Droplet treatment device and droplet treatment method

Abstract

To provide a device and method capable of stabilizing the size (volume) of droplets after fusion and the ratio of materials contained in the droplets after fusion when fusing the droplets of different types of materials by using a micro flow channel.SOLUTION: A droplet processing device includes: a flow channel system in which a first micro flow channel for flowing multiple droplets of a first type and a second micro flow channel for flowing multiple droplets of a second type merge at a junction; a first electrode which applies an electric field that promotes fusion of the droplets of the first type and the droplets of the second type to the interface between the droplets of the first type and the droplets of the second type contacting at the junction; and a second electrode that prevents the electric field generated by the first electrode from being applied to the interface between the droplets of the second type existing in the second micro flow channel.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a droplet processing device for processing the transportation and fusion of droplets, a droplet processing method, and the like. [Background technology]

[0002] In various fields such as engineering, chemistry, and biomedicine, microchannel systems that fuse tiny droplets together are used as reactors for carrying out chemical or biological reactions. In general, a microchannel is a channel with a cross-sectional side length of approximately 1 mm or less, and a mechanism that transports and fuses tiny droplets using such fine channels is sometimes called a microchannel system.

[0003] Patent Document 1 and Non-Patent Document 1 describe a device that applies an electric field to promote fusion of two types of droplets transported in a microchannel. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 2014-515696 [Non-Patent Document 1] Keunho Ahn, et al., "Electrocoalescence of drops synchronized by size-dependent flow in microfluidic channels." Applied Physics Letters, Vol. 88, No. 26, 264105, June 29, 2006 Summary of the Invention [Problem to be solved by the invention]

[0005] The devices described in Patent Document 1 and Non-Patent Document 1 have a flow channel configuration in which two microchannels join at a junction, and droplets of different types of medicinal liquids are injected from each microchannel and fused at the junction. These devices are configured to promote fusion of droplets by providing electrodes for applying an electric field near the junction.

[0006] However, when using such conventional devices, there were cases where droplets larger than the desired size (volume) were generated by fusion, or the content ratio of each chemical solution contained in the droplets generated by fusion deviated from the specified ratio.

[0007] Therefore, there was a need for an apparatus and method that could stabilize the size (volume) of the fused droplets and the ratio of materials contained in the fused droplets when fusing droplets of different types of materials using a microchannel. [Means for solving the problem]

[0008] A first aspect of the present invention is a droplet processing device comprising: a flow path system in which a first microflow path for causing a plurality of droplets of a first type to flow and a second microflow path for causing a plurality of droplets of a second type to flow meet at a confluence point; a first electrode for applying an electric field to an interface between the first type of droplets and the second type of droplets that come into contact at the confluence point, the electric field promoting fusion of the first type of droplets and the second type of droplets; and a second electrode for suppressing the application of the electric field generated by the first electrode to an interface between the second type of droplets in the second microflow path.

[0009] A second aspect of the present invention is a droplet processing method that uses a flow path system in which a first microflow path for flowing a plurality of droplets of a first type and a second microflow path for flowing a plurality of droplets of a second type join at a confluence point, and a first electrode that applies an electric field to an interface between the first type of droplets and the second type of droplets that come into contact at the confluence point, the electric field promoting fusion of the first type of droplets and the second type of droplets, characterized in that the second electrode is used to suppress the application of the electric field generated by the first electrode to the interface between the second type of droplets in the second microflow path. Effect of the Invention

[0010] According to the present invention, it is possible to realize an apparatus and method that can stabilize the size (volume) of the fused droplets and the ratio of materials contained in the fused droplets when using a microchannel to fuse droplets of different types of materials. [Brief description of the drawings]

[0011] [Figure 1] 1A and 1B are schematic cross-sectional views illustrating a microchannel device according to an embodiment. [Diagram 2] FIG. 4 is a schematic enlarged partial cross-sectional view of the vicinity of the confluence. [Diagram 3] FIG. 2 is a cross-sectional view showing the shape of a microchannel device according to an embodiment. [Figure 4] Graph showing the results of numerical analysis. [Diagram 5] 1A and 1B are schematic cross-sectional views illustrating a microchannel device according to an embodiment in which droplets of the same size are merged. [Figure 6] FIG. 1 is a schematic cross-sectional view showing an embodiment in which two microchannels intersect at an obtuse angle. [Figure 7] FIG. 1 is a schematic cross-sectional view showing an embodiment in which two microchannels intersect at an acute angle. [Figure 8] 5A to 5C are schematic cross-sectional views showing embodiments in which the electrode configuration is different. [Figure 9] FIG. 1 is a schematic cross-sectional view showing an embodiment in which three types of droplets are fused together. [Figure 10]FIG. 1 is a schematic cross-sectional view illustrating a microchannel device according to a reference embodiment. [Figure 11] FIG. 11 is a diagram illustrating a state in which an electric field is applied in the reference embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] A droplet processing device, a droplet processing method, and the like according to embodiments of the present invention will be described with reference to the drawings. The embodiments described below are merely examples, and those skilled in the art can appropriately modify and implement the detailed configurations without departing from the spirit and scope of the present invention.

[0013] In the drawings referred to in the following description of the embodiments, elements denoted by the same reference numerals have the same functions unless otherwise noted. When a plurality of identical elements are arranged in a drawing, the reference numerals and their descriptions may be omitted.

[0014] In addition, since the drawings may be represented diagrammatically for the convenience of illustration and explanation, the shape, size, arrangement, etc. of the elements depicted in the drawings may not strictly correspond to the actual objects.

[0015] [Reference form] As a result of thorough investigation of conventional devices, the inventors have discovered the reason why the size (volume) of the fused droplets and the ratio of materials contained in the fused droplets were not stable. First, the reason discovered by the inventors will be described with reference to the embodiment.

[0016] FIG. 10 is a schematic cross-sectional view for explaining a microchannel device 100 of a reference embodiment. The microchannel device 100 includes a microchannel 2 for flowing a plurality of first-type droplets 11 and a microchannel 3 for flowing a plurality of second-type droplets 12, and the microchannel 2 and the microchannel 3 are connected and merged at a junction MP. Electrodes 4 and 5 for generating an AC electric field are disposed near the junction MP. The first-type droplet 11 moving along the flow direction D1 and the second-type droplet 12 moving along the flow direction D2 meet and contact each other at the junction MP. At that time, when the electrodes 4 and 5 generate an AC electric field, the interface between the first-type droplet 11 and the second-type droplet 12 is destroyed, and the two droplets are fused. The fused droplet 13 is transported along the flow direction D3 and is used according to the purpose.

[0017] The composition of the droplets 13 after fusion is set according to the intended use of the droplets 13. In this example, a first type of droplet 11 having a relatively large volume and a second type of droplet 12 having a relatively small volume are fused to generate droplets 13 having a high content ratio of the components of the first type of droplet. The cross-sectional area of ​​the microchannel 2 that transports the first type of droplets 11 having a relatively large volume is set to be larger than the cross-sectional area of ​​the microchannel 3 that transports the second type of droplets 12. In addition, the transport of each droplet is adjusted so that the interval L1 between the first type of droplets 11 moving in the microchannel 2 is larger than the interval L2 between the second type of droplets 12 moving in the microchannel 3.

[0018] As described above, when an AC electric field is applied near the junction MP using electrodes 4 and 5, the interface between the first type of droplets 11 and the second type of droplets 12 is easily destroyed. However, in order to ensure that the droplets merge, it is necessary to apply an electric field of a predetermined strength near the junction MP.

[0019] FIG. 11 shows a schematic diagram of a state where an electric field is applied using electrodes 4 and 5. When an electric field of a predetermined strength is applied to the contact point between the first type droplet 11 and the second type droplet 12 to reliably induce fusion of the first type droplet 11 and the second type droplet 12, an electric field EF of a certain strength is applied to the area shown by the dotted line. Since the second type droplets 12 are arranged at a short interval L2, the electric field EF extends to the multiple second type droplets 12 shown by the hatching in the figure. As a result, the second type droplets 12 shown by the hatching tend to fuse together. For example, if two second type droplets 12 fuse together and the volume doubles, when the first type droplet 11 fuses with the second type droplet 12, the volume becomes larger than that of the normally fused droplet 13, and the second type droplet 12 contains twice as many components.

[0020] The inventors have discovered that if fusion of second-type droplets 12 arranged in a short distance from the confluence occurs easily, the size (volume) of the droplet after the first-type droplets 11 and the second-type droplets 12 are fused and the ratio of materials contained in the fused droplet become unstable.

[0021] [Embodiment] 1 is a schematic cross-sectional view for explaining a microchannel device 1 according to an embodiment. The droplets handled by the microchannel device are, for example, droplets of an aqueous phase or a lipophilic phase separated from each other, and can move within a microchannel. The droplets can function, for example, as a reactor for carrying out a chemical reaction. The droplets can also function as a library of oligonucleotide probes, etc.

[0022] The droplets may contain one or more selected from, for example, cells, proteins, peptides, nucleic acid sequences, oligonucleotide probes, polymerase enzymes, buffer solutions, dNTPs, organic or inorganic chemicals, and fluorescent dyes. The droplets may contain any eukaryotic or prokaryotic cells, including cells selected from, for example, human, animal, plant, fungus, bacteria, virus, protozoa, yeast, mold, algae, rickettsia, and prion. The droplets may contain, for example, white blood cells (lymphocytes) used to produce iPS cells. For example, a droplet containing a cell and a droplet containing a drug may be fed into the microfluidic device 1 and fused to induce a predetermined biochemical reaction in the fused droplet.

[0023] The microchannel device 1 according to this embodiment includes a microchannel 2 for flowing a first type of droplet 11 and a microchannel 3 for flowing a second type of droplet 12, and the microchannel 2 and the microchannel 3 are joined at a joining point MP. Electrodes 4 and 5 for generating an AC electric field are disposed near the joining point MP. The first type of droplet 11 moving along the flow direction D1 and the second type of droplet 12 moving along the flow direction D2 meet and come into contact at the joining point MP. When an AC voltage is applied between the electrodes 4 and 5 to generate an AC electric field in the surrounding space, the interface between the first type of droplet 11 and the second type of droplet 12 shown by the hatching becomes easily broken, and the two droplets merge. The fused droplet 13 moves along the flow direction D3 and is used according to the purpose.

[0024] In the present embodiment, elements common to the reference embodiment are denoted by the same reference symbols in the drawings, and descriptions thereof will be simplified or omitted. Unlike the reference embodiment, the present embodiment includes a shield electrode for shielding the second type of droplet 12 from the AC electric field generated by the electrodes 4 and 5 around at least a part of the microchannel 3 through which the second type of droplet 12 flows. In FIG. 1, the shield electrodes are illustrated as shield electrodes 10A and 10B, but the shield electrodes may be a cylindrical integrated electrode surrounding the tube of the microchannel 3, or may be an electrode pair arranged opposite to each other across the microchannel 3.

[0025] Fig. 2 shows a schematic enlarged partial cross-sectional view of the vicinity of the junction. The diagram shows a state in which the first type of droplet 11MP and the second type of droplet 12MP meet at the junction MP and come into contact with each other. In Fig. 2, the first type of droplet 11MP and the second type of droplet 12MP located at the junction are shown shaded for convenience.

[0026] In this embodiment, an AC electric field is formed using the electrodes 4 and 5, and the interface between the first type of droplet 11MP and the second type of droplet 12MP located at the joining point is destroyed to fuse the two droplets. At least while the electrodes 4 and 5 form an AC electric field, a shield potential is applied to the shield electrodes 10A and 10B. That is, while an AC voltage is applied between the electrodes 4 and 5, the potentials of the shield electrodes 10A and 10B are not floated but are fixed to a predetermined reference potential. As the reference potential (fixed potential) applied to the shield electrodes, for example, a ground potential is preferably used, but it may also be the output potential of a predetermined DC constant voltage source.

[0027] Here, in the microchannel 3, the boundary position between the second-type droplet 12MP located at the junction and the adjacent second-type droplet 12 is defined as XP. Also, the length of the second-type droplet 12 in the flow direction D2 (the longitudinal direction of the microchannel 3) (or the average particle diameter of the second-type droplet 12 in the microchannel 3) is defined as DM.

[0028] In this embodiment, it is preferable that the shield electrode 10A and the shield electrode 10B extend across the XP along the microchannel 3 to the junction point MP side beyond the XP. That is, if the distance from the XP to the lower end of the shield electrode 10A and the shield electrode 10B is X1 as viewed along the flow direction D2 of the second type droplet 12, it is preferable that X1>0. Among the boundaries between the second type droplets, the boundary that is most susceptible to the influence of the AC electric field is the boundary between the droplet 12MP closest to the junction point MP and the droplet 12 that is second closest. By making X1>0, it is possible to reduce the strength of the AC electric field at XP and suppress the fusion of these two droplets.

[0029] Moreover, it is preferable that the shield electrode 10A and the shield electrode 10B extend across XP along the microchannel 3 so as to shield at least two or more second-type droplets 12 located on the opposite side of the junction MP with respect to XP from the influence of the AC electric field. That is, if the distance from XP to the upper ends of the shield electrodes 10A and 10B is X2, it is preferable that X2>2×DM. In the microchannel 3, the AC electric field generated by the electrodes 4 and 5 tends to act more strongly at a position closer to the junction, so that in order to prevent the fusion of the second-type droplets 12 with each other, it is preferable to shield at least two droplet interfaces farther than XP.

[0030] According to this embodiment, an electric field is applied to the interface between the first type droplet 11MP and the second type droplet 12MP that come into contact at the junction MP of the microchannels to fuse them, but the provision of a shield electrode suppresses the fusion of the second type droplets 12. Therefore, it is possible to stabilize the size (volume) of the droplet after the first type droplet and the second type droplet are fused and the ratio of materials contained in the droplet after the fusion. EXAMPLES

[0031] Specific examples will be described with reference to the drawings. FIG. 3 is a cross-sectional view showing the shape of the microchannel device 1 according to the example, and the dimensions of each part are shown. The height (depth) of the microchannel and each electrode in the front-rear direction relative to the paper surface is 30 μm. PDMS (polydimethylsiloxane) is used as the base material of the microchannel device 1, and its relative dielectric constant is 2.7. The electrodes 4, 5, shield electrode 10A, and shield electrode 10B are made of metal. HFE (hydrofluoroether) is used as the liquid filling the microchannels 2 and 3, and its relative dielectric constant is 5.8.

[0032] As a comparative example, a microchannel device was set in which shield electrodes 10A and 10B were removed from the embodiment in Fig. 3. For the embodiment and comparative example, the electric field intensity at each point along the center line PL of the microchannel 3 was calculated by numerical analysis. The electric potential of the surface of each electrode was specified as a boundary condition for the numerical analysis.

[0033] The results of the numerical analysis are shown in a graph in Figure 4. The vertical axis indicates the electric field strength at each position, and the horizontal axis indicates the position on the center line PL of the microchannel 3. The scale of the horizontal axis is set to zero at the center position in the height direction of the microchannel 2 (corresponding to the center position of the first type of droplet 11MP).

[0034] In correspondence with FIG. 2, the boundary position between the first type droplet 11MP and the second type droplet 12MP located at the junction corresponds to the position of 30 [μm] on the horizontal axis of FIG. 4. Also, the boundary position XP between the second type droplet 12MP located at the junction and the adjacent second type droplet 12 corresponds to the position of 70 [μm] on the horizontal axis of FIG. 4. The length DM of the second type droplet 12 in the flow direction is 40 [μm]. In order to ensure the fusion of the first type droplet 11MP and the second type droplet 12MP, the peak electric field strength of the AC electric field required at the position of 30 [μm] on the horizontal axis is 4 [kW / mm].

[0035] In the comparative example, the potential of electrode 5 was set to 0 [V], and the potential of electrode 4 was determined so that the electric field strength at the position of 30 [μm] on the horizontal axis was 4 [kW / mm]. Under these conditions, the electric field strength distribution in the comparative example was shown by the dotted line graph in Figure 4. In the comparative example, it can be seen that at XP, which is the position where the second type of droplets contact each other, the electric field strength is about 2 [kW / mm], and there is a high probability that the interface between the second type of droplets with small radii will be destroyed and fusion will occur.

[0036] In the embodiment, the potential of electrode 5, shield electrode 10A, and shield electrode 10B was set to 0 [V], and the potential of electrode 4 was determined so that the electric field strength at the position of 30 [μm] on the horizontal axis was 4 [kW / mm]. In this state, the electric field strength distribution in the embodiment is shown by the solid line graph in Fig. 4. In the embodiment, it can be seen that the electric field strength is suppressed to about 1.2 [kW / mm] at XP, which is the position where the second type of droplets contact each other, and the probability that the interface between the second type of droplets with small radii will be destroyed and fusion will occur is extremely low.

[0037] [Other embodiments] The present invention is not limited to the above-described embodiments and examples, and many modifications are possible within the technical concept of the present invention.

[0038] In the above embodiment, an example was shown in which the first type of droplet 11 is larger than the second type of droplet 12 and the microchannel 2 has a larger cross-sectional area than the microchannel 3, but the present invention is not limited to this. For example, as shown in FIG. 5, a microchannel device 1A may be used in which the cross-sectional areas of the microchannel 2 and the microchannel 3 are substantially equal so that the first type of droplet 11 and the second type of droplet 12, which are equal in size, are fused together. Even in such a form, the provision of a shield electrode prevents the second type of droplets 12 from unnecessarily fusing together. Therefore, it is possible to stabilize the size (volume) of the droplet after the first type of droplet and the second type of droplet are fused together and the ratio of materials contained in the droplet after the fusion.

[0039] In addition, the microchannel 2 transporting the first type of droplet 11 and the microchannel 3 transporting the second type of droplet 12 do not necessarily need to intersect at right angles at the junction. For example, as in the microchannel device 1B shown in FIG. 6, the microchannel 2 and the microchannel 3 may intersect at an obtuse angle. Alternatively, as in the microchannel device 1C shown in FIG. 7, the microchannel 2 and the microchannel 3 may intersect at an acute angle. Even in these configurations, the provision of a shield electrode prevents the second type of droplets 12 from unnecessarily fusing with each other. Therefore, it is possible to stabilize the size (volume) of the droplet after the first type of droplet and the second type of droplet are fused, and the ratio of materials contained in the droplet after the fusion.

[0040] In addition, the electrodes for destroying the interface between the first type droplet 11 and the second type droplet 12 to promote fusion of the two droplets are not limited to the example of the electrodes 4 and 5 shown in the figure. For example, as in the microchannel device 1D shown in FIG. 8, the electrode 4 may be arranged at a position facing the microchannel 3, the electrodes 5A and 5B may be arranged to sandwich the electrode 4, a reference potential (for example, a ground potential) may be applied to the electrodes 5A and 5B, and an AC potential may be applied to the electrode 4. The electrodes 5A and 5B may be configured as a pair of electrodes facing each other with the electrode 4 sandwiched therebetween, or may be a cylindrical integrated electrode surrounding the electrode 4. The shield electrodes 10A and 10B may be configured as a pair of electrodes facing each other with the tube of the microchannel 3 sandwiched therebetween, or may be a cylindrical integrated electrode surrounding the tube of the microchannel 3. Even in these forms, the provision of the shield electrode suppresses unnecessary fusion of the second type droplets 12 with each other. Therefore, it is possible to stabilize the size (volume) of the droplets after the first type of droplets and the second type of droplets are fused, as well as the ratio of materials contained in the droplets after the fusion.

[0041] In addition, an AC voltage may be constantly applied to the electrodes for promoting the fusion of the droplets, but an AC voltage may be applied only when the first type of droplet 11 and the second type of droplet 12 are in the positional relationship illustrated in FIG. 2 at the junction MP. That is, an AC voltage may be applied between the electrodes 4 and 5 only when the first type of droplet 11 and the second type of droplet 12 meet and contact each other at the junction MP. A reference potential (e.g., a ground potential) may be applied to the shield electrode in synchronization with the timing of applying an AC voltage to the electrodes to promote the fusion of the droplets, but a configuration in which the reference potential is constantly applied to the shield electrode may also be used. If a reference potential is constantly applied to the shield electrode, it is possible to prevent the second type of droplets 12 from unnecessarily fusing with each other due to a noise electric field entering from the outside.

[0042] In addition, the first type of droplet 11 reaches the junction MP at intermittent timing, and a position restriction unit may be provided to prevent the second type of droplet 12 present in the microchannel 3 from flowing into the microchannel 2 while the first type of droplet 11 is not present at the junction MP. Specifically, it is preferable to slightly narrow the flow channel cross-sectional area of ​​the microchannel 3 near the junction MP so that the second type of droplet 12 does not naturally pass through the outlet of the microchannel 3. It is preferable that the second type of droplet 12 can pass only when the first type of droplet 11 reaches the junction MP and contacts the second type of droplet 12, and the contact interface between the first type of droplet 11 and the second type of droplet 12 is destroyed by the electric field and fused. The position restriction unit may be a unit that reduces the flow channel cross-sectional shape at the outlet of the microchannel 3 in a similar shape, or may be a unit that provides a protrusion so that the second type of droplet 12 is caught at the outlet of the microchannel 3.

[0043] Furthermore, the shield electrode may be provided not only on the microchannel 3 but also on the side of the microchannel 2. It is possible to suppress unnecessary fusion of the first type of droplets 11 with each other due to not only the electric field generated by applying an AC voltage between the electrodes 4 and 5 but also the noise electric field entering from the outside.

[0044] In addition, the types of droplets that fuse in the microchannel device are not limited to two, and may be, for example, a microchannel device in which droplets of the same type are transported through two microchannels and fuse at a junction. By providing a shield electrode, it is possible to stabilize the size (volume) of the droplets after the droplets fuse.

[0045] Alternatively, as shown in FIG. 9, a microchannel device 1E may be used in which a first type of droplet 11 and a second type of droplet 12 shown in a shaded area are fused to form a droplet 13, and then a third type of droplet 12A is fused downstream to form a droplet 16. Electrodes 14 and 15 for fusion of the droplet 12A and the droplet 13 shown in a shaded area at a junction and shield electrodes 113A and 113B for suppressing fusion of the third type of droplets 12A are disposed near a microchannel 3A (third microchannel) that transports the third type of droplet 12A. In the example of FIG. 10, three types of droplets are fused, but a unit having a similar configuration may be added to further fuse a fourth type of droplet, a fifth type of droplet, etc. Even in these forms, unnecessary fusion of the second type of droplets 12 or the third type of droplets 12A is suppressed by providing a shield electrode. Therefore, it is possible to stabilize the size (volume) of the droplets after the three types of droplets are fused, as well as the ratio of materials contained in the droplets after the fusion.

[0046] When implementing the present invention, all or part of the different embodiments described above may be combined.

[0047] This specification discloses at least the following: [Item 1] a flow path system in which a first microflow path for causing a plurality of droplets of a first type to flow and a second microflow path for causing a plurality of droplets of a second type to flow join at a joining point; a first electrode that applies an electric field to an interface between the first type of droplets and the second type of droplets that contact each other at the joining point, the electric field promoting fusion of the first type of droplets and the second type of droplets; a second electrode for suppressing the effect of an electric field generated by the first electrode on an interface between the second type of droplets present in the second microchannel; A droplet treatment device comprising: [Matter 2] When the first electrode exerts the electric field, a fixed potential is applied to the second electrode. 2. The droplet treatment device according to item 1, [Matter 3] The second electrode is a cylindrical electrode disposed along the second microchannel so as to surround the second microchannel. 3. The droplet treatment device according to item 1 or 2, [Matter 4] The second electrodes are an electrode pair facing each other across the second microchannel. 3. The droplet treatment device according to item 1 or 2, [Matter 5] The first electrode is located on the opposite side of the second microchannel with respect to the junction. 5. A droplet treatment device according to any one of claims 1 to 4. [Matter 6] The second electrode is located on the opposite side of the first electrode with respect to the junction. 6. A droplet treatment device according to any one of claims 1 to 5. [Matter 7] the second microchannel includes a position restriction portion for restricting a position of the second type of droplet in the vicinity of the junction; 7. A droplet treatment device according to any one of claims 1 to 6. [Matter 8] When the boundary between the second type droplet closest to the confluence and the second type droplet second closest to the confluence is XP, The second electrode extends to a position closer to the confluence than the position of the XP when the second type of droplet closest to the confluence meets the first type of droplet. 8. A droplet treatment device according to any one of claims 1 to 7. [Matter 9] When the diameter of the second type of droplet in the longitudinal direction of the second microchannel is DM, The second electrode extends over a length at least twice the DM on the opposite side of the confluence with respect to the position of the XP when the second type of droplet closest to the confluence meets the first type of droplet. 9. The droplet treatment device according to item 8, [Matter 10] In the first microchannel, a plurality of the first type of droplets are transported toward the junction at a first interval; In the second microchannel, the second type of droplets are transported toward the junction at a second interval smaller than the first interval. 10. A droplet treatment device according to any one of claims 1 to 9. [Matter 11] The first microchannel and the second microchannel are connected perpendicularly at the junction. 11. A droplet treatment device according to any one of claims 1 to 10. [Matter 12] The first microchannel and the second microchannel are connected at the junction at an acute angle. 11. A droplet treatment device according to any one of claims 1 to 10. [Matter 13] The first microchannel and the second microchannel are connected at the junction at an obtuse angle. 11. A droplet treatment device according to any one of claims 1 to 10. [Matter 14] the flow channel system includes a second junction downstream of the junction where a third microchannel for causing a plurality of third type droplets to flow joins; a third electrode for applying an electric field to an interface between the droplet obtained by fusing the first type of droplet and the second type of droplet and the third type of droplet, the electric field promoting the fusion of the droplets; and a fourth electrode for suppressing the effect of an electric field generated by the third electrode on an interface between the third type of droplets present in the third microchannel. 14. A droplet treatment device according to any one of claims 1 to 13. [Matter 15] a flow path system in which a first microflow path for causing a plurality of droplets of a first type to flow and a second microflow path for causing a plurality of droplets of a second type to flow join at a joining point; a first electrode that applies an electric field to an interface between the first type of droplets and the second type of droplets that contact each other at the joining point, the electric field promoting fusion of the first type of droplets and the second type of droplets; A method for treating droplets using using a second electrode to suppress the action of an electric field generated by the first electrode on an interface between the second type of droplets present in the second microchannel; A method for treating droplets comprising the steps of: [Matter 16] When the first electrode exerts the electric field, a fixed potential is applied to the second electrode. 16. The method for treating droplets according to item 15, [Matter 17] The second electrode is a cylindrical electrode disposed along the second microchannel so as to surround the second microchannel. 17. The method for treating droplets according to item 15 or 16, [Matter 18] The second electrodes are an electrode pair facing each other across the second microchannel. 17. The method for treating droplets according to item 15 or 16, [Matter 19] The first electrode is located on the opposite side of the second microchannel with respect to the junction. 19. A method for treating droplets according to any one of items 15 to 18, [Matter 20] The second electrode is located on the opposite side of the first electrode with respect to the junction. 20. A method for treating droplets according to any one of claims 15 to 19. [Matter 21] the second microchannel includes a position restriction portion for restricting a position of the second type of droplet in the vicinity of the junction; 21. A method for treating droplets according to any one of claims 15 to 20. [Matter 22] When the boundary between the second type droplet closest to the confluence and the second type droplet second closest to the confluence is XP, The second electrode extends to a position closer to the confluence than the position of the XP when the second type of droplet closest to the confluence meets the first type of droplet. 22. A method for treating droplets according to any one of claims 15 to 21. [Matter 23] When the length of the second type of droplet in the longitudinal direction of the second microchannel is DM, The second electrode extends over a length at least twice the DM on the opposite side of the confluence with respect to the position of the XP when the second type of droplet closest to the confluence meets the first type of droplet. 23. The method for treating droplets according to item 22. [Matter 24] In the first microchannel, a plurality of the first type of droplets are transported toward the junction at a first interval; In the second microchannel, the second type of droplets are transported toward the junction at a second interval smaller than the first interval. 24. A method for treating droplets according to any one of claims 15 to 23. [Matter 25] The first microchannel and the second microchannel are connected perpendicularly at the junction. 25. A method for treating droplets according to any one of claims 15 to 24. [Matter 26] The first microchannel and the second microchannel are connected at the junction at an acute angle. 25. A method for treating droplets according to any one of claims 15 to 24. [Matter 27] The first microchannel and the second microchannel are connected at the junction at an obtuse angle. 25. A method for treating droplets according to any one of claims 15 to 24. [Explanation of symbols]

[0048] 1, 1A, 1B, 1C, 1D···Microchannel device / 2···Microchannel / 3···Microchannel / 4, 5···Electrode / 10A, 10B···Shield electrode / 11···First type of droplet / 12···Second type of droplet / 12A···Third type of droplet / 11MP···First type of droplet / 12MP···Second type of droplet / 13···Droplet / 14, 15···Electrode / 16···Droplet / 113A, 113B···Shield electrode / MP··Confluence point

Claims

1. a flow path system in which a first microflow path for causing a plurality of droplets of a first type to flow and a second microflow path for causing a plurality of droplets of a second type to flow are joined at a joining point; a first electrode that applies an electric field to an interface between the first type of droplets and the second type of droplets that contact each other at the joining point, the electric field promoting fusion of the first type of droplets and the second type of droplets; a second electrode for suppressing the action of an electric field generated by the first electrode on an interface between the second type of droplets present in the second microchannel; A droplet treatment device comprising:

2. A fixed potential is applied to the second electrode when the first electrode exerts the electric field.

2. The droplet treatment device according to claim 1.

3. The second electrode is a cylindrical electrode disposed along the second microchannel so as to surround the second microchannel.

2. The droplet treatment device according to claim 1.

4. The second electrodes are an electrode pair facing each other across the second microchannel.

2. The droplet treatment device according to claim 1.

5. The first electrode is located on the opposite side of the second microchannel with respect to the junction.

5. A droplet treatment device according to claim 1, wherein the droplet treatment device is a droplet treatment device.

6. The second electrode is located on the opposite side of the first electrode with respect to the junction.

5. A droplet treatment device according to claim 1, wherein the droplet treatment device is a droplet treatment device.

7. the second microchannel includes a position restriction portion for restricting a position of the second type of droplet in the vicinity of the junction; 5. A droplet treatment device according to claim 1, wherein the droplet treatment device is a droplet treatment device.

8. When the boundary between the second type droplet closest to the confluence point and the second type droplet second closest to the confluence point is defined as XP, the second electrode extends to a position closer to the confluence than the position of the XP when the second type of droplet closest to the confluence meets the first type of droplet; 5. A droplet treatment device according to claim 1, wherein the droplet treatment device is a droplet treatment device.

9. When the diameter of the second type of droplet in the longitudinal direction of the second microchannel is DM, The second electrode extends over a length at least twice the DM on the opposite side of the confluence point with respect to the position of the XP when the second type of droplet closest to the confluence point meets the first type of droplet.

9. The droplet treatment device according to claim 8.

10. In the first microchannel, a plurality of the first type of droplets are transported toward the junction at a first interval; In the second microchannel, the second type of droplets are transported toward the junction at a second interval smaller than the first interval.

5. A droplet treatment device according to claim 1, wherein the droplet treatment device is a droplet treatment device.

11. The first microchannel and the second microchannel are connected perpendicularly at the junction.

5. A droplet treatment device according to claim 1, wherein the droplet treatment device is a droplet treatment device.

12. The first microchannel and the second microchannel are connected at the junction at an acute angle.

5. A droplet treatment device according to claim 1, wherein the droplet treatment device is a droplet treatment device.

13. The first microchannel and the second microchannel are connected at the junction at an obtuse angle.

5. A droplet treatment device according to claim 1, wherein the droplet treatment device is a droplet treatment device.

14. the flow channel system includes a second junction downstream of the junction where a third microchannel for causing a plurality of third type droplets to flow joins; a third electrode for applying an electric field to an interface between the droplet obtained by fusing the first type of droplet and the second type of droplet and the third type of droplet, the electric field promoting the fusion of the droplets; a fourth electrode for suppressing the action of an electric field generated by the third electrode on an interface between the third type of droplets present in the third microchannel; 5. A droplet treatment device according to claim 1, wherein the droplet treatment device is a droplet treatment device.

15. a flow path system in which a first microflow path for causing a plurality of droplets of a first type to flow and a second microflow path for causing a plurality of droplets of a second type to flow are joined at a joining point; a first electrode that applies an electric field to an interface between the first type of droplets and the second type of droplets that contact each other at the joining point, the electric field promoting fusion of the first type of droplets and the second type of droplets; A method for treating droplets using using a second electrode to suppress the action of an electric field generated by the first electrode on an interface between the second type of droplets present in the second microchannel; A method for treating droplets comprising the steps of:

16. A fixed potential is applied to the second electrode when the first electrode exerts the electric field.

16. A method for treating droplets according to claim 15.

17. The second electrode is a cylindrical electrode disposed along the second microchannel so as to surround the second microchannel.

16. A method for treating droplets according to claim 15.

18. The second electrodes are an electrode pair facing each other across the second microchannel.

16. A method for treating droplets according to claim 15.

19. The first electrode is located on the opposite side of the second microchannel with respect to the junction.

19. A method for treating droplets according to any one of claims 15 to 18.

20. The second electrode is located on the opposite side of the first electrode with respect to the junction.

19. A method for treating droplets according to any one of claims 15 to 18.

21. the second microchannel includes a position restriction portion for restricting a position of the second type of droplet in the vicinity of the junction; 19. A method for treating droplets according to any one of claims 15 to 18.

22. When the boundary between the second type droplet closest to the confluence point and the second type droplet second closest to the confluence point is defined as XP, the second electrode extends to a position closer to the confluence than the position of the XP when the second type of droplet closest to the confluence meets the first type of droplet; 19. A method for treating droplets according to any one of claims 15 to 18.

23. When the length of the second type of droplet in the longitudinal direction of the second microchannel is DM, The second electrode extends over a length at least twice the DM on the opposite side of the confluence point with respect to the position of the XP when the second type of droplet closest to the confluence point meets the first type of droplet.

23. A method for treating droplets according to claim 22.

24. In the first microchannel, a plurality of the first type of droplets are transported toward the junction at a first interval; In the second microchannel, the second type of droplets are transported toward the junction at a second interval smaller than the first interval.

19. A method for treating droplets according to any one of claims 15 to 18.

25. The first microchannel and the second microchannel are connected perpendicularly at the junction.

19. A method for treating droplets according to any one of claims 15 to 18.

26. The first microchannel and the second microchannel are connected at the junction at an acute angle.

19. A method for treating droplets according to any one of claims 15 to 18.

27. The first microchannel and the second microchannel are connected at the junction at an obtuse angle.

19. A method for treating droplets according to any one of claims 15 to 18.

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