to cover a plurality of working electrodes. After the cell suspension is dropped, a plurality of cells in the liquid sink onto the working electrode to form a cell layer. After the cell layer is formed, the extracellular potential of the cell layer is measured by a measuring device connected to the plurality of working electrodes and the reference electrode.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] After a cell suspension is dropped onto the working electrode, the cells in the droplet spread over the entire bottom surface of the droplet. However, since the size of the working electrode is extremely small compared to the bottom surface of the droplet, most of the cells will sink outside the working electrode. Then, since most of the cells do not contribute to the measurement of the extracellular potential, the cells are wasted. Since iPS cells and the like are extremely expensive, it is desired to minimize the amount of cells used as much as possible. However, if the number of cells in the cell suspension is decreased, it becomes difficult to effectively measure the extracellular potential because sufficient cells do not sink onto the working electrode.

[0006] An object of the present invention is to provide a technique capable of effectively measuring an extracellular potential even when the number of cells in a cell suspension is small.

Means for Solving the Problems

[0007] To solve the above problems, a first aspect is an extracellular potential measurement plate, which includes at least one working electrode for measuring an extracellular potential, a reference electrode, and at least one pair of dielectrophoretic electrodes that are arranged at a position closer to the working electrode than the reference electrode and to which a voltage for applying a dielectrophoretic force to cells is applied. A measurement surface onto which a cell suspension containing cells is dropped, and The extracellular potential measurement plate includes: the working electrode is located between the pair of dielectrophoretic electrodes; the pair of dielectrophoretic electrodes are arranged on the measurement surface; and the extracellular potential measurement plate further includes an insulating film that covers the entire surface of the pair of dielectrophoretic electrodes.

[0008] A second aspect is the extracellular potential measurement plate according to the first aspect, , the front wherein the working electrode and the reference electrode are arranged on the measurement surface.

[0010] The 3 aspect is the extracellular potential measurement plate according to the 1 aspect or the second aspect wherein the working electrode is arranged on the shortest path of the pair of dielectrophoretic electrodes.

[0011] The 4 aspect is the extracellular potential measurement plate according to the 3An extracellular potential measurement plate of an aspect, wherein at least one of the pair of dielectrophoresis electrodes has a shape in which the width becomes narrower as it approaches the working electrode.

[0013] No. 5 The aspect is the 1 aspect from the 4 An extracellular potential measurement plate according to any one of the aspects, wherein the measurement surface has an annular droplet control region that passes between the pair of dielectrophoresis electrodes and the reference electrode and surrounds the reference electrode and the pair of dielectrophoresis electrodes, and the contact angle of the droplet control region is larger than the contact angle of the region inside the droplet control region.

[0014] No. 6 The aspect is any one of the aspects from the first aspect to the 5 An extracellular potential measurement plate according to any one of the aspects, comprising a plurality of the working electrodes and a plurality of the pair of dielectrophoresis electrodes, and each of the working electrodes is disposed between each of the pair of dielectrophoresis electrodes.

[0015] No. 7 The aspect is the 6 An extracellular potential measurement plate of an aspect, wherein two dielectrophoresis electrodes electrically connected to each other by a common wiring are disposed between two of the working electrodes.

[0016] No. 8 The aspect is any one of the aspects from the first aspect to the 7 An extracellular potential measurement plate according to any one of the aspects, wherein the action electrode with respect to, the pair of dielectrophoresis electrodes than far away position so that a voltage for applying a dielectrophoretic force to contaminants is applied further includes a pair of dielectrophoresis sub-electrodes can be . [Advantages of the Invention]

[0017] According to the extracellular potential measurement plate of the first aspect, by applying a voltage between a pair of dielectrophoresis electrodes, cells can be attracted between the pair of dielectrophoresis electrodes. As a result, since cells can be collected on the working electrode, the extracellular potential can be effectively measured even when the number of cells is small. No.1 According to the extracellular potential measurement plate of the aspect, cells can be collected by a pair of dielectrophoresis electrodes arranged on the measurement surface. According to the extracellular potential measurement plate of the first aspect, by covering the pair of dielectrophoresis electrodes with an insulating film, it is possible to suppress the pair of dielectrophoresis electrodes from coming into direct contact with the liquid. Therefore, even when a high voltage sufficient to move cells between the pair of dielectrophoresis electrodes is applied, electrolysis of the electrode metal can be suppressed. Further, by covering the pair of dielectrophoresis electrodes with an insulating film, deterioration and wear of the electrode metal can be suppressed.

[0018] According to the extracellular potential measurement plate of the second aspect, the extracellular potential can be measured using the working electrode and the reference electrode arranged on the measurement surface.

[0020] The 3 According to the extracellular potential measurement plate of the aspect, cells can be efficiently collected on the working electrode.

[0021] The 4 According to the extracellular potential measurement plate of the aspect, a strong electric field can be generated near the working electrode, so the cell collection ability to the working electrode can be improved.

[0023] The 5 According to the extracellular potential measurement plate of the aspect, when the cell suspension is dropped onto the measurement surface, the droplet can be maintained inside the droplet control region. In this state, by applying a voltage between the pair of dielectrophoresis electrodes, the cells can be efficiently collected on the working electrode.

[0024] The 6 According to the extracellular potential measurement plate of the aspect, cells can be collected on the working electrode.

[0025] The 7 According to the extracellular potential measurement plate of the aspect, by connecting two dielectrophoresis electrodes with a common wiring, the space required for the wiring can be reduced.

[0026] The 8 According to the extracellular potential measurement plate of the aspect, when the cell suspension contains impurities, by applying a voltage that selectively attracts the impurities to a pair of dielectrophoresis sub - electrodes to the pair of dielectrophoresis sub - electrodes, the impurities can be kept away from the working electrode.

Brief Description of the Drawings

[0027]

Figure 1

Figure 2

Figure 3

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Figure 8

Figure 9

Mode for Carrying Out the Invention

[0028] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. It should be noted that the components described in this embodiment are merely examples, and the scope of the present invention is not limited only to them. In the drawings, for ease of understanding, the dimensions and numbers of each part may be exaggerated or simplified as necessary. Further, an axis extending in the vertical direction passing through the working electrode 20 is assumed, and the rotational direction around the axis is referred to as the "circumferential direction".

[0029] <1. First Embodiment> FIG. 1 is a schematic perspective view of an extracellular potential measurement plate 1 according to the first embodiment. In each figure after FIG. 1, only a part of the wiring connected to the working electrode 20, the dielectrophoresis electrodes 41, 42, and the reference electrodes 31, 32 is shown, and the detailed structure is omitted.

[0030] The extracellular potential measurement plate 1 is a container that houses and holds cells and a culture medium inside and measures the extracellular potential. The extracellular potential measurement plate 1 has an electrode on its bottom surface for measuring the electrical properties of cells or tissues housed in the extracellular potential measurement plate 1.

[0031] The extracellular potential measurement plate 1 has a main body 9 having a cup-shaped recess 90 and a measurement surface 8 constituting the bottom surface of the recess 90. The extracellular potential measurement plate 1 is a bottomed cylindrical container in which the main body 9 has one recess 90. The main body 9 has a flat bottom portion 91 and a side wall portion 92 extending upward from the edge of the bottom portion 91. The upper surface of the bottom portion 91 is the measurement surface 8. Note that the extracellular potential measurement plate 1 may be a so-called multi-well plate having a plurality of recesses 90.

[0032] In the following description, the direction parallel to the measurement surface 8 is referred to as the "horizontal direction", and the direction orthogonal to the measurement surface 8 is referred to as the "vertical direction". Note that it is not essential for the measurement surface 8 to be parallel to the horizontal direction when the extracellular potential measurement plate 1 is in use.

[0033] The extracellular potential measurement plate 1 is placed on a mounting table or the like so that the measurement surface 8 faces vertically upward. Then, a predetermined amount of suspension containing cells (hereinafter referred to as "cell suspension") is dropped onto the measurement surface 8. The dropping amount of the cell suspension is, for example, about several μL (for example, 4 μL). After the cell suspension is dropped, the extracellular potential measurement plate 1 is left in the same posture for a certain period of time. During this time, the cells contained in the dropped cell suspension sink in the liquid and form a sheet-like cell layer on the measurement surface 8.

[0034] FIG. 2 is a top view showing the measurement surface 8 of the extracellular potential measurement plate 1 shown in FIG. 1. FIG. 3 is a view showing a part of the cross section of the extracellular potential measurement plate 1 at the position along the line A-A shown in FIG. 2.

[0035] As shown in FIG. 2, an operating electrode 20, a pair of reference electrodes 31 and 32, and a pair of dielectrophoresis electrodes 41 and 42 are respectively arranged on the measurement surface 8 of the extracellular potential measurement plate 1. That is, the operating electrode 20, the reference electrodes 31 and 32, and the dielectrophoresis electrodes 41 and 42 are respectively arranged in the recess 90. Each electrode can be composed of, for example, Au, Pt, Ti, or a conductive compound such as titanium nitride (TiN) or indium tin oxide (InSnO), or a laminated structure such as Ti / Al / Ti.

[0036] The operating electrode 20 is an electrode for measuring the extracellular potential. The shape of the operating electrode 20 in a top view is square. However, the shape of the operating electrode 20 is not limited to square, and can be arbitrarily selected, such as rectangular or round.

[0037] The reference electrodes 31 and 32 are arranged at intervals in the first direction d1 which is the horizontal direction. In a plan view, the reference electrodes 31 and 32 are rectangular and extend in the second direction d2 which is horizontal and orthogonal to the first direction d1. The reference electrodes 31 and 32 are arranged with their long sides facing each other. Note that the shape of the reference electrodes 31 and 32 is not limited to rectangular, and can be arbitrarily selected, such as square or round. Also, the shape of the reference electrodes 31 and 32 may be an arc shape along the circumferential direction. Although not shown, the reference electrodes 31 and 32 are electrically connected by wiring. The reference electrode is an electrode that provides a reference point for the potential during the measurement of the extracellular potential. Note that the extracellular potential measurement plate 1 may be provided with only one of the reference electrodes 31 and 32.

[0038] The dielectrophoresis electrodes 41 and 42 are electrodes for attracting cells (or tissue pieces) in the cell suspension dropped on the measurement surface 8 between the dielectrophoresis electrodes 41 and 42. The dielectrophoresis electrodes 41 and 42 are arranged at intervals in the first direction d1.

[0039] In the first direction d1, the working electrode 20 is disposed between the dielectrophoretic electrodes 41 and 42. The dielectrophoretic electrode 41 is positioned closer to the working electrode 20 than the reference electrode 31. That is, the distance between the working electrode 20 and the dielectrophoretic electrode 41 is narrower than the distance between the working electrode 20 and the reference electrode 31. Also, the dielectrophoretic electrode 42 is positioned closer to the working electrode 20 than the reference electrode 32. That is, the distance between the working electrode 20 and the dielectrophoretic electrode 42 is narrower than the distance between the working electrode 20 and the reference electrode 32.

[0040] The working electrode 20, the reference electrodes 31 and 32, and the dielectrophoretic electrodes 41 and 42 are arranged in the first direction d1. The dielectrophoretic electrode 41 is disposed between the working electrode 20 and the reference electrode 31 in the first direction d1. Also, the dielectrophoretic electrode 42 is disposed between the working electrode 20 and the reference electrode 32 in the first direction d1. Note that it is not essential that the reference electrodes 31 and 32 and the dielectrophoretic electrodes 41 and 42 be arranged in the same direction (the first direction d1). For example, the reference electrodes 31 and 32 may be arranged in the first direction d1, and the dielectrophoretic electrodes 41 and 42 may be arranged in a direction (e.g., the second direction d2) intersecting the first direction d1.

[0041] As shown in FIG. 3, the surfaces of the working electrode 20, the reference electrodes 31 and 32, and the dielectrophoretic electrodes 41 and 42 are covered by an insulating film 50 such as a silicon oxide film (SiOx film). However, a part of the working electrode 20 is not covered by the insulating film 50 and is exposed to the outside. Also, a part of each surface of the reference electrodes 31 and 32 is not covered by the insulating film 50 and is respectively exposed to the outside. On the other hand, the entire surfaces of the dielectrophoretic electrodes 41 and 42 are completely covered by the insulating film 50 and are not exposed to the outside.

[0042] FIG. 4 is a plan view conceptually showing a state in which a large number of cells c are collected on the working electrode 20. When forming a cell layer, first, a cell suspension is dropped onto the working electrode 20 and the dielectrophoresis electrodes 41 and 42. In this state, as shown in the upper part of FIG. 4, a large number of cells c are floating in a dispersed state in the droplet. After the cell suspension is dropped, an alternating voltage corresponding to the electrical characteristics of the cells c in the cell suspension is applied between the dielectrophoresis electrodes 41 and 42. As a result, a dielectrophoretic force that attracts the cells c between the dielectrophoresis electrodes 41 and 42 acts on the large number of cells c. Then, over time, as shown in the lower part of FIG. 4, the cells c attracted between the dielectrophoresis electrodes 41 and 42 accumulate on the working electrode 20 by sedimenting. Thereby, a cell layer is formed on the working electrode 20.

[0043] As described above, according to the extracellular potential measurement plate 1, even when there are few cells c in the cell suspension, the cells c can be collected on the working electrode 20 by the dielectrophoresis electrodes 41 and 42. Thereby, since a cell layer can be formed on the working electrode 20, the extracellular potential can be measured appropriately and effectively. In addition, when measuring the extracellular potential of expensive cells such as iPS cells, the consumption amount of the cells can be reduced, so that the cost required for the measurement can be suppressed.

[0044] As shown in FIG. 2, the working electrode 20 is preferably disposed at the center of the dielectrophoresis electrodes 41 and 42. Further, the working electrode 20 is preferably disposed on the shortest path connecting the dielectrophoresis electrodes 41 and 42. Thereby, since the electric field on the working electrode 20 can be increased, the cells c can be efficiently collected on the working electrode 20.

[0045] Since the dielectrophoresis electrodes 41 and 42 are covered with the insulating film 50, contact between the dielectrophoresis electrodes 41 and 42 and the liquid is suppressed. Thereby, even when a high-frequency high voltage sufficient to move the cells c is applied between the dielectrophoresis electrodes 41 and 42, electrolysis of the electrode metal can be suppressed. In addition, since the dielectrophoresis electrodes 41 and 42 are covered with the insulating film 50, deterioration and wear of the electrode metal can be suppressed.

[0046] FIG. 5 is a diagram showing a modified example of the dielectrophoretic electrodes 41 and 42. FIG. 6 is a diagram showing another modified example of the dielectrophoretic electrodes 41 and 42. As shown in FIGS. 5 and 6, the dielectrophoretic electrodes 41 and 42 have a shape in which the width becomes narrower as they approach the working electrode 20. Specifically, in the example shown in FIG. 5, the tips of the dielectrophoretic electrodes 41 and 42 are pointed. Also, in the example shown in FIG. 6, the tips of the dielectrophoretic electrodes 41 and 42 are arc-shaped. In either case, a strong electric field can be generated near the working electrode 20, so that the ability to collect the cells c onto the working electrode 20 can be enhanced.

[0047] As shown in FIG. 2, the measurement surface 8 may have a droplet control region 60 for controlling the spread of the droplet. The droplet control region 60 has an annular shape. However, it is not essential that the shape of the droplet control region 60 is annular, and it may be a rectangular ring shape or the like. As shown in FIG. 2, the droplet control region 60 is disposed between the dielectrophoretic electrode 41 and the reference electrode 31, and between the dielectrophoretic electrode 42 and the reference electrode 32. The working electrode 20 and the dielectrophoretic electrodes 41 and 42 are disposed in the working region 62 inside the droplet control region 60. Also, the reference electrodes 31 and 32 are disposed in the reference region 64 outside the droplet control region 60.

[0048] The surface of the droplet control region 60 is made of, for example, gold (Au). On the other hand, the surface of the working region 62 (excluding the exposed portion of the working electrode 20) is made of the insulating film 50. The contact angle of the planar surface of gold (Au) is about 80°. Also, when the insulating film 50 is made of a silicon oxide film, the contact angle of the planar surface of the insulating film 50 is less than 30°. For this reason, the contact angle (about 80°) of the droplet control region 60 is larger than the contact angle (less than 30°) of the working region 62.

[0049] By making the contact angle of the droplet control region 60 larger than the contact angle of the working region 62, when a droplet is dropped onto the working region 62, it is possible to suppress the droplet from spreading outside the droplet control region 60. In this state, by applying a dielectrophoretic force to the cells c by the dielectrophoretic electrodes 41 and 42, a cell layer can be effectively formed on the working electrode 20.

[0050] The planar surface of the reference region 64 (excluding the exposed portions of the reference electrodes 31 and 32) is also covered with the insulating film 50, similar to the working region 62. Therefore, the contact angle of the droplet control region 60 becomes larger than the contact angle of the reference region 64.

[0051] Note that it is not essential for the surface of the droplet control region 60 to be composed of gold (Au). That is, as long as the contact angle of the droplet control region 60 is larger than the contact angle of the working region 62, the surface of the droplet control region 60 can be made of any material. Also, when the contact angle of the planar surface of the insulating film 50 is larger than the contact angle of the planar surface of the bottom 91, the droplet control region 60 may be defined as the region covered with the insulating film 50, and the working region 62 may be defined as the region where the bottom 91 is exposed and not covered with the insulating film 50. For example, when the insulating film 50 is made of photosensitive polyimide (contact angle of about 60° to about 70°) and the bottom 91 is made of quartz glass (contact angle of less than 30°), the contact angle of the insulating film 50 becomes larger than the contact angle of the bottom 91. At this time, by defining the droplet control region 60 as the region covered with the insulating film 50 and the working region 62 as the region where the bottom 91 is exposed, the contact angle of the droplet control region 60 can be made larger than the contact angle of the working region 62.

[0052] <2. Second Embodiment> FIG. 7 is a top view showing the measurement surface 8 of the extracellular potential measurement plate 1A according to the second embodiment. As shown in FIG. 7, the extracellular potential measurement plate 1A has four working electrodes 20 and four pairs of dielectrophoresis electrodes 41 and 42 between the reference electrodes 31 and 32. That is, the extracellular potential measurement plate 1 includes four sets of combinations of the working electrodes 20 and the dielectrophoresis electrodes 41 and 42. The four working electrodes 20 are arranged in a matrix with two rows in the second direction d2 and two columns in the first direction d1. Each working electrode 20 is arranged between a pair of dielectrophoresis electrodes 41 and 42 in the first direction d1, similar to the working electrode 20 in the first embodiment.

[0053] According to the extracellular potential measurement plate 1A, on the measurement surface 8, since a plurality of working electrodes 20 are dispersedly arranged, the extracellular potential can be measured at different positions. Also, after dropping the cell suspension, by applying a predetermined alternating voltage between each pair of dielectrophoresis electrodes 41 and 42, the cells c can be collected on each working electrode 20. Therefore, even when the number of cells is small, a cell layer can be formed on each working electrode 20, so that the extracellular potential can be measured appropriately and effectively.

[0054] Also, according to the extracellular potential measurement plate 1A, by applying different alternating voltages between each pair of dielectrophoresis electrodes 41 and 42, for each working electrode 20, cells c with different electrical characteristics can be selectively collected. Therefore, according to the characteristics such as the size or degree of maturation of the cells c contained in the cell suspension, by appropriately setting the alternating voltage applied to each pair of dielectrophoresis electrodes 41 and 42, a large number of cells c with different characteristics can be selectively separated onto each working electrode 20. And the separated cells c can be evaluated based on the measurement results of the extracellular potential.

[0055] Note that the number of the working electrodes 20 is not limited to four, and may be two or three, or five or more. Also, it is not essential that a pair of dielectrophoresis electrodes 41 and 42 are provided for one working electrode 20. That is, a pair of dielectrophoresis electrodes 41 and 42 may be provided for two or more working electrodes 20. In other words, a plurality of working electrodes 20 may be arranged between a pair of dielectrophoresis electrodes 41 and 42.

[0056] <3. Third Embodiment> FIG. 8 is a top view showing the measurement surface 8 of the extracellular potential measurement plate 1B according to the third embodiment. Similar to the extracellular potential measurement plate 1A, the extracellular potential measurement plate 1B includes four working electrodes 20 and four pairs of dielectrophoresis electrodes 41 and 42 between the reference electrodes 31 and 32. However, the dielectrophoresis electrodes 42 and 42 arranged between the two working electrodes 20 and 20 arranged in the first direction d1 are electrically connected by a common wiring 44. In this way, by connecting the dielectrophoresis electrodes 42 and 42 with the common wiring 44, the space required for wiring the plurality of dielectrophoresis electrodes 42 can be reduced. Further, by connecting the common wiring 44 to a power source or GND, the potentials of the two dielectrophoresis electrodes 42 and 42 can be controlled. Therefore, the circuit configuration of the measuring device for measuring the extracellular potential can be simplified.

[0057] <4. Fourth Embodiment> FIG. 9 is a top view showing the measurement surface 8 of the extracellular potential measurement plate 1C according to the fourth embodiment. As shown in FIG. 9, in addition to the working electrodes 20, the reference electrodes 31 and 32, and the dielectrophoresis electrodes 41 and 42, a pair of dielectrophoresis sub - electrodes 71 and 72 are arranged on the measurement surface 8 of the extracellular potential measurement plate 1C.

[0058] The dielectrophoresis sub - electrodes 71 and 72 are arranged apart from each other in the first direction d1. The shape of the dielectrophoresis sub - electrodes 71 and 72 in a top view is a rectangular shape extending in the second direction d2. The long sides of the dielectrophoresis sub - electrodes 71 and 72 face each other in the first direction d1. Note that the shape of the dielectrophoresis sub - electrodes 71 and 72 may be other than a rectangle. The dielectrophoresis sub - electrodes 71 and 72 can be made of the same metal as the dielectrophoresis electrodes 41 and 42. Also, the surfaces of the dielectrophoresis sub - electrodes 71 and 72 are covered with an insulating film 50.

[0059] The dielectrophoretic sub - electrode 71 is located closer to the working electrode 20 than the reference electrode 31. That is, the distance between the working electrode 20 and the dielectrophoretic sub - electrode 71 is narrower than the distance between the working electrode 20 and the reference electrode 31. Also, the dielectrophoretic sub - electrode 71 is located farther from the working electrode 20 than the dielectrophoretic electrode 41. That is, the distance between the working electrode 20 and the dielectrophoretic sub - electrode 71 is greater than the distance between the working electrode 20 and the dielectrophoretic electrode 41.

[0060] The dielectrophoretic sub - electrode 72 is located closer to the working electrode 20 than the reference electrode 32. Also, the dielectrophoretic sub - electrode 72 is located farther from the working electrode 20 than the dielectrophoretic electrode 42.

[0061] The working electrode 20, reference electrodes 31, 32, dielectrophoretic electrodes 41, 42, and dielectrophoretic sub - electrodes 71, 72 are arranged in the first direction d1. The dielectrophoretic sub - electrodes 71, 72 are located between the reference electrodes 31, 32 in the first direction d1. The dielectrophoretic sub - electrode 71 is located between the reference electrode 31 and the dielectrophoretic electrode 41 in the first direction d1. Also, the dielectrophoretic sub - electrode 72 is located between the reference electrode 32 and the dielectrophoretic electrode 42 in the first direction d1. The working electrode 20 and the dielectrophoretic electrodes 41, 42 are arranged between the dielectrophoretic sub - electrodes 71, 72 in the first direction d1.

[0062] When the cell suspension dropped onto the measurement surface 8 contains contaminants (such as bacteria or tissue pieces, etc.) other than the target cells c, an alternating voltage that specifically attracts the contaminants is applied between the dielectrophoretic sub - electrodes 71, 72. As a result, since the contaminants are attracted to the dielectrophoretic sub - electrodes 71, 72, the contaminants can be moved away from the working electrode 20. Therefore, on the working electrode 20, it is possible to suppress the contaminants from inhibiting the formation of the cell layer, so that the extracellular potential can be effectively measured.

[0063] In the second direction d2, the dimensions of the dielectrophoretic sub - electrodes 71, 72 are larger than those of the dielectrophoretic electrodes 41, 42. Therefore, the dielectrophoretic sub - electrodes 71, 72 can generate an electric field in a wide range in the second direction d2. Thus, contaminants can be effectively attracted.

[0064] The distance between the dielectrophoretic sub - electrodes 71, 72 is larger than the distance between the dielectrophoretic electrodes 41, 42. Therefore, the dielectrophoretic sub - electrodes 71, 72 can attract contaminants to the outside of the region between the dielectrophoretic electrodes 41, 42.

[0065] Note that it is not essential that the dielectrophoretic electrodes 41, 42 and the dielectrophoretic sub - electrodes 71, 72 are arranged in the same direction (the first direction d1). For example, the dielectrophoretic electrodes 41, 42 may be arranged in the first direction d1, and the dielectrophoretic sub - electrodes 71, 72 may be arranged in a direction intersecting the first direction d1 (for example, the second direction d2).

[0066] Also, it is not essential that the reference electrodes 31, 32 and the dielectrophoretic sub - electrodes 71, 72 are arranged in the same direction (the first direction d1). For example, the reference electrodes 31, 32 may be arranged in the first direction d1, and the dielectrophoretic sub - electrodes 71, 72 may be arranged in a direction intersecting the first direction d1 (for example, the second direction d2).

[0067] Although the present invention has been described in detail, the above description is illustrative in all aspects and the present invention is not limited thereto. Innumerable variations not illustrated can be assumed without departing from the scope of the present invention. Each configuration described in the above embodiments and each variation can be appropriately combined or omitted as long as they do not conflict with each other.

Explanation of reference numerals

[0068] 1, 1A, 1B, 1C extracellular potential measurement plates 8 measurement surfaces 20 working electrodes 31, 32 reference electrodes 41, 42 dielectrophoretic electrodes 44 Wiring 50 Insulating film 60 Droplet control region 71, 72 Dielectrophoresis sub-electrodes c Cell

Claims

1. An extracellular potential measurement plate, comprising: At least one working electrode for measuring an extracellular potential; A reference electrode; At least one pair of dielectrophoretic electrodes that are located closer to the working electrode than the reference electrode and to which a voltage for applying a dielectrophoretic force to cells is applied; A measurement surface on which a cell suspension containing cells is dropped; And comprising: The working electrode is located between the pair of dielectrophoretic electrodes; The pair of dielectrophoretic electrodes are disposed on the measurement surface; The extracellular potential measurement plate further comprises: An insulating film covering the entire surface of the pair of dielectrophoretic electrodes. An extracellular potential measurement plate.

2. The extracellular potential measurement plate according to Claim 1, Wherein the working electrode and the reference electrode are disposed on the measurement surface.

3. The extracellular potential measurement plate according to Claim 1 or Claim 2, Wherein the working electrode is disposed on the shortest path between the pair of dielectrophoretic electrodes.

4. The extracellular potential measurement plate according to Claim 3, Wherein at least one of the pair of dielectrophoretic electrodes has a shape in which the width becomes narrower as it approaches the working electrode.

5. The extracellular potential measurement plate according to any one of Claims 1 to 4, Wherein the measurement surface has: An annular droplet control region that passes between the pair of dielectrophoretic electrodes and the reference electrode and surrounds the reference electrode and the pair of dielectrophoretic electrodes, And the contact angle of the droplet control region is larger than the contact angle of the region inside the droplet control region.

6. The extracellular potential measurement plate according to any one of Claims 1 to 5, Comprising a plurality of the working electrodes; And a plurality of the pair of dielectrophoretic electrodes; And comprising: Each of the working electrodes is disposed between each pair of dielectrophoretic electrodes.

7. The extracellular potential measurement plate according to Claim 6, Wherein two of the dielectrophoretic electrodes electrically connected to each other by a common wiring are disposed between two of the working electrodes.

8. The extracellular potential measurement plate according to any one of Claims 1 to 7, A pair of dielectrophoretic sub-electrodes that are located farther from the working electrode than the pair of dielectrophoretic electrodes and to which a voltage for applying a dielectrophoretic force to contaminants is applied. An extracellular potential measurement plate further comprising

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