JP4699779B2 - Microchip - Google Patents

Description

  The present invention relates to a so-called microchip in which a fine structure (microstructure) such as a flow path (microchannel), a reaction vessel and / or a port is formed in at least one substrate. More specifically, the present invention relates to a microchip having a micromixer for mixing and stirring fluid in a microchannel.

  Recently, as is known by the names such as Microscale Total Analysis Systems (μTAS) or Lab-on-Chip, a microchannel that forms a flow path of a predetermined shape in a substrate and Providing a fine structure such as a port and performing various operations such as chemical reaction, synthesis, purification, extraction, generation and / or analysis of substances within the fine structure has been proposed and partially put into practical use. A structure manufactured for such a purpose and having a microstructure such as a microchannel and a port in a substrate is called a “microfluidic chip” or a “microchemical chip”.

  Microchips can be used for a wide range of applications such as genetic analysis, clinical diagnosis, drug screening and environmental monitoring. Compared with the same type of equipment of the common size, the microchip is (1) significantly less sample and reagent usage, (2) shorter analysis time, (3) higher sensitivity, (4) carried on-site, It can be analyzed in the field and (5) can be disposable.

  Generally, these microchips have a structure in which a substrate having a microstructure such as a microchannel and a port on one plane and a facing substrate having a target plane for sealing these microstructures are bonded together. Have. Various materials are used depending on the manufacturing method and the purpose of use of the microchip. Among them, polydimethylsiloxane (PDMS), which is a kind of silicon rubber, is used as a substrate material, and a glass substrate is used as a facing substrate. A series of microchips using is described in detail in Non-Patent Document 1.

  The flow of fluid generated in a micro structure such as a microchannel of a microchip is generally a laminar flow without generating turbulence or separation because the Reynolds number on a microscale is very small. Therefore, when two kinds of liquids flow from each microchannel and merge in another microchannel, mixing between the two kinds of liquids is only molecular diffusion performed through an interface formed between the respective laminar flows. Depends on.

  For example, in a microchip 100 having a Y-shaped microchannel as shown in FIG. 13, the liquid A flows from one microchannel 102 and the liquid B flows from the other microchannel 104, and the Y-shaped merged microchannel Pour into channel 106. In the confluence microchannel 106, a laminar flow is generated by the liquids A and B, and an interface 108 is formed at the boundary. Although the two liquids are mixed through this interface 108, the molecular diffusion does not proceed easily, and a long-distance confluence microchannel 106 is required for sufficient mixing, which is not familiar with the concept of μTAS. Therefore, a microchip often requires some effective micromixer.

In microchips, there are cases where not only liquids are mixed but also liquids and powders having a particle size of 1 μm to 100 μm must be mixed. For example, the following powders are required for a microchemical chip.
(1) Cell fragments for the purpose of extracting DNA, etc. Specifically, the DNA is extracted by mixing and stirring with a lysis buffer with an oral swab or the like.
(2) Beads that specifically adsorb DNA etc. These beads are mainly used for the purpose of purifying DNA etc. A bead is not necessarily spherical. The material is glass or synthetic resin. In order to be magnetized, a magnetic material such as iron oxide may be included.
(3) Catalytic powders These are metal powders for the purpose of promoting various chemical reactions.
(4) Powder that absorbs light Carbon powder or the like is irradiated with laser light or the like from the outside of the microchip and absorbs the light to generate local heat, which promotes the chemical reaction.
(5) Powder for generating physical action As an example, magnetic beads are used, and the beads are vibrated by an alternating magnetic field from the outside to promote powder mixing and chemical reaction.
(6) Others Visible powder is mixed in a transparent liquid to visualize the flow.

In particular, when handling a fluid containing powder, it is necessary not only to mix the fluids but also to sufficiently agitate the powder in the fluid as shown below.
(1) Dissolve the oral swab thoroughly.
(2) The DNA is efficiently adsorbed on the bead surface.
(3) Excess impurities are washed with high precision using beads with the DNA adsorbed beads.
(4) The elution buffer is used to effectively elute the DNA from the surface of the beads to which the DNA has been adsorbed.
(5) Increase the efficiency of the powder, such as catalyst action, light absorption (heat generation) action, and physical action.
(6) Uniform distribution of powder in the liquid.

In the field of microchips, Non-Patent Document 2 describes various micromixers for the purpose of efficiently mixing a plurality of fluids in a microchannel. Conventional micromixers are roughly classified into the following two types based on the principle.
(1) Passive "passive mixer" using the fluid flow itself
(2) Active "active mixer" using external force other than fluid

Examples of the microchannel structure constituting the passive mixer include the following.
(1) The microchannel is partially narrowed or widened.
(2) Provide obstacles such as pillars in the microchannel.
(3) Bend the microchannel.
(4) The microchannel is branched and rejoined (Coanda effect).

  FIG. 14 is a schematic configuration diagram of an example of a passive mixer based on the Coanda effect. A branch channel 110 is provided in the merging microchannel 106, and a Coanda effect is realized by providing a folded portion 112 downstream of the branching point of the merging microchannel 106, thereby reversing part of the flow and disturbing the flow of the two liquids. To mix and reflow into the confluence microchannel 106.

However, since the passive mixer has a complicated microchannel structure that hinders the flow, the following problems exist.
(1) Pressure loss occurs and high liquid supply pressure is required.
(2) It is difficult to control the flow rate accurately.
(3) Air accumulation easily occurs.
(4) Easily clogged with garbage.
(5) In particular, when the fluid contains powder, the complicated flow path structure hinders the flow of the powder. In an extreme case, the powder is clogged and the channel is blocked.

  FIG. 15 is a schematic configuration diagram of an example of an active mixer. An active valve 114 is disposed in the middle of the microchannel 102 through which the liquid A flows, and an active valve 116 is disposed in the middle of the microchannel 104 through which the liquid B flows. By alternately opening and closing the valves 114 and 116, the liquids A and B are caused to flow alternately in the merged microchannel 106, and the interface 118 between the two liquids is increased to promote mixing.

  In general, a passive mixer has a low mixing capacity, and a long distance microchannel is required for sufficient mixing. On the other hand, the active mixer has a higher mixing ability and is effective compared to the passive mixer. In addition, the mixing ability is greatly influenced by the flow rate and flow velocity, such as the passive mixer does not perform the mixing function at a low flow rate. However, the active mixer can perform the mixing over a wide range of flow rates.

However, the active mixer has the following problems.
(1) A valve or the like provided in the microchannel obstructs a constant flow from the upstream, and the flow becomes intermittent.
(2) Depending on the structure of the valve, etc., it may cause air accumulation, clogging of dust, and obstruction of powder flow. In some cases, the function of the valve or the like is impaired by dust or powder, and the mixer does not operate.

David C. Duffy et al., Rapid Prototyping of Microfluidic Systems in Poly (dimethylsiloxane), Analytical Chemistry, Vol.70, No.23, December 1, 1988, pp.4974-4984 Supervised by Chemistry and Micro / Nano System Study Group, Takehiko Kitamori et al., “Technology and Application of Micro Chemical Chip”, Maruzen Co., Ltd. (issued in September 2004), pp. 293-297

  Accordingly, the objects of the present invention are (1) no increase in liquid supply pressure, (2) no obstruction of a constant flow from the upstream, (3) easy control of the flow rate, and (4) air accumulation No generation, (5) no clogging of dust, (6) no loss of mixing function due to dust, (7) effective use especially for fluids containing powder, and (8) mixing of liquids In addition, the present invention provides a microchip having a micromixer having a stirring effect when powder is included.

The invention according to claim 1 as means for solving the problem comprises a first substrate and a second substrate bonded to one surface side of the first substrate , and the first substrate. In the microchip in which at least one microchannel is formed on the adhesion surface side of the second substrate ,
The first substrate on which the microchannel is formed is made of silicone resin ,
A micromixer is disposed in the middle of the microchannel,
The micromixer is
(1) a volume expansion portion having a width larger than the width before and after the microchannel;
(2) By deforming and restoring a part of the wall surface of the volume expanding section to change the volume of the volume expanding section, the two types of fluids in a laminar flow state are disturbed to stir and mix both fluids. It is a microchip characterized by comprising one means.

The invention according to claim 2 as means for solving the above-mentioned problems is that the volume expanding portion is formed symmetrically with respect to the longitudinal axis of the microchannel, and the longitudinal direction of the symmetrical volume expanding portion is For each half part with respect to the direction axis, by deforming and restoring part of the wall surface and changing the volume of the half part, the flow of the two types of fluid in the laminar flow state is disturbed, and both fluids are stirred and mixed 2. The microchip according to claim 1, wherein means for performing the operation are respectively provided.

As a means for solving the above-mentioned problem, the invention according to claim 3 includes two types of laminar flow states by changing a volume of the volume expanding portion by deforming and restoring a part of the wall surface of the volume expanding portion . Means for disturbing the flow of the fluid and stirring and mixing both fluids is a pressure chamber having the wall surface of the volume expanding portion as a partition wall, and a pressure applying means is connected to the pressure chamber. 3. The microchip according to claim 1, wherein the pressure of the pressure chamber is changed to deform and restore a part of the wall surface of the volume expanding portion to change the volume of the volume expanding portion. .

  As a means for solving the above-mentioned problem, the invention according to claim 4 is characterized in that the first substrate is made of polydimethylsiloxane, and the second substrate is made of polydimethylsiloxane, glass, silicon, polystyrene, acrylic resin, polymethyl methacrylate, It consists of one kind of material selected from the group consisting of polycarbonate, and at least one microchannel is formed on the side of the first substrate to be bonded to the second substrate, and in the middle of the microchannel, the microchannel A symmetrical volume expansion portion is formed with respect to the longitudinal axis of the microchannel, and a wall surface of each half volume expansion portion with respect to each half volume expansion portion with respect to the longitudinal axis of the microchannel The pressure chambers are arranged symmetrically with respect to the longitudinal axis with the partition walls being used as partition walls. Is a microchip described.

  As a means for solving the above-mentioned problem, the invention according to claim 5 is characterized in that a third substrate is further bonded to the upper surface of the first substrate, and the first substrate is polydimethyl having a relatively thin film thickness. A single material selected from the group consisting of polydimethylsiloxane, glass, silicon, polystyrene, acrylic resin, polymethylmethacrylate, and polycarbonate, which is made of siloxane and in which the third substrate is thicker than the thickness of the first substrate. The third substrate has a plane area equal to or larger than the plane area of the volume expanding portion and the pressure chamber on the bonding surface side of the third substrate with the first substrate, and has a predetermined height. The microchip according to any one of claims 1 to 4, further comprising an atmospheric pressure chamber communicating with the atmosphere.

As a means for solving the above-mentioned problem, the invention according to claim 6 is characterized in that the first substrate is made of polydimethylsiloxane, the second substrate is made of polydimethylsiloxane or glass, and the second substrate of the first substrate is made. At least one microchannel is formed on the adhesion surface side with the substrate, and a volume expansion portion symmetrical to the longitudinal axis of the microchannel is formed in the middle of the microchannel,
A third substrate is further bonded to the upper surface of the first substrate, the first substrate is relatively thin, the third substrate is thicker than the first substrate, and the third substrate The upper wall surface of each half volume expansion portion with respect to the longitudinal axis of the microchannel is used as a partition wall on the bonding surface side of the substrate with the first substrate so as to overlap at least part of each half volume expansion portion. The microchip according to claim 1, wherein at least one pressure chamber is disposed in the microchip.

  In the invention according to claim 7 as means for solving the above-mentioned problem, a pressure chamber is provided for each half volume expansion portion, and a pressure applying means is connected to the pressure chamber, 7. The volume of the volume expanding portion is changed by changing and restoring a part of the upper wall surface of the volume expanding portion by changing the pressure of the pressure chamber through the pressure applying means. It is a microchip.

The microchip of the present invention has a structure in which the microchannel of the micromixer portion is not narrowed, bent, obstructed, branched or rejoined, and does not hinder the flow of fluid. Further, since the first variable volume part and the second variable volume part arranged in the middle of the microchannel are changed in volume complementarily, the total volume change does not occur. Therefore, there is no influence of excessive pressure fluctuation on the microchannels before and after the micromixer.
As a result, (1) there is no increase in liquid feeding pressure due to the provision of a micromixer,
(2) A constant flow from upstream is not obstructed. That is, the flow rate is uniform and stable,
(3) Since there is no excessive pressure generation, it is easy to control the flow rate accurately.
(4) There is no air pool,
(5) Garbage is not clogged.
Various effects such as (6) not impairing the mixing function by dust, and (7) being able to be effectively used especially for fluid containing powder are obtained. .
Moreover, the effect of stirring by the micromixer of the present invention can be obtained even for a fluid that remains without flow.

  The microchip of the present invention will be specifically described below with reference to the drawings. FIG. 1 is a partial schematic plan view of an example of the microchip of the present invention. FIG. 2 is a partial schematic cross-sectional view taken along line II-II in FIG. The microchip 1 of the present invention comprises a combination of a first substrate 3 and a second substrate (face-to-face substrate) 5 as in the conventional microchip. The first substrate 3 is made of a silicone resin such as PDMS, and the second substrate 5 is made of one kind of material selected from the group consisting of PDMS, glass, silicon, polystyrene, acrylic resin, polymethyl methacrylate, and polycarbonate. . The first substrate 3 is provided with a microchannel 7 for flowing a liquid or a powder-containing liquid. A micromixer 9 is disposed in the middle of the microchannel 7. The micromixer 9 has a first pressure chamber 11 and a second pressure chamber 13 facing each other with the microchannel 7 interposed therebetween. Corresponding to the position of the first pressure chamber 11, the first variable volume portion 15 in which the width of the microchannel 7 is enlarged and the width of the microchannel 7 corresponding to the position of the second pressure chamber 13. An enlarged second variable volume portion 17 is formed. The first pressure chamber 11 and the first variable volume portion 15 are separated from each other by an arc-shaped first partition wall 19. Similarly, the second pressure chamber 13, the second variable volume portion 17, Are separated by an arc-shaped second partition wall 21. A pressure line 23 for applying a positive pressure or a negative pressure is connected to the first pressure chamber 11, and similarly, a pressure for applying a positive pressure or a negative pressure to the second pressure chamber 13. A pipeline 25 is connected. In addition to a gas such as air, a liquid such as oil can be fed into the pressure lines 23 and 25. The shape of the partition wall between the pressure chamber and the variable volume portion is not limited to the illustrated arc shape, and an appropriate shape such as a trapezoidal shape can be adopted. The microchannel and the variable volume portion may be disposed on the second substrate side. In the micromixer of the present invention, the first variable volume section 15 and the second variable volume section 17 are collectively referred to as a volume expansion section, but any one of them can be referred to as a volume expansion section. Therefore, the micromixer of the present invention can also have a volume expanding section composed of only one of the first variable volume section 15 and the second variable volume section 17.

  The first variable volume portion 15 and the second variable volume portion 17 are each formed by widening a part of the microchannel 7 so as to have an arcuate shape. Thereby, the fluid flowing through the variable volume portion and the microchannel in the vicinity thereof can flow smoothly without being largely hindered by the flow. In addition, since there is nothing that blocks the microchannel itself, dust and the like are not easily clogged, and bubbles are not generated or stayed. In particular, a fluid containing powder can flow without obstacles.

  FIG. 3 is a schematic partial sectional view for explaining the operation of the micromixer 9 of the present invention. In FIG. 3A, when a pressure higher than this pressure is applied to the first pressure chamber 11 and the second pressure chamber 13 with reference to the pressure in the flow path of the microchannel 7, the first substrate 3 is elastic. Since it is formed from the body PDMS, the first pressure chamber 11 and the second pressure chamber 13 are enlarged and deformed mainly in the upper direction of the microchip. Along with this, the first partition wall 19 and the second partition wall 21 configured to be thin and easily deformed are also extended upward, and the expansion deformation of the pressure chamber is caused by the adjacent first variable volume portion 15 and the second partition wall. This affects the variable volume portion 17 and increases the respective volumes. On the other hand, in FIG. 3B, when a pressure lower than this pressure is applied to the first pressure chamber 11 and the second pressure chamber 17 with reference to the pressure in the flow path of the microchannel 7, the first pressure chamber 11 The pressure chamber 11 and the second pressure chamber 13 are reduced and deformed mainly in the lower direction of the microchip. Accordingly, the first partition wall 19 and the second partition wall 21 configured to be thin and easily deformed are also compressed in the lower direction, and the contraction deformation of the pressure chamber is caused by the adjacent first variable volume portion 15 and the second partition wall. The variable volume portion 17 is affected and the respective volumes are reduced.

  It is not necessary to apply a positive pressure or a negative pressure to each pressure chamber at the same time. Therefore, when a positive pressure is applied to the first pressure chamber 11, the second pressure chamber 13 can be in an equal pressure state, a positive pressure state, or a negative pressure state. Similarly, when a positive pressure is applied to the second pressure chamber 13, the first pressure chamber 11 can be in an equal pressure state, a positive pressure state, or a negative pressure state. Thus, by applying a positive pressure and / or a negative pressure to the pressure chamber, the volume of the variable volume portion can be changed, and the flow of two types of fluids in a laminar flow state can be changed by the volume change of the variable volume portion. It is possible to mix both fluids with disturbance. It is preferable to appropriately select the shape and operating pressure of the variable volume portion so that the amount of change in the volume of the variable volume portion is approximately half the volume of the microchannel at the position of the variable volume portion.

  FIG. 4 is a partial schematic plan view of another example of the microchip of the present invention. FIG. 5 is a partial schematic cross-sectional view taken along line VV in FIG. Unlike the microchip 1 shown in FIGS. 1 and 2, in the microchip 1 </ b> A shown in FIGS. 4 and 5, a third substrate 27 is bonded to the upper surface of the first substrate 3. An atmospheric pressure chamber 29 having an area covering the entire variable volume portions 15 and 17 and the pressure chambers 11 and 13 in the first substrate 3 is disposed on the bonding surface side of the third substrate. The atmospheric pressure chamber 29 has a pipe line 31 communicating with the atmosphere as necessary. The pressure chambers 11 and 13 are separated from the atmospheric pressure chamber 29 by a thin film 33 made of a PDMS elastic body of the first substrate 3. The thickness of the thin film 33 is about 100 μm, for example.

  When the first substrate 3 and the second substrate (face-to-face substrate) 5 are used alone, the thickness of the first substrate 3 is about 1 mm to several mm, and is relatively thick as a microchip substrate. Even if the material has rubber elasticity such as PDMS, the pressure chambers 11 and 13, the partition walls 19 and 21, and the variable volume portions 15 and 17 are not necessarily deformable enough. Therefore, in order to facilitate the deformation of the pressure chambers 11 and 13, the partition walls 19 and 21, and the variable volume portions 15 and 17, a third substrate 27 is bonded to the upper surface of the first substrate 3, and this third substrate An atmospheric pressure chamber 29 is provided on the bonding surface side of 27, that is, on the pressure chambers 11 and 13.

  FIG. 6A is a schematic partial cross-sectional view for explaining the effect when the atmospheric pressure chamber 29 is provided in the micromixer 9A shown in FIGS. As shown in FIG. 6A, when the pressure chamber 11 or 13 is at the same pressure as the atmospheric pressure, the thin film 33 is not deformed. As shown in (b), when the pressure chamber 11 or 13 is brought into a negative pressure state, the thin film 33 is bent toward the pressure chamber, and the pressure chamber is easily deformed in a direction in which the volume decreases. As the volume of the pressure chamber decreases, the variable volume portion 15 or 17 is deformed as shown in FIG. On the other hand, as shown in (c), when the pressure chamber 11 or 13 is brought into a positive pressure state, the thin film 33 is bent toward the atmospheric pressure chamber, and the pressure chamber is easily deformed in the direction of increasing the volume. As the volume of the pressure chamber increases, the variable volume portion 15 or 17 is deformed as shown in FIG.

  If only the deformation of the pressure chamber is to be facilitated, all the upper part of the atmospheric pressure chamber may be opened, but the provision of the atmospheric pressure chamber having a finite height is because of the following effects. As shown in FIG. 6C, when the pressure chambers 11 and 13 are set to a positive pressure, if the thin film 33 is deformed by the height of the atmospheric pressure chamber 29, the deformation is suppressed and acts as a stopper. Therefore, there is an effect of preventing the thin film 33 from being damaged when a high positive pressure is applied to the pressure chambers 11 and 13.

  FIG. 6B is an enlarged plan photographic view demonstrating the effect when the atmospheric pressure chamber 29 is provided in the micromixer 9A shown in FIGS. FIG. 6 (i) shows that when the two types of liquids flowing from the Y-shaped microchannel enter the volume expansion portion of the micromixer of the present invention from the merged microchannel, the first pressure chamber 11 is set to a positive pressure, FIG. 6 (ii) is a photograph of a state in which the second pressure chamber 13 is set to a negative pressure, and FIG. 6 (ii) is a photograph of a state in which the first pressure chamber 11 is set to a negative pressure and the second pressure chamber 13 is set to a positive pressure. is there. When the pressure chamber is expanding, the inside of the pressure chamber appears clear, and when the pressure chamber is contracted, the inside of the pressure chamber appears dull in gray. The liquid is pushed from the variable volume part direction in which the pressure chamber is reduced toward the variable volume part direction in which the pressure chamber is enlarged (that is, in the direction of the solid arrow in the photograph). Thus, it was demonstrated that both liquids were mixed in the volume expansion part of the micromixer and flowed downstream of the microchannel as a uniform single liquid without a laminar interface.

  FIG. 7 is a partial schematic plan view of another example of the microchip of the present invention, and FIG. 8 is a partial schematic sectional view taken along line VIII-VIII in FIG. The microchip 1B shown in FIG. 7 and FIG. 8 includes a first substrate 3 bonded to the upper surface of the second substrate (facing substrate) 5 and a third substrate bonded to the upper surface of the first substrate 3. It has a three-layer structure consisting of a substrate 27. The microchannel 7 is disposed on the lower surface side of the first substrate 3, and the first variable volume portion 15 </ b> B and the second variable volume portion 15 </ b> B having a shape in which the microchannel 7 is widened at an appropriate position of the microchannel 7. The variable volume portion 17B is disposed. The first pressure chamber 11B and the second pressure chamber 13B are disposed on the lower surface side of the third substrate 27 at positions corresponding to the first variable volume portion 15B and the second variable volume portion 17B. Has been. A pressure line 23B for applying a positive pressure or a negative pressure is connected to the first pressure chamber 11B, and similarly, a pressure for applying a positive pressure or a negative pressure to the second pressure chamber 13B. Pipe line 25B is connected. In addition to a gas such as air, a liquid such as oil can be fed into the pressure lines 23B and 25B. The positions of the first substrate 3 corresponding to the first variable volume portion 15B and the second variable volume portion 17B are separated from the first pressure chamber 11B and the second pressure chamber 13B by the thin film 33B.

  FIG. 9 is a schematic partial schematic cross-sectional view for explaining the operation of the micromixer 9B in the microchip 1B shown in FIGS. As shown in FIG. 9A, for example, when the first pressure chamber 11B is set to a positive pressure with respect to the pressure of the microchannel 7, the thin film 33B below the first pressure chamber 11B is pushed downward. Thus, the volume of the first variable volume portion 15B decreases. On the other hand, as shown in FIG. 9B, for example, when the first pressure chamber 11B is set to a negative pressure relative to the pressure of the microchannel 7, the thin film 33B below the first pressure chamber 11B is directed upward. Thus, the volume of the first variable volume portion 15B increases. The second pressure chamber 13B can operate similarly. Similarly to the above, when a positive pressure is applied to the first pressure chamber 11B, the second pressure chamber 13B can be in one of a constant pressure state, a positive pressure state, or a negative pressure state. When a positive pressure is applied to the second pressure chamber 13B, the first pressure chamber 11B can be in an equal pressure state, a positive pressure state, or a negative pressure state. Thus, by applying a positive pressure and / or a negative pressure to the pressure chamber, the volume of the variable volume portion can be changed, and the flow of two types of fluids in a laminar flow state can be changed by the volume change of the variable volume portion. It is possible to mix both fluids with disturbance. It is preferable to appropriately select the shape of the variable volume section and the pressure chamber and the operation pressure so that the amount of change in the capacity of the variable volume section is approximately half the volume of the microchannel at the position of the variable volume section.

FIG. 10 is a partial schematic view for explaining the flow states of two types of fluids formed by the operation of the micromixer 9B in the microchip 1B shown in FIGS. The first pressure chamber 11B and the second pressure chamber 13B are alternately and alternately operated, and the volumes of the first variable volume portion 15B and the second variable volume portion 17B are alternately and alternately changed. That is, when the volume of the first variable volume portion 15B is increased, the volume of the second variable volume portion 17B is decreased, and when the volume of the first variable volume portion 15B is decreased, the second variable volume portion 15B is decreased. The volume of the part 17B is increased by B. Thereby, the interfaces of the liquids A and B meander on the downstream side of the micromixer 9B. Furthermore, the period of the alternating operation is set to about twice the time for the liquid to pass in front of the micromixer 9B. Because of this and the volume change amount is approximately half of the volume of the microchannel 7 in front of the micromixer 9B, the liquids A and B on the downstream side of the micromixer 9B flow almost alternately as shown in FIG. Become.
FIG. 10 shows the mixing operation in the case where a flow is generated, but the effect of stirring can be achieved by changing the volumes of the first variable volume portion 15B and the second variable volume portion 17B even when there is no flow. Is obtained. In that case, the first pressure chamber 11B and the second pressure chamber 13B do not necessarily need to be operated alternately.

  The preferred embodiments of the micromixer of the present invention have been described above, but the micromixer of the present invention is not limited to the illustrated embodiment. For example, although the illustrated micromixer is provided with two pressure chambers so as to be opposed to the variable volume portion disposed symmetrically in the middle of the microchannel, the number of pressure chambers may be one. Further, only one variable volume portion may be provided, and it is not always necessary to have a symmetrical shape.

A microchip 1B having the micromixer 9B shown in FIGS. 7 and 8 was manufactured. A PDMS substrate having a thickness of 200 μm was used as the first substrate 3. A glass substrate having a thickness of 1 mm was used as the second substrate 5. A PDMS substrate having a thickness of 2 mm was used as the third substrate 27. A volume expansion part and a micromixer were disposed 1 mm downstream from the confluence of the Y-shaped microchannel. The volume at the time of non-pressurization of each variable volume part was about 6 nL. (Thus, the total volume of the volume expansion portion is about 12 nL.) Each pressure chamber was a columnar shape with a diameter of 0.5 mm, the height when not pressurized was 55 μm, and the volume was about 11 nL. The working pressure was a positive pressure of 100 KPa (kilopascal) and a negative pressure of -70 KPa. In the pressure operation method, positive pressure and negative pressure were alternately applied to each pressure chamber. Therefore, the opposite pressure was always applied to the first pressure chamber and the second pressure chamber.
Two types of liquids (red ink and water) were allowed to flow through the microchannel 7 of the microchip 1B, and a demonstration test of the micromixer 9B was performed. The experimental conditions were that the width of the Y-shaped microchannel before joining was 100 μm and the height was 55 μm, and the width of the microchannel 7 after joining was 200 μm and the height was 55 μm. The flow rate was 0.5 μL / min (each solution was 0.25 μL / min), and the flow rate was 0.76 mm / sec (calculated value). The operation period of the micromixer 9B was 0.4 seconds (positive and negative every 0.2 seconds), and the moving distance of the fluid in 0.4 seconds was 0.3 mm.
When the micromixer 9B was stopped and operated, the state of the fluid at about 1 mm downstream of the micromixer 9B was confirmed with a microscope. As shown in FIG. 11 (A), when the micromixer 9B was stopped, a laminar flow interface between the two liquids was clearly observed, but the micromixer 9B was operated as shown in FIG. 11 (B). In this case, the interface became unclear and it was confirmed that the two liquids were sufficiently mixed.
Further, on the upstream side of the micromixer 9B, it was confirmed that even when the micromixer 9B was operated, the interface of the laminar flow by the two liquids was not disturbed and the flow was not disturbed by the micromixer 9B.

A microchip 1B having the same micromixer 9B as in Example 1 was manufactured. The working pressure was a positive pressure of 70 KPa (kilopascal) and a negative pressure of -70 KPa. Other experimental conditions and pressure operating methods were the same as those in Example 1. As fluid A, a suspension in which resin powder (silica beads) having a particle size of several μm having a function of specifically adsorbing DNA is mixed with ethanol is used, and as fluid B, DNA and other impurities are used. The contained solution (mainly medium is distilled water and ethanol) was used. This is an operation for adsorbing DNA in fluid B onto silica beads in fluid A as part of the DNA purification process.
FIG. 12 is a photograph of a still image showing a state in which a micromixer is provided 1 mm after the fluids A and B are merged by a Y-shaped microchannel and two liquids are mixed. Liquids A and B are separated in a laminar flow on the upstream side of the micromixer, but the two liquids are mixed on the downstream side of the micromixer, and the resin powder is distributed almost uniformly in the microchannel. confirmed.

  The preferred embodiments of the micromixer of the present invention have been specifically described above, but the present invention is not limited to the disclosed embodiments, and various modifications can be made. The micromixer of the present invention can be mounted in a microchip from the viewpoint of μTAS and Lab-on-Chip. The microchip of the present invention can incorporate one or more of the micromixers disclosed in the present specification and shown in the accompanying drawings. Such a microchip having the epoch-making micromixer of the present invention in its inside is remarkably improved in practicality and economy. As a result, the microchip of the present invention can be suitably used effectively in various fields such as medicine, veterinary medicine, dentistry, pharmacy, life science, food, agriculture, and fisheries. In particular, the microchip of the present invention is an optimal microchip for fluorescent antibody method, in situ hybridization, etc., immunological disease test, cell culture, virus fixation, pathological test, cytology, biopsy histology, blood test, bacterial test , Protein analysis, DNA analysis, RNA analysis, etc. can be used at low cost.

It is a partial outline top view of an example of the microchip of the present invention. FIG. 2 is a partial schematic cross-sectional view taken along line II-II in FIG. 1. It is a typical fragmentary sectional view explaining operation of micromixer 9 of the present invention. It is a partial general | schematic top view of another example of the microchip of this invention. FIG. 5 is a partial schematic cross-sectional view taken along line VV in FIG. 4. FIG. 6 is a schematic partial cross-sectional view illustrating an effect when an atmospheric pressure chamber 29 is provided in the micromixer 9A shown in FIGS. 4 and 5. FIG. 6 is an enlarged plan view showing the effect when the atmospheric pressure chamber 29 is provided in the micromixer 9 </ b> A shown in FIGS. 4 and 5. It is a partial general | schematic top view of the other example of the microchip of this invention. FIG. 8 is a partial schematic cross-sectional view taken along line VIII-VIII in FIG. 7. 9 is a schematic partial schematic cross-sectional view for explaining the operation of a micromixer 9B in the microchip 1B shown in FIGS. 7 and 8. FIG. It is a partial schematic diagram explaining the state of the flow of two types of fluids formed by the operation of the micromixer 9B in the microchip 1B shown in FIGS. FIG. 3 is an enlarged plan view showing the operation of the micromixer in Example 1. FIG. 6 is an enlarged plan view showing the operation of the micromixer in Example 2. It is a partial schematic diagram of an example of a conventional microchip having a Y-shaped microchannel. It is a typical partial block diagram of an example of the passive mixer by a Coanda effect. It is a typical partial block diagram of an example of an active mixer.

Explanation of symbols

1, 1A, 1B Microchip of the present invention 3 First substrate 5 Second substrate (facing substrate)
7 Microchannel 9, 9A, 9B Micromixer 11, 11B First pressure chamber 13, 13B Second pressure chamber 15, 15B First variable volume portion 17, 17B Second variable volume portion 19 First partition wall 21 Second partition wall 23, 23B Pressure line 25, 25B Pressure line 27 Third substrate 29 Atmospheric pressure chamber 31 Atmospheric communication line 33, 33B Thin film portion of first substrate

Claims (7)

A first substrate and a second substrate bonded to one surface side of the first substrate, and at least one microchannel on the bonding surface side of the first substrate with the second substrate In the microchip on which is formed,
The first substrate on which the microchannel is formed is made of silicone resin ,
A micromixer is disposed in the middle of the microchannel,
The micromixer is
(1) a volume expansion portion having a width larger than the width before and after the microchannel;
(2) By deforming and restoring a part of the wall surface of the volume expanding section to change the volume of the volume expanding section, the two types of fluids in a laminar flow state are disturbed to stir and mix both fluids. A microchip comprising one means. The volume expanding portion is formed symmetrically with respect to the longitudinal axis of the microchannel, and a part of the wall surface is deformed for each half of the symmetrical volume expanding portion with respect to the longitudinal axis. And a means for stirring and mixing the two fluids by disturbing the flow of two kinds of fluids in a laminar flow state by changing the volume of the half part by restoring. The microchip described. The means for stirring and mixing both fluids by disturbing the flow of two kinds of fluids in a laminar flow state by deforming and restoring a part of the wall surface of the volume expanding part to change the volume of the volume expanding part, A pressure chamber having a wall surface of the volume expanding portion as a partition wall, and a pressure applying unit is connected to the pressure chamber, and the pressure of the pressure chamber is changed by changing the pressure of the pressure chamber through the pressure applying unit. The microchip according to claim 1 or 2, wherein a part of the volume expansion portion is changed by being deformed and restored. The first substrate is made of polydimethylsiloxane, the second substrate is made of one material selected from the group consisting of polydimethylsiloxane, glass, silicon, polystyrene, acrylic resin, polymethyl methacrylate and polycarbonate, At least one microchannel is formed on the bonding surface side of one substrate with the second substrate, and a volume expansion portion symmetrical to the longitudinal axis of the microchannel is formed in the middle of the microchannel. The pressure chambers are symmetrical with respect to the longitudinal axis with respect to the half volume expansion portion with respect to the longitudinal axis of the microchannel, with the wall surface of each half volume expansion portion as a partition wall. The microchip according to claim 1, wherein the microchip is disposed. A third substrate is further bonded to the upper surface of the first substrate, the first substrate is made of polydimethylsiloxane having a relatively thin film thickness, and the third substrate is a thickness of the first substrate. An adhesive surface of the third substrate to the first substrate, which is made of one kind of material selected from the group consisting of polydimethylsiloxane, glass, silicon, polystyrene, acrylic resin, polymethyl methacrylate, and polycarbonate. On the side, an atmospheric pressure chamber having a plane area equal to or larger than the plane area of the volume expanding portion and the pressure chamber and communicating with the atmosphere having a predetermined height is further disposed. The microchip according to claim 1 , wherein the microchip is characterized in that The first substrate is made of polydimethylsiloxane, the second substrate is made of polydimethylsiloxane or glass, and at least one microchannel is formed on the bonding surface side of the first substrate with the second substrate. A volume expansion portion symmetrical to the longitudinal axis of the microchannel is formed in the middle of the microchannel,
A third substrate is further bonded to the upper surface of the first substrate, the first substrate is relatively thin, the third substrate is thicker than the first substrate, and the third substrate The upper wall surface of each half volume expansion portion with respect to the longitudinal axis of the microchannel is used as a partition wall on the bonding surface side of the substrate with the first substrate so as to overlap at least part of each half volume expansion portion. The microchip according to claim 1, wherein at least one pressure chamber is disposed on the microchip. A pressure chamber is provided for each half of the volume expansion section, and pressure application means is connected to the pressure chamber, and the volume can be changed by changing the pressure in the pressure chamber via the pressure application means. The microchip according to claim 6, wherein a part of the upper wall surface of the enlarged portion is deformed and restored to change the volume of the volume enlarged portion.