Device capable of simultaneously measuring myocardial specific contractility and action potential

Abstract

The present invention addresses the problem of providing a device for simultaneously measuring an electrical signal and a contractile force using a highly mature cardiac muscle tissue having a 3D / oriented structure close to a cardiac muscle structure in a living body. As a solution, provided is a device for measuring the contractility of a cardiac muscle tissue, which is provided with a contractile part that includes a rod-like artificial cardiac muscle tissue that has a three-dimensional structure and in which cardiac muscle cells are oriented in the longitudinal direction, and which is used to measure the contractility of the contractile part.

Description

TECHNICAL FIELD

[0001] The present application relates to artificial myocardial tissue, its use, and a method for producing the same. BACKGROUND

[0002] In the past, toxicity evaluation of pharmaceuticals and drug development have used primary cells derived from animals, animals, but there are various problems such as species differences, batch differences, and the like, with human biological tissues. In addition, there is currently a guideline that requires nonclinical tests related to cardiac toxicity electrocardiogram QT prolongation to be performed for all pharmaceuticals. There is a possibility that drugs that can have a lethal arrhythmia-inducing activity due to QT prolongation are withdrawn from the market, delayed in approval, or abandoned in development. Due to the successful establishment of human iPS cells, the application of iPS cells using cardiomyocytes derived from human iPS cells for toxicity evaluation, pharmacokinetic evaluation, and the like is highly sought after in the industry. Although the problems of differentiation induction efficiency and purity of cardiomyocytes derived from human iPS cells have been basically solved, there are still issues such as low maturity of induced cardiomyocytes, cells not being oriented, weak muscle contraction force, frequent occurrence of arrhythmia with respect to QT prolongation when performing toxicity evaluation of pharmaceuticals, large batch differences, and the like, and a method for evaluating the safety / effectiveness of pharmaceuticals using highly mature cardiomyocytes having the same structure as cardiac tissue in vivo is desired to be developed.

[0003] On the other hand, the functional evaluation method of cardiomyocytes so far has generally used a method of measuring action potential using a multi-electrode and a method of measuring contraction force based on cell movement, electrical resistance, and the like. The multi-electrode array for measuring action potential has the following disadvantages: (1) the adhesion of the multi-electrode chip to the cells is weak, the cells are not uniform and easily clump, and are easily peeled off from the electrode chip. For this reason, with respect to pacing, the direction of excitation propagation of the electrical signal is scattered, and arrhythmia often occurs due to the addition of drugs. In addition, it is not possible to culture cells on the multi-electrode for a long period of time. (2) The cardiomyocytes on the multi-electrode chip become a random structure and do not have the original myocardial orientation structure. (3) Although it is possible to measure two-dimensional (2D) cardiomyocytes, it is not possible to measure myocardial tissue having a thickness. The method of cell movement imaging, electrical resistance, which is most commonly used in the measurement of contraction force of cardiomyocytes, is suitable for myocardial contraction force evaluation by 2D cardiomyocyte beat behavior analysis, but cannot be adapted to three-dimensional (3D) myocardial tissue having a thickness and having an orientation structure.

[0004] PRIOR ART DOCUMENTS

[0005] NON-PATENT LITERATURE

[0006] NON-PATENT LITERATURE 1: T. Hayakawa et. al., Journal of Molecular and Cellular Caridology, 77, 178-191, 2014

[0007] Non-patent literature 2: F. Qian et. al., Lab on a Chip, 17, 1732-1739, 2017

[0008] Non-patent literature 3: T. Ohys et. al., Lab on a Chip, 21, 3899-3909, 2021

[0009] Non-patent literature 4: J.U. Lind et. al., Lab on a Chip, 17 3692-3703

[0010] Non-patent literature 5: Yimu Zhao et. al., Cell 176, 913-927

[0011] Non-patent literature 6: I.Mannhardt, et. al., Stem Cell Reports, 15, 983-998,2020 SUMMARY

[0012] PROBLEMS TO BE SOLVED BY THE INVENTION

[0013] The existing method for evaluating the function of cardiomyocytes can measure the action potential and the contractility specific to the myocardium alone, but the present inventors and others needed to develop a device / method for measuring both functions simultaneously in the same environment. In recent years, several methods for measuring the action potential and the contractility simultaneously have been reported, but all are methods for evaluating cardiomyocytes in 2D. Therefore, the object of the present invention is to provide a device for measuring the electrical signal and the contractility simultaneously using highly mature myocardial tissue having a 3D / or orientation structure close to the myocardial structure in vivo.

[0014] SOLUTION TO THE PROBLEM

[0015] The present inventors and others conducted intensive research in order to solve the above problem, and as a result, found that by designing a device having a contraction portion containing a rod-shaped artificial myocardial tissue as a device capable of measuring the contractility of the contraction portion, a device for measuring the contractility of highly mature myocardial tissue having a structure close to the myocardial structure in vivo can be provided, wherein the rod-shaped artificial myocardial tissue has a three-dimensional structure and the cardiomyocytes are oriented in the long axis direction. The device can be easily designed to be capable of measuring the electrical signal simultaneously. The present invention was further researched based on this insight and completed, including the following means.

[0016] Item 1.

[0017] An apparatus for measuring contractility of myocardial tissue, comprising a contractility section including a rod-shaped artificial myocardial tissue having a three-dimensional structure and in which myocardial cells are oriented in a long axis direction, the apparatus being used to measure contractility of the contractility section.

[0018] Item 2.

[0019] The apparatus for measuring contractility of myocardial tissue according to item 1, wherein the artificial myocardial tissue is obtained by culturing myocardial cells on a surface having a contact angle with water of 95° or more.

[0020] Item 3.

[0021] The apparatus for measuring contractility of myocardial tissue according to item 1 or 2, further comprising a marker section including non-contractile myocardial tissue, the contractility section being combined with the marker section so as to enable measurement of contractility of the contractility section based on a degree of movement of the marker section.

[0022] Item 4.

[0023] The apparatus for measuring contractility of myocardial tissue according to any one of items 1 to 3, further comprising an action potential measurement section including artificial myocardial tissue having a three-dimensional structure and in which myocardial cells are oriented, the action potential measurement section being used to measure an action potential using a plurality of electrodes.

[0024] Item 5.

[0025] A method for producing a rod-shaped artificial myocardial tissue having a three-dimensional structure and in which myocardial cells are oriented in a long axis direction, the method comprising a step of obtaining the artificial myocardial tissue by culturing myocardial cells on a surface having a contact angle with water of 95° or more.

[0026] Item 6.

[0027] The method according to item 5, wherein, in the step, the rod-shaped artificial myocardial tissue is formed on a line connecting two regions (B) having a surface with a contact angle with water of 85° or less by combining a region (A) having a surface with a contact angle with water of 95° or more with the two regions (B) and culturing myocardial cells in the regions (A) and (B).

[0028] Effects of the Invention

[0029] According to the present invention, an apparatus for measuring contractility of highly mature myocardial tissue having a structure close to that of myocardial tissue in vivo can be provided. The apparatus can be easily designed to enable simultaneous measurement of electrical signals.

[0030] Explanation of Reference Signs

[0031] Figure 1 FIG. 1 is a schematic view of an example of a device for measuring contractile force.

[0032] Figure 2 FIG. 2 is a photograph of an example of a device for measuring contractile force.

[0033] Figure 3 FIG. 3 is a schematic view showing the principle of measurement of a device for measuring contractile force.

[0034] Figure 4 FIG. 4 is an example of a measurement result using a device for measuring contractile force.

[0035] Figure 5 FIG. 5 is an example of a measurement result using a device for measuring contractile force (effect of addition of E4031).

[0036] Figure 6 FIG. 6 is an example of a measurement result using a device for measuring contractile force (effect of addition of verapamil).

[0037] Figure 7 FIG. 7 is an example of a measurement result using a device for measuring contractile force (evaluation of drug response using cardiomyocytes derived from normal / disease iPS cells).

[0038] Figure 8 FIG. 8 is a schematic view showing an example of an application example of a device for measuring contractile force.

[0039] Figure 9 FIG. 9 is a photograph showing measurement results of contact angles of various materials with respect to water.

[0040] Figure 10 FIG. 10 is a graph showing measurement results of contact angles of various materials with respect to water. DETAILED DESCRIPTION

[0041] 1. Apparatus for measuring contractility of myocardial tissue

[0042] The device for measuring contractile force of myocardial tissue of the present application includes a contraction portion containing a rod-shaped artificial myocardial tissue having a three-dimensional structure and in which cardiomyocytes are oriented in the direction of the long axis, and is used for measuring the contractile force of the contraction portion.

[0043] With the device for measuring contractile force of myocardial tissue of the present application, the contraction portion contains a rod-shaped artificial myocardial tissue having a three-dimensional structure and in which cardiomyocytes are oriented in the direction of the long axis, and the contractile force of the contraction portion can be measured. Therefore, the contractile force of a highly mature myocardial tissue having a structure similar to that of myocardial tissue in vivo can be measured. In addition, as described later, the device can be easily designed to enable simultaneous measurement of electrical signals.

[0044] The artificial myocardial tissue can be obtained by culturing the myocardial cells on a surface having a contact angle with water of 95° or more. Preferably, in the culturing step, the myocardial cells are cultured in the above-mentioned regions (A) and (B) by combining the region (A) having a surface with a contact angle with water of 95° or more with two regions (B) capable of non-oriented culturing, so as to form the above-mentioned rod-shaped artificial myocardial tissue on the line connecting the two regions (B).

[0045] For example, when an elongated piece (strip) (a) having a surface with a contact angle with water of 95° or more is prepared, the two ends in the long axis direction are combined with a substrate (b) having a surface with a contact angle with water of 85° or less, and the myocardial cells are suspended-cultured thereon using a liquid medium, the myocardial cells are first easily aggregated on the substrates (b) at the two ends, and myocardial cell groups are formed thereon. On the other hand, the present inventors have found that the adhesion of the myocardial cells is weak on the elongated piece (strip) (a) having a surface with a contact angle with water of 95° or more, and thus the myocardial cells are difficult to aggregate compared with the substrates (b) at the two ends, but gradually aggregate in the central portion of the elongated piece (strip) (a) in the long axis direction by continued culturing, so as to form a rod-shaped artificial myocardial tissue oriented in the long axis direction in the form of a bridge between the myocardial cell groups at the two ends. The present inventors have confirmed that this rod-shaped artificial myocardial tissue has a three-dimensional structure and the myocardial cells are oriented in the long axis direction, and becomes a highly mature myocardial tissue having a structure close to the myocardial structure in vivo. By using this principle, the shape of the surface having a contact angle with water of 95° or more (the elongated piece (strip)) is irrelevant, and in addition, an artificial myocardial tissue having a desired shape can be obtained. In addition, by using this principle, an artificial myocardial tissue can be obtained regardless of the presence or absence of the substrate (b).

[0046] Note that, in the initial stage of the start of the culturing, it is preferable to perform plasma treatment on the surface of the above-mentioned elongated piece (strip) (a) in order to easily aggregate the myocardial cells thereon. In this case, the contact angle of the surface with water temporarily decreases to 85° or less, and thus, after the start of the culturing, the myocardial cells are easily aggregated on the entire surface of the above-mentioned elongated piece (strip) (a), but the effect of the plasma treatment gradually decreases during the continued culturing, and the contact angle of the surface with water gradually returns to the value before the plasma treatment, and thus, as described above, the myocardial cells are gradually aggregated in the central portion of the above-mentioned elongated piece (strip) (a).

[0047] From the viewpoint of efficiently obtaining the artificial myocardial tissue, the surface having a contact angle with water of 95° or more preferably has a contact angle with water of 100° or more, and more preferably a contact angle with water of 105° or more. Note that, from the viewpoint of efficiently obtaining the artificial myocardial tissue, the surface preferably has a contact angle with water of 120° or less, more preferably 115° or less, and further preferably 110° or less.

[0048] The surface having a contact angle with water of 95° or more is not particularly limited as long as the contact angle with water is within the above range, and examples include silicone (silicone resin), and PDMS (polydimethylsiloxane), silicone rubber, and the like, with PDMS being particularly preferred.

[0049] From the viewpoint of efficiently obtaining the artificial myocardial tissue, the substrate (b) having a surface with a contact angle with water of 85° or less preferably has a contact angle with water of 80° or less, more preferably a contact angle with water of 75° or less, and further preferably a contact angle with water of 70° or less. Note that, from the viewpoint of efficiently obtaining the artificial myocardial tissue, the substrate (b) preferably has a contact angle with water of 50° or more, and more preferably 60° or more.

[0050] The contact angle with water of the substrate (b) can be selected from a wide range of materials known to be suitable for cell culture, and examples include polyimide, polyethylene terephthalate, polyvinyl imine, polystyrene, glass, and the like. Alternatively, the oriented fiber described later can be used as the substrate (b). In this case, the artificial myocardial tissue formed in this region can be oriented.

[0051] Note that, in the present application, the contact angle with water is determined by irradiating a droplet on the surface of the measurement target with light, capturing an image of the droplet from the opposite side using a camera, and calculating the result by image analysis.

[0052] The above-described rod-shaped artificial myocardial tissue highly expresses β-MHC, which is a marker of maturation. Note that, in the present application, whether or not the myocardial tissue highly expresses β-MHC can be confirmed by immunohistological staining.

[0053] From the viewpoint of facilitating measurement of the contractile force, the width in the direction of the culture surface of the above-described rod-shaped artificial myocardial tissue is preferably 0.03 to 30 mm, more preferably 0.1 to 10 mm, and further preferably 0.3 to 3 mm. From the same viewpoint, the width of the above-described rod-shaped artificial myocardial tissue in the direction perpendicular to the culture surface is preferably 0.003 to 30 mm, more preferably 0.03 to 3 mm, and further preferably 0.1 to 1 mm.

[0054] The kind of the cardiomyocytes can be appropriately selected depending on the purpose of the measurement. For example, in the case of cardiac toxicity evaluation for pharmaceuticals and the like, cardiomyocytes derived from normal human iPS cells can be used. In addition, in the case of drug development, as needed, cardiomyocytes derived from heart disease iPS cells can also be used.

[0055] As an example of the specific structure of the device for measuring the contractility of the myocardial tissue of the present application, as shown in Figure 3 , a structure in which a substrate having a hollow periphery region formed with a contraction portion at the bottom can be given. In the case of adopting such a structure, the contraction portion easily becomes a suspended state, and has the advantage that the measurement of the contractility is easily performed. Also, as needed, as shown in Figure 3 , a structure surrounded by a partition member can be adopted.

[0056] In the above case, the material of the member having a hollow is not particularly limited, and for example, polyethylene terephthalate, polyethylene imine, polystyrene, and the like can be given.

[0057] In the above case, as the purpose of the partition member, preventing the liquid medium from leaking to the outside can be given, and the shape is not particularly limited as long as the purpose can be achieved, and for example, a ring-shaped member can be made. The material of the partition member is not particularly limited, and for example, PDMS (polydimethylsiloxane), polystyrene, silicone rubber, glass, and the like can be given.

[0058] The device for measuring the contractility of the myocardial tissue of the present application can further include a marker portion including a non-contractile myocardial tissue, and the contraction portion is combined with the marker portion to be able to measure the contractility of the contraction portion from the degree of movement of the marker portion.

[0059] Specifically, the contraction portion and the marker portion are suspended in the liquid medium, and when the myocardium beats, the moving distance of the suspended marker portion is detected by an image recognition technique, the size and the temporal change of the motion vector are recorded, and the force is calculated by re-transformation, whereby the contractility can be measured.

[0060] More specifically, the contractility measurement based on the moving distance of the marker portion can be performed, for example, as follows. As shown in Figure 3 , a device for contracting myocardial tissue "MicroTester" (Cell Scale Co.) is used. Since the sensor in contact with the tissue moves together with the myocardium, the moving distance of the sensor is recorded with a motion image. Then, using the "MUSCLEMOTION" plug-in of the free software "ImageJ", the displacement curve of the sensor at different times is obtained. Finally, using this information, the force inside the cell received by the sensor at different times is transformed.

[0061] In the above example, such a marking portion can be contained in the region (B) in which the cardiac muscle tissue is formed on a surface having a contact angle with water of 85° or less.

[0062] Note that, in the present application, "non-contractile cardiac muscle tissue" means that the contractility is low compared with the rod-shaped artificial cardiac muscle tissue of the contractile portion, and does not necessarily mean that it does not have any contractility. This is because the orientation of the cardiomyocytes is lower than that of the rod-shaped artificial cardiac muscle tissue of the contractile portion.

[0063] The device for measuring the contractile force of the cardiac muscle tissue of the present application can further include an action potential measuring portion containing an artificial cardiac muscle tissue having a three-dimensional structure and in which cardiomyocytes are oriented, and the action potential measuring portion is used to measure the action potential using a multi-electrode. Thus, a device for simultaneously measuring an electrical signal and a contractile force can be provided.

[0064] Specifically, an existing multi-electrode system for measuring an electrical signal can be applied, and a part of the device is adhered to a multi-electrode chip to measure the action potential.

[0065] The method for obtaining the artificial cardiac muscle tissue having a three-dimensional structure and in which cardiomyocytes are oriented of the action potential measuring portion is not particularly limited. For example, as reported by the present inventors, the cardiomyocytes can be cultured by using an oriented fiber as a scaffold for the cells (J. Li et. al., 2017 Stem Cell Reports, 9, 1-14, 2017). As the oriented fiber, for example, an oriented fiber obtained by using a polymer as a raw material and by an electrospinning method, or the like, can be used. The polymer can be widely selected according to the purpose of use, as long as it does not adversely affect the proliferation and physiological activity of the cardiomyocytes. Examples include a lactic acid / glycolic acid copolymer (PLGA), a polylactic acid (PLA), a polystyrene (PS), a polyethylene terephthalate (PET), and gelatin, collagen, and the like.

[0066] The diameter of the oriented fiber is not particularly limited, and for example, an oriented fiber having a diameter of 0.1 to 10 μm, preferably 1 to 8 μm, and more preferably 3 to 5 μm can be used.

[0067] In the case where the multi-electrode system is applied and a part of the artificial cardiac muscle tissue is adhered to the multi-electrode chip to measure the action potential, in order to obtain an artificial cardiac muscle tissue having a desired area, it is necessary to prepare the oriented fiber in a sheet shape having the area.

[0068] The number of fibers (density) per 1 mm width in the short axis direction (a direction orthogonal to the orientation direction) of the oriented fiber can vary depending on the diameter of the fiber used. The density is 10 fibers / mm or more, preferably 30 to 15,000 fibers / mm, and more preferably 50 to 13,000 fibers / mm.

[0069] For example, a device provided with one of the above-described contraction section and the above-described action potential measuring section is set to a size that can be housed in one hole of a multi-well microplate (for example, a 24-well, 48-well, or 96-well multi-well plate is common), the device is used as one unit, and a plurality of units of the device are connected so as to be housed in different holes of the multi-well microplate, whereby simultaneous measurement of a plurality of units of the device can be performed using a common multi-well microplate.

[0070] 2. Method for producing rod-shaped artificial myocardial tissue

[0071] The method for producing a rod-shaped artificial myocardial tissue having a three-dimensional structure and in which myocardial cells are oriented in the long axis direction according to the present application includes a step of obtaining the above-described artificial myocardial tissue by culturing myocardial cells on a surface having a contact angle with water of 95° or more.

[0072] In the above-described step, the culturing method is not particularly limited, and as the culturing method of myocardial cells, a known method can be appropriately selected. The culturing can be performed in a stationary state or can be performed while being shaken.

[0073] In the above-described step, a region (A) having a surface with a contact angle with water of 95° or more is combined with two regions (B) each having a surface with a contact angle with water of 85° or less, and myocardial cells are cultured in the above-described regions (A) and (B), whereby the above-described rod-shaped artificial myocardial tissue can be formed on a line connecting the two regions (B). By this step, the above-described device for measuring the contractile force of myocardial tissue having a marker section including non-contractile myocardial tissue can be produced.

[0074] Example

[0075] Hereinafter, the present application will be described with reference to examples, but the present application is not limited to these examples and the like.

[0076] (1) Fiber sheet processing

[0077] PLGA (75 / 25; Sigma-Aldrich, USA) and hexafluoro-2-propanol (HFIP, Wako Pure Chemical Industries, Tokyo, Japan) were mixed in a centrifuge tube (1.2 g: 3 mL, w / v) and used to synthesize fibers using an automatic fiber production device (NF-103, MECC, Fukuoka, Japan). Specifically, the mixed solution was filled into a 3 mL syringe and connected to the anode of a high-voltage power source (10 kV) with a needle of inner diameter 0.6 mm. An aluminum foil sheet was placed on the surface of a drum. The drum was rotated at a speed of 1000 rpm, and the fibers of PLGA flying from the needle were collected on the aluminum foil sheet. The distance between the tip of the needle and the drum was kept at 15 cm, and the spinning process was set to 60 minutes. Then, the fiber sheet collected on the aluminum foil was transferred to the device. Evaluation of the fibers was performed by observation with a scanning electron microscope.

[0078] (2) Manufacture of apparatus

[0079] PDMS (SYLGARD 184; Dow Corning, Midland, MI, USA) was flowed into a culture plate (Nunc Cell Culture Plate, Thermo fisher) and cured at 80°C overnight to make a PDMS sheet of 1 mm thickness. A spin coater was used to flow PDMS onto a silicon wafer rotating at a speed of 1500 rpm, and cured at 80°C overnight to make a PDMS sheet of 100 pm thickness. Using a cutter (SV-8, Roland DG), the PDMS sheet was cut into a long strip (3 mm * 1 mm). A biopsy punch (Kai medical, Japan) was used to make a PDMS ring (outer diameter = 8 mm, inner diameter = 6 mm). For the PET sheet (SFL-A4, AS ONE), a biopsy punch of diameter 8 mm was used to make a round sheet, and 2 holes of 2 mm for mounting the PDMS strip and the fiber sheet were made in the round sheet. The PDMS ring and the PET round sheet were mounted. The fiber sheet was transferred to the PET round sheet using an adhesive transfer tap (3M (registered trademark)). The PDMS strip was moved so as to be attached to the PET round sheet using tweezers. A polyimide (PI) sheet (3-1966-06, AS ONE) was punched using a biopsy punch of 1 mm to make a round sheet. The round sheet was attached to the PDMS strip to make a force sensor (device for measuring shrinkage force) Figure 1 ). The device was treated with plasma for 2 minutes before seeding the cells.

[0080] The present application constructs a myocardial tissue having a three-dimensional / oriented structure using a three-dimensional / oriented fiber technique. In addition, by applying an existing multi-electrode system for measuring an electrical signal, a part of the device is bonded to a multi-electrode chip to measure an action potential. Furthermore, a part of the device is suspended, and when the myocardium beats, the moving distance of the outside of the circle of the circle is detected by image recognition technology, and the size and temporal change of the motion vector are recorded, and are reconverted to calculate the force Figures 2-4 ).

[0081] The cells used in the measurement cannot be said to be the same every time. As shown below, using the device produced in the present application, it is possible to measure the changes in electrical signals and contractile force caused by the addition of a drug under the same conditions using the same myocardial cells.

[0082] (3) Measurement results of apparatus

[0083] E4031 is an antiarrhythmic drug having a HERG potassium channel blocking effect. With an increase in concentration, QT prolongation is observed from 100 nM. On the other hand, it was confirmed that the contractile force gradually weakens with an increase in concentration Figure 5 ).

[0084] Verapamil is an antiarrhythmic drug having a calcium channel inhibitory effect. With an increase in concentration, the beating frequency gradually increases, and when the concentration rises to 10 μM, the action potential stops. The contractile force gradually weakens, and at a concentration of 1 μM, it is almost impossible to measure Figure 6 ).

[0085] Furthermore, using myocardial cells derived from normal / disease iPS cells, drug response evaluation was performed, and effectiveness evaluation was performed. As a result, it was found that the electrical signal and contractile force of a hetero myocardium, which is a hybrid of myosin binding protein C (MYBPC3), a hypertrophic cardiomyopathy (HCM) sarcomere-related factor, did not differ from normal myocardial cells. On the other hand, by the technology of the present application, it was clarified that in the case of a homozygous mutant myocardium, no difference was found in the electrical signal from normal / heterozygous, but the contractile force was reduced Figure 7 ).

[0086] On the other hand, in the existing method so far, the sample needs to be discarded after one measurement, but in the case of the present system, reutilization of the sample and the evaluation system is possible, and thus cost reduction is also achieved. It is possible to meet the needs of easy operation and handling, energy production, and high-throughput drug development, and it is possible to upgrade to a device for 24 / 48 / 96 wells Figure 8 ).

[0087] (4) Measurement of contact angle of various materials with water

[0088] This time, in addition to the various materials used in the examples (polyimide, polyethylene terephthalate, PDMS), a silicone rubber was prepared separately, and the contact angle with water was measured. In addition, the contact angle with water after plasma treatment was also measured in the same manner. The results are shown in Figure 9 and Figure 10 .

Claims

1. An apparatus for measuring the contractile force of myocardial tissue, comprising a contractile portion of rod-shaped artificial myocardial tissue having a three-dimensional structure and myocardial cells oriented along the long axis, the apparatus being used to measure the contractile force of the contractile portion.

2. The device for measuring the contractility of myocardial tissue according to claim 1, wherein, The artificial myocardial tissue is obtained by culturing myocardial cells on a surface with a water contact angle of 95° or greater.

3. The device for measuring the contractility of myocardial tissue according to claim 1 or 2, wherein, It also includes a marker portion containing non-contractile myocardial tissue, wherein the contractile portion is combined with the marker portion to enable the contractile force of the contractile portion to be measured based on the mobility of the marker portion.

4. The device for measuring the contractility of myocardial tissue according to claim 1 or 2, wherein, It also includes an action potential measurement unit containing artificial myocardial tissue, which has a three-dimensional structure and the myocardial cells are oriented, and the action potential measurement unit is used to measure action potentials using multiple electrodes.

5. A method for manufacturing a rod-shaped artificial myocardial tissue, the rod-shaped artificial myocardial tissue having a three-dimensional structure and myocardial cells oriented along the long axis, the manufacturing method comprising the step of obtaining the artificial myocardial tissue by culturing myocardial cells on a surface with a water contact angle of 95° or greater.

6. The manufacturing method according to claim 5, wherein, In the process, cardiomyocytes are cultured in regions (A) and (B) by combining a region (A) having a surface with a water contact angle of 95° or more with two regions (B) having a surface with a water contact angle of 85° or less, thereby forming the rod-shaped artificial myocardial tissue on the line connecting the two regions (B).

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