JP2018148817A - Droplet formation device and droplet formation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a droplet forming device which uses a small amount of particle suspension and is excellent in discharge stability even when the amount of liquid held in the liquid holding means fluctuates.SOLUTION: The droplet forming device comprises: a liquid holding means for holding a particle suspension; a liquid supply means for supplying the particle suspension to the liquid holding means; a droplet discharge means formed with a nozzle for discharging a droplet of the particle suspension held by the liquid holding means from the nozzle by means of vibrations; and a pressure control device that is connected to or formed integrally with the liquid supply means and that controls the pressure within the liquid holding means.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a droplet forming apparatus and a droplet forming method.

  In recent years, with the advancement of stem cell technology, a technology is known in which a plurality of cells are ejected from an inkjet head of a droplet forming apparatus to form a tissue body.

For example, a droplet forming apparatus has been proposed that includes a liquid holding unit that holds a cell solution, a film-like member that discharges the cell solution as a droplet from a nozzle by vibration, and an air opening portion (for example, Patent Document 1). reference).
Further, as a droplet forming device that controls the pressure acting on the liquid using air, the pressure acting on the ink in the head is kept within an appropriate range by the pressure control means for controlling the pressure in the space in the tank. An inkjet image forming apparatus has been proposed (see, for example, Patent Document 2).

  An object of the present invention is to provide a droplet forming apparatus that is excellent in ejection stability even when the amount of particle suspension used is small and the amount of liquid held in a liquid holding means varies.

  The droplet forming apparatus according to the present invention as means for solving the above-mentioned problems includes a liquid holding means for holding a particle suspension, a liquid supply means for supplying the particle suspension to the liquid holding means, and a nozzle. A droplet discharge means for discharging the particle suspension held in the liquid holding means as droplets from the nozzle by vibration, and connected to or integrated with the liquid supply means. Pressure control means for controlling the pressure.

  According to the present invention, it is possible to provide a droplet forming apparatus that is excellent in ejection stability even when the amount of particle suspension used is small and the amount of liquid retained in the liquid retaining means varies.

FIG. 1 is a schematic diagram illustrating an example of a droplet forming apparatus according to the first embodiment. FIG. 2 is a schematic diagram for explaining the direct supply of the cell suspension from the liquid supply means to the liquid holding means in the droplet forming apparatus of the first embodiment. FIG. 3 is a schematic diagram illustrating an example of a droplet forming apparatus according to a modification of the first embodiment. FIG. 4 is a schematic diagram illustrating an example of a droplet forming apparatus according to the second embodiment.

(Droplet forming apparatus and droplet forming method)
The droplet forming apparatus of the present invention includes a liquid holding unit that holds a particle suspension, a liquid supply unit that supplies the particle suspension to the liquid holding unit, and a nozzle that is formed and held in the liquid holding unit. Droplet discharge means for discharging the particle suspension as droplets from the nozzle by vibration, pressure control means for connecting or integrating with the liquid supply means, and controlling the pressure in the liquid holding means, It is preferable to have at least one of a liquid amount detection unit and a liquid amount calculation unit, and further include other units as necessary.

The droplet forming method of the present invention preferably forms a droplet by the droplet forming apparatus of the present invention, and preferably includes at least one of a liquid amount detection step and a liquid amount calculation step, and if necessary, other These steps are included.
The liquid amount detection step and the liquid amount calculation step can be performed by the liquid amount detection unit and the liquid amount calculation unit, and the other steps can be performed by the other unit.
Hereinafter, the droplet forming method of the present invention will be described through the description of the droplet forming apparatus of the present invention.

In the droplet forming apparatus and the droplet forming method of the present invention that form a conventional particle suspension as droplets, the particle suspension held by the liquid holding means by liquid supply and droplet discharge is used. If the amount of the turbid liquid varies even by a small amount of about 1 mm to 5 mm in depth, the pressure applied to the nozzle of the ejection head varies by about 10 Pa to 50 Pa, and the size and speed of the ejected droplets change. This is based on the knowledge that there is a problem that the discharge stability is lowered.
In this regard, it is possible to reduce the fluctuation of the liquid level of the retained particle suspension by increasing the cross-sectional area of the liquid holding means.
The droplet forming apparatus and the droplet forming method of the present invention are required to be provided with a liquid holding means having a large cross-sectional area, a tank independent of the head, etc., in the conventional droplet forming apparatus and inkjet image forming apparatus. This is based on the knowledge that there is a problem that it cannot be applied in the case of a small amount of particle suspension because the amount of liquid increases.

  As a result of intensive studies to solve the above-described problems, the present inventors have obtained the following knowledge. Specifically, when the liquid volume of the particle suspension in the liquid holding means is large, the hydraulic head pressure applied to the nozzle is high, and when the liquid volume of the particle suspension in the liquid holding means is small, The water head pressure applied to the nozzle is low. Therefore, in the droplet forming apparatus, the pressure control means is based on the water head pressure (hereinafter sometimes referred to as “design water head pressure”) when the particle suspension holds a set amount of the particle suspension in the liquid holding means. Then, the pressure in the liquid holding means is controlled in accordance with the water head pressure applied to the nozzle by the particle suspension actually held in the liquid holding means, and the pressure applied to the nozzle is brought close to the designed water head pressure. As a result, the water head pressure applied to the nozzle becomes almost constant regardless of the amount of the particle suspension in the liquid holding means, so that the variation in the size and speed of the liquid droplets discharged from the nozzle can be reduced. Thus, even when the amount of liquid held in the liquid holding means varies, the discharge stability can be improved.

<Liquid holding means>
The liquid holding means is means for holding a particle suspension.
There is no restriction | limiting in particular about the shape of the said liquid holding means, a magnitude | size, a material, and a structure, According to the objective, it can select suitably.
Examples of the material for the liquid holding means include metals such as stainless steel, nickel, and aluminum, silicon, ceramics, and polymer materials.

<Liquid supply means>
The liquid supply means is means for supplying the particle suspension to the liquid holding means.
The shape, size, material, and structure of the liquid supply means are not particularly limited and can be appropriately selected according to the purpose.

  There is no restriction | limiting in particular as said liquid supply means, According to the objective, it can select suitably, For example, a micropipette, a syringe, a tube etc. are mentioned. Further, the particle suspension may be supplied by a user. Further, the liquid supply means may be configured to automatically supply the particle suspension to the liquid holding means when, for example, the amount of the particle suspension in the liquid holding means becomes a specified amount or less. Good. These may be used individually by 1 type and may use 2 or more types together.

The liquid supply means may supply the particle suspension directly to the liquid holding means, or may supply the liquid suspension via other means.
When the particle suspension is directly supplied from the liquid supply means to the liquid holding means, since the path through which the particle suspension passes is short, even if the particle suspension is a very small amount of about 10 μL, for example, The liquid can be supplied to the liquid holding means without waste. This is particularly effective when the particle suspension is not available in large quantities, is expensive, and it is difficult to hold the particles in the liquid holding means for a long time.

<Droplet discharge means>
The droplet discharge means is means for forming a nozzle and discharging the particle suspension held in the liquid holding means as droplets from the nozzle by vibration.

  The nozzle is preferably formed as a substantially circular through hole substantially at the center of the film member.

In the droplet forming apparatus of the present invention, the nozzle diameter is preferably 20 μm or more and 200 μm or less, and more preferably 60 μm or more and 150 μm or less.
The diameter of the nozzle is not particularly limited and may be appropriately selected depending on the intended purpose. However, in order to prevent the particles of the particle suspension from clogging the nozzle, it is preferably set to be twice or more the particle diameter. . When animal cells, particularly human cells are used as the particles, the size of the cells is generally about 10 μm to 30 μm. Therefore, the nozzle diameter is preferably 20 μm or more. Further, if the droplet becomes too large, it becomes difficult to form a minute droplet. Therefore, the nozzle diameter is preferably 200 μm or less.

-Membrane member-
The droplet discharge means is preferably made of a film member.
The film-like member is a member in which a nozzle is formed and the liquid held in the liquid holding means is discharged as droplets from the nozzle by vibration due to its amplitude motion. The membrane member is vibrated by the vibrating member.
The membrane member is a member disposed at the lower end of the liquid holding means, and a nozzle that is a through hole is formed at the approximate center of the membrane member.
The particle suspension held in the liquid holding means is discharged as droplets from the nozzle by the vibration of the film-like member.

There is no restriction | limiting in particular about the planar shape of a membranous member, a magnitude | size, a material, and a structure, According to the objective, it can select suitably.
Examples of the planar shape of the film member include a polygon such as a circle, an ellipse, a rectangle, a square, and a rhombus.

The material of the film-like member is not particularly limited and can be appropriately selected according to the purpose. However, if it is too soft, the film-like member vibrates easily, and it is difficult to immediately suppress vibration when not discharging. Therefore, it is preferable to use a material having a certain degree of hardness, and examples thereof include metals, ceramics, and polymer materials.
Moreover, as a material of the film-like member, it is preferable that the adhesion of the particle suspension to the particles is low. In particular, when cells are used as the particles, the adhesion of cells to the membrane member is generally considered to depend on the contact angle with water in the material of the membrane member. When the hydrophilicity is high, or when the hydrophobicity of the material of the membrane member is high, the adhesion of cells to the membrane member tends to be low.
Examples of the highly hydrophilic material include ceramics such as metals and metal oxides. In addition, examples of the material having high hydrophobicity include a fluororesin.
Specific examples of the material for the film member include stainless steel, nickel, aluminum, silicon dioxide, alumina, and zirconia.
Alternatively, the surface of the membrane member may be coated to reduce the adherence of cells to the membrane member. Specifically, the surface of the membrane member may be coated with a material such as a metal, a metal oxide, or a synthetic phospholipid polymer imitating a cell membrane.
Examples of the synthetic phospholipid polymer imitating the cell membrane include 2-methacryloyloxyethyl phosphorylcholine (trade name: Lipidure, manufactured by NOF Corporation).

-Vibration member-
The droplet discharge means preferably discharges the droplet from the nozzle by vibrating the film-like member by a vibrating member.

The vibrating member is formed on the upper surface or the lower surface of the film member.
There is no restriction | limiting in particular about the shape of a vibration member, a magnitude | size, a material, and a structure, According to the objective, it can select suitably.
The shape of the vibrating member is not particularly limited and can be appropriately designed according to the shape of the film-like member. For example, when the planar shape of the film-like member is a circle, the shape is flat around the nozzle. It is preferable to form an annular (ring-shaped) vibration member.

When a piezoelectric element is used as the vibrating member, for example, a structure in which electrodes for applying a voltage to the upper surface and the lower surface of the piezoelectric material are provided. In this case, by applying a voltage between the upper and lower electrodes of the piezoelectric element from the driving means, a compressive stress is applied in the lateral direction of the film, and the film member can be vibrated in the vertical direction of the film.
There is no restriction | limiting in particular as said piezoelectric material, According to the objective, it can select suitably, For example, lead zirconate titanate (PZT), bismuth iron oxide, a niobate metal substance, barium titanate, or these Examples include materials added with metals and different oxides.

Further, as the vibration member, for example, a member having a linear expansion coefficient different from that of the film member may be attached to the film member, and the member having a different linear expansion coefficient may be heated to vibrate the film member. .
In this case, it is preferable that a heater is attached to a member having a different linear expansion coefficient and the heater is heated to vibrate the film-like member when a member having a different linear expansion coefficient is energized.

<Pressure control means>
The pressure control means is means for controlling the pressure in the liquid holding means by being connected to or integrated with the liquid supply means.

When the liquid volume of the particle suspension in the liquid holding means is large, the water head pressure applied to the nozzle becomes high, and when the liquid volume of the particle suspension in the liquid holding means is small, the nozzle The head pressure applied to the water becomes lower.
Therefore, in the droplet forming device, the design water head pressure is used as a reference, and the pressure control means is arranged in the liquid holding means according to the water head pressure applied to the nozzle by the particle suspension actually held in the liquid holding means. The pressure applied to the nozzle is brought close to the design head pressure. As a result, regardless of the amount of the particle suspension in the liquid holding means, the water head pressure applied to the nozzle is substantially constant, so that the size and speed of the droplets discharged from the nozzle are changed. Can be small.

The pressure control means is not particularly limited as long as it is connected to or integrated with the liquid supply means and controls the pressure in the liquid holding means, and can be appropriately designed according to the purpose. Examples include a micropipette, a syringe, and a tube.
The pressure control method includes, for example, supplying or sucking liquid into the liquid holding means, introducing pressurized air into the liquid holding means, or sucking air existing in the liquid holding means. Can be mentioned.

The liquid supply means and the pressure control means may be separate bodies or may be integrated, but the point in effectively using the space in the droplet forming device and the particles in the liquid holding means Since it is not necessary to provide a configuration for automatically supplying the particle suspension to the liquid holding means when the liquid amount of the suspension becomes equal to or less than the predetermined amount, it is preferable to be integrated.
The configuration in which the liquid supply unit and the pressure control unit are integrated includes, for example, a configuration in which the pressure control unit has a function as a liquid supply unit. Specifically, a configuration in which a micropipette, a syringe, a tube, or the like is used as a liquid supply unit / pressure control unit can be given.

  The difference between the maximum value and the minimum value in the pressure in the liquid holding means is preferably 5 Pa or more and 200 Pa or less, and more preferably 10 Pa or more and 100 Pa or less, from the viewpoint of making the hydraulic head pressure applied to the nozzle substantially constant.

<Liquid volume detection means, liquid volume calculation means, liquid volume detection method, and liquid volume calculation method>
The droplet forming apparatus of the present invention preferably further includes at least one of a liquid amount detection unit and a liquid amount calculation unit.
The liquid amount detecting method and the liquid amount calculating method in the droplet forming method of the present invention can be performed by the liquid amount detecting means and the liquid amount calculating means of the droplet forming apparatus of the present invention.

There is no restriction | limiting in particular as said liquid amount detection means, According to the objective, it can select suitably, For example, the electrode etc. which are arrange | positioned in the depth direction of the inner wall face of a liquid holding means are mentioned. When the particle suspension contains a salt, the conductivity becomes high, so that the depth of the particle suspension can be detected by examining the conduction between the plurality of electrodes, the resistance value, and the like. it can.
Further, as the liquid amount detecting means, for example, the light emitted from the light emitting element is reflected by the liquid surface of the particle suspension, a position sensor is disposed at a position based on the principle of triangulation, and the light is applied to the position sensor. , The distance from the position of the light incident on the position sensor to the liquid surface of the particle suspension may be calculated.

The liquid amount calculating means is not particularly limited and can be appropriately selected depending on the purpose. For example, the received signal of the position sensor can be obtained from the particle suspension based on a preset conversion formula or look-up table. For example, it can be converted into the amount of turbid liquid.
Further, as the liquid amount calculating means, the consumption amount of the particle suspension is calculated by the number of times the particle suspension held in the liquid holding means is ejected as droplets from the nozzle, and a preset conversion formula or look-up is performed. Conversion to the liquid volume of the cell suspension based on the up table can be mentioned.

  Since the droplet forming apparatus of the present invention has at least one of the liquid amount detecting unit and the liquid amount calculating unit, the depth of the liquid amount of the particle suspension in the liquid holding unit can be determined. By obtaining the water head pressure applied to the nozzle by the particle suspension, the pressure in the liquid holding means can be controlled, and the pressure applied to the nozzle can be brought close to the design water head pressure.

<Other means and other processes>
The droplet discharge device of the present invention may have other means as necessary. There is no restriction | limiting in particular as said other means, According to the objective, it can select suitably, For example, a light irradiation means, a light-receiving means, a drive means, a recording means etc. are mentioned.
The droplet forming method of the present invention may include other steps as necessary. There is no restriction | limiting in particular as said other process, According to the objective, it can select suitably, For example, a light irradiation process, a light reception process, a drive process, a recording process etc. are mentioned.

<Particle suspension>
The droplet forming apparatus of the present invention includes a particle suspension. The particle suspension contains at least one particle, and further contains other components as necessary.
There is no restriction | limiting in particular as said particle | grain suspension, Although it can select suitably according to the objective, The cell suspension containing a cell is preferable.
The cell suspension is preferably in a state where cells are dispersed.

-Cell suspension-
The cell suspension contains cells and a liquid, and further contains other components as necessary.
Examples of the cells include animal cells, and particularly human-derived animal cells. Further, the liquid is preferably a liquid having high affinity with the cells, and examples thereof include water.
The cell suspension preferably further contains a salt in order to adjust the osmotic pressure between the liquid and the cells. The cell suspension preferably further contains a pH adjusting agent in order to adjust the pH.
As the cell suspension, an appropriately prepared solution may be used. For example, the prepared cells are suspended in phosphate buffered saline (PBS solution) in which a pH-adjusted Tris buffer aqueous solution, a metal salt such as Ca, K, or Na is added in the same manner as the culture solution. Etc.

The cells are preferably collected from the medium after being cultured in the medium.
The medium for culturing the cells is not particularly limited as long as it is a commonly used cell culture medium, and can be appropriately selected according to the purpose such as the type of cells to be used. For example, “Revised Culture Cell Experiment Handbook” Examples include serum-free medium and serum-containing medium described on pages 61 and 62 of (Publishing: Yodosha Co., Ltd.).
Examples of the serum-free medium include ham medium such as BME medium, MEM medium, αMEM medium, DMEM medium, IMDM medium, RPMI medium, F10 medium, F12 medium, MCDB104, MCDB107, MCDB131, MCDB151, MCDB170, MCDB202, etc. MCDB medium, RITC80-7 medium, ES medium, DM-160 medium, Fisher medium, WE medium, RPMI1640 medium, and a mixture of two or more thereof, various cell growth factors, cell adhesion factors, hormones, binding proteins, lipids , Antibiotics, amino acids and the like.
A serum such as fetal calf serum may be added to the serum-free medium.

A commercially available product can be used as the medium, and examples of the commercially available product include a serum-free medium (registered trademark: Gibco, manufactured by Thermo Fisher Scientific Co., Ltd.).
The medium is preferably free of animal-derived components in consideration of the final clinical application of cell tissues.

  Hereinafter, embodiments of the droplet forming apparatus of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to these embodiments.

<First Embodiment>
FIG. 1 is a schematic diagram illustrating an example of a droplet forming apparatus according to the first embodiment.
1 includes a liquid holding unit 11, a lid 15, a micropipette 16 as a liquid supply unit and a pressure control unit, a nozzle 121 as a droplet discharge unit, and a film-like member 12. have. The liquid holding means 11 holds a cell suspension 300 containing cells 350 as a particle suspension.
The micropipette 16 can control the pressure in the liquid holding means 11.
The film member 12 is fixed to the lower end of the liquid holding means 11, and a nozzle 121 that is a through hole is formed at the approximate center of the film member 12. The cell suspension 300 held in the liquid holding unit 11 is ejected as a droplet from the nozzle 121 by the vibration of the membrane member 12.

When the liquid volume of the cell suspension 300 in the liquid holding means 11 is large, the hydraulic head pressure applied to the nozzle 121 is high, and when the liquid volume of the cell suspension 300 in the liquid holding means 11 is small, the nozzle 121 is used. The head pressure applied to the water becomes lower.
In the droplet forming apparatus 10, the micropipette 16 as the liquid supply unit and the pressure control unit supplies the cell suspension 300 into the liquid holding unit 11 with the design head pressure as a reference, and also supplies the liquid holding unit 11 with the cell suspension 300. The pressure in the liquid holding means 11 is controlled according to the water head pressure applied to the nozzle 121 by the cell suspension 300 being held, and the pressure applied to the nozzle 121 is brought close to the designed water head pressure. Therefore, regardless of the amount of the cell suspension 300 in the liquid holding means 11, the hydraulic head pressure applied to the nozzle 121 becomes substantially constant, and fluctuations in the size and speed of the droplets discharged from the nozzle 121 are reduced. can do.

A piezoelectric element 13 as a vibration member is formed on the lower surface side of the film member 12. The shape of the piezoelectric element 13 can be designed according to the shape of the film-like member 12. For example, when the planar shape of the film-like member 12 is circular, the planar shape is annular around the nozzle 121 ( A ring-shaped piezoelectric element 13 can be formed.
The piezoelectric element 13 has a structure in which electrodes for applying a voltage are provided on the upper surface and the lower surface of a piezoelectric material. By applying a voltage between the upper and lower electrodes of the piezoelectric element 13, a compressive stress is applied in the lateral direction of the film. The membrane member 12 can be vibrated in the vertical direction of the membrane.

In the droplet forming apparatus 10, an electrode 14 is disposed in the depth direction of the inner wall surface of the liquid holding unit 11 as a liquid amount detection unit.
Since the cell suspension 300 is generally composed of an aqueous solution containing a salt, the cell suspension 300 has high conductivity, and the depth of the liquid amount of the cell suspension 300 is determined by examining the conduction between the plurality of electrodes 14 and the resistance value. Can be detected.

FIG. 2 is a schematic diagram for explaining the direct supply of the cell suspension from the liquid supply means to the liquid holding means in the droplet forming apparatus of the first embodiment.
In the droplet forming apparatus 10A in FIG. 2, the cell suspension 300 is directly supplied from the micropipette 16 as the liquid supply means to the liquid holding means 11. In such a configuration, since the path through which the cell suspension 300 passes is short, even when the cell suspension 300 is a very small amount of about 10 μL, for example, the cell suspension 300 can be transferred to the liquid holding means 11 without waste. Can be supplied. In particular, the cell suspension 300 is not available in large quantities, is expensive, and is effective when it is difficult to hold the cells 350 in the liquid holding means 11 for a long time.

<< Modification of First Embodiment >>
FIG. 3 is a schematic diagram illustrating an example of a droplet forming apparatus according to a modification of the first embodiment. In the first embodiment, the same components as those already described in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  A droplet forming apparatus 10B shown in FIG. 3 is configured by sequentially connecting a micropipette 16, a valve 19B, a chamber 21, a valve 19A, and a pipe 20 as pressure control means. A pressure control means such as a syringe (not shown) is further connected in the direction opposite to the chamber 21 of the pipe 20.

When pressurizing the gas phase 111, the valve 19 </ b> A is opened after the valve 19 </ b> B is closed, and pressurized air is introduced into the pipe 20. Thereafter, the valve 19A is closed, the micropipette 16 is pushed into and tightly contacted with the lid 15, and then the valve 19B is opened to introduce pressurized air into the gas phase 111. At this time, by making the volume of the chamber 21 sufficiently smaller than the volume of the gas phase 111, the pressure increase width of the gas phase 111 can be reduced, so that a high-precision pump and pressure gauge are not used. A minute pressure of about 10 Pa to 50 Pa can be controlled.
Further, by repeating the opening and closing a plurality of times, the pressure of the gas phase 111 can be increased stepwise, so that the water head pressure applied to the nozzle can be controlled.

<Second Embodiment>
FIG. 4 is a schematic diagram illustrating an example of a droplet forming apparatus according to the second embodiment. In the first embodiment, the same components as those already described in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  In the droplet forming apparatus 10C of FIG. 4, a light emitting element 17 and a position sensor 18 are arranged above the liquid holding unit 11 as a liquid amount detecting unit. The lid 15 is made of a transparent material.

The light emitted from the light emitting element 17 is specularly reflected by the liquid surface 300A, the liquid surface 300B, etc. of the cell suspension 300, and enters the position sensor 18 arranged based on the principle of triangulation. Thereby, the distance from the position of the light incident on the position sensor 18 to the liquid surface of the cell suspension 300 can be calculated.
Note that a conversion formula or a lookup table may be set in advance, and the reception signal of the position sensor 18 may be converted into the liquid volume of the cell suspension 300 to serve as a liquid volume calculation unit.

Aspects of the present invention are as follows, for example.
<1> liquid holding means for holding the particle suspension;
Liquid supply means for supplying the particle suspension to the liquid holding means;
A droplet discharge means for forming a nozzle and discharging the particle suspension held in the liquid holding means as droplets from the nozzle by vibration; and
A droplet forming apparatus comprising pressure control means connected to or integrated with the liquid supply means to control the pressure in the liquid holding means.
<2> The droplet forming apparatus according to <1>, wherein the droplet discharge unit is a film-like member.
<3> The droplet forming apparatus according to <2>, further including a vibrating member that vibrates the film-like member.
<4> The droplet forming apparatus according to any one of <2> to <3>, wherein a material of the film-shaped member is at least one of metal, ceramics, and a polymer material.
<5> The droplet forming apparatus according to any one of <1> to <4>, further including at least one of a liquid amount detection unit and a liquid amount calculation unit.
<6> The droplet forming device according to any one of <1> to <5>, wherein the particles of the particle suspension are cells.
<7> The droplet forming apparatus according to <6>, wherein the medium for culturing the cells does not contain an animal-derived component.
<8> The droplet forming apparatus according to any one of <1> to <7>, wherein the liquid supply unit and the pressure control unit are integrated.
<9> The droplet forming apparatus according to any one of <1> to <8>, wherein the pressure control unit includes a valve and a chamber.
<10> The droplet forming apparatus according to any one of <1> to <9>, wherein the nozzle has a diameter of 20 μm to 200 μm.
<11> The droplet forming apparatus according to <10>, wherein the nozzle has a diameter of 60 μm to 200 μm.
<12> The droplet forming apparatus according to any one of <1> to <11>, wherein a difference between a maximum value and a minimum value in the pressure in the liquid holding unit is 5 Pa or more and 200 Pa or less.
<13> The liquid supply unit has a configuration of automatically supplying the particle suspension to the liquid holding unit when the liquid amount of the particle suspension in the liquid holding unit becomes equal to or less than a predetermined amount. > To <12>.
<14> The droplet forming apparatus according to any one of <1> to <13>, wherein the particle suspension further includes a salt.
<15> The droplet forming apparatus according to any one of <1> to <14>, wherein the particle suspension further includes a pH adjusting agent.
<16> A droplet forming method, wherein a droplet is formed by the droplet forming apparatus according to any one of <1> to <15>.
<17> The droplet forming method according to <16>, further including at least one of a liquid amount detection step and a liquid amount calculation step.

  According to the droplet forming apparatus described in any one of <1> to <15> and the droplet forming method described in any one of <16> to <17>, the conventional problems are solved, The object of the invention can be achieved.

DESCRIPTION OF SYMBOLS 10, 10A, 10B, 10C Droplet formation apparatus 11 Liquid holding means 12 Film-like member 13 Piezoelectric element 14 Electrode 15 Lid 16 Micropipette 17 Light emitting element 18 Position sensor 19A, 19B Valve 20 Piping 21 Chamber 111 Gas phase 121 Nozzle 300 Cell Suspension 300A, 300B Liquid level 320 Liquid 350 cells

Japanese Patent Application Laid-Open No. 2006-116489 JP 2006-326855 A

Claims (8)

Liquid holding means for holding the particle suspension;
Liquid supply means for supplying the particle suspension to the liquid holding means;
A droplet discharge means for forming a nozzle and discharging the particle suspension held in the liquid holding means as droplets from the nozzle by vibration; and
A droplet forming apparatus comprising: a pressure control unit that is connected to or integrated with the liquid supply unit and controls a pressure in the liquid holding unit.   The droplet forming apparatus according to claim 1, wherein the droplet discharging means is made of a film-like member.   The droplet forming apparatus according to claim 1, further comprising at least one of a liquid amount detection unit and a liquid amount calculation unit.   The droplet forming apparatus according to claim 1, wherein the particles of the particle suspension are cells.   The droplet forming apparatus according to claim 1, wherein the liquid supply unit and the pressure control unit are integrated.   The droplet forming apparatus according to claim 1, wherein the pressure control unit includes a valve and a chamber.   The droplet forming apparatus according to claim 1, wherein a difference between a maximum value and a minimum value in the pressure in the liquid holding unit is 5 Pa or more and 200 Pa or less.   A droplet forming method comprising forming a droplet by the droplet forming apparatus according to claim 1.

Images