Liquid injection method, liquid injection device, and liquid cartridge

Abstract

To provide a liquid injection method which can inhibit a waste of a liquid, and to provide a liquid injection device and a liquid cartridge.SOLUTION: A liquid cartridge includes: a liquid discharge head which discharges a liquid; a passage which is connected to the liquid discharge head and may supply the liquid to the liquid discharge head; and an opening which is connected to the passage and provided so as to be wider than the passage. In a liquid injection method, the liquid is injected from a liquid injection device to the liquid cartridge. The liquid is directly injected into the passage.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a liquid injection method, a liquid injection device, and a liquid cartridge.

Background Art

[0002] Patent Document 1 describes a method of uniformly injecting ink in a short time by piercing an ink injection needle into an ink holding member housed in an ink tank and injecting the ink.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the method of Patent Document 1, it is necessary to separately guide the ink injected into the ink holding member to the discharge port by suction from the discharge port or the like. However, there is a problem that by performing suction, ink is discharged from the discharge port to some extent, and the ink is wasted.

[0005] Therefore, the present invention provides a liquid injection method, a liquid injection device, and a liquid cartridge capable of suppressing wasteful consumption of liquid.

Means for Solving the Problems

[0006] Therefore, the liquid injection method of the present invention is a liquid injection method for injecting liquid from a liquid injector into a liquid cartridge including a liquid discharge head that discharges liquid, a flow path connected to the liquid discharge head and capable of supplying liquid to the liquid discharge head, and an opening connected to the flow path and provided wider than the flow path, The liquid discharge head comprises a discharge port forming material having a discharge port, wherein the minute contact angle of the discharge port forming material with respect to pure water is 40° or more and 90° or less. characterized in that the liquid is directly injected into the flow path.

Effects of the Invention

[0007] According to the present invention, a liquid injection method, a liquid injection device, and a liquid cartridge can be provided that can suppress the wasteful consumption of liquid. [Brief explanation of the drawing]

[0008] [Figure 1] This is a diagram showing a liquid cartridge. [Figure 2] This diagram shows how liquid is dripped into an opening. [Figure 3] This is a diagram illustrating the pinning effect of wetness. [Figure 4] This diagram illustrates a method of injecting liquid using a micropipette. [Figure 5] This diagram shows the flow path into which the pipette tip of a micropipette is inserted. [Figure 6] This is a diagram showing a liquid injection device. [Figure 7] This diagram shows a pipette tip inserted into a short channel. [Modes for carrying out the invention]

[0009] The present invention will be further described below with reference to preferred embodiments, but the present invention is not limited to the following embodiments. In this specification, unless otherwise specified, physical property values ​​are given at room temperature (25°C).

[0010] <<First Embodiment>> A first embodiment of the present invention will be described below with reference to the drawings.

[0011] Figure 1(a) is a perspective view showing the liquid cartridge 11 in this embodiment, Figure 1(b) is a cross-sectional view of Ib-Ib in Figure 1(a), and Figure 1(c) is a partially enlarged view showing the liquid ejection head 21 in Figure 1(b). The liquid cartridge 11 comprises an opening 24 and a flow path 23 provided between the opening 24 and the liquid ejection head 21. The liquid ejection head 21 ejects liquid using the ejection principle of an inkjet method. The flow path 23 is configured to supply liquid to the liquid ejection head 21 and is narrowed to efficiently guide the liquid into the narrow common supply passage 22 of the liquid ejection head 21. The opening 24 can also store liquid and has a slope that connects to the flow path 23, and is formed to widen from the flow path 23 by the slope. The liquid supplied from the flow path 23 to the liquid ejection head 21 is supplied to the ejection port 31 via the supply flow path 22 of the liquid ejection head 21. The liquid supplied to the discharge port 31 is discharged from the discharge port 31 by the action of the heating element 33.

[0012] The liquid discharge head 21 includes a silicon substrate 34, a heating element 33 provided thereon, and a discharge port 31 formed by a discharge port forming material 35. The supply channel (hereinafter also referred to as the common supply channel) 22 and the channel 23 are installed to communicate with each other. A total of 320 discharge ports 31 are arranged on both sides of the supply channel 22 at predetermined intervals along the longitudinal direction.

[0013] Figures 2(a) to 2(c) show the process of dropping liquid into the opening 24. Here, we investigated whether it is possible to fill the liquid dispensing head 21 with liquid by dropping liquid onto the inclined surface of the opening 24 using a micropipette, which is a liquid injector. Here, pure water 27 was used as a representative example of a liquid that is difficult to fill. As shown in Figure 2(a), pure water 27 was dropped onto the inclined surface of the opening 24 using the pipette tip 25 of the micropipette. Subsequently, as shown in Figure 2(b), the pure water 27 was repelled by the wetting pinning effect at the angled part of the connection between the opening 24 and the flow path 23, and did not flow into the flow path 23. When dropping continued, as shown in Figure 2(c), the pure water 27 remained in place, forming a meniscus at the connection between the opening 24 and the flow path 23 and blocking the flow path 23, and the liquid dispensing head 21 was not filled with pure water 27.

[0014] In other words, when dropping liquid onto the inclined surface of the opening 24, simply dropping the liquid was not enough to fill the liquid discharge head 21. The liquid discharge head 21 could not be filled unless suction or other means were performed from the liquid discharge head 21 side.

[0015] Figure 3 illustrates the pinning effect of wetting. The pinning effect of wetting is the phenomenon in which, when a liquid droplet reaches a surface with a bend, it cannot proceed further until the contact angle becomes θ+α, which is the contact angle θ plus the bend angle α. Even if the surface is rounded, the fact remains that it becomes difficult for the liquid droplet to proceed. As shown in Figure 3(a), a liquid droplet with a contact angle θ remains in place, unable to cross the surface with the bend until the contact angle becomes θ+α, as shown in Figure 3(b). At the contact angle θ+α, the liquid droplet proceeds across the surface with the bend, as shown in Figure 3(c). However, as shown in Figure 2(b), if the path ahead after crossing the surface with the bend narrows, the pure water 27 blocks the flow path 23 and accumulates in the opening 24, as shown in Figure 2(c), before crossing the bend.

[0016] Therefore, in this embodiment, in order to avoid blockage of the flow path 23 due to the pinning effect of wetting, the liquid is injected directly into the flow path 23 using a micropipette.

[0017] FIG. 4 is a diagram showing a method of injecting a liquid using the micropipette of the present embodiment. The pipette tip 25 of the micropipette gradually narrows as it goes toward the tip while the outer shape is inclined. Further, the liquid cartridge 11 includes a flow path 23 into which a liquid can be directly injected. In the present embodiment, as shown in FIG. 4, the tip 26 of the pipette tip 25 (liquid injection portion) is directly inserted into the flow path 23, and pure water 27 is injected. As a result, the pure water 27 reached the common supply path 22 of the liquid ejection head 21 from the flow path 23. When the pure water 27 reaches the common supply path 22, the liquid ejection head 21 is filled with the pure water 27 due to the action of capillary force and wettability. <​​​​​​​​​​​​​​Alternatively, the size of the droplet discharged from the pipette tip 25 can be controlled to make the droplet smaller in diameter than the width of the channel 23, and the liquid can be injected directly into the channel 23 from the top of the channel 23 without going through the opening 24, as with the pipette tip 29.

[0022] Figure 5 shows the state in which the pipette tip 25 of a micropipette is inserted into the channel 23, as viewed from the opening 24 side. In Figure 4, the channel 23 appears to be blocked when the pipette tip 25 of the micropipette is inserted into the channel 23. However, as shown in Figure 5, the channel 23 is groove-shaped and extends in the direction of arrow Y, so the channel 23 is not blocked even when the pipette tip 25 is inserted. Therefore, when pure water 27 is injected into the channel 23, even when the pipette tip 25 is inserted, the air that was inside the channel 23 can flow out to the opening 24 side from the communication part of the channel 23 where the pipette tip 25 is not inserted.

[0023] It should be noted that the flow path 23 may be blocked by a micropipette on the side of the opening 24. This is because even if the flow path 23 is blocked by a micropipette, the air present in the common supply passage 22 of the flow path 23 and the liquid dispensing head 21 can gradually flow out from the outlet 31. However, from the viewpoint of smoother filling, it is preferable that a portion of the flow path 23 is in communication with the atmosphere on the side of the opening 24, even when the pipette tip 25 is inserted into the flow path 23.

[0024] After the liquid dispensing head 21 is filled with pure water 27, if injection continues, the pure water 27 will pass over the connection point between the flow path 23 and the opening 24 and be stored in the opening 24. If the pipette tip 25 is withdrawn from this state while it is still inserted into the flow path 23, the pure water 27 stored in the opening 24 will flow back into the flow path 23 without being pinned down. This is thought to be because the pure water 27 already present in the flow path 23 and the pure water 27 stored in the opening 24 are not separated as droplets but are a single bulk liquid.

[0025] Furthermore, it is preferable that the wettability of the walls of the flow path 23 and the opening 24 be reduced so that the amount of liquid remaining on the walls is reduced, and it is preferable that the contact angle with pure water of at least one of the walls of the flow path 23 and the opening 24 is 90° or more. The contact angle can be measured by known methods.

[0026] The discharge port forming material 35 (see Figure 1(c)) that forms the discharge port 31 preferably has high wettability in order to naturally guide the liquid to the liquid discharge head 21. However, if the wettability is too high, components in the liquid may be adsorbed or clogged. Therefore, it is preferable that the minute contact angle with pure water on the surface of the discharge port forming material 35 is between 40° and 90°. The minute contact angle can be measured by known methods.

[0027] In the above explanation, pure water was given as the liquid injected into channel 23, but other liquids such as black or color liquids used in image formation may also be used. Furthermore, the liquid may be resist, metal nanoparticle solution, carbon nanotube solution, UV curing material, functional polymer liquid, DNA, cell solution, etc., and the liquids listed here are merely examples and are not particularly limited. The benefit of not wasting liquid is particularly evident when the liquid is used in small quantities, is expensive, or has poor wettability.

[0028] For example, liquids containing at least one of cells, nucleic acids, proteins, labeling substances, hormones, and ribonucleotides, which are used in the field of biotechnology, are suitable as the liquids of this embodiment. In one example, when using cell suspensions, small amounts of liquid, less than 100 μl, may be handled. Even with such small amounts, by applying this embodiment, the liquid can be filled into the liquid dispensing head 21 without suction from the face surface 36. Aseptic operation is important in the field of biotechnology, and one of the advantages is that there is no need to contact the face surface 36 with the suction member, thus eliminating the risk of contamination. Furthermore, it is preferable that the liquid cartridge is sterilized. In addition, adherent cells, which have the property of adhering to the wall surface, are often used as cell types, but adhesion to the wall surface can be suppressed by keeping the wettability (contact angle and micro-contact angle) of the channel 23, opening 24, and dispensing port forming material 35 within the preferred range described above. Furthermore, when the liquid injected into the channel 23 contains at least one of cells, nucleic acids, proteins, labeling substances, hormones, and ribonucleotides, it is preferable that the time from injection to dispensing is short from the viewpoint of dispensing performance. Specifically, the time from the injection of liquid into a flow path that can supply liquid to the liquid discharge head to the discharge of liquid from the discharge port of the liquid discharge head is preferably within 10 minutes, more preferably within 5 minutes, and even more preferably within 2 minutes.

[0029] If the liquid dispensing head 21 is wet with liquid, it is preferable to remove the liquid by drying it before injecting the liquid. This is because if the liquid dispensing head 21 is wet with liquid, tiny bubbles may form, making filling difficult. For example, when used in the biotechnology field as described above, sterilization with heated steam may be performed, but such operations tend to cause water to accumulate inside the liquid dispensing head. In such cases, it is preferable to dry the inside of the liquid dispensing head 21 beforehand before injecting the liquid into the flow path. Also, depending on the type of cells contained in the liquid, the liquid to be injected may need to be handled at a temperature lower than room temperature (25°C). However, if the liquid dispensing head is cooled from room temperature to the temperature of the liquid being injected, condensation may form inside the liquid dispensing head, resulting in the liquid not being dispensed properly. Therefore, it is preferable to inject the liquid into the liquid dispensing head under an atmosphere with a dew point lower than the temperature of the cell suspension.

[0030] In this way, the liquid is directly injected into the channel 23 using the micropipette 104. This makes it possible to provide a liquid injection method, liquid injection device, and liquid cartridge that can suppress the consumption of unnecessary liquid.

[0031] <Examples> The following provides a detailed explanation with reference to examples and comparative examples. However, the following examples do not limit the scope of the invention unless they exceed the gist of the invention. Furthermore, unless otherwise specified, "%" in the following descriptions refers to volume.

[0032] <Example 1> In this embodiment, the following liquid, liquid cartridge, liquid injector, and liquid injection device were used to inject the liquid into the liquid cartridge. The liquid injection was performed with the liquid injection part inserted into the flow path.

[0033] (liquid) The liquid used in this example was a cell suspension lightly colored with trypan blue. This liquid was prepared as follows: RAW264.7, a cell line established from mouse monocytic leukemia, was purchased from the American Type Culture Collection. This cell line was then dispersed in 20 ml of D-MEM (Thermo Fisher Scientific) medium containing 10% FBS, 1% P / S (Sigma-Aldrich), and 1% MEM-NEAA, to a concentration of 2 million cells / ml. Subsequently, 2 million cells were seeded into each 100 mm polystyrene dish (Corning). The cells were grown by incubation at 37 degrees Celsius in the presence of 5% CO2. After 2-4 days, it was confirmed that the cells covered approximately 70% of the bottom surface area of ​​the dish. The supernatant medium was then removed. After rinsing with PBS, the cells were detached from the dish using PBS containing 0.25% trypsin and 1 mM EDTA (Thermo Fisher Scientific). The macrophages were then collected from the dish. FBS stands for fetal bovine serum, P / S for penicillin-streptomycin, MEM-NEAA for MEM non-essential amino acids, D-MEM for Dulbecco's Modified Eagle Medium, PBS for phosphate-buffered saline, and EDTA for ethylenediaminetetraacetic acid.

[0034] To the recovered cell suspension, the above-mentioned culture medium was added to a sterile centrifuge tube until the total volume reached 50 ml. The suspension was then treated for 5 minutes in a centrifuge (Hitachi CF16RX II) set to 4°C and 90G to allow the cells to settle. After carefully removing the supernatant of the settled cell pellet, the cell pellet was added to the above-mentioned culture medium to obtain a cell suspension. This suspension was cultured twice again following the same procedure.

[0035] During the third procedure, the required number of cells were separated into a centrifuge tube and centrifuged, and the supernatant of the settled cell pellet was gently removed. Then, a solution of 1x phosphate-sodium chloride buffer (1×PBS) (Thermo Fisher Scientific, pH=7.4) and 0.4 mass / vol% trypan blue solution mixed in a 9:1 ratio was added and mixed with a micropipette to obtain a liquid with a cell concentration of 1 million cells / ml.

[0036] (Liquid cartridge) The liquid cartridge 11 used in this embodiment was the one described in Figures 1(a) to (c). The length of the channel 23 was 6 mm, the width of the channel 23 was 1 mm, and the aspect ratio (the ratio of length to width in this case) of the channel 23 was 6. The channel 23 and the opening 24 were made of polypropylene, and the contact angle with pure water at their walls was measured to be 105° using a contact angle meter (Kyowa Interface Science Co., Ltd., DMo-701). The minute contact angle of the discharge port forming material 35 was measured to be 55° using a minute contact angle meter (Microjet Co., Ltd., DropMeasure). When measuring the minute contact angle of the discharge port forming material 35, a section was carefully cut out with a utility knife, and the measurement was taken on the side that comes into contact with the liquid, i.e., the side opposite to the face surface.

[0037] (liquid syringe) As the liquid injector, a micropipette 104 (Eppendorf, Reference2, 20-200μL, yellow) fitted with a pipette tip (Eppendorf, epT.IPS2-200μL, biopur) was used.

[0038] (liquid injection device) Figure 6 shows the liquid injection device 101 used in this embodiment. The liquid injection device 101 has a holding part 105 for the liquid cartridge 11 and a holding part 103 for the micropipette 104, and is equipped with an adjustment mechanism that allows the relative positional relationship between them to be adjusted by the stage 102.

[0039] The micropipette 104 is configured such that the outer diameter of the tip is smaller than the width of the opening 24, and further, the outer diameter of the tip is smaller than the width of the flow path 23.

[0040] The liquid injection device 101 is a device that holds the liquid cartridge 11 and the micropipette 104 (liquid injector), and can control the relative position of the liquid cartridge 11 and the micropipette 104, as well as the injection operation. The liquid injection device 101 may also have a liquid injector.

[0041] In this embodiment, a pre-dried liquid cartridge 11 and a micropipette 104 with 50 μl of liquid measured out were attached to the liquid injection device 101, and the stage 102 was moved to insert the pipette tip 25 of the micropipette 104 into the flow path 23.

[0042] With the pipette tip 25 inserted into the flow path 23, the discharge button on the micropipette 104 was pressed to inject liquid into the liquid cartridge 11. At this time, the flow path 23 was not blocked by the pipette tip 25 and was in communication with the atmosphere at the opening 24, allowing the injected liquid to fill the liquid dispensing head 21.

[0043] (evaluation) The liquid cartridge 11 was attached to a serial-type inkjet recording device (not shown), and 10 shots of liquid were sequentially ejected onto the paper from each nozzle. The time from liquid injection to ejection was 5 minutes. Since the liquid was colored with trypan blue, the ejection results could be visually determined, and liquid was ejected from all 320 nozzles without any failures. Subsequently, 1000 shots were ejected sequentially from each nozzle, and the ejection remained stable without any failures.

[0044] Upon observing the flow path 23 after discharge, it was found that the walls of the flow path 23 were not wet, and there was no liquid adhering to the walls and being wasted.

[0045] <Comparative Example 1> In the liquid injection, the procedure was the same as in Example 1, except that the pipette tip 25 was not inserted into the flow path 23, but the liquid was dripped onto the wall of the opening 24. As a result, when the operation of sequentially dispensing 10 shots from each outlet 31 was performed, all of them failed to dispense. Subsequently, when the operation of sequentially dispensing 1000 shots from each outlet 31 was performed, failure to dispense occurred at all outlets.

[0046] <Comparative Example 2> 200 μl of liquid was dropped onto the wall of the opening 24 in the same manner as in Comparative Example 1. Then, the liquid was forcibly filled into the liquid discharge head 21 by drawing it in through the face surface of the liquid discharge head 21 with an aspirator. The liquid injection was carried out in the same manner as in Comparative Example 1, except for these steps. As a result, when 10 shots were sequentially discharged from each discharge port, liquid was discharged from all 320 discharge ports, and there were no instances of non-discharge. However, when the amount of liquid drawn into the aspirator was measured, it was 100 μl, indicating that the amount drawn into the aspirator was wasted.

[0047] <Example 2> The evaluation was carried out in the same manner as in Example 1, except that the flow path 23 and the opening 24 were formed from ABS resin. The contact angle of this ABS resin with pure water was 75°. No non-discharge occurred, but when the flow path 23 was observed after discharge, the wall surface of the flow path 23 was slightly wet with liquid, and a small amount of liquid remained on the wall surface, but it was not at a level that would cause problems.

[0048] <Example 3> The evaluation was carried out in the same manner as in Example 1, except that the minute contact angle of the discharge port forming material 35 with pure water was set to 25°. When 10 shots were sequentially discharged from each discharge port, non-discharge occurred at 30 ports. It is thought that cells adhered to the discharge port forming material 35, causing blockage at the discharge port 31. When the time from liquid injection to discharge was set to 2 minutes, no non-discharge occurred.

[0049] <<Second Embodiment>> A second embodiment of the present invention will be described below with reference to the drawings. Since the basic configuration of this embodiment is the same as that of the above embodiment, only the characteristic configuration will be described below.

[0050] Figure 7(a) shows a state in which a pipette tip 25 is inserted into a liquid cartridge 11 with a short flow path 23. When the length of the flow path 23, which is the distance from the opening 24 to the liquid dispensing head 21, is short, as shown in Figure 7, the tip 26 of the pipette tip 25 may come into contact with the liquid dispensing head 21, potentially damaging the liquid dispensing head 21.

[0051] Therefore, in this embodiment, as shown in Figure 7(b), the shape and size of the pipette tip 25 and the width and length of the flow path 23 are configured such that the tapered portion of the pipette tip 25 contacts the inlet of the flow path 23 before the tip 26 of the pipette tip 25 reaches the liquid dispensing head 21. The inclined contact surface of the pipette tip 25 contacts the inlet (contact portion) of the flow path 23 before the tip 26 of the pipette tip 25 reaches the liquid dispensing head 21. With this configuration, it is possible to prevent damage to the liquid dispensing head 21 caused by the tip 26 of the pipette tip 25 contacting the liquid dispensing head 21.

[0052] Thus, it is preferable that the micropipette 104 or the liquid cartridge 11 is equipped with a mechanism to hold the pipette tip 25 (liquid injection part) in a state where it does not come into contact with the liquid dispensing head 21 when it is inserted into the flow path. Alternatively, this may be achieved through the relationship between both the micropipette 104 and the liquid cartridge 11, or it may be provided by the liquid injection device 101, but it is more preferable that the liquid cartridge 11 has it.

[0053] Examples of the mechanisms that the liquid cartridge 11 may have include configurations in which a portion narrower than the pipette tip 25 exists within the flow path so that the tip 26 of the pipette tip 25 does not reach the liquid dispensing head 21, and configurations in which the flow path 23 is curved. Furthermore, there is a configuration in which the flow path 23 comes into contact with the tapered portion of the pipette tip 25 before the pipette tip 25 reaches the liquid dispensing head 21. In particular, an aspect ratio of 2 or more of the flow path 23 is preferable because it does not come into contact with the liquid dispensing head 21 in many general-purpose pipette tips 25, and a ratio of 6 or more is more preferable.

[0054] <Example 4> Liquid injection was performed in the same manner as in Example 1, except that the length of the channel 23 was 1 mm, the width of the channel 23 was 1 mm, and the aspect ratio of the channel 23 was set to 1. By carefully moving the stage 102 of the liquid injection device 101, it was possible to insert the pipette tip 25 into the channel 23. However, if the stage 102 was pushed too hard due to an incorrect operating distance, the tip 26 of the pipette tip 25 would come into contact with the liquid dispensing head 21, sometimes damaging the liquid dispensing head 21.

[0055] <<Third Embodiment>> In this embodiment, a configuration in which a dispensing device equipped with a liquid cartridge 11 is used as a compound introduction device for introducing a compound into cells is described. The liquid dispensing head 21 is filled with a liquid containing the compound and the cells into which the compound is introduced. In this embodiment, this liquid is called a cell suspension (also called a cell-containing liquid). The liquid dispensing head 21 may also be called a cell-processed liquid dispensing head. The cell suspension dispensed from the liquid dispensing head 21 contains cells into which the compound has been introduced. In the following description, the compound to be introduced into cells will be appropriately referred to as the "target compound".

[0056] (Target compound for introduction) The compound to be introduced can be appropriately selected according to the purpose. Examples of compounds that can be introduced include nucleic acids, proteins, or labeling substances. However, the compound is not limited to these examples as long as it is small enough to be encapsulated within the target cell. However, from the viewpoint of minimizing damage to cells, the size of the compound is preferably one-fifth or less of the average diameter of the cell, and more preferably one-tenth or less. Typical compounds that can be applied in this embodiment include nucleic acids such as DNA or RNA.

[0057] (cell type) The cells handled in this embodiment include adherent cells, suspension cells, spheroids (aggregated cells), etc. The average diameter of the cells is such that they can be discharged from the discharge port 31, for example, between 1 μm and 100 μm.

[0058] (Cell suspension) A cell suspension comprises at least one target compound and at least one target cell, and is primarily composed of water. In this invention, the cell suspension is a state in which cells are dispersed in a liquid. The cells in the cell suspension only need to be in a state where they can be dispersed in the liquid by stirring, and may settle in the liquid when left standing. Furthermore, it is preferable to include other components as appropriate to enable cell survival during and after the introduction process.

[0059] (Water and water-soluble organic solvents) The cell suspension used in this embodiment can be an aqueous liquid medium containing water or a mixture of water and a water-soluble organic solvent. A cell suspension can be obtained by adding cells and the target compound to the aqueous liquid medium.

[0060] (Compound introduction method) In the compound introduction method of this embodiment, cells cultured by adherent culture or suspension culture are separated into individual cells or small cell clumps by the action of enzymes, etc. Then, using a centrifuge or the like, only the cells are allowed to settle using the difference in specific gravity. After that, the supernatant medium other than the cells is removed, and a medium containing the target compound is added and mixed using a pipette or stirrer to prepare a cell suspension.

[0061] Large cell clumps are removed by passing the prepared cell suspension through a cell strainer with a diameter similar to the minimum diameter of the flow path in the liquid dispensing head 21. The prepared cell suspension is then introduced into the liquid dispensing head 21 using a micropipette or the like. If the cell suspension smoothly fills the outlet 31 of the liquid dispensing head 21 due to wetting by surface tension, the introduction operation is performed as soon as it is filled.

[0062] Subsequently, by driving the energy generation element in the liquid dispensing head 21, the cell suspension is dispensed from the dispensing port 31 into the substrate or culture medium. The dispensed cells contain the target compound.

[0063] 11 Ink Cartridges 21 Liquid dispensing head 23 Flow channels 24 openings 25 pipette tips 26 Tip 27 Pure water 31 Discharge port 34 Silicon substrate 101 Liquid injection device 104 Micropipette

Claims

1. A liquid injection method for injecting liquid from a liquid injector into a liquid cartridge comprising a liquid dispensing head for dispensing liquid, a flow path connected to the liquid dispensing head and capable of supplying liquid to the liquid dispensing head, and an opening connected to the flow path and provided wider than the flow path, The liquid discharge head comprises a discharge port forming material having a discharge port, and the minute contact angle of the discharge port forming material with pure water is 40° or more and 90° or less. A liquid injection method characterized by directly injecting the liquid into the flow path.

2. The liquid injection method according to claim 1, characterized in that the tip of the liquid injection section, which includes the tip of the liquid injector and gradually narrows while its outer shape slopes toward the tip, is inserted into the flow path to inject the liquid.

3. The liquid injection method according to claim 2, characterized in that, before the tip reaches the liquid discharge head, the inclined surface of the liquid injection part is brought into contact with a part of the flow path, thereby injecting the liquid while maintaining a state in which the tip and the liquid discharge head do not come into contact.

4. The liquid injection method according to any one of claims 1 to 3, characterized in that a portion of the flow path is in communication with the atmosphere on the opening side when the liquid is injected.

5. A liquid injection method according to any one of claims 1 to 4, characterized in that the liquid in the liquid discharge head is removed before the liquid is injected into the flow path.

6. A liquid injection method according to any one of claims 1 to 5, characterized by injecting a liquid containing at least one of cells, nucleic acids, proteins, labeling substances, hormones, and ribonucleotides.

7. The liquid injection method according to any one of claims 1 to 6, characterized in that at least one of the surfaces of the flow path and the opening has a contact angle of 90° or more with respect to pure water.

8. The liquid injection method according to any one of claims 1 to 7, characterized in that the flow path is a groove, and the aspect ratio obtained by dividing the depth of the flow path by its width is 6 or more, and liquid is injected from the liquid injector into the liquid cartridge having the flow path.

9. A liquid injection method according to any one of claims 1 to 8, characterized in that liquid is injected from a liquid injector into the liquid cartridge equipped with the liquid ejection head that ejects liquid using the ejection principle of an inkjet method.

10. A liquid dispensing head that dispenses liquid from the outlet, A flow path connected to the liquid discharge head and capable of supplying liquid to the liquid discharge head, An opening connected to the aforementioned flow path and provided wider than the aforementioned flow path, A liquid cartridge equipped with a liquid injector into which liquid is injected, The liquid discharge head comprises a discharge port forming material on which the discharge port is formed, and the minute contact angle of the discharge port forming material with respect to pure water is 40° or more and 90° or less. The liquid cartridge is characterized in that the flow path is provided so that liquid can be directly injected into the flow path, and its width is greater than that of the tip of the liquid injector.

11. The aforementioned flow path is provided so that the tip of the liquid injection section, which includes the tip of the liquid injector and gradually narrows while its outer shape slopes toward the tip, can be inserted into it. The liquid cartridge according to claim 10, characterized in that liquid is injected while the aforementioned tip is inserted.

12. The liquid cartridge according to claim 11, characterized in that it has a contact portion that the inclined contact surface of the liquid injection portion contacts before the tip reaches the liquid discharge head.

13. The liquid cartridge according to claim 11 or 12, characterized in that the flow path has a communication portion such that when the tip is inserted into the flow path, a part of the flow path communicates with the atmosphere on the opening side.

14. The liquid cartridge according to any one of claims 10 to 13, characterized in that at least one of the surfaces provided by the flow path and the opening has a contact angle of 90° or more with respect to pure water.

15. The liquid cartridge according to any one of claims 10 to 14, characterized in that the flow path is a groove, and the aspect ratio obtained by dividing the depth of the flow path by its width is 6 or more.

16. The liquid cartridge according to any one of claims 10 to 15, characterized in that the liquid dispensing head dispenses a liquid containing at least one of cells, nucleic acids, proteins, labeling substances, hormones, and ribonucleotides.

17. The liquid cartridge according to any one of claims 10 to 16, characterized in that the liquid ejection head ejects liquid using the ejection principle of an inkjet method.

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