JP6949356B2 - Microfluidic chip for droplet production - Google Patents

Description

The present invention relates to a microfluidic chip for producing droplets.

In fields such as biotechnology and chemical manufacturing, the dispersed phase (droplet) in a dispersed solution (emulsion) in which both the dispersed phase and the continuous phase are liquids is widely used as a material for forming microreaction vessels and microcells. Has been done.

Usually, a microfluidic chip is used for producing a droplet, and as a microfluidic chip for producing a droplet, for example, there is one described in Patent Document 1.

The microfluidic chip described in Patent Document 1 includes a plate-shaped chip body formed of a synthetic resin capable of occluding gas, and a substrate bonded to one surface of the chip body in an airtightly sealed state. doing.
The chip body is provided with first to third liquid reservoirs and first to third pipelines extending from the bottoms of the first to third liquid reservoirs and connecting to each other at one point.

Then, the microfluidic chip is degassed under reduced pressure with the third liquid reservoir covered, and after degassing, the third liquid reservoir is placed under atmospheric pressure with the lid covered. , The liquid that becomes the continuous phase is injected into the first liquid reservoir, while the liquid that becomes the dispersed phase is injected into the second liquid reservoir.

In this way, due to the gas storage action of the synthetic resin, the liquid that becomes a continuous phase from the first liquid reservoir is sent to the third liquid reservoir through the first conduit, and at the same time, is dispersed from the second liquid reservoir. The phase liquid is sent to the third liquid reservoir through the second conduit, and an emulsion is formed at the connecting portion between the first and second conduits and the third conduit, and the third A liquid droplet that becomes a dispersed phase is collected together with a liquid that becomes a continuous phase in the liquid reservoir.

This microfluidic chip for producing droplets eliminates the need for a syringe pump or other micropump for feeding the liquid as a continuous phase and the liquid as a dispersed phase to the first and second liquid reservoirs, respectively. Therefore, the droplets can be easily produced at low cost.
However, there is a problem that the maximum number of droplets that can be produced per second is about 10, and the productivity of the droplets is very low.

Japanese Unexamined Patent Publication No. 2015-211931

Therefore, an object of the present invention is to provide a microfluidic chip capable of mass-producing droplets at low cost and in a short time.

In order to solve the above problems, according to the present invention, a plate-shaped chip body formed of a synthetic resin capable of storing a gas and a first substrate bonded to one surface of the chip body in close contact with each other. On the other surface of the chip body, a first liquid reservoir for storing a liquid to be a continuous phase, a second liquid reservoir for storing a liquid to be a dispersed phase, and a third liquid reservoir for collecting droplets are provided. The liquid reservoir is opened, and the chip main body is provided with first to third pipelines extending from the bottoms of the first to third liquid reservoirs and connecting to each other at one point, and further, the chip main body is provided with first to third pipelines. A second substrate is provided in close contact with the other surface, and the second substrate is provided with first and second through holes that match the first and second liquid reservoirs, respectively. Further, it is formed inside the chip body, between the chip body and the second substrate, or both of them, and has a closed microstructural space communicating with the third liquid reservoir. A microfluidic chip for producing droplets is provided.

According to a preferred embodiment of the present invention, the microstructure space is composed of fine grooves formed in a mesh shape on the other surface of the chip body, and the mesh-like fine grooves are the third. It is formed so as to connect to the opening edge of the liquid reservoir of the above, but not to reach the opening edge of the first and second liquid reservoirs and the outer edge of the other surface.
According to another preferred embodiment of the present invention, the mesh-like fine grooves are composed of grid-like fine grooves.

According to the present invention, the chip body of a microfluidic chip is formed of a synthetic resin capable of occluding gas, and the first and second substrates are bonded to both sides of the chip body in a close contact state, and the inside of the chip body is also formed. , Or between the chip body and the second substrate, or both, a closed microstructure space communicating with the third liquid reservoir was formed, and the internal space of the third liquid reservoir was expanded by the microstructure space. ..

As a result, when the microfluidic chip is placed under reduced pressure, the chip body is degassed, and also from the inside of the first to third liquid reservoirs (including the microstructural space) and the first to third pipelines. Air is released to the outside.
Then, when the degassed microfluidic chip is placed under atmospheric pressure, air is directed from the first and second liquid reservoirs to the third liquid reservoir (including the microstructural space) through the first to third pipelines. At this time, when the liquid that becomes the continuous phase and the liquid that becomes the dispersed phase are injected into the first and second liquid reservoirs, the liquid that becomes the continuous phase autonomously passes through the first conduit. At the same time that the liquid is sent to the third liquid reservoir, the liquid to be the dispersed phase is autonomously sent to the third liquid reservoir through the second conduit, and the first and second liquids are sent. An emulsion is formed at the connecting portion between the conduit and the third conduit, and droplets of the liquid to be the dispersed phase are collected together with the liquid to be the continuous phase in the third liquid reservoir.

This process of liquid transfer and emulsion formation continues as long as the closed space left in the third liquid reservoir (including the microstructure space) is maintained in a reduced pressure state.
By the way, the level of decompression increases as the rate of dissolution (occlusion) of air in the closed space into the chip body increases, and the rate of liquid feeding and emulsion formation increases as the level of decompression increases.

In this case, the volume of the closed space is V, the area of the chip body occupied in the closed space is S, and the larger the S / V ratio, the higher the dissolution (occlusion) rate of air in the closed space into the chip body. As a result, the speed of liquid feeding and emulsion formation increases.

Then, according to the present invention, by communicating the microstructure space with the third liquid reservoir and expanding the third liquid reservoir, the S / V ratio is significantly increased as compared with the case of the third liquid reservoir alone. This made it possible to mass-produce droplets in a short time.

It is a perspective view of the microfluidic chip for manufacturing a droplet according to 1 Example of this invention. It is a perspective view which partially disassembled the microfluidic chip for manufacturing a droplet of FIG. It is a figure which shows the arrangement of the liquid pool and the conduit of the microfluidic chip for manufacturing a droplet of FIG. 1, (A) is a plan view, (B) is an enlarged view of a part of (A). It is a vertical cross-sectional view of the vicinity of the third liquid reservoir of the microfluidic chip for manufacturing droplets of FIG. It is a figure which shows the grid-like fine groove of the microfluidic chip for manufacturing a droplet of FIG. 1, (A) is a plan view which shows the size of the formation region of the groove, (B) is one It is an enlarged view of the part, (C) is a cross-sectional view along the XX line of (B). It is a graph which shows the experimental result, (A) is a graph which shows the time-dependent change of the droplet generation rate and the total number of droplets generated by the microfluidic chip for droplet production of the present invention, and (B) has a microstructure space. It is a graph which shows the time change of the droplet generation rate and the total number of droplets generated by a microfluidic chip for producing droplets.

Hereinafter, the configuration of the present invention will be described with reference to the accompanying drawings, based on preferred embodiments.
FIG. 1 is a perspective view of a microfluidic chip for producing droplets according to an embodiment of the present invention, and FIG. 2 is a perspective view of the microfluidic chip for producing droplets of FIG. 1 partially disassembled. FIG. 3A is a plan view showing the arrangement of the liquid reservoir and the pipeline of the microfluidic chip for producing droplets of FIG. 1, and FIG. 3B is an enlarged view of a part of FIG. 3A. Further, FIG. 4 is a vertical cross-sectional view of the vicinity of the third liquid reservoir of the microfluidic chip for producing droplets of FIG.

With reference to FIGS. 1 and 2, the microfluidic chip for producing droplets according to the present invention has a plate-shaped chip body 1 having a constant thickness and formed of a synthetic resin capable of occluding gas. In this example, polydimethylsiloxane (PDMS) is used as the synthetic resin that forms the chip body 1.

The chip body 1 is provided with three columnar holes 2 to 4 penetrating from one surface 1a side to the other surface 1b side. In this case, the diameters of the three holes 2 to 4 are set so that the total value of the volume of the first hole 2 and the volume of the second hole 3 is smaller than the volume of the third hole 4. It is set.

As shown in FIGS. 3A and 3B, one surface 1a of the chip body 1 has a fine first groove 5 connected to the opening edge of the first hole 2 and an opening edge of the second hole 3. A fine second groove 6 to be connected and a fine third groove 7 to be connected to the opening edge of the third hole 4 are provided, and the first to third grooves 5 to 7 are connected to each other at one point P. ing.

The first to third grooves 5 to 7 are formed in a tapered shape from the front side of the connection point P toward the connection point P, respectively.
In this embodiment, each of the first to third grooves 5 to 7 has the same depth over the entire length thereof, and a wide portion 5a to extend from the related holes 2 to 4 to the front of the connection point P. It is composed of 7a, tapered portions 5b to 7b which are connected to the tips of wide portions 5a to 7a and gradually narrow in width, and narrow portions 5c to 7c extending from the tips of the tapered portions 5b to 7b to the connection point P. ..

Further, at the connection point P, the first to third grooves 5 to 7 are one of the first and second grooves 5 and 6 (in this embodiment, the first groove 5) and the third groove. 7 becomes a straight line, and the other of the first and second grooves 5, 6 (in this embodiment, the second groove 6) is arranged orthogonal to the third groove 7 so as to be T-shaped with each other. It is connected.

With reference to FIGS. 1, 2 and 4, the first substrate 8 is in close contact with the surface (one surface 1a) of the chip body 1 provided with the first to third grooves 5 to 7. It is joined with. In this case, due to the strong self-adsorption property of PDMS forming the chip body 1, the chip body 1 and the first substrate 8 can be joined in close contact with each other simply by bringing them into contact with each other.

The first substrate 8 is made of an acrylic plate in this embodiment.
The material for forming the first substrate 8 is not limited to this embodiment, and the first substrate 8 is made of a synthetic resin of a different type from the acrylic resin or a synthetic resin of the same type as the resin forming the chip body 1. It may be formed, or a glass plate may be used as the first substrate 8.

By joining the chip body 1 and the first substrate 8, one end openings (openings on one surface 1a side) of the first to third holes 2 to 4 of the chip body 1 are closed, and the microfluidic chip is formed. The first to third liquid reservoirs m _{1 to} m _{3 of the above} are formed, and the upper openings of the first to third grooves 5 to 7 of the chip body 1 are closed to form the first microfluidic chip. ~ Third pipelines n _{1 to} n ₃ are formed.

Then, the first _{liquid reservoir m 1} functions as a liquid reservoir for storing the liquid which becomes the continuous phase, and the second liquid reservoir m ₂ functions as a liquid reservoir for storing the liquid which becomes the dispersed phase, and the third liquid reservoir m 2 functions. The _{liquid reservoir m 3} of the above functions as a liquid reservoir for collecting droplets.

_{The two-dimensional arrangement of the first to third} liquid reservoirs m _{1 to} m 3 and the first to third pipelines n _{1 to} n ₃ is not limited to the above embodiment, and may vary. A modified example is possible.
A plurality of, for example, in the above embodiment, is provided with the first to third liquid reservoir _m 1 ~m ₃ only one pair to the microfluidic chip, the first to third set of reservoir _m 1 ~m ₃ It may be provided as a set.

In the above embodiment, first through but the third line n ₁ ~n ₃ is connected in a T-shape with each other, the second conduit n ₂ extending from the second liquid reservoir m ₂ pair At the connection point P, the set of the first pipeline n _{1 and} the pair of the second and third pipelines n ₂ and n ₃ may be connected to each other in a cross shape.
Alternatively, the chip body 1 is provided with two first liquid reservoirs m ₁ and one second and third liquid reservoirs m ₂ and m ₃ , respectively, and extends from the two first liquid reservoirs m _1. A set of two first pipelines n _{1 and} a pair of second and third pipelines n ₂ and n ₃ may be connected to each other in a cross shape at one point.

FIG. 5A is a plan view showing the size of the formation region of the grid-shaped fine groove 9, FIG. 5B is an enlarged view of a part of the grid-shaped fine groove 9, and FIG. 5C is a view. It is sectional drawing along the XX line of 5B.
With reference to FIGS. 2 and 5A to 5C, fine grooves 9 are formed in a grid shape on the other surface 1b of the chip body 1.

The grid-shaped fine grooves 9 are _{connected to the third liquid reservoir m 3 , but do not reach the opening edges of the first and second} liquid reservoirs m ₁ and m 2 and the outer edge of the other surface 1 b. It has become.
In this embodiment, the grid-shaped fine grooves 9 are formed by subjecting the other surface 1b of the chip body 1 to fine grooves in the vertical and horizontal directions by using a laser marker. The method of forming the grid-shaped fine grooves 9 is not limited to this embodiment.
Further, the two-dimensional formation pattern of the fine groove 9 is not particularly limited, and may have any shape as long as it has a mesh shape.

As shown in FIGS. 1 and 2, the second substrate 10 is joined to the other surface 1b (the surface on which the grid-like fine grooves 9 are formed) of the chip body 1 in a close contact state, and the second substrate 10 is joined. The substrate 10 is provided with first and second through holes 11 and 12 matching the first and _{second liquid reservoirs m 1} and m 2, respectively.
In this case as well, as in the case of the first substrate 8, due to the strong self-adsorption property of PDMS forming the chip body 1, the chip body 1 and the second substrate 10 are simply brought into contact with each other to join them in close contact with each other. can do.

The second substrate 10 is made of an acrylic plate in this embodiment.
The material for forming the second substrate 10 is not limited to this embodiment, and the second substrate 10 is made of a synthetic resin of a different type from the acrylic resin or a synthetic resin of the same type as the resin forming the chip body 1. It may be formed, or a glass plate may be used as the second substrate 10. Further, the second substrate 10 may be formed of a material different from that of the first substrate 8.

As shown in FIG. 4, by joining the chip body 1 and the second substrate 10, the upper opening of the grid-like fine groove 9 is closed, and the third substrate 10 is sandwiched between the chip body 1 and the second substrate 10. communicating with closed microstructure space f is formed on the sump m _3. By the microstructure space f, the internal space of the third liquid reservoir m ₃ is expanded.

Next, a mode of use of the microfluidic chip for producing droplets of the present invention will be described.
First, the microfluidic chip is placed under reduced pressure to degas the chip body 1, and the first to third liquid reservoirs m1 to m3 (including the microstructure space f) and the first to third liquid _{reservoirs m 1 to m 3 (including the microstructure space f).} Air is also discharged to the outside from the inside of the pipelines n _{1 to} n _3.

The degassed microfluidic chip is then placed under atmospheric pressure. As a result, dissolution (occlusal) of air into the chip body 1 is started, and at the same time, the first and second liquid reservoirs m ₁ , m ₂ through the first to third pipelines n _{1 to} n _{3 are used} . Air flows into the liquid reservoir m ₃ (including the microstructure space f) of No. 3, and at this time, the liquid and the dispersed phase which are continuous phases are formed _{in the first and second liquid reservoirs m 1} and m _{2, respectively.} Liquid is injected.

In this way, the liquid that becomes the continuous phase is autonomously _{sent to the third} liquid reservoir m3 through the _first conduit n1, and at the same time, the liquid that becomes the dispersed phase is autonomously second. Liquid is sent through the conduit n _{2 toward the third} liquid reservoir m 3, and the emulsion is formed at the connection point P between the first and second conduits n ₁ , n ₂ and the third conduit n _3. A liquid droplet that is formed and becomes a dispersed phase is collected in a _third liquid reservoir m3 together with a liquid that becomes a continuous phase.

This process of liquid feed and the emulsion product, the third reservoir m ₃ enclosed space that is left _{(microstructure} including space f) in the lasts is maintained in a reduced pressure state.
By the way, the level of depressurization increases as the rate of dissolution (occlusion) of air in the closed space into the chip body 1 increases, and the rate of liquid feeding and emulsion formation increases as the level of decompression increases.

In this case, the volume of the closed space is V, the area of the chip body 1 occupying the closed space is S, and the larger the S / V ratio, the higher the dissolution (occlusion) rate of air in the closed space into the chip body. As a result, the speed of liquid feeding and emulsion formation increases.

According to the present invention, made to communicate with the microstructure space f to a third reservoir m ₃ extends third reservoir m _3, the ratio S / V than in the third reservoir m ₃ alone By increasing the amount significantly, the speed of liquid feeding and emulsion formation was increased, so that it became possible to mass-produce droplets in a short time.

Further, according to the present invention, a micro pump such as a syringe pump for sending a liquid to be a continuous phase and a liquid to be a dispersed phase from the first and second liquid reservoirs to the third liquid reservoir, respectively. It becomes unnecessary, and if the liquids that become the continuous phase and the liquids that become the dispersed phases are injected into the first and second liquid reservoirs, respectively, each liquid autonomously flows toward the third liquid reservoir. There is no need to control the flow rate of the liquid. In this way, the droplet can be produced easily and at low cost.

Although the preferred embodiment of the present invention has been described above, the configuration of the present invention is not limited to the above embodiment, and various modifications can be devised within the scope of the matters described in the appended claims.
For example, in the above embodiment, the fine structural space f is formed between the chip main body 1 and the second substrate 10 by the grid-shaped fine grooves 9 formed on the other surface 1b of the chip main body 1, but the fine structural space f is formed. f, the internal chip body 1 or between chip body 1 and the second substrate 10, or formed on both of them, what if only a closed space communicates with the third liquid reservoir m ₃ It may be configured, and in this case, it is preferable that the configuration is such that the S / V ratio as large as possible can be obtained.

[experiment]
Next, in order to confirm the effect of the present invention, an experiment was conducted and the result was evaluated.
In the experiment, a microfluidic chip having the same configuration as that shown in FIGS. 1 to 5 was prepared. The dimensions of each part of the microfluidic chip are as follows.
(I) Chip body 1: Length 50 mm x width 70 mm x thickness 4 mm
(One side 1a side)
-Diameter of the first liquid reservoir m ₁ : d ₁ = 6 mm
-Diameter of the second liquid reservoir m ₂ : d ₂ = 4 mm
- third of the diameter of the reservoir _{m 3:} d ₃ = 8mm
-Distance between the center of the first liquid reservoir m ₁ and the point P in the _{lateral direction of the chip body: L 1} = 7 mm
-Distance between the center of the second liquid reservoir m ₂ and the point P in the _{lateral direction of the chip body: L 2} = 7 mm
_{-Distance between the center of the second liquid reservoir m 2} (first liquid reservoir m ₁ ) and the point P in the vertical direction of the chip body _{L 3} = 7.5 mm
-Distance between the center of the third liquid reservoir m ₃ and the point P in the _{vertical direction of the chip body L 4} + L ₅ = 7.5 mm
- of the chip body longitudinal direction, the distance between the connection point between the center and the third conduit _{n 3} of the third liquid reservoir _{m 3:} L 5 = 1mm
- first to third line _n 1 ~n ₃ depth: 50 [mu] m
- first to third line _n 1 ~n ₃ of the wide portion 5a, 6a, 7a of the respective _widths: d 4 = 250 [mu] m
- length of each of the first to third line _n 1 ~n ₃ of the tapered portion _{5b, 6b, 7b: d 5} = 300μm
- first to third line _n 1 ~n _third narrow portion 5c, 6c, 7c of the respective _widths: d 6 = 50 [mu] m
- the length of the first conduit _{n 1} narrow portion 5c _d 7 = 0.2 mm
_{The length d 8} = 0.2 mm of the narrow portion 6c of the second pipeline n _2.
- length of the third conduit _{n 3} of narrow portions 7c _d 9 = 2 mm
(The other surface 1b side)
-Size of the formation region of the grid-like fine groove 9 (see FIG. 5A)
L ₆ = 50 mm, L ₇ = 34 mm, L ₈ = 25 mm, L ₉ = 25 mm, L ₁₀ = 17 mm, L ₁₁ = 17 mm
-Width of the groove portion forming the grid-like fine groove 9 d ₁₀ = 40 μm
・ Depth of the groove portion forming the grid-like fine groove 9 d ₁₁ = 5 μm
・ Spacing between grids d ₁₂ = 120 μm
(Ii) First substrate 8: length 52 mm × width 76 mm × thickness 2 mm
(Iii) Second substrate 10: length 50 mm × width 70 mm × thickness 2 mm
-Diameter of the first through hole 11: 6 mm
-Diameter of the second through hole 12: 4 mm

In the above design specifications, the total volume (V) of the fine structure space f based on the grid-like fine grooves 9 is 2.22 × 10 ^-3 cm ³ , and the chip body 1 (PDMS) occupying the fine structure space f. ) Occupies 9.60 × 10 ^-1 cm ² , so S / V = 432 cm ^-1 .
Further, for the third liquid reservoir m ₃ , S / V = 5.0 cm ^-1 .
Therefore, the S / V of _{the third liquid reservoir m 3} expanded by the fine structure space f ^{is 9.6 cm -1} .

This microfluidic chip is housed in a vacuum desiccator with a built-in pump, the pump is operated to depressurize the inside of the desiccator, and when the inside of the desiccator reaches a predetermined pressure value, the pump is stopped to depressurize the inside of the desiccator for 90 minutes. The state was maintained and the microfluidic chip was degassed.

After degassing completion, with introducing the outside air into the desiccator, quickly in the desiccator, was injected first oil phase in reservoir _{m 1} (Novec7500 containing 2% Pico-Surf (R) 1) 150 [mu] L, the 20 μL of an aqueous phase (0.18 (w / v)% indicocarmine solution) was injected into _{m 2} of the liquid reservoir of 2.

Then, to generate a water-in-oil (emulsion) in the connecting point P between the first and second conduit n _1, n ₂ and the third conduit n _3, it was collected in a third reservoir m ₃ ..
At this time, a high-speed camera (DITECT, HAS-D71) connected to an inverted fluorescence microscope (WRAYMER, AXJ-5300TPHFL MODEL) was used to record the formation of water droplets in oil at the connection point P.

After the process of forming water droplets in oil was completed, the recorded image was analyzed to measure the time change of the droplet formation rate with reference to the time point at which the oil phase and the liquid phase intersected at the connection point P. Furthermore, the time change of the total number of droplets produced was calculated by integrating the obtained generation rates.
The results are shown in the graph of FIG. 6A. In the graph of FIG. 6A, the vertical axis represents the droplet generation rate (Hz) or the total number of droplets generated, and the horizontal axis represents time (min). Further, the curve I represents the rate of droplet formation, and the curve II represents the total number of droplets generated.

Next, as a comparative example, a microfluidic chip different from that shown in FIGS. 1 to 5 only in that it does not have a grid-like fine groove 9 is prepared, and using this microfluidic chip, the same as above Then, droplets were produced, and the state of water droplets in oil at the connection point P of the microfluidic chip was recorded on a high-speed camera.

Then, in the same manner as before, by analyzing the recorded image, the time change of the droplet formation rate was measured with reference to the time point at which the oil phase and the liquid phase intersected at the connection point P. Furthermore, the time change of the total number of droplets produced was calculated by integrating the obtained generation rates.
The results are shown in the graph of FIG. 6B. In the graph of FIG. 6B, the vertical axis represents the droplet generation rate (Hz) or the total number of droplets generated, and the horizontal axis represents time (min). Further, the curve I represents the rate of droplet formation, and the curve II represents the total number of droplets generated.

From the comparison between the graph of FIG. 6A and the graph of FIG. 6B, _{by expanding the third} liquid reservoir m3 by the microstructural space, the rate of droplet formation is dramatically increased, and the liquid per fixed time is accompanied by this. It was confirmed that the total number of drops produced also increased significantly.

1 Chip body 1a One surface 1b The other surface 2 First hole 3 Second hole 4 Third hole 5 First groove 6 Second groove 7 Third groove 8 First substrate 9 Grid-like Fine groove 10 Second substrate 11 First through hole 12 Second through hole f Microstructure space m ₁ First liquid reservoir m ₂ Second liquid reservoir m ₃ Third liquid reservoir n ₁ First Pipeline n ₂ Second lineage n ₃ Third lineway P Connection point

Claims (3)

A plate-shaped chip body made of synthetic resin that can occlude gas,
A first substrate bonded to one surface of the chip body in close contact with the chip body is provided.
On the other surface of the chip body, a first liquid reservoir for storing a liquid to be a continuous phase, a second liquid reservoir for storing a liquid to be a dispersed phase, and a third liquid reservoir for collecting droplets are formed. Open and
The chip main body is provided with first to third pipelines extending from the bottoms of the first to third liquid reservoirs and connecting to each other at one point, and further.
A second substrate is provided, which is closely bonded to the other surface of the chip body.
The second substrate is provided with first and second through holes that match the first and second liquid reservoirs, respectively, and further.
It is characterized by having a closed microstructural space formed inside the chip body, between the chip body and the second substrate, or both of them, and communicating with the third liquid reservoir. Microfluidic chips for droplet production. The microstructural space is composed of mesh-like fine grooves formed on the other surface of the chip body, and the mesh-like fine grooves are connected to the opening edge of the third liquid reservoir. The microfluidic chip for producing a droplet according to claim 1, wherein the microfluidic chip for producing a droplet is formed so as not to reach the opening edge of the first and second liquid reservoirs and the outer edge of the other surface. The microfluidic chip for producing droplets according to claim 2, wherein the mesh-like fine grooves are formed of grid-like fine grooves.

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